Endocrine review

1. Endocrine review Topics: thyroid, parathyroid, adrenals, pancreas, miscellaneous

2. A 40 y/o man presents with weakness and easy fatigability of 2 months duration. PE is unremarkable. Lab studies show serum calcium of 11.5, inorganic phosphorous 2.4, and high serum PTH level of 58. A radionuclide bone scan fails to show any areas of increased uptake. Which of the following is the most likely cause of these findings? • A) Chronic renal failure • B) Parathyroid adenoma • C) Parathyroid carcinoma • D) Parathyroid hyperplasia • E) Hypervitaminosis D • F) Medullary thyroid carcinoma

3. Hyperparathyroidism • The answer is B • Primary hyperparathyroidism • Most common cause is a pituitary adenoma. Increased PTH causes an elevation in calcium and a decrease in phosphate levels • STONES, BONES, GROANS, AND PSYCHIC OVERTONES • Osteitisfibrosacystica- bone pain and brown tumors • Secondary hyperparathyroidism • Chronic renal disease (beware of a DM patient in q stem) causes retention of phosphorous which drives calcium levels down and PTH secretion up parathyroid hyperplasia • LOW calcium levels, HIGH phosphate due to retention

4. A 50-year-old man has been diagnosed with a follicular neoplasm of the thyroid. He undergoes a total thyroidectomy. Within a day following surgery, he is noted to have tingling sensations and neuromuscular irritability. Which of the following serum laboratory tests should be ordered immediately to determine further therapy for this man? • A) TSH • B) Parathormone • C) Total thyroxine • D) Ionized calcium • E) Calcitonin • F) Iodine

5. Hypoparathyroidism • The answer is D • The parathyroids can be inadvertently removed or traumatized with thyroid surgery, resulting in post-operative hypocalcemia • Patients will have LOW serum calcium leading to tetany (remember DiGeorge syndrome or thyroid surgery) • Chvostek’s sign and Trousseau’s sign, carpopedal spasm • Pseudohypoparathyroidism • AD condition where the kidney does not respond to PTH leading to increased PTH • Pts will have shortened stature and shortened 4th/5th digits and MR

6. A 27 y/o woman experienced sudden severe abdominal pain. On PE, she had marked abdominal tenderness and guarding. Labs: serum glucose 76, calcium 12.2, phosphorous 2.6, parathyroid hormone 62. During surgery 4 enlarged parathyroid glands were removed. After surgery her serum calcium returned to normal. Three years later she develops upper GI hemorrhage. An endoscopy and biopsy show multiple gastric ulcerations. Abdominal MRI shows multiple mass lesions in the pancreas. In surgery, multiple gastrinomas are found. Two years later she develops galactorrhea. Which of the following lesions is now most likely to be present? • A) Medullary carcinoma of the thyroid • B) Adrenal pheochromocytoma • C) Small cell anaplastic carcinoma of the lung • D) Endometrial carcinoma • E) Pituitary adenoma

7. MEN Syndrome • The Answer is E • The patient has MEN I syndrome • 3 P’s: pancreas (insulinoma, gastrinoma, VIPoma), parathyroid, pituitary (adenoma) • MEN IIA • Medullary carcinoma of thyroid, pheochromocytoma, parathroid • MEN IIB • Medullary carcinoma of thyroid, pheochromocytoma. mucosal neuromas, intestinal ganglioneuromas, marfanoidfeatures, delayed puberty • All are autosomal dominant

8. A 57-year-old man is found comatose. On physical examination he has decreased skin turgor. Laboratory studies show a blood glucose of 780 mg/dl. Urinalysis reveals no ketosis or proteinuria, though there is 4+ glucosuria. Which of the following is the most likely diagnosis? • A) Islet cell tumor secreting glucagon • B) Type I diabetes mellitus • C) Cushing syndrome • D) Ingestion of a large quantity of sugar • E) Type II diabetes mellitus

9. Diabetes complications • The answer is E • The complication of diabetes mellitus known as nonketotichyperosmolarcoma is most typical for type II diabetes mellitus • Most affected persons have increased insulin resistance, not an absolute lack of insulin secretion. Thus, there is NO ketoacidosis accompanying the hyperglycemia. • DKA is seen in DM I patients with an increased anion gap metabolic acidosis • Key is pts will have ELEVATED blood and urinary ketones

