Endocrine III

Question 1

What is the likely diagnosis in a patient taking risperidone that presents with fatigue and headache with low TSH/LH and mildly elevated prolactin on laboratory exam?

Answer 1

Non-functioning (gonadotroph) pituitary adenoma

presence of hypopituitarism (e.g. hypothyroidism, hypogonadism) helps distinguish pituitary adenoma from medication side effect

Question 2

What is the likely diagnosis in a patient that develops pallor, tachycardia, and severe hypertension without fever after induction of anesthesia? The patient has a history of frequent headaches and hypertension.

Answer 2

Pheochromocytoma

episodes of pheochromocytoma can be precipitated by medications, especially anesthetic agents, and surgical procedures; normal temperature helps differentiate pheochromocytoma from thyroid storm (typically elevated temp.)

Question 3

What is the likely diagnosis in a patient that develops post-operative high fever, tachycardia, hypertension, and lid lag with no muscle rigidity? Serum creatinine kinase is slightly elevated.

Answer 3

Thyroid storm

typically triggered by a specific event in patients with undiagnosed or inadequately treated hyperthyroidism (e.g. surgery, trauma, infection, CT scan with contrast due to acute iodine load)

Question 4

What is the likely diagnosis in a patient that presents with constipation, cold intolerance, low libido, and hypoglycemia with eosinophilia on laboratory exam?

Answer 4

Hypopituitarism

patient is experiencing secondary hypothyroidism, secondary adrenal insufficiency, and hypogonadotropic hypogonadism

Question 5

What is the likely diagnosis in a patient that received multiple blood transfusions and develops paresthesias, carpal spasm, and hyperreflexia?

Answer 5

Hypocalcemia

citrate in transfused blood binds ionized calcium, causing hypocalcemia, especially in patients with impaired hepatic function (decreased clearance of citrate by the liver)

Question 6

What is the likely diagnosis in a patient with a family history of kidney stones and stomach ulcers that presents with refractory peptic ulcer disease, hypercalcemia, and low serum phosphorus?

Answer 6

MEN1

peptic ulcer disease due to gastrinoma (ZE syndrome); hypercalcemia/low phosphorus due to hyperparathyroidism

Question 7

What is the likely diagnosis in a patient with a long history of Hashimoto thyroiditis that develops a rapidly enlarging, firm goiter with dysphagia, hoarseness, and fever?

Answer 7

Thyroid lymphoma

patients can exhibit “B symptoms” (e.g. night sweats, weight loss, fever), as well as symptoms of retrosternal extension (e.g. dysphagia, hoarseness); may also have facial plethora and cyanosis when raising the arms above the head due to compression of the subclavian vein and IJV between the clavicle and thyroid (Pemberton sign)

Question 8

What is the likely diagnosis in a patient with a malignant thyroid nodule, elevated calcitonin, and a family history of thyroid cancer?

Answer 8

MEN2 (A or B)

elevated calcitonin is suggestive of medullary thyroid carcinoma

Question 9

What is the likely diagnosis in a patient with a pituitary mass and the laboratory values below?

Prolactin: 250 ng/mL (normal, < 15)

LH: low

TSH: normal

Answer 9

Prolactinoma

most common primary pituitary tumor; low LH due to inhibition of GnRH by prolactin

Question 10

What is the likely diagnosis in a patient with a pituitary mass and the laboratory values below?

Prolactin: 45 ng/mL (normal, < 15)

LH: low

TSH: low

Answer 10

Non-functional (gonadotroph) pituitary adenoma

mild elevation in prolactin due to compression of dopaminergic pathways; low LH/TSH due to compression of thyrotrophs and gonadotrophs

Question 11

What is the likely diagnosis in a patient with an acute MI complicated by cardiogenic shock that develops a low total T3 level despite normal TSH/free T4?

Answer 11

Euthyroid sick syndrome (low T3 syndrome)

thought to result from decreased peripheral 5’-deiodination of T4; any patient with an acute, severe illness can have abnormal TFTs

Question 12

What is the likely diagnosis in a patient with celiac sprue that develops diffuse bone pain, muscle weakness, and the laboratory results below?

