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
Laron syndrome
dwarfism
Defective growth hormone receptors–>INC linear growth
INC GH, INC IGF-1
short height, small head circumference, characteristic facies with saddle nose and prominent forehead, delayed skeletal maturation, small genitalia
Syndrome of inappropriate
antidiuretic hormone secretion (SIADH)
Characterized by:
- Excessive free water retention
- Euvolemic hyponatremia with continued urinary Na+ excretion
- Urine osmolality > serum osmolality
Causes include:
- Ectopic ADH (eg, small cell lung cancer)
- CNS disorders/head trauma
- Pulmonary disease
- Drugs (eg, cyclophosphamide)
Hypopituitarism
Undersecretion of ALL pituitary hormones due to:
- Nonsecreting pituitary adenoma, craniopharyngioma
- Sheehan syndrome
- Empty sella syndrome
- Pituitary apoplexy
- Brain injury
- Radiation
Diabetic ketoacidosis
One of the most feared complications of diabetes Type I
SX
DKA is Deadly
- Delirium/psychosis
- Kussmaul respirations (rapid/deep breathing)
- Abdominal pain/nausea/vomiting
-Dehydration
- Fruity breath odor (due to exhaled acetone).
Complication
mucormycosis (usually caused by Rhizopus infection), cerebral edema, cardiac arrhythmias, heart failure.
Hyperosmolar hyperglycemia nonketonic syndrome (HHNS)
State of profound hyperglycemia-induced dehydration and INC serum osmolarity, classically seen
in elderly type 2 diabetics with limited ability to drink
SX
thirst, polyuria, lethargy, focal
neurological deficits (eg, seizures), can progress to coma and death if left untreated
LAB
Glucagonoma
Tumor of pancreatic α cells –>overproduction of glucagon
SX dermatitis (necrolytic migratory erythema) diabetes (hyperglycemia) DVT declining weight depression
Insulinoma
Tumor of pancreatic β cells–>overproduction of insulin hypoglycemia
SX
Whipple triad:
low blood glucose, symptoms of hypoglycemia (eg, lethargy, syncope, diplopia), and resolution of
symptoms after normalization of glucose levels
Somatostatinoma
Tumor of pancreatic δ cells–>overproduction of somatostatin–>DEC secretion of secretin, cholecystokinin, glucagon, insulin, gastrin
SX
diabetes/glucose intolerance,
steatorrhea, gallstones
Carcinoid syndrome
Rare syndrome caused by carcinoid tumors
(neuroendocrine cells)
Most common malignancy in the small intestine
HISTO prominent rosettes, especially metastatic small bowel tumors, which secrete high levels of serotonin (5-HT)
SX
recurrent diarrhea, cutaneous flushing, asthmatic wheezing, right-sided valvular heart disease (tricuspid regurgitation, pulmonic stenosis)
LAB
5-hydroxyindoleacetic acid (5-HIAA) in urine, niacin deficiency (pellagra).
Zollinger-Ellison syndrome
Gastrin-secreting tumor (gastrinoma) of pancreas or duodenum
***Acid hypersecretion causes
recurrent ulcers in duodenum and jejunum
SX
abdominal pain, diarrhea
Positive secretin stimulation test
May be associated with MEN 1.
Multiple endocrine
neoplasias 1
(MEN 1)
mutation of MEN1 (menin, a
tumor suppressor, chromosome 11)
- Pituitary tumors (prolactin or GH)
- Pancreatic endocrine tumors—Zollinger-Ellison syndrome, insulinomas, VIPomas,
glucagonomas (rare) - Parathyroid adenomas
3 P’s: Pituitary, Parathyroid, and
Pancreas
“Diamond”
Multiple endocrine neoplasias 2 (MEN 2)
mutation in RET (codes for
receptor tyrosine kinase) in cells of neural crest
origin
- Parathyroid hyperplasia
- Medullary thyroid carcinoma—neoplasm of parafollicular or C cells
- Pheochromocytoma
2 P’s: Parathyroids and
Pheochromocytoma
“Square”
Multiple endocrine neoplasias 3 (MEN 3)
Associated with marfanoid habitus; mutation in
RET gene
- Medullary thyroid carcinoma
- Pheochromocytoma
- Mucosal neuromas (oral/intestinal
ganglioneuromatosis)
1 P: Pheochromocytoma
“Triangle”