10. A 45 y/o man feels a small lump on the side of his neck. His doctor palpates a firm, painless, 1.5 cm cervical lymph node. The thyroid gland is not enlarged. Labs include serum glucose of 83, creatinine 1.2, calcium 9.1, phosphorous of 3.3, thyroxine 8.7, and TSH 2.3. A FNA of the thyroid gland is performed and the cells are examined microscopically. Which of the following is the most likely diagnosis? • A) Papillary carcinoma • B) Parathyroid carcinoma • C) Medullary carcinoma • D) Follicular carcinoma • E) Anaplastic carcinoma

11. Thyroid cancer • The answer is A • Papillary carcinoma • Most common • Psammoma bodies • LYMPHATIC INVASION • Follicular • HEMATOGENOUS SPREAD- mets to bone, lung, liver • Medullary • From C cells that make CALCITONIN and stain positive with Congo red staining • Anaplastic • BAD: Older patients; uncommon; poor prognosis

12. A 40-year-old woman notes increasing enlargement and discomfort in her neck over the past week. Her doctor palpates a diffuse, symmetrical enlargement with tenderness in the region of the thyroid gland. Thyroid function tests show serum TSH of 0.8 mU/L and thyroxine of 11.9 micrograms/dL. She is referred to an endocrinologist, but the next available appointment is in 8 weeks. When the endocrinologist examines the patient, the thyroid is no longer palpable and there is no pain. Repeat thyroid function tests reveal a serum TSH of 3.8 mU/L and thyroxine of 5.7 micrograms/dL. Which of the following thyroid diseases is most likely to produce these findings? • A) Toxic multinodular goiter • B) DeQuervain (subacute) thyroiditis • C) Hashimoto thyroiditis • D) Graves disease • E) Riedel thyroiditis • F) Iodine deficiency

13. Thyroiditis • The answer is B • Subacute (de Quervain’s) thyroiditis • Self-limited disease • Patients may initially be hyperthyroid, then hypothyroid, then euthyroid due to transient damage of thyroid follicles • Tenderthryoid and post-viral infection common • Decreased uptake on thyroid scan • Toxic multinodular goiter (Plummer syndrome) • Hyperfunctioning nodule within a goiter • Will not produce signs of inflammation. Increased levels of T3/T4 released and produced a HOT nodule on thyroid scan

14. A 2 y/o male child is brought to the doctor due to FTT. PE shows the child is short and has coarse facial features, a protruding tongue, and an umbilical hernia. Profound MR is apparent. A deficiency of which of the following hormones is most likely to explain these findings? • A) corstisol • B) norepinephrine • C) somatostatin • D) thyroxine • E) insulin

15. CRETINISM • The answer is D • Cretinism • Uncommon when there is routine testing and treatment at birth • Due to lack of maternal dietary iodine in pregnancy • Myxedema is the term used for older children and adults

16. A 46 y/o woman has experienced a feeling of fullness in her neck for the past year. Her energy level is decreased. Her thyroid gland is diffusely and symmetrically enlarged and non tender. She has dry, course skin and alopecia. The figure shows the microscopic appearance of the thyroid. Which of the following antibodies is likely to be found in this patients serum? • A) Antimitochondrial • B) Antithyroidperoxidase • C) Anti- double stranded DNA • D) Anti- Jo 1 • E) Anti-parietal cell • F) Anti- centromere • G) Anti- TSH R

17. Hashimotosthyroiditis • The answer is B • Hashimotosthyroiditis • + antithyroidperoxidase (microsomal) and antithyroglobulin antibodies • Hurthle cells (pink) • Other autoantibodies: MUST KNOW FOR STEP 1 • Antimitochondrial- primary biliary sclerosis • Anti- double stranded DNA- specific for SLE • Anti- Jo 1- polymyositis • Anti-parietal cell- pernicious anemia • Anti- centromere- scleroderma (CREST) • Graves disease • Cause of hyperthyroidism • Autoantibodies bind to the TSH receptor and mimic action of TSH leading to increased levels of T4 and ultimately decreased levels of TSH

