Week 7 Study sheet for chapter 25

• From the Personl learning transcripts

• Week 7: Diabetes Mellitus broken down into bullets with simple explanations:

  Diabetes Mellitus — Simple Bullet Breakdown

  Big idea

  • Diabetes mellitus is a disease of glucose regulation.

    • This means the body has trouble keeping blood sugar at a normal level.

  • The body normally tries to keep blood glucose from getting:

    • Too high

    • Too low

  ---

  Normal blood glucose regulation

  Hyperglycemia

  • Hyperglycemia means high blood glucose.

  • When blood sugar is too high:

    • The beta cells of the pancreas release insulin.

  • Insulin helps move glucose:

    • Out of the blood

    • Into the body’s cells

  • This lowers blood glucose.

  Simple explanation

  • Insulin is like a key that helps sugar leave the bloodstream and enter the cells.

  ---

  Hypoglycemia

  • Hypoglycemia means low blood glucose.

  • When blood sugar is too low:

    • The pancreas releases glucagon.

  • Glucagon tells the liver to release glucose into the blood.

  • Other hormones can also raise blood glucose:

    • Epinephrine

    • Cortisol

    • Growth hormone

  Simple explanation

  • When blood sugar drops too low, the body tries to raise it back up.

  ---

  What diabetes mellitus is

  • Diabetes has 2 main types:

    • Type 1 diabetes—-Lack of insulin

      • destruction of the autoimmune cells - destruction of the beta cells of the pancreas **** Insulin moves glucose out of the blood —→into the cells

    • Type 2 diabetes— the pancreas can produce insulin

      • BUT the cells become resistant to accepting it

      • THE BODY RESPONDS BY PRODUCING more INSULIN

      • INSULIN IS UNABLE TO CARRY OUT ITS WORK

      • BLOOD GLUCOSE STAY ELVATED

      • FAT CELLS ARE RESISTANT TO INSULIN

  • Both types are marked by:

    • High blood glucose

    • This is called hyperglycemia

  ---

  Type 1 diabetes

  • In type 1 diabetes, the body has little or no insulin.

  • The most common cause is:

    • Autoimmune destruction of the beta cells of the pancreas

  • If there is no insulin:

    • Glucose stays in the blood

    • Glucose cannot move into the cells well

  Simple explanation

  • In type 1 diabetes, the body destroys the cells that make insulin.

  ---

  Type 2 diabetes

  • In type 2 diabetes, the pancreas can still make insulin.

  • The problem is that the body’s cells become:

    • Resistant to insulin

  • The body tries to fix this by making:

    • More insulin

  • But the insulin still does not work well enough.

  • Blood glucose stays high.

  Risk factors for type 2 diabetes

  • Obesity

  • Lack of physical activity

  • Fat cells are especially resistant to insulin

  Simple explanation

  • In type 2 diabetes, insulin is present, but the cells do not respond to it correctly.

  ---

  How diabetes is diagnosed

  • Diabetes is diagnosed with blood glucose testing because it is a disease of hyperglycemia.

  Common tests

  • Fasting blood glucose

    • Checks blood sugar after not eating for a period of time.

  • Oral glucose tolerance test

    • Checks how the body handles glucose after drinking a sugary liquid.

  • Glycated hemoglobin test (A1c)

    • Shows average blood glucose control over the past 3 months.

  Simple explanation

  • These tests help show whether blood sugar is staying too high.

  ---

  Why is diabetes serious

  • Diabetes can cause serious complications.

  • Good treatment focuses on:

    • Controlling blood glucose levels

  ---

  Treatment of type 1 diabetes

  • Type 1 diabetes always requires insulin.

  Simple explanation

  • Because the body does not make enough insulin, insulin must be given from outside the body.

  ---

  Treatment of type 2 diabetes

  • Type 2 diabetes is usually treated in steps.

  Stepwise treatment approach

  • First: lifestyle changes

  • Next: one oral antidiabetic medicine

  • Then: a combination of oral medicines

  • Finally: insulin may be added if blood sugar is still not controlled

  Simple explanation

  • Type 2 diabetes treatment usually starts simple and becomes stronger if needed.

  ---

  Lifestyle modifications for diabetes

  1. Healthy diet and weight control

  • Patients should try to reach and maintain an ideal body weight.

  • Diet may include:

    • Low-fat diet

    • Low-sodium diet

    • Carbohydrate counting

    • Eating based on the glycemic index

    • Regular meal schedules

  Simple explanation

  • Food choices and meal timing help control blood sugar.

  ---

  2. Exercise

  • Exercise helps:

    • Maintain weight

    • Increase glucose uptake into cells

  • People with diabetes must watch for:

    • Hypoglycemia during exercise

  • Insulin may need to be reduced before exercise.

  Simple explanation

  • Exercise lowers blood sugar, so patients must be careful it does not drop too low.

  ---

  3. Monitoring and health maintenance

  • Patients should:

    • Check their own blood glucose

    • Keep blood pressure normal

    • Keep blood lipids normal

    • Have regular cardiac assessments

  Simple explanation

  • Diabetes care is not just about sugar—it also includes heart and blood vessel health.

  ---

  Oral antidiabetic medications

  Main organs involved in glucose regulation

  • Liver

    • Makes glucose and releases it into the blood

  • Small intestine

    • Absorbs glucose into the body

  • Pancreas

    • Releases insulin to lower blood glucose

  Simple explanation

  • These organs all affect how much sugar is in the blood.

  ---

  Types of oral medications

  Sulfonylureas and meglitinides

  • Help the pancreas produce insulin

  Simple explanation

  • These drugs help the pancreas release more insulin.

  ---

  Biguanides and thiazolidinediones

  1. Help stop the liver from making too much glucose

  2. Help body cells become more sensitive to insulin

  Simple explanation

  • These drugs lower glucose production and help insulin work better.

  ---

  Insulin therapy

  • Some people with type 2 diabetes need insulin.

  • All people with type 1 diabetes need insulin.

  • All insulin is injectable.

  Simple explanation

  • Insulin is given by injection because it cannot be taken as a regular pill.

  ---

  Categories of insulin

  Conventional insulin

  • Synthetic human insulin

  Insulin analogues

  • Designed to better copy how the body’s own insulin works

  Simple explanation

  • Some insulins are standard forms, and some are made to act more like natural insulin.

  ---

  Insulin by onset of action

  Rapid-acting insulin

  • Starts working in 30 minutes to 1 hour

  Intermediate-acting insulin

  • Starts working in 2 to 4 hours

  Long-acting insulin

  • Starts working in 3 to 10 hours

  • Each patient’s insulin plan is based on:

    • Their own needs

  Simple explanation

  • Different insulins start working at different times, so treatment is individualized.

  ---

  Final main point

  • No matter which treatment is used, the goal is the same:

    • Keep blood glucose within a normal range

  Simple explanation

  • The main purpose of diabetes treatment is steady blood sugar control.

  ---

  Simple medical terms

  • Diabetes mellitus = disease where blood glucose is too high

  • Glucose = sugar in the blood used for energy

  • Hyperglycemia = high blood sugar

  • Hypoglycemia = low blood sugar

  • Insulin = hormone that moves glucose into cells

  • Glucagon = hormone that raises blood sugar

  • Beta cells = pancreas cells that make insulin

  • Insulin resistance = cells do not respond well to insulin

  • A1c = test showing average blood sugar over 3 months

  • Sulfonylureas = drugs that help the pancreas release insulin

  • Meglitinides = drugs that increase insulin release

  • Biguanides = drugs that reduce liver glucose production

  • Thiazolidinediones = drugs that improve insulin sensitivity

  • Glycemic control = keeping blood sugar in a healthy range

  If you want, I can also turn this into a short study guide, quiz review sheet, or flashcards.

🧠 Complete Endocrine System Study Guide — Full Review

SECTION 1: INDIVIDUAL QUESTIONS & ANSWERS

Q1: Which statement is INCORRECT about the Endocrine System?

