Board Pearlsin Endocrinology

Part 2

Rey Vivo, MDAssistant Professor of Medicine

Texas Tech University Health Sciences Center

Objectives

• Discuss frequently tested Endocrine cases in the IM Boards– Pituitary– Cushing’s, Adrenal Incidentaloma– Amenorrhea, Hirsutism, Anorexia vs. Bulimia– Calcium homeostasis, Parathyroid, Bone disorders– Hemochromatosis, Wilson’s disease– Diabetes insipidus

• Examine practice questions from MKSAP and other sources

Calcium homeostasis:Parathyroid, Vit. D, Bone diseases

Hypercalcemia CausesIncreased bone resorption

Primary and secondary hyperparthyroidism (usually 10.5 – 11.0 mg/dL)Malignancy (usually >13 mg/dL)Others: hyperthyroid, Paget’s, etc.

Increased intestinal calcium absorption

Increased calcium intake (renal disease)Hypervitaminosis D (e.g. sarcoidosis)

Miscellaneous

Thiazides, lithium, rhabdomyolysis, theophylline toxicity, etc.

PTH homeostasis plasma Ca PTH

Bone Kidney

Resorption

Release ofCa, PO4

PO4 excretion

Careabsorption

Calcitriolformation

IntestinalCaHPO4

absorption

Hypercalcemia

• PEARLS:– Indications for surgery in hyperparathyroidism:

• 1. Calcium >11.5 mg/dL• 2. 24-hour urinary calcium >400 mg• 3. Age <50 • 4. Symtomatic: kidney stones, osteoporosis, dehydration

MKSAP Q #10• 48F is seen for serum calcium of 11.4 mg/dL. DEXA scan showed

T scores at the lumbar spine and L femoral neck of -0.88 and -0.55 respectively. There is no history of renal stones, bone fractures, cognitive impairment or fatigue. Intact PTH is 115 pg/mL, creatinine 0.9 mg/dL. The urine calcium/creatinine clearance ratio is >0.01 but the 24-hr. urine calcium excretion is 250 mg. What is the best next step in management?

• A. Observation• B. IV pamidronate• C. Mammography• D. Parathyroidectomy• E. Low calcium diet

MKSAP Q #118• A 30F is found to have asymptomatic hypercalcemia. She notes

occasional milky discharge from her breasts. Her menses have been irregular for the past year. Both her mother and her sister have been diagnosed with pituitary tumors and hypercalcemia. Her estimated oral calcium intake is 600 mg/d. On PE, she has expressible galactorrhea. Funduscopic examination and visual field testing are normal. Labs: calcium 11.2 mg/dL, phosphorus 2.5 mg/dL, chloride 109 meq/L, albumin 4.8 g/dL, intact PTH 55 pg/mL, prolactin 142 ng/mL. Which therapy is most likely to correct the patient's hypercalcemia?

• A. An oral bisphosphonate • B. Surgery to remove a parathyroid adenoma • C. Surgery to remove a pheochromocytoma • D. Surgery to remove 3½ parathyroid glands • E. Surgery to remove a pituitary tumor

MEN syndromes

• PEARLS:

MEN-I Parathyroid + pituitary + pancreatic

MEN-IIa Parathyroid + pheochromocytoma + medullary thyroid CA

MEN-IIb Pheochromocytoma + medullary thyroid CA + neuroganglioma

MKSAP Q #41• A 42M is evaluated for an anterior neck mass. He has a family

history of thyroid CA and hyperparathyroidism. On PE, BP is 147/85 and pulse rate is 88/min; he has a 3-cm right thyroid nodule and bilateral anterior cervical lymphadenopathy. Lungs are clear and cardiac examination reveals a 2/6 systolic ejection murmur; there is no pedal edema. Labs: TSH 1.4 µU/mL, calcium 10.6 mg/dL, and microscopic hematuria. Fine-needle aspiration biopsy of the nodule suggests medullary thyroid cancer. What is the most appropriate next step?

• A. Serum calcitonin level • B. Repeat biopsy with immunostaining for calcitonin • C. Serum PTH level • D. Urine metanephrines • E. Urine calcium, phosphate, and citrate

Bone disorders

Condition Calcium Phosphorus Alk. Phos. PTH

Osteoporosis N N N N

Osteomalacia N/Low Low High High

Paget’s N N/Sl. High Very High N

CKD Low High N/High High

MKSAP Q #36• A 60M is evaluated for increasing fatigue, malaise, and bone pain

over the past 2 years. He has chronic alcoholism, HTN, and gout. He was started on pancreatic enzymes 8 years ago when he developed steatorrhea and weight loss. He stopped drinking then. He suffered a Colles wrist fracture 18 months ago. A recent digital rectal examination showed a normal prostate gland, and his PSA level is 2.0 ng/mL. He does not have fevers, chills, or night sweats. On PE, there is generalized tenderness of the bones. Proximal muscle weakness is noted along with a waddling gait. Labs: hematocrit 34%, calcium 7.2 mg/dL, phosphorus 2.2 mg/dL, albumin 3.5 g/dL, alkaline phosphatase 290 U/L. Xrays of the long bones reveal bilateral radiolucent bands on the femur. Next best step?

• A. Osteoporosis • B. Osteomalacia • C. Paget's disease of bone • D. Metastatic prostate cancer • E. Paraneoplastic syndrome

Board Q

• 82F with osteoporosis and severe kyphosis has been taking alendronate and calcium + Vitamin D supplements with good adherence. However, she still complains of bone pains. What is the best step in management?

