Endocrinology LD Overview

thyroid nodule dx

Initial

-TSH: low = hot, normal/high = cold (malignant)

-free T4

-thyroid ultrasound

-malignancy reg flag: size >1cm, irregular margin, taller than wide, hypoechoic

Confirmatory

-fine needle aspiration biopsy

-radioactive iodine uptake scan

Classification

-TIRADS score used to guide decision on FNA biopsy = score >3

-Bethesda are the results obtained from FNA

thyroid cancer dx

Initial

-TSH: low = hot, normal/high = cold (malignant)

-free T4

-thyroid ultrasound

-malignancy reg flag: size >1cm, irregular margin, taller than wide, hypoechoic

Labs

-serum calcitonin = elevated in medullary thyroid carcinoma

-serum thyroglobulin = elevated in most metastatic papillary and follicular tumors

Confirmatory

-fine needle aspiration biopsy

-radioactive iodine uptake scan

-PET scan, TNM staging

MEN syndrome dx

Genetic testing

-MEN 1: MEN1 gene

-MEN 2: RET proto oncogene

-early testing is crucial

pheochromocytoma dx

Labs

-plasma fractionated free metanephrines = elevated

Confirmatory

-urinary fractionated metanephrines = elevated

Imaging

-non contrast CT scan

-never perform needle biopsy

parathyroid carcinoma dx

Labs

-serum calcium and PTH levels = elevated

Imaging

-initial: neck ultrasound

Confirmatory

-histopathology

adrenal adenomas dx

Inital

-presenting signs and symptomas

Imahing

-CT scan: well circumscribed, homogenous, low attenuation

hypercalcemia of malignancy dx

Labs

-total calcium and ionized calcium = elevated

-low or normal PTH

-PTHrP = elevated (confirmatory)

Imaging

-aimed at identifying underlying malignancy

Cushing syndrome dx

-exclude the presence of endogenous glucocorticoid intake or other disease that cause hypercortisolism

First line

1. bedtime salivary cortisol: elevated

-2 swabs and collect saliva, done 2 nights after 10-11pm

2. 24 hour urinary free cortisol excretion: elevated

-collect urine, elevated on 2 separate occasions

3. overnight low dose dexamethasone suppression test: abnormal

-suppressed = rule out cushing

-if abnormal use high dose dexamethasone test: partially suppressed = pituitary cause, unsuppressed = ectopic

Once hypercortisolsm is confirmed

-plasma ACTH level = high (Cushing disease)

-plasma ACTH level = low (Cushing syndrome)