• Anterior pituitary secretes ACTH

• Adrenal cortex secretes cortisol

• ✅ Pancreas alpha cells secrete calcitonin ← INCORRECT STATEMENT

• Parathyroid gland secretes parathyroid hormone

Why it's wrong:

• Pancreas alpha cells actually secrete glucagon (raises blood glucose)

• Calcitonin is secreted by parafollicular C-cells of the THYROID gland

• All other statements are correct:

  • Anterior pituitary → ACTH ✅

  • Adrenal cortex → cortisol ✅

  • Parathyroid → PTH ✅

Pancreatic cell memory tool:

• Alpha cells = Glucagon

• Beta cells = Insulin

• Delta cells = Somatostatin

Q2: Woman with panhypopituitarism after pituitary "stroke" during delivery

• ✅ Answer: Sheehan's Syndrome

Why:

• Occurs exclusively in females postpartum

• Severe hemorrhage/hypotension during delivery

• Enlarged pituitary during pregnancy becomes vulnerable to ischemia

• Blood supply cut off → pituitary necrosis

• Result = panhypopituitarism (all pituitary hormones lost)

• First signs = failure to lactate + absent menstruation

Why others wrong:

• Empty Sella = pituitary compression, not postpartum ischemia

• Craniopharyngioma = Rathke's pouch tumor, unrelated to delivery

• Pituitary adenoma = benign tumor, unrelated to delivery

Q3: 10-year-old boy falling below standard deviation on growth chart

• ✅ Answer: Check serum growth hormone levels

Why:

• GH = primary regulator of linear growth in children

• Child is pre-pubertal → sex hormones not yet relevant

• LH/FSH = relevant for puberty assessment, not primary growth failure

• ADH = regulates water balance, zero role in linear growth

• GH deficiency features:

  • Short stature with normal proportions

  • Chubby/cherubic facial appearance

  • Delayed bone age on X-ray

  • Normal intelligence

Q4: TV reporter with neck mass noticed by viewers

• ✅ Answer: Ultrasound of the thyroid gland

Why:

• Gold standard first-line imaging for any thyroid mass

• Confirms mass, characterizes it (solid vs cystic)

• Risk stratifies for malignancy

• Guides FNA biopsy decision

Pathway:

• Ultrasound FIRST → FNA if suspicious → Surgery if malignant

Why others wrong:

• Radioiodine scan = comes AFTER ultrasound

• X-ray = poor soft tissue resolution

• MRI of head = evaluates brain, not thyroid

Q5: Female with fatigue, weight gain, cold intolerance, puffy face, bradycardia

• ✅ Answer: High TSH, Low T3 and T4

Why — Primary Hypothyroidism:

Thyroid gland FAILS
        ↓
T3 and T4 levels DROP
        ↓
Pituitary detects low levels
        ↓
Pituitary releases MORE TSH (compensates)
        ↓
Result: HIGH TSH + LOW T3/T4

Symptom explanations:

• Fatigue/depression/lethargy = low metabolism from insufficient thyroid hormone

• Weight gain = decreased metabolic rate

• Cold intolerance = reduced thermogenesis

• Puffy face (myxedema) = glycosaminoglycan accumulation

• Cold dry skin = reduced circulation

• Hair loss = thyroid hormone needed for hair follicle cycling

• Bradycardia = low T3/T4 slows cardiac conduction

Most likely cause: Hashimoto's thyroiditis Treatment: Levothyroxine

Why others wrong:

• High TSH + High T3/T4 = physiologically contradictory

• Low TSH + High T3/T4 = hyperthyroidism (opposite)

• Low TSH + Low T3/T4 = secondary/central hypothyroidism

Q6: Post-thyroidectomy — all four parathyroid glands removed

• ✅ Answer: Hyperparathyroidism would NOT occur

Why:

• No parathyroid tissue = no PTH production

• Cannot have EXCESS PTH with NO glands remaining

What WILL happen:

• Hypoparathyroidism = no PTH

• No PTH → calcium cannot be reabsorbed from bone, kidneys, gut

• HYPOCALCEMIA develops

• Trousseau's sign ✅ = carpal spasm with BP cuff inflation

• Chvostek's sign ✅ = facial twitch when tapping facial nerve

Treatment: Calcium + Calcitriol (active Vitamin D) supplementation

Q7: Female with resistant hypertension on 5 meds, flushing, tachycardia, not overweight

• ✅ Answer: 24-hour urine collection for catecholamine metabolites

Suspected diagnosis: Pheochromocytoma

Classic triad:

• Headache

• Sweating (diaphoresis)

• Tachycardia + palpitations

• PLUS resistant hypertension

Why 24-hour urine:

• Pheochromocytoma = adrenal medulla tumor

• Secretes excess epinephrine, norepinephrine, dopamine

• These break down to metanephrines, normetanephrines, VMA

• All measured in 24-hour urine collection

• Biochemical testing ALWAYS before imaging

Why others wrong:

• MRI brain = no neurological symptoms

• CT abdomen = comes AFTER biochemical confirmation; contrast can trigger hypertensive crisis

• Cardiac stress test = evaluates coronary disease, not this presentation

The "10% Tumor" rules:

• 10% bilateral

• 10% malignant

• 10% extra-adrenal

• 10% familial

• 10% in children

⚠ Never give beta-blockers alone (unopposed alpha → hypertensive crisis) ⚠ Never give contrast CT before biochemical confirmation

Q8: Which would NOT be a finding in DKA?

• ✅ Answer: Metabolic alkalosis

DKA Classic Triad:

DKA CLASSIC TRIAD:
├── HYPERGLYCEMIA (>250 mg/dL) ✅
├── KETOSIS (positive ketones) ✅
└── METABOLIC ACIDOSIS (pH <7.3) ✅

CLASSIC SYMPTOMS:
├── Abdominal pain ✅
├── Nausea and vomiting ✅
├── Kussmaul breathing
│     (deep rapid breathing — compensating for acidosis)
├── Fruity/acetone breath
│     (acetone ketone exhaled)
├── Dehydration/volume depletion
└── Altered mental status (severe cases)

Why metabolic alkalosis CANNOT occur:

No Insulin
    ↓
Cells cannot use glucose
    ↓
Body breaks down FAT for energy
    ↓
Ketone bodies produced
(Acetoacetate, Beta-hydroxybutyrate)
    ↓
Ketones are ACIDS
    ↓
METABOLIC ACIDOSIS — NOT alkalosis

Expected DKA findings:

• Hyperglycemia ✅ = no insulin → glucose accumulates

• Metabolic acidosis ✅ = ketones are acids → pH drops

• Volume contraction ✅ = osmotic diuresis causes massive fluid loss

Q9: 55-year-old Type 2 diabetic, glucose 800, pH 7.52, NO ketones

• ✅ Answer: IV fluid boluses FIRST

Diagnosis: HHS (Hyperosmolar Hyperglycemic State)

Why IV fluids first:

Glucose 800 mg/dL
    ↓
Extreme osmotic diuresis
    ↓
Massive fluid losses (8-10 LITERS)
    ↓
Severe dehydration + hypotension
    ↓
FLUIDS FIRST — restore circulation

Why NOT others first:

• IV insulin before fluids = osmotic shift → vascular collapse → FATAL

• Glucagon = raises glucose, completely contraindicated

• IV potassium = check levels first, give after fluids

DKA vs HHS comparison:

Q10: What do Type 1 and Type 2 diabetics have in common?

• ✅ Answer: Both lead to same endpoints of damage to eyes, kidneys, heart

Why:

• Both cause chronic hyperglycemia

• Chronic hyperglycemia damages blood vessels and nerves THE SAME WAY

• Regardless of cause (autoimmune vs insulin resistance)

Shared microvascular complications:

• Retinopathy = eye damage → blindness

• Nephropathy = kidney damage → ESRD

• Neuropathy = nerve damage → numbness/tingling/pain

Shared macrovascular complications:

• Coronary artery disease

• Cerebrovascular disease (stroke)

• Peripheral arterial disease

Why others wrong:

• NOT all Type 2 require insulin (oral meds often sufficient)

• Millions of Type 2 remain UNDIAGNOSED

• Type 1 patients are NOT obese and produce NO insulin

Q11: Lab reflecting average blood glucose over 90 days

• ✅ Answer: Hemoglobin A1c (HbA1c)

Why:

• Measures % of hemoglobin coated with glucose (glycated)

• Red blood cells live ~90-120 days

• HbA1c reflects glucose exposure over entire lifespan of RBC

HbA1c interpretation:

• <5.7% = Normal

• 5.7-6.4% = Prediabetes

• ≥6.5% = Diabetes

• <7.0% = Target for diabetics

• 
  

Why others wrong:

• Microalbumin = screens for kidney damage, NOT glucose

• Fasting glucose = single point in time only

• OGTT = diagnostic test, not 90-day average

HbA1c limitations:

• Falsely LOW in: hemolytic anemia, blood transfusions, sickle cell

• Falsely HIGH in: iron deficiency anemia, kidney failure

Q12: Which patient is LEAST likely to develop gestational diabetes?

