Endocrine System

A comprehensive set of study flashcards covering adrenal disorders, thyroid disorders, and diabetes management, aligned with the lecture notes.

What can mineralocorticoid and glucocorticoid deficiency lead to, and what are the common presentations of the resulting crisis?

Adrenal crisis: life‑threatening emergency with shock from cardiovascular collapse, abdominal tenderness, fever, weight loss, possible hyperpigmentation, and electrolyte abnormalities.

What are the classic features of Diabetic Ketoacidosis (DKA) and the typical blood glucose range seen in DKA?

DKA presents with anion gap metabolic acidosis, ketonemia, and hyperglycemia; serum glucose often ranges from about 350 to 500 mg/dL (often <800).

What signs indicate volume depletion in DKA and hyperosmolar hyperglycemic state (HHS)?

Decreased skin turgor, dry axillae and oral mucosa, low JVP, tachycardia, and hypotension if severe.

Which symptoms are commonly associated with DKA, including abdominal and respiratory findings?

Abdominal pain, fruity breath odor, and Kussmaul respirations (rapid deep hyperventilation).

What is hyperprolactinemia and what are its typical presentations?

Hyperprolactinemia is increased prolactin levels in the blood and can indicate a pituitary adenoma; slow onset with amenorrhea in women, galactorrhea in both sexes, and headaches/vision changes if a mass effect occurs.

How is hypoglycemia defined and what are common symptoms of hypoglycemia?

Hypoglycemia is <70 mg/dL; symptoms include weakness, hand tremors, anxiety, potential syncope, and difficulty concentrating.

How does the American Diabetes Association classify hypoglycemia levels 1, 2, and 3?

Level 1: glucose >54 to <70 mg/dL; Level 2: <54 mg/dL; Level 3: severe event with altered mental/physical status needing assistance.

What is myxedema coma, and what key labs are checked when suspected?

A medical emergency from severe hypothyroidism; check serum T4, TSH, and cortisol; high mortality if not treated promptly.

What is a pheochromocytoma and what is the typical attack pattern?

A rare adrenal tumor causing episodic headaches, diaphoresis, tachycardia, and hypertension with normal vitals between attacks.

What triggers pheochromocytoma episodes?

Physical exertion, anxiety, stress, surgery, anesthesia, changes in position, labor; foods high in tyramine; MAOIs; stimulant drugs.

What are key features and risk factors for thyroid cancer?

Single thyroid nodule, possible cervical lymphadenopathy, hoarseness; radiation exposure in childhood; higher prevalence in women; metastasis via lymphatics.

What are the typical symptoms of new-onset Type 1 Diabetes in children and adolescents?

Polydipsia, polyuria, weight loss, polyphagia (abnormally strong, incessant sensation of hunger); blurred vision; fruity breath and ketonuria; DKA can occur; peaks at ages 4–6 and 10–14.

What is the basic concept of negative feedback in the endocrine system?

Low active hormones increase production; high hormone levels suppress production; hypothalamus stimulates anterior pituitary to release stimulating hormones for target organs.

What are the main hormones produced by the anterior pituitary and their target organs?

FSH/LH/TSH stimulate ovaries/thyroid; GH stimulates somatic growth; ACTH (Adrenocorticotropic hormone ) stimulates adrenals to produce cortisol/aldosterone; Prolactin affects lactation; MSH (melanocyte-stimulating hormones) influences melatonin production.

Where is the pituitary gland located and what are its two lobes called?

Located at the sella turcica; two lobes: anterior (adenohypophysis) and posterior (neurohypophysis).

What is the role of the parathyroid glands?

Produce parathyroid hormone (PTH) to regulate calcium balance via bones, kidneys, and GI tract.

What is the pineal gland’s primary function?

Produces melatonin to regulate the sleep–wake cycle; darkness increases and light suppresses melatonin.

What is Addison’s disease and what causes it?

Primary adrenal insufficiency with mineralocorticoid and glucocorticoid deficiency, often autoimmune destruction of the adrenal gland.

