Endocrinology Week 4 Summary

Question 16

List three tests used in the diagnosis of Cushing’s syndrome (at least 2/3 should be abnormal to make the diagnosis).

Increased production of cortisol: increased 24 hour urine free cortisol

Lack of suppression: 1 mg dexamethasone suppression test (patient takes 1 mg of dexamethasone between 11 pm- midnight, 8 AM serum cortisol does not suppress to <50 nmol/L (50-140 nmol/L “grey zone”)

Lack of diurnal variation: elevated serum or salivary midnight cortisol

Question 17

Mr. MacDonald is a 73 year-old man who reports a 20-pound weight loss and hyperpigmentation, and you find him to have new-onset hypertension and hypokalemia.

What is the likeliest endocrine diagnosis?

Ectopic ACTH production, causing Cushing’s syndrome.

What is the likeliest underlying etiology?

Small cell lung cancer.

Question 18

Alice Smyth is a 42 year-old woman who is referred to you by a neurosurgeon who saw her for carpal tunnel syndrome, but became concerned that she may have acromegaly.

List 10 clinical manifestations of acromegaly.

  • Facial changes:
    • proganthism
    • enlarged nose/tongue
    • frontal bossing
  • Enlarged hands and feet
  • Cardiomegaly/CHF
  • Metabolic syndrome:
    • hypertension
    • hypertriglyceridemia
    • diabetes mellitus
  • Osteoporosis
  • Hypercalcemia
  • BPH
  • Multinodular goiter
  • Carpal tunnel syndrome
  • Obstructive sleep apnea
  • Colonic polyps
  • Skin tags, hyperhydrosis

How do you screen for and confirm the diagnosis of acromegaly?

Screen for elevated IGF-1 level.

Diagnose with 2 hour 75 g glucose suppression test.
If normal: GH suppresses to <1

Question 19

You are examining Alice Smith (with ?acromegaly).

How can a pituitary tumor affect the cranial nerves (list two mechanisms)? What cranial nerves can be affected?

Upward growth – affects the optic chiasm:

  • Cranial nerve II

Lateral growth into the cavernous sinuses:

  • Cranial nerves III, IV, V1, V2, VI

How do you examine the patient for damage to these nerves?

Cranial nerve II:

  • visual acuity
  • visual fields (including red pin) looking for bitemporal hemianopsia
  • PERLA (looking for RAPD)
  • fundoscopy (R/O optic disc pallor)

Cranial nerves III, IV, VI:

  • EOMS (diplopia)

Cranial nerve V1, V2:

  • sensation forehead and cheek
  • corneal reflex

Question 20

Ursula Nnaobi presents to the emergency room with a 2-month history of weight loss, nausea and weakness. She appears very thin (55 kg), chronically ill, with a blood pressure of 90/70, heart rate 102 lying, and you can’t detect her blood pressure when she stands up. She is diffusely hyperpigmented, with hypopigmented patches.

What diagnosis do you suspect?

Adrenal insufficiency.

How will you make the diagnosis?

Baseline ACTH level.

Cortrosyn stimulation test:

  1. Administer 250 ug of ACTH iv or im
  2. Check serum cortisol at baseline and one hour later (normal stimulated cortisol will be >500 nmol/L)
  3. Treat with normal saline, dexamethasone simultaneously if patient is unstable (plus DDAVP if hyponatremic so hyponatremia does not resolve too quickly)

Write a prescription for what medication(s) she will go home on.

Cortef 10 mg q AM, 5 mg q PM po
Florinef 0.1 mg daily po

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