• ✅ Answer: 25-year-old female with BMI of 24

Why lowest risk:

• Young age (25) = lower risk category

• Normal BMI (18.5-24.9) = no obesity

• No other risk factors mentioned

Why others HIGH risk:

• 45-year-old smoker = advanced maternal age + insulin resistance from smoking

• Prior macrosomic baby = STRONG predictor of GDM recurrence

• BMI 45 = obesity is STRONGEST risk factor for GDM

GDM pathophysiology:

Normal pregnancy hormones cause insulin resistance
    ↓
Pancreas compensates by producing more insulin
    ↓
When risk factors present (obesity, age, smoking)
    ↓
Baseline insulin resistance ALREADY exists
    ↓
Cannot compensate → GDM develops

⚠️ 50-70% of GDM patients develop Type 2 diabetes within 10 years ⚠ Screen with OGTT at 6-12 weeks postpartum

Q13: Type 1 diabetic, elevated creatinine/BUN, large protein in urine, on ACE inhibitor

• ✅ Answer: Diabetic nephropathy

Pathophysiology:

Chronic hyperglycemia
    ↓
Damages glomerular capillaries
    ↓
Glomerular hyperfiltration (early)
    ↓
Thickening of glomerular basement membrane
    ↓
Kimmelstiel-Wilson nodules (PATHOGNOMONIC)
    ↓
Glomerulosclerosis → proteinuria
    ↓
Progressive loss of kidney function → CKD → ESRD

Stages of diabetic nephropathy:

• Stage 1: Hyperfiltration, GFR >90

• Stage 2: Silent, microalbuminuria begins

• Stage 3: Microalbuminuria (30-300 mg/day)

• Stage 4: Macroproteinuria >300 mg/day ← This patient

• Stage 5: ESRD, GFR <15

Why ACE inhibitors:

• Dilate efferent arteriole → reduce intraglomerular pressure

• Decrease proteinuria → slow kidney damage progression

Why others wrong:

• Arteriosclerosis = large vessel damage (heart, brain, legs)

• Retinopathy = eye damage

• Neuropathy = nerve damage

⚠ Diabetic nephropathy = leading cause of ESRD in United States

Q14: Which diabetic patient is LEAST likely to have hypoglycemia?

• ✅ Answer: Diabetic patient who feels cold and THIRSTY

Why thirst rules out hypoglycemia:

THIRST = sign of HYPERGLYCEMIA
High glucose → osmotic diuresis
    ↓
Body loses fluid → dehydration
    ↓
THIRST develops to compensate
    ↓
Thirst does NOT occur in hypoglycemia

Hypoglycemia symptoms the others had:

• Sweating + confusion = adrenergic + neuroglycopenic ✅

• Sleepy + confused = brain starved of glucose ✅

• Hungry + shaking = adrenergic response ✅

Two categories of hypoglycemia symptoms:

• Adrenergic: sweating, shaking, tachycardia, anxiety, pallor, hunger

• Neuroglycopenic: confusion, lethargy, headache, seizures, loss of consciousness

Treatment — Rule of 15:

• 15g fast-acting carbs → wait 15 min → recheck

• If still <70 mg/dL → repeat

• Unconscious: IV D50 or IM glucagon

Q15: Forensic insulin murder case

• ✅ Answer: Check victim's serum insulin level and C-peptide

The forensic key — C-peptide:

Natural insulin production:
Proinsulin cleaved into:
├── Insulin
└── C-peptide (equal amounts always)

Injected (exogenous) insulin:
Contains insulin ONLY
└── NO C-peptide included

Murder proof:

• HIGH insulin + ABSENT/LOW C-peptide = injected externally = HOMICIDE PROVEN

Why others wrong:

• Suspect's labs = expected to be abnormal (he's diabetic) — proves nothing

• HbA1c = 90-day average, cannot detect acute injection

• Fasting glucose = already normal after death, glucose normalizes post-mortem

Q16: 45-year-old with enlarging hands, feet, forehead + temporal vision loss

• ✅ Answer: "I suspect a pituitary tumor — you have acromegaly"

Key distinctions:

EXCESS GROWTH HORMONE TIMING:

Before growth plates close (childhood):
    ↓
LINEAR HEIGHT INCREASES → GIGANTISM

After growth plates close (adulthood):
    ↓
Cannot grow taller
Bones grow WIDER/THICKER → ACROMEGALY

This patient:

• Adult (45) + normal height = ACROMEGALY

• Hands/feet/forehead enlarging = acral growth

• Temporal vision loss = bitemporal hemianopsia = pituitary tumor compressing optic chiasm

Classic acromegaly features:

• Frontal bossing (enlarged forehead) ✅

• Enlarged hands and feet ✅

• Jaw enlargement (prognathism)

• Widened teeth spacing (diastema)

• Coarse facial features

• Deep husky voice

• Carpal tunnel syndrome

• Diabetes (GH causes insulin resistance)

• Bitemporal hemianopsia ✅

Why others wrong:

• Sheehan's = postpartum females only

• Thyroid tumor ≠ gigantism

• Empty Sella = pituitary hypofunction, not excess GH

Q17: Hyperthyroid patient with thyroid nodule — confirm "hot nodule"

• ✅ Answer: Radioactive iodine uptake scan (RAIU)

Why:

Thyroid naturally absorbs iodine
    ↓
Radioactive iodine (I-123) given
    ↓
Scanner detects WHERE iodine concentrates
    ↓
HOT nodule = LIGHTS UP BRIGHTLY
(Autonomously absorbing all iodine)
    ↓
Rest of thyroid = DARK (suppressed)
    ↓
CONFIRMS toxic hot nodule ✅

RAIU scan patterns:

• Hot nodule = single bright spot, rest dark → Toxic adenoma

• Diffuse uptake = entire gland lights up → Graves' disease

• Multiple hot areas = several bright spots → Toxic multinodular goiter

• Cold nodule = dark spot → Suspicious for malignancy

Why others wrong:

• Ultrasound = shows structure NOT function

• Octreotide scan = for neuroendocrine tumors (carcinoid, pheo)

• Sestamibi scan = for parathyroid adenomas, NOT thyroid function

Q18: 18-year-old thin female, glucose 800, positive ketones, pH 7.22

• ✅ Answer: Type 1 diabetes mellitus with DKA

Why Type 1:

• 18 years old = young age ✅

• Very thin ✅

• No prior medical history (new onset) ✅

• Autoimmune beta cell destruction = zero insulin

Why DKA (not HHS):

• Positive ketones ✅

• pH 7.22 (acidotic) ✅

• Large urine ketones ✅

• HHS = NO ketones + NO acidosis

DKA pathophysiology:

Zero insulin production (Type 1)
    ↓
├── Glucose accumulates → hyperglycemia
│       → osmotic diuresis
│       → nausea/vomiting/abdominal pain
│
└── Body breaks down FAT (thinks it's starving)
        ↓
        Ketone bodies produced
        ↓
        KETOSIS → METABOLIC ACIDOSIS
        ↓
        pH drops to 7.22

Q19: 55-year-old on steroids 20 years, obese, moon face, buffalo hump, HbA1c 10.1%

• ✅ Answer: Type 2 diabetes mellitus with Cushing's syndrome

Two diagnoses:

Cushing's syndrome from steroids:

20 years of oral corticosteroids
    ↓
Exogenous cortisol excess
    ↓
Moon face ✅ (round full face)
Buffalo hump ✅ (fat pad base of neck)
Central obesity ✅
Hyperglycemia ✅
Hypertension
Osteoporosis

Type 2 diabetes from steroids:

Excess cortisol
    ↓
Stimulates gluconeogenesis
Inhibits glucose uptake
Promotes insulin resistance
    ↓
TYPE 2 DIABETES ✅

Cushing's vs Addison's:

⚠ NEVER abruptly stop long-term steroids → adrenal crisis

Q20: Byetta (Exenatide) — what does it do to lower glucose?

