Endocrinology

Question 1

adrenal carcinoma and adrenal insufficiency

Answer 1

• rare, excess production of steroids and adrenal androgen precursors
• sxs: cushing syndrome-like presentation, virilization
• dx: CT with contrast, FNA not indicated
• tx: early detection and complete surgical removal (adrenalectomy), adjuvant tx with mitotane (especially if >8cm, vascular invasion or Ki67 index >10%), steroid replacement, mets to liver and lung
• hyperpigmentation is most pronounced in skin areas exposed to increased friction or shear stress and is increased by sunlight
• hyponatremia is primarily caused by mineralocorticoid def but can also occur in secondary adrenal insuff dt diminished inhibition of antidiuretic hormone (ADH) release by cortisol, resulting in mild SIADH

Question 2

fatigue

Answer 2

• difficulty or inability to initiate activity and is a perception of generalized weakness
• associated with: concentration and memory difficulties, emotional fatigue/stability
• psychologic: depression, anxiety, somatization disorder, malnutrition or drug addiction
• pharmacologic: hypnotics, antiHTN med, antidepressants, drug abuse and withdrawal
• endocrine-metabolic: hypothyroid, DM, apathetic hyperthyroid, pit insuff, hypercalc, adrenal insuff, chronic renal failure, hepatic failure
• neoplastic-hematologic: occult malig, severe anemia
• infectious: endocarditis, TB, mono, hep, parasitic dz, HIV, CMV
• cardio: chronic HF, COPD
• connective tissue: rheumatoid arth
• disturbed sleep: sleep apnea, esophageal reflux, allergic rhinitis, psych causes
• idiopathic: idiopathich chronic fatigue, chronic fatigue syndrome, fibromyalgia

Question 3

heat and cold intolerance

Answer 3

• heat intolerance ddx: hyperthyroidism
• cold intolerance ddx: myxedema (hypothyroidism
  
  • myxedema coma: rare condition, precipitating factors (cold exposure, infxn, trauma, narcotics)
    
    • sxs: depressed state of consciousness, profound hypothermia, resp depression
    • tx: supportive tx for BP and breathing, IV thyroxine, IV hydrocortisone
    • high mortality rate (50-75%)

Question 4

palpitations

Answer 4

• ddx: hyperthyroid, pheochromocytoma

Question 5

tremors

Answer 5

• ddx: hyperthyroidism, thyrotoxicosis
  
  • mcc thyrotoxicosis = grave’s dz
    
    • 80%, metabolically active gland, MCC of hyperthyroidism, mostly younger women with other autoimmune conditions, Autoimmune (thyroid stimulating IgG Ab binds TSH receptors on surface o f thyroid cells triggering synthesis of excess thyroid hormone)
    • sxs: pretibial myxedema, exophthalmos (periorbital edema, diplopia, or proptosis), thyroid bruit, diffusely enlarged, symmetric, nontender gland
    • dx: measurement of thyroid Abs (anti-TPO high, TSI high), scintigraphy (diffuse uptake)
    • tx: antithyroid meds, radioactive iodine preferred, saline eye drops and tight fitting sunglasses, high dose steroids with orbital decompresison surgery and ocular radiation tx for severe exophthalmos

Question 6

hyperthyroidism

Answer 6

• associated: afib
• subclinical hyperthyroidsim = low TSH, normal T3/T4
• sxs: anxiety, insomnia, irritability, palps, wt loss, heat intolerance, sweating, D, increased freq, oligomen, tremor, hyperactivity, tremulousness
• signs: moist skin, tachycardia, hyperreflexia, flushed, diaphoretic, wide pulse pressure
• dx: Primary hyperthyroid - TFTs (TSH low, total T3 high, free T4 high)
  
  • ​autoantibody tests (antithyroid peroxidase Ab, TS-immunoglob
  • scintigraphy (thyroid scan) - if etiology unclear after initial labs
• tx: propranolol, methimazole, propylthiouracil (can . use in preg and thyroid storm), RAI tx, thyroidectomy

Question 7

hypothyroidism

Answer 7

• primary: failure of thyroid to produce sufficient T3 (iatrogenic - prior tx of hyper thyroid, hashimotos)
• secondary: hypothyroid dt pituitary dz, low TSH/free T4
• tertiary: dt hypothal dz (TRH def), low TSH/free T4
• associated: carpal tunnel syndrome
• sxs: constipation, fatigue, lethargy, weakness, wt gain, depression, menorrhagia, cold intolerance, cramps, slow mentation, inability to concentrate, dull expresion, m weakness, arthralgias, hoarseness
• signs: dry, rough skin, coarse hair, palpable enlarged thyroid, brittle nails, puffy face and eyelids, yellowing of skin (carotenemia), decreased DTRs
• dx: thyroid fn tests
  
  • primary: high TSH (most sensitive)
  • secondary: low TSH
  • tertiary: low TSH
  • free T4 low in clinically overt
  • Ab testing, CBC (normocytic anemia MC)
• tx: levothyroxine (T4) → effects in 2-4wk →monitor TSH and clinical state periodically