-serum DHEA level: ACTH dependent

Imaging

-MRI brain/pituitary to find tumor as a cause

primary adrenal insufficiency dx

Initial

-total serum cortisol between 6-8am: low = adrenal insufficiency

-intermediate level = move on to confirmatory

-high level = rule out

-plasma ACTH

Confirmatory

-ACTH stimulation test: lack of rise = primary

- IV 250mg dose of ACTH (Cosyntropin), measured at 0, 30, 60min

Supportive

-serum electrolytes: hyponatremia, hyperkalemia, hypoglycemia

-plasma renin activity and aldosterone levels

Etiology

-21 hydroxylase antibodies = + for autoimmune

-T scan of adrenal gland

-TB test

-HIV testing

secondary adrenal insufficiency dx

Initial

-total serum cortisol between 6-8am: low = adrenal insufficiency

-intermediate level = move on to confirmatory

-high level = rule out

-plasma ACTH

Confirmatory

-ACTH stimulation test: normal = secondary

- IV 250mg dose of ACTH (Cosyntropin), measured at 0, 30, 60min

acute adrenal crisis dx

-measure serum cortisol and plasma ACTH

-hypotension + low serum cortisol = suggestive of crisis

-serum ACTH = elevated for primary AI and low for secondary AI

-other labs: Hyperkalemia, Hyponatremia, Hypoglycemia

congenital adrenal hyperplasia dx

Prenatally

-newborn screening serum 17 hydroxyprogesterone

Postnatally

-serum 21 hydroxylase deficiency testing

hyperaldosteronism dx

Primary

-plasma aldosterone concentration = elevated

-plasma renin activity = low

-PAC:PRA (aldosterone/renin) ratio = elevated

-all antihypertensives should be stopped before testing

Secondary

-plasma renin activity = elevated

-most common cause is diuretic therapy

Confirmation

-24 hour urine aldosterone, sodium, creatinine

-fludrocortisone suppression test

-saline suppression testing

Imaging

-CT adrenals for adenoma or hyperplasia

type 1 DM dx

Step 1: suspicion

-classic sx + random glucose >200

-fasting glucose >126 (8 hour fast) = diagnosis

-2 hour glucose >200

-HbA1c >6.5 = diagnostic for MONITORING

Step 2: confirm

-anti-GAS antibodies (most common)

-anti-IA2

Step 3: assess Beta cell function

-C-peptide level = <0.6

-will distinguish T1 from T2

Step 4: rule out DKA

-serum or urine ketones = if present indicated DKA

-arterial blood gas

-BMP

GAD 65

-need to have everything else before ordering

-positive test indicates presence of autoantibodies which is characteristic of T1DM

islet autoantibodies

-appear when B cells are damaged

-can be used to estimate individuals risk of developing T1DM

Diabetic Ketoacidosis (DKA) dx

Step 1: assess DKA

-hyperglycemia: glucose >250

-pH <7.35

-serum ketones >3

Step 2: calculate anion gap

-anion gap = NA + (Cl + HCO3) = >10-12

Step 3: severity

-mild: 7.25-7.3, HCO3 15-18

-mod: 7.0-7.24, HCO2 10-14

-severe: <7, HCO3 <10

Step 4

-CBC, blood culture

-chest X ray, urinalysis

-ECG, lipase

when to check for ketones

-blood sugar >300

-nauseated and vomiting, abdominal pain

-cold or flu

-feel tired all the tome

Hyperosmolar Hyperglycemic State (HHS) dx

Step 1

-hyperglycemia: glucose >600

-hyperosmolality >320

-altered mental

-serum ketones <3

-pH >7.35

Step 2

-effective osmolality = 2(Na) + glucose/18

-320 confirms hyperosmolar state

-350 associated with coma

Step 3

-glasgow scale for mental status

-degree of dehydration

Step 4

-CBC, cultures, CMP, urinalysis, chest X ray, EC

hypoglycemia dx

Step 1

-glucose <70

-non diabetic <55 with sx

Step 2: Whipples triad

-sx consistent with hypoglycemia

-low plasma glucose concentration

-relief of sx with glucose administration

Step 3

-mild: patient can self treat

-mod: requires assistance but tolerate oral

-severe: parenteral therapy or glucagon

Step 4: etiology in non diabetics

-72 hour supervised fast = gold standard

-insulin, C peptide

-sulfonylurea, cortisol

dawn phenomenon dx

-check blood glucose at bedtime, 3am, upon waking

-pattern: normal bedtime > normal/elevated 3 am > elevated morning

-continuous glucose monitoring can confirm

Somogyi effect dx

-check blood glucose at bedtime, 3am, upon waking

-pattern: normal bedtime > low 3 am > elevated morning

-look for signs of nocturnal hypoglyecima

latent autoimmune diabetes in adults (LADA) dx

Step 1

-clinical suspicion

Step 2

-GAD antibodies > 10 = most common

-IA-2 antibodies

-ZnT8 antibodies

Step 3

-fasting C peptide

-fasting glucose >126

-HbA1c >7

metabolic syndrome dx

Presence of 3/5 criteria:

-elevated waist circumference >40 men, >35 women

-elevated triglycerides >150

-reduced HDL <40 men, <50 women

-elevated BP >135/85

-elevated fasting glucose >100

Tx for any of these criteria also counts

-FLP, HbA1c, BP, waist circumference

gestational diabetes dx

-all asymptomatic women screened 24 weeks

-50g screening test at 24-28 weeks >140 = abnormal

-if first test is abnormal then 100g 3 hour oral glucose test

-fasting >95

-1 hour >180

-2 hour >155

-3 hour >140

prediabetes dx

1. fasting plasma glucose = 100-125

2. 2 hour plasma glucose = 140-199

2. HbA1c = 5.7-6.4%

type 2 DM dx

1. fasting plasma glucose = >126

2. glucose tolerance = fasting >126 or 2 hour >200

-test of choice for gestational diabetes

3. HbA1c = >6.5

-diagnostic test of choice and monitor tx

4. random plasma glucose + sx = >200 + symptoms

type 2 DM screening

-tests used: fasting plasma glucose, 2 hour OGTT, HbA1c

Universal screening

-35 for all adults every 3 years for normal results

High risk: earlier and more often

-BMI >25 and

-first degree relative, africans, hx of CVD, HDL <35, PCOS, physically inactive, gestational diabetes, prediabetes, HIV, antipsychotic therapy

Children

-start at 10 or onset of puberty in overweight

-if normal screen every 3 years

diabetic retinopathy dx

Dx

-fundoscopic dilated eye exam

-annual screening in diabetic patients

diabetic nephropathy dx

Dx

-decreased renal function + proteinuria + hx of DM

-urine albumin-creatinine ratio

-screening yearly: goal <30

diabetic neuropathy dx

Dx

-comprehensive foot exam

-screening yearly foot exam

-skin inspection, pulses, ankle reflexes, proprioception of great toe, vibratory sensation, monofilament exam

cardiovascular complication dx

Dx

-blood pressure screening at every visit <130/80

-lipid screening: dx at <40 > at dx and every 5 years

peripheral artery disease dx

Dx

-ankle brachial index, angiography

diabetic foot ulcer

-neuropathy, vascular insufficiency, infection

Prevention

-regular foot exam

-full monofilament exam yearly

hyperparathyroidism dx

Initial workup

-serum calcium, serum PTH, phosphorus

-serum 25(OH)vitD, serum creatinine, 24 hour urine

-DEXA scan, renal US or CT

Primary

-increase PTH + increase calcium + decrease phosphorus

Secondary

-increase PTH, low to normal calcium + increase phosphorus and vit D

Tertiary

-increase PTH + increase calcium

Primary hyperparathyroidism dx

Step 1

-BMP shows elevated calcium levels >10.2

-Paynes formula

Step 2

-PTH level = elevated

-confirmatory

Step 3

-parathyroid ultrasound to show parathyroid adenoma

-Vit d levels

secondary and tertiary hyperparathyroidism dx

Secondary

-elevated PTH + low or normal Ca + high phosphorus (due to impaired phosphate excretion by kidney)

-vit D levels

Tertiary

-elevated PTH + high Ca

-loss of normal feedback loop

Other labs

-serum creatinine, eGFR

-urinary calcium and phosphate

-ALP level

hypoparathyroidism dx

Labs

-low calcium + high phosphorus + low PTH

-24 hour urine calcium

-genetic testing for DiGeorge

-DEXA, CT/MRI

-EKG

DiGeorge Syndrome

-22q11.2 deletion syndrome

-parathyroid glands fail to develop properly or absent

Sx

-cardiac anomalies, abnormal facies, thymic hypoplasia, cleft palate, hypocalcemia

-CATCH-22

Tx

-lifelong calcium and Vit D

-regular monitoring of calcium

-thymic transplant

hypothyroidism dx

-TSH = high

If abnormal

-free T4

-if decreased = overt hypothyroidism

-if normal = subclinical hypothyroidism

Once diagnosis is confirmed establish etiology

-TPO and Tg antibodies

-present in 95% of patients with autoimmune hypothyroidism

Imaging

-not a primary tool used to assess structure

-first: ultrasound

-thyroid scintigraphy for functional status

congenital hypothyroidism dx

-TSH testing screening in newborns

-serum TSH, T4

autoimmune Hashimoto thyroiditis

-cell mediated and antibody mediated destruction of thyroid gland

-autoantibodies against thyroid peroxidase, thyroglobulin, TSH receptor

Subclinical hypothyroidism

-compensation phase: normal thyroid hormones are maintained to rise TSH

-later unbound T4 levels fall and TSH level rise further > sx become apparent

hyperthyroidism dx

Labs

-low TSH

-free T4 ordered when TSH is abnormal = high

Determine etiology

-thyroid stimulating immunoglobin

-radioactive iodine uptake scan (scintigraphy) = general hig uptake suggest Grave disease