• ✅ Answer: Raises insulin levels postprandially

Mechanism:

Byetta = GLP-1 receptor agonist
    ↓
Mimics natural GLP-1 incretin hormone
    ↓
Activates GLP-1 receptors on beta cells
    ↓
RAISES insulin postprandially ✅
    ↓
ALSO:
├── Suppresses glucagon ✅
├── Slows gastric emptying ✅
└── Suppresses appetite → weight loss ✅

Glucose-dependent mechanism:

• Only stimulates insulin when glucose is elevated

• Very LOW hypoglycemia risk

• Must inject within 60 minutes BEFORE meals

Q21: Acromegaly is caused by ___

• ✅ Answer: Excess growth hormone

Other hormones cause different diseases:

• Excess ADH = SIADH

• Excess cortisol = Cushing's syndrome

• Excess thyroid hormone = hyperthyroidism

• Excess GH = ACROMEGALY (adults) or GIGANTISM (children)

Q22: SIADH — select all that apply

• ✅ Answers: Fluid retention + Hypervolemia

Pathophysiology:

Excess ADH
    ↓
Kidneys retain excess water
    ↓
├── FLUID RETENTION ✅
├── HYPERVOLEMIA ✅
├── Dilute plasma (hyponatremia)
└── Concentrated urine

Wrong answers:

• Dehydration = OPPOSITE (occurs in Diabetes Insipidus)

• Thirst = sign of dehydration, SUPPRESSED in SIADH

• Concentrated plasma = OPPOSITE, plasma becomes DILUTE

⚠ Correct sodium SLOWLY — max 8-10 mEq/L per 24 hours ⚠ Too fast = Osmotic Demyelination Syndrome (ODS) → permanent neurological damage

Q23: Central diabetes insipidus — select all that apply

• ✅ Answers: Results in excess water secretion + Increased plasma osmolarity

Pathophysiology:

Posterior pituitary DAMAGED
    ↓
INSUFFICIENT ADH
    ↓
Kidneys cannot retain water
    ↓
EXCESS WATER SECRETION ✅ (polyuria 3-20 L/day)
    ↓
Blood becomes concentrated
    ↓
INCREASED PLASMA OSMOLARITY ✅

Wrong answers:

• Increased blood glucose = NO relationship to glucose

• Another form of diabetes mellitus = shares word "diabetes" (polyuria) ONLY

• Caused by oversecretion of ADH = OPPOSITE, caused by deficiency

Treatment: Desmopressin (DDAVP) = synthetic ADH replacement

Q24: Graves' disease — select all that apply

• ✅ Answers: Is a form of hyperthyroidism + Results in elevated thyroid hormones

Pathophysiology:

TSI antibodies produced by immune system
    ↓
TSI mimics TSH → binds TSH receptors
    ↓
Thyroid continuously overstimulated
    ↓
EXCESS T3/T4 = HYPERTHYROIDISM ✅
ELEVATED THYROID HORMONES ✅

Classic Graves' triad:

• Hyperthyroidism ✅

• Goiter ✅

• Exophthalmos (bulging eyes)

Wrong answers:

• Autoimmune of posterior pituitary = affects THYROID not pituitary

• Weight gain, bradycardia, fatigue = HYPOTHYROID symptoms (exact opposite)

• Neurogenic disorder = it is AUTOIMMUNE not neurogenic

Q25: Hypofunction of endocrine gland — select all that apply

• ✅ Answers: Hashimoto's thyroiditis + Central diabetes insipidus

Why:

• Hashimoto's = autoimmune DESTROYS thyroid → LOW T3/T4 = hypofunction ✅

• Central DI = posterior pituitary INSUFFICIENT ADH = hypofunction ✅

Why others wrong:

• Graves' disease = HYPERFUNCTION (excess T3/T4)

• SIADH = HYPERFUNCTION (excess ADH)

• Acromegaly = HYPERFUNCTION (excess GH)

SECTION 2: JANELLE'S CASE STUDY (Questions 26-33)

30-year-old female presenting with anxiety, palpitations, weight loss

Q26: What hormone disorder causes weight loss?

• ✅ Answer: Thyroid hyperfunction

Why:

Excess T3/T4
    ↓
Metabolic rate dramatically INCREASES
    ↓
Body burns calories at accelerated rate
    ↓
WEIGHT LOSS despite normal/increased eating ✅

Thyroid hypofunction causes weight GAIN (opposite)

Q27: Which hormone increases resting heart rate and BP?

• ✅ Answer: Thyroid hormone

How:

Excess T3/T4
    ↓
Acts directly on cardiovascular system:
├── Increases heart rate (chronotropy) ✅
├── Increases cardiac contractility (inotropy)
├── Increases cardiac output
└── Increases systolic blood pressure ✅

Why others wrong:

• Oxytocin = uterine contractions/bonding, no significant CV effect

• Growth hormone = minimal direct cardiovascular effect

• ADH = affects fluid balance, not primary HR driver

Q28: Which statement about neck enlargement is true?

• ✅ Answer: Enlargement of thyroid can make neck appear fuller

Why:

TSI antibodies overstimulate thyroid
    ↓
Thyroid enlarges from continuous stimulation
    ↓
GOITER forms
    ↓
Visible in anterior neck
    ↓
Makes neck appear FULLER ✅

Why others wrong:

• Parathyroid NOT visible in anterior neck (tiny, on posterior surface of thyroid)

• Palpate with GENTLE force ONLY (aggressive palpation → thyroid storm)

• Neck enlargement does NOT always mean cancer (most goiters benign)

Q29: High free T3/T4, undetectable TSH and TRH — what disorder?

• ✅ Answer: Primary thyroid hyperfunction

Understanding the levels:

PRIMARY = problem at THYROID GLAND itself

Thyroid autonomously overproduces T3/T4
    ↓
High T3/T4 feeds back negatively
    ↓
SUPPRESSES pituitary → TSH undetectable ✅
SUPPRESSES hypothalamus → TRH undetectable ✅
    ↓
TSH and TRH being low = NORMAL RESPONSE
to high thyroid hormones
NOT the cause of the problem

Primary vs Secondary vs Tertiary:

• Primary = THYROID problem → T3/T4 abnormal first

• Secondary = PITUITARY problem → TSH abnormal

• Tertiary = HYPOTHALAMUS problem → TRH abnormal

Q30: Elevated thyroid stimulating antibodies confirm what diagnosis?

• ✅ Answer: Graves' disease

TSI antibodies = PATHOGNOMONIC for Graves' disease

TSI antibodies
    ↓
Continuously stimulate thyroid
    ↓
Explains ALL of Janelle's symptoms:
├── Anxiety/nervousness ✅
├── Palpitations/tachycardia ✅
├── Weight loss ✅
├── Hair loss ✅
├── Diarrhea ✅
├── Heat intolerance ✅
├── Hand tremors ✅
└── Goiter ✅

Why others wrong:

• Hashimoto's = anti-TPO antibodies → causes hypothyroidism (OPPOSITE)

• Cushing's = excess cortisol, moon face, weight gain

• SIADH = ADH disorder, completely unrelated

Q31: What other endocrine tissue is near the thyroid?

• ✅ Answer: Parathyroid glands

Anatomy:

FOUR parathyroid glands
├── 2 superior
└── 2 inferior
Located on POSTERIOR surface of thyroid
Each = size of a grain of rice

Surgical risk:

Thyroidectomy performed
    ↓
Parathyroid glands are:
├── Tiny (rice grain sized)
├── Directly attached to thyroid
└── Easy to accidentally remove
    ↓
If removed:
NO PTH PRODUCTION
    ↓
HYPOCALCEMIA → life-threatening

Why others wrong:

• Adrenal glands = top of kidneys (abdomen)

• Pituitary = base of brain (head)

• Pineal = center of brain (head)

Q32: If parathyroid damaged during surgery, what is physician most concerned about?

