Endocrinology Week 7 Summary

Question 31

How do you counsel someone starting on a bisphosphonate?

How to take it:

  • First thing in morning with 8 oz of water on an empty stomach
  • No food or water for at 30 minutes afterwards
  • Remain upright until after eating

Why to take it:
The use of Alendronate reduced vertebral and hip fractures by 50% and 30% respectively in FIT trial, in patients who had had a prior vertebral fracture (there was no hip effect if they had had no prior fracture, unless also had frank osteoporosis, in which case vertebra and hip were protected).

Potential side effects:

  • GI mucosal irritation, especially if instructions are not followed
  • Osteonecrosis of jaw, especially with superimposed cancer: do dental work first
  • Bone, muscle or joint pain
  • Diaphyseal fractures of the femur
  • Transient hypocalcemia
  • Do not use if creatinine clearance is <35 ml/min

Question 32

In a patient with hypercalcemia and an asymptomatic renal stone, how would you differentiate various causes of hypercalcemia?

Serum calcium PTH Urine calcium excretion
Primary hyperparathyroidism High High High
Familial Hypocalciuric hypercalcemia High High Low
Lithium use Normal/High High High
Hydrochlorothiazide use Normal/High Normal Low

Question 33

Describe 5 ways Paget’s disease can present.

  • Asymptomatic with high ALP
  • High output cardiac failure
  • Bone pain/deformity/fracture
  • Hypercalcemia (especially with immobilization)
  • Conductive deafness
    • also compression of cranial nerves 2,5, and 7
  • Osteosarcoma

Question 34

List 6 diagnoses on the differential for hypocalcemia.

Hypocalcemia with low PTH (hypoparathyroidism):

  • Surgical/Autoimmune destruction of the parathyroid glands
  • Abnormal parathyroid gland development
  • Altered regulation of PTH

Hypocalcemia with high PTH:

  • PTH resistance (impaired PTH action)
  • Vitamin D deficiency/resistance
  • Extravascular deposition
    • Hyperphosphatemia
    • Osteoblastic metastases
    • Acute pancreatitis
  • Sepsis or severe illness

Disorders of magnesium metabolism:

  • Drugs:
    • Calcium chelators
    • Bisphosphonates
    • Cinacalcet
    • Chemotherapy
    • Foscarnet
    • Fluoride poisoning

What are two clinical findings in the patient with hypocalcemia?

  • Trousseau’s sign
  • Chvostek’s sign: twitching facial muscles when the facial nerve is tapped on

How do you treat severe hypocalcemia (corrected calcium <1.85, or calcium between 1.85-2 mmol/L with symptoms/signs)?

  1. 1 vial calcium gluconate (1 g of calcium/10 mL vial) in 50 mL of D5W over 5 minutes iv
  2. then give 1 mg/kg/ml iv for 5-10 hours, checking serum calcium levels in 6 hours
  3. eventually switch to oral calcium carbonate 1250 mg bid (=500 mg of elemental calcium) tid +/- rocaltriol 0.25 mcg od-bid

Question 35

Robert Smith is a 29-year old man who presents with low libido and erectile dysfunction for the past year. On examination, he has decreased male pattern hair growth, and testes are small and soft, penis is normal. Bioavailable tesosterone is undetectable, LH is 25 (high), FSH is 40 (high).

List 6 conditions in your differential.

  • Prior radiation or chemotherapy
  • Testicular torsion (bilateral) or trauma
  • Mumps orchitis
  • Autoimmune
  • Chronic disease
  • Environmental toxins
  • Drugs:
    • Ketozonazole
    • Chronic Glucocorticoid therapy

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