18. The mother of an 11-month-old infant had noted enlargement of the baby's abdomen within the past month. This is confirmed by the osteopathic physician, who notes that the baby is otherwise normally developed. An abdominal CT scan reveals a 6 cm mass, with some scattered calcifications, above the kidney on the right. Laboratory studies show a greatly elevated urinary vanillylmandelic acid (VMA), while the urinary homovanillic acid (HVA) is only slightly increased. The mass is removed and microscopically is composed of sheets of small blue cells. Which of the following is the most likely diagnosis? • A) Congenital adrenal hyperplasia • B) Adrenal cortical carcinoma • C) Neuroblastoma • D) Non-Hodgkin lymphoma • E) Pheochromocytoma • F) Aldosteronoma

19. NEUROBLASTOMA • The answer is C • The baby has a neuroblastoma, one of the most common childhood tumors • These tumors produce catecholamine precursors such as vanillylmandelic acid (VMA) and homovanillic acid (HVA) in small amounts, so hypertension is unusual. • Adults will have the equivalent to this tumor = pheochromocytoma

20. A 45-year-old man has a 4 month history of non-focal, generalized headaches. On physical examination he is found to have a blood pressure of 170/110 mm Hg. Laboratory studies show a serum sodium of 146 mmol/L, potassium 2.3 mmol/L, chloride 103 mmol/L, CO2 27 mmol/L, glucose 82 mg/dL, and creatinine 1.2 mg/dL. His plasma renin activity is 0.1 ng/mL/hr and his serum aldosterone 65 ng/mL. Which of the following is the most likely cause for his findings? • A) 21-hydroxylase enzyme deficiency • B) Adrenal cortical adenoma • C) Pituitary adenoma • D) Exogenous corticosteroid administration • E) Renal cell carcinoma

21. HYPERALDOSTERONISM • The answer is B • Primary hyperaldosteronism (Conn syndrome) • The history points to an aldosterone secreting neoplasm, which is usually a small adrenal cortical adenoma adenoma • High alderosterone causes HYPOKALEMIA, metabolic alkalosis and LOW plasma renin levels • Remember: HIGH ALDOSTERONE AND LOW RENIN • Secondary hyperaldosteronism • Usually due to renal artery stenosis- kidney has decreased blood flow and that activates renin • HIGH RENIN levels

22. Over the past 6 months, a 42 y/o man has experienced increasing fatigue and weight gain in a truncal distribution. He has proximal muscle weakness. Fasting serum glucose is 155, 8am serum cortisol level is elevated at 54 and serum corticotropin is 63. Which of the following tests is most likely to be helpful in the diagnosis? • A) MRI of the brain • B) Abdominal CT of the adrenals • C) Serum assay for glycosylated hemoglobin • D) Biopsy of the gastrocnemius • E) Assay for urinary catecholamines

23. Cushing’s syndrome • Cushing’s disease • Due to a primary pituitary adenoma leading to increased ACTH • Primary adrenal hyperplasia/ neoplasia • Low ACTH • Ectopic ACTH production • Small cell lung cancer can lead to increased ACTH • Iatrogenic • MOST COMMON • Leads to decreased ACTH • Aside: Addison’s disease • Deficiency of cortisol and aldosterone from adrenal atrophy • SKIN HYPERPIGMENTATION from Increased ACTH

25. A 15-year-old boy has had worsening headaches for 2 months. On examination he has diminished peripheral vision, but no loss of visual acuity. A head CT scan reveals a 4 cm mass expanding the sellaturcica and eroding the sphenoid bone. The mass is cystic with scattered calcifications. Which of the following is the most likely diagnosis? • A) Prolactinoma • B) Metastatic seminoma • C) Empty sella syndrome • D) Glioblastomamultiforme • E) Craniopharyngioma • F) Osteosarcoma

26. Craniopharyngeoma • The answer is E • Craniopharyngioma • Rare and sporadic neoplasm of older children and young adults • Produce a mass effect in the region of the sella and can impinge upon the optic chiasm. • The microscopic features suggest embryologic origin from Rathke'spouch • Empty Sella Syndrome • Rare and seen in obese women • Herniation of arachnoid through diaphragmasella and hyperprolactinemia

27. topics that you may see on step 1 but were not covered in this review • Pheochromocytoma– rare but boards love this Q– remember rule of 10’s and the patient will always have the classic presentation • DI and SIADH • Carcinoid syndrome- again this will have a classic presentation- remember rule of 3’s (1/3 metastasize, 1/3 have a 2nd malignancy, 1/3 multiple) • Acromegaly • KNOW THE PHARM IN FIRST AID