• ✅ Answer: Hypocalcemia

Why:

No PTH
    ↓
├── Cannot resorb calcium from bones
├── Cannot reabsorb calcium in kidneys
└── Cannot activate Vitamin D → no intestinal calcium absorption
    ↓
ALL CALCIUM REGULATION LOST
    ↓
SEVERE HYPOCALCEMIA ✅

Hypocalcemia progression:

Mild: Perioral tingling (FIRST sign), fingertip tingling
    ↓
Moderate: Muscle cramps, Trousseau's sign, Chvostek's sign
    ↓
Severe: Tetany, LARYNGOSPASM ← LIFE THREATENING
    ↓
Critical: Seizures, cardiac arrhythmias, DEATH

Why others wrong:

• Hypernatremia = ADH/dehydration issue, PTH has NO role in sodium

• Hypokalemia = aldosterone issue, PTH has NO role in potassium

• Diuresis = ADH/glucose issue, not from PTH loss

Q33: If thyroid removed, what medication will Janelle need?

• ✅ Answer: Levothyroxine

Why:

Thyroid removed
    ↓
No T3/T4 production
    ↓
Without replacement → HYPOTHYROIDISM
    ↓
LEVOTHYROXINE (synthetic T4) ✅
    ↓
Taken DAILY FOR LIFE

Administration rules:

• Take same time every day

• Morning on EMPTY stomach

• 30-60 minutes before breakfast

• Avoid calcium, iron, antacids (block absorption)

Why others wrong:

• Naproxen = NSAID, pain relief, no thyroid effect

• Amantadine = antiviral/antiparkinsonian, no thyroid effect

• Herceptin = HER2+ breast cancer drug, no thyroid effect

SECTION 3: ADDITIONAL QUESTIONS

Q34: Excess ADH is associated with which condition?

• ✅ Answer: SIADH

SIADH = Syndrome of INAPPROPRIATE Antidiuretic Hormone

• The name literally contains the answer

• Excess ADH → kidneys retain water → dilutional hyponatremia

Complete SIADH vs Central DI comparison:

Q35: A patient with central DI ___

• ✅ Answer: Will have increased urine output

Why:

No ADH
    ↓
Kidneys cannot retain water
    ↓
Massive polyuria (3-20 liters/day) ✅
    ↓
14x normal urine output

Classic triad:

• Polyuria ✅ (3-20 L/day)

• Polydipsia (extreme thirst — compensatory)

• Nocturia (waking multiple times nightly)

Why others wrong:

• Edema = SIADH (water retained), NOT DI

• Higher metabolism = thyroid hormone effect, NOT ADH

• Drinks LESS water = OPPOSITE, extreme polydipsia occurs

Q36: Hyperfunction of ___ causing excess GH may cause ___

• ✅ Answer: Anterior pituitary; acromegaly

Why:

ANTERIOR PITUITARY
Contains somatotroph cells
    ↓
HYPERFUNCTION
    ↓
Somatotroph adenoma
    ↓
EXCESS GH
    ↓
GH → stimulates IGF-1
    ↓
Growth plates CLOSED (adult)
    ↓
ACROMEGALY ✅

Anterior vs Posterior pituitary:

• Anterior = produces GH, TSH, ACTH, FSH, LH, Prolactin ✅

• Posterior = stores/releases ADH and Oxytocin ONLY

• Posterior does NOT produce GH — EVER

Why others wrong:

• Hypothalamus produces GHRH (not GH itself)

• Posterior pituitary = ADH + oxytocin ONLY

• Graves' = autoimmune thyroid disorder, unrelated to GH

Q37: Patient with decreased T3 and T4 — select all expected findings

• ✅ Answers: Weight gain + Decreased heart rate + Fatigue

Why:

LOW T3/T4 = HYPOTHYROIDISM
Everything SLOWS DOWN:

Metabolism slows → WEIGHT GAIN ✅
Cardiac stimulation reduced → BRADYCARDIA ✅
Cellular energy reduced → FATIGUE ✅

Wrong answers:

• Feeling hot = HYPERTHYROID (excess T3/T4 = heat intolerance)

• Weight loss = HYPERTHYROID (excess T3/T4 = increased metabolism)

Complete comparison:

Q38: Most common cause of thyroid hyperfunction is ___

• ✅ Answer: Graves' disease

Why:

• Accounts for 60-80% of ALL hyperthyroidism cases

• TSI antibodies continuously overstimulate thyroid

Why others wrong:

• Hashimoto's = causes HYPOthyroidism (destroys thyroid)

• Pituitary tumor = extremely RARE cause of hyperthyroidism

• Elevated TSH = feature of HYPOTHYROIDISM (compensatory response)

SECTION 4: COUNTER-REGULATORY HORMONES & DIABETES QUESTIONS

Q39: Hormones released to counteract hypoglycemia — select all that apply

• ✅ Answers: Glucagon, Epinephrine, Cortisol, Growth Hormone

• ❌ Insulin = WRONG (lowers glucose, would worsen hypoglycemia)

Counter-regulatory response timeline:

HYPOGLYCEMIA DETECTED:

IMMEDIATE (seconds-minutes):
├── Insulin SUPPRESSED first
└── GLUCAGON released
      → Rapid glycogen breakdown
      → Quick glucose release ✅

EARLY (minutes):
└── EPINEPHRINE released
      → Glycogenolysis + gluconeogenesis
      → Produces warning SYMPTOMS
      (Sweating, shaking, tachycardia) ✅

DELAYED (hours — prolonged fasting):
├── CORTISOL released
│     → Protein breakdown → gluconeogenesis ✅
└── GROWTH HORMONE released
      → Fat breakdown → insulin resistance
      → Glucose preservation ✅

All four mechanisms:

• Glucagon = breaks down liver glycogen → rapid glucose release (FASTEST)

• Epinephrine = glycogenolysis + gluconeogenesis + causes hypoglycemia SYMPTOMS

• Cortisol = gluconeogenesis from protein breakdown (sustained response)

• Growth hormone = causes insulin resistance + lipolysis (sustained response)

Q40: True statements about Type 2 diabetes in your aunt — select all that apply

• ✅ Answers: Obesity and inactivity are risk factors + Cells demonstrate insulin resistance

Core mechanism:

Genetic predisposition + Obesity + Inactivity
    ↓
INSULIN RESISTANCE develops ✅
    ↓
Cells IGNORE insulin signal
    ↓
Pancreas compensates → MORE insulin
    ↓
Eventually beta cells EXHAUSTED
    ↓
Relative insulin deficiency
    ↓
HYPERGLYCEMIA → TYPE 2 DIABETES

Why wrong answers are wrong:

• "Body no longer produces insulin" = TYPE 1, not Type 2 (still produces insulin)

• "Blood glucose lower than normal" = OPPOSITE, Type 2 = HYPERGLYCEMIA

• "Autoimmune attack of beta cells" = TYPE 1, not Type 2

Type 1 vs Type 2:

Q41: Tests to diagnose Type 2 diabetes — select all that apply

• ✅ Answers: Fasting blood glucose + OGTT + A1c

Three diagnostic tests:

Wrong answers:

• Hemoglobin and hematocrit = diagnoses ANEMIA, not diabetes

• Dexamethasone suppression test = diagnoses CUSHING'S SYNDROME, not diabetes

Confirmation rules:

• Symptomatic = ONE abnormal test sufficient

• Asymptomatic = TWO abnormal tests required

Q42: Diabetics should eat approximately ___ % calories from carbohydrates

• ✅ Answer: 50%

Daily caloric distribution:

• Carbohydrates = 50% (45-60% acceptable range) ✅

• Fats = 30-35%

• Protein = 15-20%

Why not 0%, 25%, or 30%:

• Brain requires glucose as PRIMARY fuel

• Red blood cells depend ENTIRELY on glucose

• Complete elimination = dangerous hypoglycemia risk

• Too restrictive = insufficient energy, unsustainable

Good vs bad carbohydrates:

