Endocrinology- Pathology Flashcards
Cushing syndrome
- Etiology
Exogenous corticosteroids— Most common cause.
Primary adrenal adenoma, hyperplasia, or carcinoma.
ACTH-secreting pituitary adenoma (Cushing disease); paraneoplastic ACTH secretion.
*Cushing disease is responsible for the majority of endogenous cases of Cushing syndrome.
Cushing syndrome
- Clinical manifestations
Hypertension, weight gain, moon facies, abdominal striae and truncal obesity, buffalo hump, skin changes (eg, thinning, striae), hirsutism, osteoporosis, hyperglycemia (insulin resistance), amenorrhea, immunosuppression
Cushing syndrome
- Diagnosis
- Screening tests include: free cortisol on 24-hr urinalysis, midnight salivary cortisol, and no suppression with overnight low-dose dexamethasone test.
- Measure serum ACTH. If low, suspect adrenal tumor or exogenous glucocorticoids. If high, distinguish between Cushing disease and ectopic ACTH secretion
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Adrenal insufficiency
- Sympots
- Treatment
Symptoms include weakness, fatigue, orthostatic hypotension, muscle aches, weight loss, GI disturbances, sugar and/ or salt cravings.
Treatment: glucocorticoid/ mineralocorticoid replacement.
Adrenal insufficiency
- Diagnosis
measurement of serum electrolytes, morning/random serum cortisol and ACTH, and response to ACTH stimulation test.
Alternatively, can use metyrapone stimulation test: metyrapone blocks last step of cortisol synthesis (In 1° adrenal insufficiency, ACTH is high but 11-deoxycortisol
remains low after test. In 2°/3° adrenal insufficiency, both ACTH and 11-deoxycortisol remain low after test).
Primary adrenal insufficiency
loss of gland function: hypotension, hyperkalemia, metabolic acidosis, skin and mucosal hyperpigmentation
Acute—sudden onset (eg, due to massive hemorrhage). May present with shock in acute adrenal crisis.
Chronic—Addison disease. Due to adrenal atrophy or destruction by disease (autoimmune destruction most common in the Western world; TB most common in the
developing world).
Waterhouse-Friderichsen syndrome
acute 1° adrenal insufficiency due to adrenal hemorrhage associated with septicemia (usually Neisseria meningitidis), DIC, endotoxic shock.
Secondary adrenal insufficiency
Tertiary adrenal insufficiency
Seen with pituitary ACTH production. No skin/mucosal hyperpigmentation, no hyperkalemia.
Seen in patients with chronic exogenous steroid use, precipitated by abrupt withdrawal.
Hyperaldosteronism
- Clinical manifestations
hypertension, low or normal K+, metabolic alkalosis. 1° hyperaldosteronism does not directly cause edema due
to aldosterone escape mechanism.
Primary hyperaldosteronism
adrenal adenoma (Conn syndrome) or bilateral adrenal hyperplasia. high aldosterone, low renin. Causes resistant hypertension.
Secondary hyperaldosteronism
Seen in patients with renovascular hypertension, juxtaglomerular cell tumors (renin-producing), and edema (eg, cirrhosis, heart failure, nephrotic syndrome).
Neuroendocrine
tumors
Heterogeneous group of neoplasms that begin in specialized cells called neuroendocrine cells.
Cells contain amine precursor uptake decarboxylase (APUD) and secrete different hormones.
Most tumors arise in the GI system (eg, carcinoid, gastrinoma), pancreas (eg, insulinoma, glucagonoma), and lungs (eg, small cell carcinoma).
Neuroblastoma
Most common tumor of the adrenal medulla in children, usually < 4 years old. Originates from Neural crest cells. Occurs anywhere along the sympathetic chain.
Neuroblastoma
- Clinical features
Most common presentation is abdominal distension and a firm, irregular mass that can cross the midline (vs Wilms tumor, which is smooth and unilateral). Less likely to develop hypertension than with pheochromocytoma.
Can also present with opsoclonus-myoclonus syndrome (“dancing eyes-dancing feet”).
Neuroblastoma
- Diagnosis
HVA and VMA (catecholamine metabolites) in urine. Homer-Wright rosettes characteristic of neuroblastoma and medulloblastoma. Bombesin and NSE ⊕.
Associated with overexpression of N-myc oncogene. Classified as an APUD tumor.
Pheochromocytoma
-Etiology
Most common tumor of the adrenal medulla in
adults. Derived from chromaffin cells (arise from neural crest).
May be associated with germline mutations (eg,
NF-1, VHL, RET [MEN 2A, 2B]).
Rule of 10’s: 10% malignant 10% bilateral 10% extra-adrenal (eg, bladder wall, organ of Zuckerkandl) 10% calcify 10% kids
Pheochromocytoma
- Symptoms
episodic hypertension. May also secrete EPO, polycythemia. Symptoms occur in “spells”—relapse and remit
Episodic hyperadrenergic symptoms (5 P’s): Pressure (high BP) Pain (headache) Perspiration Palpitations (tachycardia) Pallor