Ca2+: normal

Phosphate: low

PTH: high

Alkaline phosphatase: high

Answer 12

What is the likely diagnosis in a patient with celiac sprue that develops diffuse bone pain, muscle weakness, and the laboratory results below?

Ca2+: normal

Phosphate: low

PTH: high

Alkaline phosphatase: high

Osteomalacia

Question 13

What is the likely diagnosis in a patient with flushing, diarrhea, wheezing, and a heart murmur that increases with inspiration?

Answer 13

Carcinoid syndrome

Question 14

What is the likely diagnosis in a patient with flushing, watery diarrhea, hypokalemia, and achlorhydria?

Answer 14

VIPoma

i.e. WDHA syndrome; typically involves the pancreatic tail (abdominal imaging can localize the tumor)

Question 15

What is the likely diagnosis in a patient with headaches, weight loss, intermittent palpitations, and visual disturbances? Laboratory exam reveals elevated T3/T4 and TSH.

Answer 15

TSH-secreting pituitary adenoma

inappropriately normal or elevated TSH with elevated T3/T4 helps rule out TSH-independent hyperthyroidism (e.g. Grave’s disease)

Question 16

What is the likely diagnosis in a patient with hypercalcemia, elevated PTH, and high urine Ca2+?

Answer 16

Primary hyperparathyroidism

high urine Ca2+ helps distinguish from familial hypocalciuric hypercalcemia

Question 17

What is the likely diagnosis in a patient with hypercalcemia, elevated PTH, and low urine Ca2+?

Answer 17

Familial hypocalciuric hypercalcemia

patients are typically asymptomatic

Question 18

What is the likely diagnosis in a patient with increasing polyuria/polydipsia with hypernatremia, high serum osmolality, and low urine osmolality?

Answer 18

Diabetes insipidus

serum Na+ > 145 mEq/L with dilute urine excludes primary polydipsia and favors diabetes insipidus

Question 19

What is the likely diagnosis in a patient with increasing polyuria/polydipsia with hyponatremia, low serum osmolality, and low urine osmolality?

Answer 19

Primary polydipsia

serum Na+ < 137 mEq/L with dilute urine favors primary polydipsia and excludes diabetes insipidus

Question 20

What is the likely diagnosis in a patient with low urine osmolality that does not improve significantly following water deprivation and administration of desmopressin?

Answer 20

Nephrogenic diabetes insipidus

Question 21

What is the likely diagnosis in a patient with low urine osmolality that improves by > 50% following administration of desmopressin?

Answer 21

Central diabetes insipidus

Question 22

What is the likely diagnosis in a patient with low urine osmolality that improves to > 600 mOsm/kg after 2-3 hours of water deprivation?

Answer 22

Primary polydipsia

Question 23

What is the likely diagnosis in a patient with weight loss, tachycardia, anti-thyroid peroxidase antibodies, and the physical exam findings below?

Thyroid gland: normal size, non-tender

TSH: low

Free T4: high

Radioactive iodine uptake: < 5%

Answer 23

What is the likely diagnosis in a patient with weight loss, tachycardia, anti-thyroid peroxidase antibodies, and the physical exam findings below?

Thyroid gland: normal size, non-tender

TSH: low

Free T4: high

Radioactive iodine uptake: < 5%

Painless (silent) thyroiditis

painless thyroiditis is often a self-limited hyperthyroid phase of Hashimoto thyroiditis

Question 24

What is the likely diagnosis in a patient with weight loss/tachycardia and a diffusely tender thyroid with low TSH and high free T4?

Answer 24

Subacute (de Quervain) thyroiditis

typically follows an upper respiratory infection; treatment is symptomatic (e.g. NSAIDs, beta-blockers)

Question 25

What is the likely diagnosis in a patient with well-controlled diabetes that develops diarrhea, weight loss, anemia, and erythematous plaques with central clearing?

Answer 25

Glucagonoma rash is consistent with necrolytic migratory erythema; glucagonoma diagnosis confirmed with glucagon levels \> 500 pg/mL

Question 26

What is the likely diagnosis in a tall patient with kyphoscoliosis, neuromas on the lip/tongue, and medullary thyroid cancer?