• GOOD: Whole grains, vegetables, legumes, fresh fruits, low-fat dairy

• BAD: White bread/rice, sugary beverages, candy, pastries, processed snacks

SECTION 5: MR. THOMAS CASE STUDY (Questions 43-51)

58-year-old attorney with metabolic syndrome and Type 2 diabetes

Q43: Which results suggest metabolic syndrome? — select all that apply

• ✅ Answers: Waist circumference (41"), Triglycerides (155), HDL (37), Fasting glucose (105)

Metabolic syndrome — need 3 of 5 criteria:

Mr. Thomas meets 4 of 5 = Metabolic syndrome confirmed

Root cause of all findings:

Insulin resistance + Abdominal obesity
    ↓
├── Visceral fat releases inflammatory cytokines
├── Liver increases VLDL → elevated triglycerides
├── HDL production decreases
└── Glucose cannot enter cells efficiently
    ↓
ALL FIVE CRITERIA DRIVEN BY
INSULIN RESISTANCE ✅

Q44: Tests ordered to assess diabetes in Mr. Thomas

• ✅ Answer: OGTT, A1c

Why each test:

• OGTT = tests postprandial glycemic control (glucose challenge → 2-hour response)

• A1c = evaluates glycemic control during prior 3 months (90-day average)

Why others wrong:

• ICAs = islet cell antibodies → diagnose TYPE 1 autoimmune, not postprandial testing

• C-peptide = measures insulin production, NOT 3-month glucose average

• OGTT, C-peptide = timing correct but C-peptide doesn't measure 3-month control

Q45: Results that confirm DM for OGTT and A1c respectively

• ✅ Answer: ≥200 mg/dL, ≥6.5%

OGTT threshold:

• Normal = <140 mg/dL

• Prediabetes = 140-199 mg/dL

• DIABETES = ≥200 mg/dL ✅

A1c threshold:

• Normal = <5.7%

• Prediabetes = 5.7-6.4%

• DIABETES = ≥6.5% ✅

Why ≥126 mg/dL is wrong for OGTT:

• 126 mg/dL threshold = FASTING blood glucose ONLY

• OGTT uses higher threshold (≥200) because it measures AFTER glucose load

Q46: Postprandial glucose — when to check and target

• ✅ Answer: 2 hours, ≤180 mg/dL

Why 2 hours:

Meal consumed (Time 0)
    ↓
0-60 minutes = glucose still rising
60-90 minutes = approaching peak
2 HOURS = peaked and beginning to return ✅
Most meaningful measurement time

Why ≤180 mg/dL (not ≤100):

• Even non-diabetics rise to 120-140 mg/dL after meals

• ≤100 mg/dL postprandial is physiologically unrealistic

• Would cause dangerous hypoglycemia in medicated patients

ADA targets:

• Preprandial = 80-130 mg/dL

• 2-hour postprandial = ≤180 mg/dL ✅

• Bedtime = 100-140 mg/dL

• HbA1c = <7.0%

Q47: Percentage of calories from carbohydrates

• ✅ Answer: 50%

Same as Q42 — consistent ADA guideline of ~50% carbohydrates

Plate method for Mr. Thomas:

┌─────────────────────────────┐
│    NON-STARCHY VEGETABLES   │
│         (1/2 plate)         │
├──────────────┬──────────────┤
│  LEAN        │  COMPLEX     │
│  PROTEIN     │  CARBS       │
│  (1/4 plate) │  (1/4 plate) │
└──────────────┴──────────────┘

Q48: Recommended range for preprandial blood glucose

• ✅ Answer: 80 to 130 mg/dL

Mr. Thomas averaging 150 mg/dL preprandial:

150 mg/dL > 130 mg/dL (upper limit)
    ↓
20 mg/dL ABOVE target
    ↓
Diabetes not optimally controlled
    ↓
Will push postprandial glucose even higher
    ↓
Contributes to higher HbA1c
    ↓
Increased complication risk

Why others wrong:

• <100 mg/dL = NON-diabetic fasting normal, too strict for diabetics on medications → hypoglycemia risk

• 140-180 mg/dL = POSTPRANDIAL target, not preprandial

• 120-180 mg/dL = not a recognized ADA target range

Q49: Medication to stimulate insulin secretion

• ✅ Answer: Meglitinides

Mechanism:

Meglitinides bind K+ATP channels
on pancreatic BETA CELLS
    ↓
Channels CLOSE → membrane depolarizes
    ↓
Voltage-gated Ca²⁺ channels OPEN
    ↓
Calcium enters beta cell
    ↓
Insulin granules released
    ↓
INSULIN SECRETED ✅

Examples: Repaglinide (Prandin), Nateglinide (Starlix) Key feature: Short-acting, taken before meals

Why others wrong:

• Thiazolidinediones = improve insulin SENSITIVITY (PPAR-gamma receptors)

• Biguanides = reduce liver glucose production + sensitivity (NOT secretion)

• Alpha-glucosidase inhibitors = block carb absorption in intestines (NOT pancreas)

All diabetes medication classes:

• STIMULATE insulin secretion = Meglitinides ✅ + Sulfonylureas

• IMPROVE insulin sensitivity = Biguanides + TZDs

• SLOW carb absorption = Alpha-glucosidase inhibitors

• MIMIC incretins = GLP-1 agonists + DPP-4 inhibitors

• EXCRETE glucose = SGLT-2 inhibitors

• REPLACE insulin = Insulin therapy

Q50: Type of synthetic insulin prescribed

• ✅ Answer: Insulin analogue

Three clues in question:

• "Synthetic preparation" ✅

• "Mimics physiological insulin" ✅

• "Structure DIFFERS from natural form" ✅

What insulin analogues are:

Human insulin gene identified
    ↓
Inserted into bacteria/yeast
    ↓
Amino acid sequence MODIFIED
at specific positions
    ↓
INSULIN ANALOGUE created:
├── Structure differs ✅
└── Function mimics natural insulin ✅

Types:

• Rapid-acting: Lispro (Humalog), Aspart (NovoLog), Glulisine (Apidra)

  • Onset 10-15 min, Peak 1-2 hr, Duration 3-5 hr

• Long-acting: Glargine (Lantus), Detemir (Levemir)

  • Onset 1-2 hr, NO peak, Duration 20-24 hr

Why others wrong:

• Conventional insulin = matches natural structure, not different

• Endogenous insulin = produced by body's own pancreas, not synthetic

• Unconventional insulin = not a real pharmacological term

Q51: Name of insulin regimen for Mr. Thomas

• ✅ Answer: Basal-bolus

Two components:

BASAL (Long-acting) — ONCE DAILY ✅
└── Glargine (Lantus) / Detemir (Levemir)
    Given at bedtime
    Controls fasting + between-meal glucose
    Peakless, 20-24 hour duration

BOLUS (Rapid-acting) — BEFORE EACH MEAL ✅
└── Lispro/Aspart/Glulisine
    Given 3x daily
    Controls postprandial glucose spikes
    Onset 10-15 minutes

How it mimics natural physiology:

Normal pancreatic secretion:
├── Continuous low-level BASAL insulin (background)
└── Meal-triggered BOLUS insulin spikes
    ↓
BASAL-BOLUS regimen replicates BOTH ✅
Most physiologically accurate available

Why others wrong:

• Constant-duration = not a real insulin regimen

• Peak-valley = not a recognized regimen

• Intermittent-rotation = rotation refers to injection SITES, not regimen type

SECTION 6: ADDITIONAL TEST QUESTIONS (Questions 52-71)

Q52: Patient with elevated BP, confusion, abdominal MRI for adrenal tumor

• ✅ Answer: Pheochromocytoma

Why:

• Elevated BP = catecholamine excess from adrenal medulla tumor

• Confusion = severe hypertension effects on brain

• Abdominal MRI = looking for adrenal gland tumor

• Pheochromocytoma = tumor of adrenal medulla = classic

Q53: Diagnostic test to rule out ectopic ACTH-secreting tumors

• ✅ Answer: Octreotide scintigraphy

Why:

• Ectopic ACTH tumors (small cell lung cancer, carcinoid) express somatostatin receptors

• Octreotide = somatostatin analogue tagged with radioactive tracer

• Binds to somatostatin receptors on ectopic ACTH tumors

• Scanner detects WHERE octreotide concentrates = tumor location

• Can find tumors ANYWHERE in the body ✅

Why others wrong:

• Contrast MRI = good for pituitary but misses small ectopic tumors throughout body

• Chest X-ray = too limited, misses many locations

• Abdominal CT = only covers abdomen, misses other locations

Q54: Signs/symptoms NOT seen in severe diabetes insipidus

• ✅ Answer: Gynecomastia

Why gynecomastia does NOT occur:

• Gynecomastia = male breast tissue enlargement

• Caused by: excess estrogen, prolactin, or low testosterone

• DI is a water/ADH disorder — NO hormonal effect on breast tissue

• Completely unrelated to ADH deficiency

What IS seen in severe DI:

• Dry mucous membranes ✅ = severe dehydration

• Poor skin turgor ✅ = severe dehydration

• Orthostatic hypotension ✅ = volume depletion from massive water loss

Q55: Pineal tumor — which would NOT be a symptom?