Question 8

hyperparathyroidism etiology and sxs

Answer 8

• Primary: one or more glands produce inappropriate PTH relative to Ca2+
  
  • MCC: parathyroid adenoma
• secondary: high PTH and low or nl Ca2+
  
  • MCC: chronic renal failure, vitD def, renal hypercalciuria, most found incidentally by hypercalcemia on routine labs, most F>50
• sxs: most asxatic; stones, bones, groans, psychiatric overtones
  
  • stones: nephrolithiasis, frequent urination
  • bones: body aches and pains, osteitis fibrosa cystica (brown tumors - predisposes to fx), weakness
  • groans: abdominal pain, constipation, N/V/A
  • psychiatric overtones: depression, fatigue, anorexia, sleep disturbance, anxiety, lethargy
• signs: HTN, dec DTRs

Question 9

hyperparathyroidism dx and tx

Answer 9

• dx: serum Ca2+ HIGH, serum phosphate LOW, serum PTH HIGH (first line)
  
  • total and ionized Ca2+ high, alb low, urine caAMP high
  • XR: subperiosteal bone resorption, osteopenia
• tx: if serum Ca2+ >12 - IV fluid resuscitation; otherwise follow up
  
  • primary: BB, k-phos supplement, dietary calcium restriction, bisphosphonates, calcimimetic agents (calcinet), parathyroidectomy
  • secondary: 400IU vitD (calcitriol) daily for vitD deficiency (annual Ca and Cr measurements, annual KUB for stones, DEXA q2-3y), PO Ca, dietary phos restriction for renail failure

Question 10

pheochromocytoma etiology, sxs

Answer 10

• rare, secrete catecholamines from adrenal medulla, arise from chromaffin cells (adrenal medulla) or from sympathetic ganglia (extrarenal)
• associated with MEN 2A and MEN 2B, von recklinghausen neurofibromatosis, von hippellindau dz
• sxs: paroxysms of HA, profuse sweating, palps, wt loss, feelings of warmth along with episodic (later sustained) hypertension, sometimes severe, feeling of impending doom
• signs: tachycardia

Question 11

pheochromocytoma dx and tx

Answer 11

• dx: 24h urine metanephrines, plasma mets > urine mets, CT or MRI, glucosuria, hyperlip, hypokalemia, hypercalcemia
• tx: give clonidine if equivocal results, tumor resection with ligation of venous drainage (laparoscopic adrenalectomy) - alpha blockers (phenoxybenzamine x10-14d prior to surgery to control BP and replete intravascular volume), beta blockers - propranolol 2-3d prior to surgery to control HR
  
  • fatal if left undiagnosed and treated

Question 12

thyroid nodules

Answer 12

• cancer found in 4-10% of investigated nodules
• sxs: fixed nodule without mvmt on swallowing (firm, irregular), hx of radiation tx to neck or family hx, rapid progression, obstructive sxs = vocal cord paralysis, dysphagia, odynophagia
• signs: must be >1cm to be palpable on exam
• dx: thyroid tests (TSH, T3, T4, serum calcitonin high), thyroid US (only differentiates solid vs cystic), FNA bx (even if clinically and chem euthyroid, if palpable or >1.5cm, only reliable test that differentiates benign vs malig, reliable for all cancers, except follicular - if indeterminate - RAI uptake
• tx: benign - observe 1y, fu with US, radioactive iodine tx (prefer if <40y and reliable for lifetime T4 - levothyroxine; for overactive thyroid w/o risk of subsequent cancer, leukemia, or other malig), thyroidectomy (cold nodules)

Question 13

thyroid cancer - differentiated papillary thyroid carcinoma

Answer 13

• F>M 3:1
• MC type (80-90%), least aggressive, slow growth and spread
• RF: hx of radiation to head/neck, papillary cancers are characterized histologically by psammoma bodies
• sxs: typically found incidentally on exam - thyroid nodule
• dx: TSH normal, T3/T4 normal, thyroid US differentiates solid vs cystic, FNA required for dx (psammoma bodies), RAI uptake +
• tx: total thyroidectomy with limited cervical lymph node removal
  
  • complications: vocal cord paralysis, hypoparathyroidism (hypocalcemia), hypothyroid
  • postop radioactive iodine ablation tx
  • spreads via lymphatics in neck, metastasizes to cervical lymph nodes

Question 14

medullary thyroid carcinoma

Answer 14

• neuroendocrine tumor of the parafollicular or C cells of the thyroid gland, 3-5% of thyroid carcinomas
• associated with familial syndromes in about 1/3 of the cases (MEN 2A or 2B)
• sxs: dysphagia, hoarseness, diarrhea, facial flushing
• signs: palpable solitary thyroid nodule (MC presentation) in upper portion of thyroid lobe, cervical lymph nodes palpable
• dx: US of neck (hypoechoic microcalcifications), labs (calcitonin elevated, CEA), FNA bx (diagnostic), genetic testing for germline RET mutations
• tx: total thyroidectomy most commonly recommended
  
  • thyroxine tx started immediately post-op to maintain euthyroidism
• health maintenance: measure serum calcitonin and CEA 2-3mos after surgery to ro residual dz (if undetectable, measure levels twice yearly x2y, then annually if stable, neck US 6-12mo postop