What constitutes an adrenal crisis, and what is the initial management?

Acute cortisol deficiency causing shock; immediate IV fluids and glucocorticoid administration (e.g., IV hydrocortisone) with intensive supportive care.

What tests establish a diagnosis of primary vs secondary/tertiary adrenal insufficiency?

Serum ACTH, renin, cortisol, and aldosterone; ACTH stimulation test (250 mcg) to exclude primary insufficiency; CRH (Corticotropin-Releasing Hormone) testing differentiates secondary from tertiary.

What is Cushing’s syndrome and how is it distinguished from Cushing’s disease?

Cushing’s syndrome is hypercortisolism from any cause; Cushing’s disease is ACTH excess from a pituitary source (often tumor). Iatrogenic Cushing’s is due to exogenous glucocorticoids.

What are characteristic clinical features of Cushing’s syndrome?

Moon face, buffalo hump, facial plethora, striae, weight gain, edema, hirsutism, HTN, glucose intolerance, osteoporosis risk.

Which laboratory findings are commonly seen in Cushing’s syndrome?

Electrolyte abnormalities like hypokalemia and hypernatremia; hyperglycemia; leukocytosis; elevated cortisol/ACTH depending on cause.

What are the first-line tests used to screen for Cushing’s syndrome?

Late-night salivary cortisol, 24-hour urinary free cortisol, or overnight 1 mg dexamethasone suppression test.

What is the goal of Cushing’s treatment?

Reverse signs/symptoms and comorbidities by normalizing cortisol; eradicate tumor if present; taper exogenous steroids if iatrogenic.

What are the typical symptoms of both Addison’s disease and Cushing’s syndrome to distinguish them clinically?

Addison’s: hyperpigmentation, orthostatic hypotension, salt craving; Cushing’s: moon face, central obesity, striae, HTN.

What is the primary difference between Type 1 and Type 2 Diabetes Mellitus in terms of pathophysiology?

Type 1: autoimmune destruction of pancreatic beta cells with insulin deficiency; Type 2: insulin resistance with impaired insulin secretion over time.

What are the key risk factors and prevalence features of Type 2 Diabetes Mellitus?

BMI ≥25 kg/m2 (≥23 in Asians); family history; central obesity; sedentary lifestyle; HTN; dyslipidemia; CKD; majority of cases (>90% in U.S.).

What constitutes Metabolic Syndrome and how many criteria are needed for diagnosis?

A cluster of conditions that increases the risk of heart disease, stroke and diabetes requiring three of the following for diagnosis: abdominal obesity; HTN (≥130/85 or treatment); TG ≥150 mg/dL; HDL <40 (men) or <50 (women); fasting glucose ≥100 mg/dL.

What defines prediabetes and the criteria used to identify it?

A blood sugar level that is higher than what's considered healthy, but not high enough to be type 2 diabetes. A1C 5.7–6.4%; fasting glucose 100–125 mg/dL; 2-hour OGTT 140–199 mg/dL.

What are the diagnostic criteria for diabetes mellitus?

A1C ≥6.5% or FPG ≥126 mg/dL or classic hyperglycemia symptoms with random glucose ≥200 mg/dL or 2-hour OGTT ≥200 mg/dL.

What are key monitoring tests and preventive care recommendations for diabetes management?

A1C every 2–3 months until controlled, then every 6–12 months; lipid panel; urine albumin excretion; electrolytes and thyroid function; vaccines and BP targets.

What is metformin’s (biguanide) role in Type 2 DM and what are its notable considerations?

First-line agent that decreases gluconeogenesis and intestinal glucose absorption and improves insulin sensitivity; watch for GI effects and B12 deficiency; hold with IV contrast (48 hours before/after).

What are common sulfonylureas and their safety considerations?

‘ides’- First-gen: chlorpropamide (not commonly used due to hypoglycemia risk); second-gen: glipizide, glyburide, glimepiride; risk of hypoglycemia and weight gain; hepatic/renal function monitoring.

What are thiazolidinediones (TZDs) and their cautions?