• ✅ Answer: Conjunctivitis

Why conjunctivitis does NOT occur:

• Conjunctivitis = eye INFECTION/inflammation from bacteria/virus/allergen

• NOT caused by brain tumors

• Infectious/allergic condition, NOT neurological

What DOES occur with pineal tumor:

• Seizures ✅ = pressure on brain tissue

• Memory disturbances ✅ = compression of nearby brain structures

• Visual changes ✅ = pineal gland near superior colliculus → affects eye movement/vision

Q56: Disorder caused by decrease in cortisol from adrenal gland

• ✅ Answer: Addison's disease

Why:

Adrenal gland FAILS or DESTROYED
    ↓
Insufficient cortisol + aldosterone production
    ↓
ADDISON'S DISEASE ✅

Classic Addison's features:

• Weight loss

• Hypotension

• Hypoglycemia

• Hyponatremia

• Hyperkalemia

• Hyperpigmentation (bronze skin — ACTH elevated, stimulates melanocytes)

• Extreme fatigue/weakness

Why others wrong:

• Hypothyroidism = low T3/T4 (thyroid), not cortisol

• Cushing's = EXCESS cortisol (opposite)

• Diabetes mellitus = insulin/glucose disorder, not cortisol deficiency

Q57: Patient with coarsening facial features, enlarged facial bones, high BP, bitemporal hemianopsia, enlarged hands and feet — which test would NOT be helpful?

• ✅ Answer: Ultrasonography

Why ultrasonography NOT helpful:

• Ultrasound = used for thyroid, abdomen, soft tissue

• Cannot image BRAIN or PITUITARY gland effectively

• Skull blocks ultrasound waves

• No role in diagnosing pituitary tumors/acromegaly

Why others ARE helpful:

• MRI of whole head ✅ = best imaging for pituitary adenoma

• CT scan of whole head ✅ = can visualize pituitary and skull changes

• Serum growth hormone level ✅ = directly measures excess GH causing acromegaly

Diagnosis = Acromegaly (all classic features present)

Q58: Sheehan's syndrome patient with hypothyroidism but LOW TSH — why?

• ✅ Answer: Secondary hypothyroidism

Why:

Sheehan's syndrome = PITUITARY destroyed
    ↓
Pituitary CANNOT produce TSH
    ↓
Without TSH stimulation
    ↓
Thyroid has NO signal to produce T3/T4
    ↓
T3/T4 LOW + TSH LOW ✅
    ↓
SECONDARY HYPOTHYROIDISM
(Problem at PITUITARY level)
    ↓
NOT primary (primary = TSH would be HIGH
as compensation)

Primary vs Secondary hypothyroidism:

Q59: Excessively thirsty, dilute polyuria, poor skin turgor, low BP, pituitary tumor on CT

• ✅ Answer: Diabetes insipidus

Why:

Pituitary tumor
    ↓
Compresses/destroys posterior pituitary
    ↓
INSUFFICIENT ADH production
    ↓
Kidneys cannot retain water
    ↓
├── Massive dilute polyuria ✅
├── Extreme thirst (polydipsia) ✅
├── Poor skin turgor ✅ (dehydration)
└── Low blood pressure ✅ (volume depletion)
    ↓
DIABETES INSIPIDUS ✅

Why others wrong:

• Cushing's = excess cortisol, weight gain, moon face, no polyuria

• Hyperprolactinemia = excess prolactin, galactorrhea, amenorrhea

• Dwarfism = GH deficiency in CHILDHOOD, not these symptoms

Q60: Loss of two or more pituitary hormones

• ✅ Answer: Hypopituitarism

Why:

• Hypo = under/deficient

• Pituitary = pituitary gland

• Hypopituitarism = deficiency of TWO OR MORE pituitary hormones

Why others wrong:

• Sheehan's syndrome = specific TYPE of hypopituitarism (postpartum)

• Hyperpituitarism = EXCESS pituitary hormones (opposite)

• Empty Sella syndrome = pituitary compressed/flattened, may or may not cause deficiency

Q61: Patient with "hot gland" by sestamibi scan, hypercalcemia — which statement is NOT CORRECT?

• ✅ Answer: "This patient has increased osteoblast activity due to increased PTH"

Why this is INCORRECT:

Excess PTH (hyperparathyroidism)
    ↓
Stimulates OSTEOCLASTS (not osteoblasts)
    ↓
Osteoclasts BREAK DOWN bone
    ↓
Calcium released from bones → hypercalcemia
    ↓
OSTEOCLAST activity increases ✅
OSTEOBLAST activity does NOT increase ❌

Memory tool:

• OsteoCLASTs = CRUSH/destroy bone (PTH stimulates these)

• OsteoBLASTs = BUILD new bone (NOT stimulated by PTH)

Why other statements ARE correct:

• "Increase water intake to prevent kidney stones" ✅ = hypercalcemia → calcium kidney stones

• "Will likely have surgery" ✅ = parathyroidectomy is treatment for hyperparathyroidism

• "Prescribed calcitonin to inhibit bone breakdown" ✅ = calcitonin opposes PTH, inhibits osteoclasts

Q62: Confused inpatient diabetic, glucose 40 mg/dL — BEST fastest treatment?

• ✅ Answer: Administering 50 mL of 50% dextrose intravenously pushed

Why:

Patient is CONFUSED (cannot swallow safely)
    ↓
Oral juice CONTRAINDICATED in confused patient
(Aspiration risk)
    ↓
Glucose 40 mg/dL = SEVERE hypoglycemia
    ↓
Need FASTEST correction possible
    ↓
50 mL of 50% Dextrose (D50) IV push ✅
    ↓
= 25 grams of glucose
    ↓
Directly into bloodstream
    ↓
FASTEST possible correction

Why others wrong:

• Sweetened orange juice = CANNOT give orally to confused patient (aspiration risk) ❌

• Glucagon subcutaneous = slower onset (15-20 min), works indirectly, less reliable ❌

• 25g glucose in 1L 1/2 NS over 6 hours = WAY TOO SLOW for severe acute hypoglycemia ❌

Q63: Patient in 301 gets sweaty, pale, dizzy after medications — what happened?

• ✅ Answer: Patient is hypoglycemic as he got insulin from 302 instead of vancomycin

Why:

Distracted nurse
    ↓
Gave INSULIN (from room 302's medication)
to patient in 301 (non-diabetic)
instead of VANCOMYCIN
    ↓
Non-diabetic received insulin
    ↓
No glucose abnormality before injection
    ↓
Insulin drives glucose INTO cells
    ↓
Blood glucose CRASHES
    ↓
HYPOGLYCEMIA develops ~1 hour later ✅
    ↓
Symptoms: sweaty, pale, dizzy,
lightheaded, confused ✅

Why others wrong:

• Allergic reaction = would show hives, rash, respiratory distress, NOT this pattern

• Fever from cellulitis = would show hot skin, elevated temp, NOT sudden onset like this

• Feigning illness = clinical presentation consistent with real hypoglycemia; nurse was distracted

⚠ Critical patient safety lesson: Always verify patient identity AND medication before administering

Q64: Adolescent Type 1 diabetic skipping insulin to avoid weight gain

• ✅ Answer: Insulin purging

Why:

Type 1 diabetic deliberately skips insulin
    ↓
Without insulin:
├── Glucose cannot enter cells
├── Body burns fat for energy
├── Weight loss occurs
└── HbA1c rises dangerously
    ↓
Using insulin omission as weight control
    ↓
INSULIN PURGING ✅
(Also called Diabulimia)

Why others wrong:

• Psychological insulin resistance = fear/reluctance to START insulin, not skipping to lose weight

• Hyperinsulinism = EXCESS insulin production, opposite problem

• Diabetic neuropathy = complication from chronic hyperglycemia, not a behavior

⚠ Extremely dangerous — leads to:

• Recurrent DKA

• Accelerated microvascular complications

• Premature death

• Requires psychiatric + endocrine co-management

Q65: Glucose 75 at 11pm, 30 at 3am, 170 at 7am — what mechanism?

