PATH - General Flashcards
Cushing Syndrome
INC cortisol due to a variety of causes:
-Exogenous corticosteroids (#1 cause)
-Primary adrenal adenoma, hyperplasia, or carcinoma
-ACTH-secreting pituitary adenoma (Cushing disease); paraneoplastic ACTH secretion (eg, small cell lung cancer, bronchial carcinoids)
SX
Hypertension, weight gain, moon facies, abdominal striae and truncal obesity, buffalo hump,
skin changes (thinning, striae), osteoporosis, hyperglycemia (insulin resistance), amenorrhea,
immunosuppression
SCREENING
- INC free cortisol on 24-hr urinalysis
- INC midnight salivary cortisoL
- no suppression with overnight low-dose dexamethasone test
Primary adrenal insufficiency
Deficiency of aldosterone and cortisol production due to loss of gland function
SX hypotension (hyponatremic volume contraction), hyperkalemia, metabolic acidosis, skin and mucosal hyper pigmentation
Primary Pigments the skin/mucosa.
Addison disease
Chronic 1° adrenal insufficiency
Due to adrenal atrophy or destruction by disease
(autoimmune destruction most common in the Western world; TB most common in the
developing world).
SX
hypotension, hyperkalemia, metabolic acidosis, skin and mucosal hyperpigmentation
Waterhouse-Friderichsen syndrome
acute 1° adrenal insufficiency
due to adrenal hemorrhage associated with septicemia
(usually Neisseria meningitidis), DIC, endotoxic shock.
Hyperaldosteronism
Increased secretion of aldosterone from adrenal gland.
Clinical features include hypertension, or
normal K+, metabolic alkalosis.
No edema due to aldosterone escape mechanism.
Primary
hyperaldosteronism
Seen with adrenal adenoma (Conn syndrome) or idiopathic adrenal hyperplasia.
INC aldosterone
DEC renin
Secondary
hyperaldosteronism
Seen in patients with renovascular hypertension, juxtaglomerular cell tumor (due to independent
activation of renin-angiotensin-aldosterone system).
INC aldosterone
INC renin
Primary hyperparathyroidism
Usually due to parathyroid adenoma or hyperplasia
LAB
Hypercalcemia, hypercalciuria, hypophosphatemia, INC PTH,
INC ALP, INC cAMP in urine
SX
present with weakness and
constipation (“groans”), abdominal/flank pain
(kidney stones, acute pancreatitis), depression
(“psychiatric overtones”).
Osteitis fibrosa cystica—cystic bone spaces filled with brown fibrous tissue (“brown
tumor” consisting of osteoclasts and deposited
hemosiderin from hemorrhages; causes bone
pain).
“Stones, bones, groans, and psychiatric overtones.”
Secondary
hyperparathyroidism
2° hyperplasia due to DEC Ca2+ absorption and/or INC PO43−
most often in chronic renal disease
LAB
*Hypocalcemia,
hyperphosphatemia in chronic renal failure
INC ALP, INC PTH
SX
Renal osteodystrophy—renal disease 2° and 3° hyperparathyroidism–>bone lesions
Tertiary
hyperparathyroidism
Refractory (autonomous) hyperparathyroidism
resulting from chronic renal disease.
LAB
INC(x2) PTH, INC Ca2+
SX
Renal osteodystrophy—renal disease 2° and 3° hyperparathyroidism–>bone lesions
Hypoparathyroidism
Due to accidental surgical excision of parathyroid glands, autoimmune destruction, or DiGeorge syndrome.
Findings
tetany, hypocalcemia, hyperphosphatemia.
- Chvostek sign—tapping of facial nerve (tap the *Cheek) contraction of facial muscles.
- Trousseau sign—occlusion of brachial artery with BP cuff (cuff the *Triceps) carpal spasm.
Pseudohypoparathyroidism type 1A (Albright hereditary osteodystrophy)
Autosomal dominant
Due to defective Gs protein α-subunit causing end-organ
resistance to PTH.
unresponsiveness of
kidney to PTH–>hypocalcemia despite INC PTH levels
SX
shortened 4th/5th digits,
short stature
Familial hypocalciuric
hypercalcemia
Defective Ca2+-sensing receptor (CaSR) in multiple tissues (eg, parathyroids, kidneys).
Higher than normal Ca2+ levels required to suppress PTH
Pituitary adenoma
Benign tumor, most commonly prolactinoma (arises from lactotrophs).
Nonfunctional tumors present with mass effect (bitemporal hemianopia, hypopituitarism, headache).
Functional tumor presentation
is based on the hormone produced.
TX
bromocriptine,
cabergoline
transsphenoidal resection
Nelson syndrome
Enlargement of existing ACTH-secreting pituitary adenoma after bilateral adrenalectomy for
refractory Cushing disease
SX
hyperpigmentation, headaches and bitemporal hemianopia