-US for pregnant

-if Graves: TSI and TRAb antibodies

thyroiditis

-most common: chronic Hashimoto thyroiditis

-postpartum thyroiditis and subacute lymphocytic thyroiditis > transient hyperthyroidism

-TPO antibodies or Tg antibodies = high

painful subacute thyroiditis dx

Dx

-antithyroid antibodies = low, ESR = elevated

-hyperthyroid > euthyroid > hypothyroid > euthyroid

-biopsy = multinucleated giant cells

infectious suppurative thyroiditis dx

Dx

-febrile with leukocytosis

-elevated ESR

-thyroid function = normal

IgA related thyroiditis

-replacement of thyroid tissue with fibrosis tissue > thyroid gland become form and fixed

Sx

-hypothyroidism

-difficulty swallowing

-hard woody thyroid gland

Tx

-thyroid hormone replacement

-surgery for severe cases

acromegaly dx

Labs

-first line: serum IGF-1 level = elevated

Confirmatory

-oral glucose tolerance test with GH measurement = GH fails to suppress

Imaging

-MRI pituitary to assess for pituitary adenoma

-visual field testing

gigantism dx

-clinical suspicion

Labs

-IGF-1 levels = elevated

-GH suppression test = failure to suppress

-genetic testing

Imaging

-MRI pituitary for pituitary adenomas

-visual field testing

-bone assessment

dwarfism dx

Labs

-FGFR3 mutation

-IGF-1 levels

-GH stimulation test

-thyroid function test, CBC, CMP

Imaging

-US: width to femur length ration = higher

-Xray/MRI/CT: small flat squared iliac wings, large skull, shortened vertebral body

pituitary adenoma dx

Labs

-prolactin, GH, IGF-1

-TSH, free T4, ACTH, cortisol

-FSH, LH, testosterone

Imaging

-gold standard: MRI pituitary with gadolinium

hypopituitarism dx

Labs

-8 am cortisol, ACTH

-TSH, free T4

-FSH, LH, testosterone, prolactin, IGF-1

-insulin tolerance test = gold standard for GH and ACTH

Imaging

-MRI pituitary with godolinium

hyperpituitarism dx

Labs

-prolactin = elevated

-GH = IGF level, OGTT, GH measurement

-ACTH = 24 hour urine cortisol, dexamethasone suppression test

-TSH = elevated

prolactinomas dx

Labs

-serum prolactin = 200 strongly suggests prolactinoma

-pregnancy test, TSH, free T4, CMP

Imaging

-MRI pituitary with gadolinium

diabetes insipidus dx

Labs

-24 hour urine volume, serum osmolality and sodium

-urine volume >3L

-urine osmolality <300, serum osmolality >295

-gold standard = water deprivation test <300

Desmopressin stimulation test

-central = >50% increase in urine osmolality

-nephrogenic = <50% increase in urine osmolality

Imaging

-MRI brain with gadolinium

SIADH dx

Schwartz-Bartter criteria

-serum sodium <135

-serum osmolality <275

-urine osmolality >100

-urine NA >30

-clinical euvolemia

-normal renal, adrenal, thyroid function

-rule out meds

Imaging

-identify underlying cause

male primary hypogonadism dx

Step 1

-total testosterone = <200

-free testosterone = 18-60 <35, >70yo <30

-free and total testosterone = low

-nonfasting in the morning

Step 2

-differentiate primary from secondary

-serum LH = high

Step 3

-karyotype for klinefelter's

-serum prolactin = normal in primary

male secondary hypogonadism dx

Step 1

-total testosterone = <200

-free testosterone = 18-60 <35, >70yo <30

-free and total testosterone = low

-nonfasting in the morning

-repeat

Step 2

-differentiate primary from secondary

-serum LH = low

Step 3

-serum PRL: elevated if prolactinoma present

-MRI of pituitary/hypothalamus to search for lesion

females hypogonadism dx

Step 1

-primary = elevated FSH/LH, low estrogen

-secondary = low FSH/LH, low estrogen

Step 2

-primary: karyotypes, ultrasound

-secondary: serum prolactin, MRI of pituitary/hypothalamus