‘glitazones’- Actos (pioglitazone) and Rosiglitazone (Avandia); improve insulin sensitivity but cause fluid retention/edema, weight gain, liver function concerns, and are contraindicated in NYHA class III/IV HF.

What are GLP-1 receptor agonists and their major benefits and risks?

‘tides'- Exenatide and liraglutide; promote weight loss and may reduce CV risk; GI side effects; potential pancreatitis; avoid in personal/family history of medullary thyroid carcinoma or Multiple endocrine neoplasia, type 2 (MEN2- inherited disorder that causes tumors in hormone-making glands); little hypoglycemia risk alone.

What are SGLT2 inhibitors and their main effects and precautions?

‘gliflozins'- Canagliflozin, dapagliflozin, empagliflozin; promote glucosuria, reduce CV events and CKD progression; risks include polyuria, genital infections, volume depletion, and caution with frequent UTIs or fracture risk; monitor renal function.

What are DPP-4 (dipeptidyl peptidase 4) inhibitors and their clinical use?

‘gliptins’- Sitagliptin, saxagliptin, linagliptin, alogliptin; increase incretin effect and insulin secretion; not first-line; potential joint pain, rare CV risks; caution in CKD.

What is pramlintide and when is it used?

Amylin analog; slows glucagon secretion and gastric emptying; induces satiety and weight loss; used with mealtime insulin in Type 1 or Type 2; boxed warning for severe hypoglycemia with insulin.

What are the core prandial and basal insulin types and their onset/duration characteristics?

Prandial: rapid-acting analogs (lispro/aspart/glulisine) with onset 15–30 min; Regular insulin with onset ~30 min; Basal: glargine and detemir with long duration ~23hrs; NPH is intermediate-acting.

What is the role of insulin pumps and injection sites in diabetes management?

Pumps require training and can improve glycemic control; injections can be given in abdomen, leg, arm, or buttock with fastest absorption from the abdomen; rotate sites.

What is the standard insulin dosing principle for understanding meals versus basal needs?

Rapid-acting insulin covers meals (bolus); regular covers meals in some regimens; NPH covers basal needs (breakfast to dinner); glargine/detemir provide once-daily basal coverage.

What are the general targets for nonpregnant adults with diabetes regarding A1C, fasting glucose, and postprandial glucose?

A1C ≤7% (individualize; ≤8% acceptable in some); fasting glucose 80–130 mg/dL; postprandial glucose <180 mg/dL (2 hours after meals).

What is the recommended approach to exercise and hypoglycemia risk in diabetes management?

Exercise increases glucose utilization; monitor glucose more frequently; consume simple carbs before exercise and complex carbs after to prevent post-exercise hypoglycemia.

What is the dawn phenomenon in diabetes care, and how is it assessed?

Early-morning hyperglycemia due to growth hormone surge at night; assess glucose patterns 3–4 hours after last meal and around 3 a.m. to determine if insulin dosing needs adjustment.

What are key signs of diabetic retinopathy and the screening intervals for type 1 and type 2 DM?

Neovascularization, microaneurysms, cotton-wool spots, hard exudates; Type 1 screen after age 10; Type 2 at diagnosis; subsequent exams every 6–12 months.

What are the essential diabetic foot care practices?

Wear protective footwear, podiatrist annual check, daily foot inspection, proper nail trimming, report redness or trauma immediately; assess neuropathy with monofilament and vibration testing.

What is Charcot’s foot and its significance in diabetes?

Neuropathic arthropathy causing deformity of the foot due to loss of sensation and abnormal joint/bone integrity.

What are typical thyroid storm features and the urgency of management?

Life-threatening thyrotoxicosis with rapidly rising HR, BP, and temperature; altered mental status; requires immediate hospitalization and treatment.

What are the main diagnostic markers for Graves’ disease?

Very low TSH with high free T4 and T3; TRAb (TSH-Receptor Antibodies)/TSI (Thyroid-Stimulating Immunoglobulin) positive; TPO antibodies may be positive; exam may show exophthalmos and lid lag.