Answer 26

MEN 2B pheochromocytoma may be initially asymptomatic; MEN2A and MEN2B are associated with RET mutations

Question 27

What is the likely diagnosis in a young female with irregular menses, hirsutism, and elevated serum testosterone with no abdominal striae?

Answer 27

Polycystic ovary syndrome

Question 28

What is the likely diagnosis in a young patient with hypertension that develops severe hypokalemia after beginning a low-dose thiazide diuretic?

Answer 28

Primary hyperaldosteronism patients with mild primary hyperaldosteronism are prone to developing diuretic-induced hypokalemia; other findings include metabolic alkalosis and mild hypernatremia

Question 29

What is the likely diagnosis in a young patient with nausea/vomiting, weight loss, and polydipsia? Laboratory exam is significant for low HCO3- and high blood glucose/K+ levels.

Answer 29

Diabetic ketoacidosis

Question 30

What is the likely diagnosis in a young woman that develops amenorrhea, weight gain, hypertension, hirsutism, muscle weakness, and easy bruising?

Answer 30

Cushing syndrome Cushing syndrome may be similar in presentation to PCOS (obesity, hirsutism, amenorrhea), but PCOS does not cause muscle weakness nor easy bruisability

Question 31

What is the likely diagnosis in an African-American patient that presents with dark urine that stains positive with Prussian blue after being treated for a urinary tract infection?

Answer 31

G6PD deficiency positive stain indicates presence of hemosiderin in the urine due to hemolysis; hemolytic episodes are often precipitated by infection or medications (increased oxidative stress)

Question 32

What is the likely diagnosis in an asymptomatic patient with a slightly elevated TSH despite normal free T3/T4 levels?

Answer 32

Subclinical hypothyroidism characterized by normal T3/T4 levels with a mildly elevated TSH and no symptoms of hypothyroidism

Question 33

What is the likely diagnosis in an elderly diabetic patient that develops weakness and blurred vision after a viral URI with a markedly elevated serum glucose (\> 1000 mg/dL) on laboratory exam?

Answer 33

Hyperosmolar hyperglycemic state frequently presents with severe hyperglycemia and increased serum osmolality without acidosis/ketonemia

Question 34

What is the likely diagnosis in an insulin-dependent diabetic patient with anorexia, nausea/vomiting, early satiety, and post-prandial hypoglycemia without heartburn or epigastric pain?

Answer 34

Diabetic gastroparesis hypoglycemic episodes due to insulin administration prior to meals followed by impaired gastric emptying and delayed absorption

Question 35

What is the likely diagnosis in an obese young woman that presents with male-pattern baldness, excessive acne, and amenorrhea?

Answer 35

Polycystic ovarian syndrome

Question 36

What is the likely diagnosis in an older patient with memory changes, weight gain, fatigue, and constipation?

Answer 36

Hypothyroidism

Question 37

What is the likely diagnosis in an older patient with significant smoking history that presents with hypercalcemia and low PTH?

Answer 37

Humoral hypercalcemia of malignancy due to secretion of PTHrP from squamous cell lung cancer

Question 38

What is the likely etiology of hypercalcemia in a patient that develops symptoms 4 weeks after a severe motor vehicle accident left the patient a quadriplegic?

Answer 38

Immobilization due to increased osteoclastic bone resorption, especially in individuals with a high baseline rate of turnover (e.g. young individuals, Paget's disease patients); characterized by high Ca2+ and low PTH

Question 39

What is the likely etiology of hyperthyroidism in a patient with a normal sized thyroid, diffusely decreased radioactive iodine uptake, and low serum thyroglobulin?

Answer 39

Exogenous hormone low RAIU suggests release of preformed hormone or exogenous hormone intake; low thyroglobulin helps differentiate exogenous hormone intake from thyroiditis (high thyroglobulin)

Question 40

What is the likely etiology of hyperthyroidism in a patient with elevated free T3/T4, low TSH, and the radioactive iodine scan below?

Answer 40

Toxic adenoma due to autonomous thyroid hormone production