• ✅ Answer: Somogyi effect

Why — Somogyi effect explained:

Long-acting insulin given at night
    ↓
Too much insulin overnight
    ↓
NOCTURNAL HYPOGLYCEMIA at 3am (30 mg/dL) ✅
    ↓
Body releases counter-regulatory hormones:
├── Glucagon
├── Epinephrine
├── Cortisol
└── Growth hormone
    ↓
REBOUND HYPERGLYCEMIA by morning
(170 mg/dL at 7am) ✅
    ↓
SOMOGYI EFFECT = nocturnal hypoglycemia
followed by rebound morning hyperglycemia

Somogyi vs Dawn Phenomenon:

Q66: Symptom NOT observed in severe nocturnal hypoglycemia

• ✅ Answer: Severe dehydration

Why dehydration does NOT occur:

• Dehydration = from excess fluid LOSS (polyuria, sweating excessively, vomiting)

• Nocturnal hypoglycemia = blood glucose LOW, not high

• No osmotic diuresis (that requires HIGH glucose)

• No massive fluid losses occur during hypoglycemia

What DOES occur in nocturnal hypoglycemia:

• Vivid nightmares ✅ = brain hypoglycemia during sleep

• Sleep disturbance ✅ = adrenergic response awakens patient

• Morning headache ✅ = from overnight cerebral glucose deprivation

Q67: First-line medication for newly diagnosed Type 2 diabetic

• ✅ Answer: Metformin (Glucophage)

Why:

Type 2 diabetes first-line:
    ↓
METFORMIN ✅
    ↓
├── Reduces liver glucose production
├── Improves insulin sensitivity
├── Weight neutral/modest weight loss
├── Cardiovascular protective
├── Inexpensive and widely available
└── Very LOW hypoglycemia risk

Why others wrong:

• Expensive incretin mimetic = second or third line, not first line

• IV insulin = for hospitalized/critically ill or Type 1, not newly diagnosed Type 2 outpatient

• Loop diuretic = treats fluid retention/heart failure/hypertension, NOT diabetes

Q68: Type 1 diabetic — pH 7.21, glucose 650, high ketones, bicarbonate 8 mEq/L

• ✅ Answer: Diabetic ketoacidosis

Why — all DKA criteria met:

DKA CLASSIC TRIAD:
├── HYPERGLYCEMIA (>250 mg/dL) ✅ — glucose 650
├── KETOSIS (positive ketones) ✅ — high serum ketones
└── METABOLIC ACIDOSIS (pH <7.3) ✅ — pH 7.21

ADDITIONAL CONFIRMATION:
└── Bicarbonate 8 mEq/L (very low) ✅
    = Body exhausted buffering capacity
    Normal bicarb = 22-26 mEq/L
    Very low = severe acidosis confirmed

Why others wrong:

• HHS = NO ketones + NO acidosis (normal pH)

• "Compromised by another illness" = incomplete diagnosis; labs clearly show DKA

• Prediabetes = glucose 100-125 mg/dL, NO ketones, NO acidosis

Q69: Patient on Byetta (GLP-1 agonist) — which is NOT an effect?

• ✅ Answer: Increase in postprandial glucagon

Why increase in glucagon is NOT an effect:

GLP-1 agonists (Byetta) SUPPRESS glucagon ✅
    ↓
Glucagon raises blood glucose
    ↓
SUPPRESSING glucagon = lowers glucose
    ↓
INCREASING glucagon = raises glucose ❌
= OPPOSITE of what Byetta does

What Byetta DOES do:

• Suppression of postprandial glucagon ✅ (lowers glucose)

• Delay in gastric emptying ✅ (slows glucose absorption)

• Glucose-dependent insulin secretion ✅ (raises insulin after meals)

• Appetite suppression ✅ (promotes weight loss)

Q70: Nurse without diabetes having repeated hypoglycemia (50-60 mg/dL) — factitious hypoglycemia — which labs prove exogenous insulin use?

• ✅ Answer: C-peptide level and serum insulin

Why — same principle as murder case:

If nurse injecting exogenous insulin:
    ↓
HIGH serum insulin ✅
    ↓
LOW/ABSENT C-peptide ✅
    ↓
Natural insulin production:
Always = Insulin + C-peptide together
    ↓
Injected insulin:
= Insulin WITHOUT C-peptide
    ↓
HIGH insulin + LOW C-peptide = PROOF
of exogenous insulin injection ✅

Why others wrong:

• Serum glucose + glucagon = glucose already known (40-60 mg/dL), glucagon tells us nothing about source of insulin

• Serum glucagon + insulin = glucagon irrelevant here; missing C-peptide which is KEY

• Serum insulin only = shows high insulin but cannot prove it's exogenous without C-peptide comparison

Q71: Lab that tells average glucose over 90-100 days and diagnoses diabetes

• ✅ Answer: Hemoglobin A1c

Why:

• Measures glycated hemoglobin (glucose attached to hemoglobin)

• Reflects glucose exposure over 90-120 day lifespan of RBC

• Diagnoses diabetes at ≥6.5% ✅

• Monitors diabetes control (goal <7.0%)

• No fasting required

Why others wrong:

• C-peptide = measures insulin PRODUCTION, not glucose average

• OGTT = 2-hour glucose tolerance test, not 90-day average

• Islet cell autoantibodies = diagnose TYPE 1 autoimmune destruction, not glucose average

🔑 MASTER KEY CONCEPTS SUMMARY

Thyroid Disorders Quick Reference:

Diabetes Types Quick Reference:

Pituitary Disorders Quick Reference:

Calcium Regulation Quick Reference:

Adrenal Disorders Quick Reference:

Insulin Types Quick Reference:

Diabetes Medication Quick Reference:

Critical Lab Values Quick Reference:

1. TSI antibodies = Graves' disease (pathognomonic)

2. Anti-TPO antibodies = Hashimoto's thyroiditis

3. High TSH + Low T3/T4 = Primary hypothyroidism

4. Low TSH + High T3/T4 = Primary hyperthyroidism

5. Low TSH + Low T3/T4 = Secondary hypothyroidism (pituitary failure)

6. C-peptide absent + High insulin = Injected (exogenous) insulin

7. Hot nodule = Radioiodine scan to confirm

8. Acromegaly = Excess GH from ANTERIOR pituitary in adults

9. Gigantism = Excess GH BEFORE growth plates close in children

10. DKA = Type 1 + ketones + acidosis (pH <7.3)

11. HHS = Type 2 + NO ketones + NO acidosis + glucose >600 + massive dehydration

12. Fluids FIRST in both DKA and HHS before insulin

13. SIADH = Excess ADH → hyponatremia + fluid retention

14. Central DI = Deficient ADH → polyuria + hypernatremia

15. Pheochromocytoma = 24-hour urine catecholamines FIRST (biochemical before imaging)

16. Cushing's = Excess cortisol → moon face + buffalo hump + weight gain + hyperglycemia

17. Addison's = Deficient cortisol → weight loss + hypotension + hyperpigmentation

18. Sheehan's = Postpartum pituitary necrosis → panhypopituitarism

19. Somogyi effect = Nocturnal hypo → rebound morning hyperglycemia

20. Metformin = First-line Type 2 diabetes treatment always