• A. Start Fentanyl patch• B. Add calcitonin• C. Add estrogen• D. Refer to pain clinic

MKSAP Q #14• A 78F is evaluated for fatigue, irritability, and depression. She is a

resident of a nursing home and her ambulation is limited by right-sided hemiparesis following a stroke 3 years ago. She has type 2 DM, HTN and hyperlipidemia. Medications include glipizide, simvastatin, aspirin, lisinopril, furosemide and amlodipine. PE reveals a positive Chvostek's sign on the right side, dry skin, brittle nails, and coarse hair. Labs: BUN18 mg/dL, creatinine 1.2 mg/dL, albumin 3.5 g/dL, calcium 7.2 mg/dL, alkaline phosphatase 260 U/L. What is the most approprioate next step?

• A. Parathyroid sestamibi scan • B. 25-hydroxyvitamin D • C. 1,25-dihydroxyvitamin D3 • D. Calcitonin

MKSAP Q #133• A 75F is seen after a recent fractured hip. She has HTN and

hypothyroidism but has not been on any medications for the past year. She lives alone and seldom leaves her house. She has a scanty diet and does not consume dairy products. She does not smoke cigarettes or drink alcohol. On PE, she has moderate dorsal kyphosis, a small firm goiter, and diffuse muscle weakness. Bone densitometry confirms low bone mass in her spine (T-score −2.9) and the unaffected hip (T-score −3.4). Labs: CBC normal, calcium 8.6 mg/dL, phosphorus 2.4 mg/dL, alkaline phosphatase165 U/L, TSH 21 µU/mL. Which serum tests would be most helpful in determining the cause of this patient's skeletal disease?

• A. Parathyroid hormone • B. 25-dihydroxyvitamin D • C. 1,25-dihydroxyvitamin D3 • D. Osteocalcin • E. Protein electrophoresis

Hemochromatosis,Wilson’s disease

PEARLSHemochromatosis Wilson’s

Presentation Hypogonadism, DM, liver dysfunction, large joint arthritis, skin hyperpigmentation, cardiomyopathy/arrhythmias

Hepatic – hepatitis, cirrhosisExtrahepatic – neuropsych (movement, cognitive disorder), kidney, bloodKayser Fleischer ring

Defect Abnormal iron accumulation HFE gene

Increased copper deposition

Diagnosis High ferritin, iron, transferrin Low serum ceruloplasmin

Treatment Phlebotomy, Iron chelationDietary restriction

Penicillamine

MKSAP Q #63• 42M presents with decreased libido, erectile dysfunction and

general fatigue. He does not take any medications. He also mentions that he has to shave only every other day and that he has nocturia. On PE, he is well developed but mildly overweight (BMI 26). BP is 126/80, pulse rate is 70/min. He has normal fundi and visual fields; decreased body hair and slightly soft testes; skin is somewhat tan, but he has recently been on a tropical vacation. His family history is significant for type 2 DM. Labs: CBC normal, fasting glucose160 mg/dL, ALT 55 U/L, AST 68 U/L, urinalysis shows mild glucosuria. Repeat fasting glucose is 135 mg/dL. Which test will confirm the most likely diagnosis?

• A. Serum FSH, LH, and iron studies • B. Liver biopsy • C. Hepatitis serologies • D. Liver ultrasound • E. Inferior petrosal sinus sampling for ACTH and cortisol levels

MKSAP Q #72• 42M is evaluated for poor libido, fatigue, and progressive skin

darkening. He underwent a normal puberty and has two children 8 and 10 years old. He denies vision loss, gynecomastia, or cold intolerance. His only other medical problem is arthritis in the hands. Family history is negative for calcium or pituitary tumors, and a maternal uncle had cryptogenic cirrhosis. PE: full visual fields, soft 12-mL testes, and bilateral swollen metacarpophalangeal joints. The skin is dark. Labs: hematocrit 50%, LH 0.2 mU/mL, FSH 0.2 mU/mL, prolactin 4 ng/mL, testosterone 128 ng/dL, PSA 0.2 ng/mL. Best next step?

• A. Gonadotropin-releasing hormone stimulation test • B. Karyotype • C. MRI of the head • D. Measurement of serum transferrin saturation and ferritin • E. Therapeutic trial of testosterone

Diabetes Insipidus

PEARLS

Normal Central DI

Nephrogenic DI

Primary Polydipsia

Urine osm after dehydration

Increased No increase No increase Partial increase

Urine osm after vasopressin

< 5% increase

> 50% increase

No increase < 9% increase

MKSAP Q #49• A 34F is seen for polyuria and polydipsia. She has depression, is

overweight and has a family history of DM. She is taking no meds. Fasting glucose is 100 mg/dL and there is no glucosuria. However, her urine SG is <1.005. Her measured 24-hour urine output is 7 to 8 L/d. Serum Na is 140 meq/L; electrolytes are otherwise normal. A water deprivation test is performed: serum Na rises to 148 meq/L, the urine osmolality remains <300 mosm/kg H2O and the plasma osmolality increases to 299 mosm/kg H2O. Despite no oral intake during the test, her urine output remains on average 275 mL/h. At this time, blood is collected for measurement of ADH, and 1 µg of vasopressin is administered subcutaneously. One hour later, the urine osmolality increases to 600 mosm/kg H2O and the urine output decreases to less than 100 mL/h. The blood ADH level is pending. Most likely diagnosis?

• A. Normal, no evidence of pathology • B. Nephrogenic diabetes insipidus • C. Central diabetes insipidus • D. Primary polydipsia

Thank you