How is hyperthyroidism diagnosed and what tests differentiate Graves’ from other causes?

Low TSH with elevated T4/T3; TRAb/TSI positive for Graves; TPO antibodies may be positive; RAIU (Radioactive Iodine Uptake) helps distinguish Graves from toxic multinodular goiter or adenoma.

What are the first-line medications for hyperthyroidism and their key considerations?

Methimazole (Tapazole) or propylthiouracil (PTU); PTU preferred in the first trimester; monitor CBC and LFTs for side effects; beta-blockers for symptom control; consider radioactive iodine therapy.

What is the role of beta-blockers in hyperthyroidism management?

Adjunctive treatment to alleviate symptoms such as tachycardia, palpitations, and tremor while thyroid hormone levels are controlled.

What is Radioactive Iodine (RAI) therapy in hyperthyroidism and its major consequence?

Permanent destruction of the thyroid gland leading to lifelong hypothyroidism requiring thyroid hormone replacement.

What are common thyroid imaging and biopsy procedures used in evaluation?

Ultrasound for goiter/nodules; fine-needle aspiration biopsy for cancer diagnosis; thyroid scan with RAIU to characterize nodules.

What are the typical laboratory findings to distinguish hypothyroidism from subclinical hypothyroidism?

Overt hypothyroidism: high TSH with low free T4; subclinical hypothyroidism: elevated TSH with normal free T4.

What antibodies are most commonly evaluated in Hashimoto’s thyroiditis and Graves’ disease?

Hashimoto’s: TPO antibodies commonly positive; Graves’: TRAb/TSI and TPO can be positive.

What is the standard dosing strategy for levothyroxine (Synthroid) in adults with overt hypothyroidism?

Average replacement is about 1.6 mcg/kg/day (range 50–200+ mcg/day); start at 25–50 mcg/day in older patients or those with cardiovascular disease; adjust every 4–6 weeks until TSH normalizes.

How often should TSH be checked once thyroid hormone therapy stabilizes, and what is the target TSH range?

Recheck every 6–12 months when stable; target TSH approximately 0.4–4.0 mU/L, with adjustments made to keep TSH in the normal range.

What is Armour thyroid and when might it be considered?

Desiccated thyroid (pork thyroid) containing both T3 and T4; considered by some as an alternative to synthetic levothyroxine, but not first-line.

What are common causes of primary hypothyroidism besides Hashimoto’s thyroiditis?

Postpartum thyroiditis (within 1yr of pregnancy, miscarriage or abortion) and thyroid ablation with radioactive iodine; medication effects (e.g., lithium, amiodarone) can also affect thyroid function.

What is subclinical hypothyroidism, and how should it be managed in older adults?

Elevated TSH with normal free T4; management is individualized; often observe and recheck rather than treat aggressively in older adults.

What is the typical approach to diagnosing subclinical hypothyroidism with regard to TSH and free T4 testing?

If TSH >5.0 mU/L, obtain free T4 to assess whether overt or subclinical hypothyroidism is present and guide treatment.

What is the typical long-term goal for levothyroxine therapy in terms of patient education and monitoring?

Educate patients to report palpitations or tremors; maintain TSH in normal range; use consistent dosing and avoid abrupt changes; ensure proper absorption (e.g., take on an empty stomach).

What are common presentation features of Graves’ ophthalmopathy?

Lid lag, exophthalmos, periorbital edema, and occasionally diplopia due to extraocular muscle involvement.

What is the role of TSH in thyroid disease testing and management?

TSH is the primary screening and monitoring test; levels guide dosing of thyroid hormone and assessment of treatment response.

What is the recommended vaccination and preventive care plan for adults with diabetes?

Influenza, pneumococcal, Tdap, hepatitis B, zoster vaccines, and COVID-19 vaccines as indicated; regular eye, foot, and dental care; BP and lipid management.

What is the general rule for addressing hyperglycemia during illness or surgery in diabetes?

Do not stop antidiabetic medications; closely monitor glucose; adjust doses as needed; ensure hydration and electrolyte balance.