6/18 UWorld Flashcards
What is the presentation of secondary adrenal insufficiency
o Lack of cortisol due to decreased ACTH = weakness, fatigue, weight loss
o Aldosterone synthesis is preserved (controlled by RAAS) à no hypotension or hyperkalemia
o ACTH low = no hyperpigmentation
What is a neuroblastoma
- Most common tumor of adrenal medulla in children
- Can occur anywhere along the sympathetic chain
- Most common presentation:
- Abd distension with firm mass that may cross midline (vs. Wilms tumor which in unilateral)
- Less likely to develop HTN than pheochromocytoma
- Increased HVA and VMA (catecholamine metabolites) in urine
- Homer Wright rosettes (also seen in medulloblastoma)
- Bombesin and NSE +
- Associated with overexpression of N-myc gene
Differentiate Cushing disease vs. Cushing syndrome
Cushing syndrome = increased cortisol
Cushing disease = increased cortisol secondary to ACTH-secreting pituitary adenoma
What is Jod-Basedow phenomenon
Thyrotoxicosis if a patient with iodine deficiency and partially autonomous thyroid tissue is made iodine replete
What is Riedel thyroiditis and its presentation
- Thyroid replaced by fibrous tissue
- Fibrosis may extend to local structures, mimicking anaplastic carcinoma
- Presentation:
- Euthyroid or hypothyroid
- Fixed, hard (rock-like), painless goiter
What are the 2 main types of chronic complications in diabetes
- Nonenzymatic glycosylation (leads to leaky vessels)
- Small vessel disease
- Retinopathy
- Nephropathy
- Large vessel disease
- Atherosclerosis, CAD, MI
- Gangrene
- Small vessel disease
- Osmotic damage
- Recall:
- Glucose -> (aldose reductase) -> sorbitol -> (sorbitol dehydrogenase) -> fructose
- Sorbitol accumulation in organs with aldose reductase and decreased or absent sorbitol dehydrogenase
- Sorbitol is an osmol that increases osmotic pressure causing:
- Neuropathy (glove and stocking)
- Cataracts
- Nephropathy
- Recall:
What is familial hypocalciuric hypercalcemia
- Due to defective G-coupled Ca2+ sensing receptors (e.g. parathyroids, kidney)
- Higher levels of Ca2+ are needed in order to suppress PTH
- Causes excessive renal Ca2+ reuptake, leading to mild hypercalcemia and hypocalciuria with normal to increased PTH levels
What is Albright hereditary osteodystrophy
- Pseudohypoparathyroidism type 1a (Albright hereditary osteodystrophy)
- Unresponsiveness of kidney to PTH à hypocalcemia despite elevated PTH
- Characterized by short stature, short metacarpal, and short metatarsals
- Autosomal dominant disorder
- Due to defective Cs protein a-subunit, causing end-organ resistance to PTH
- Defect must be inherited by mother due to imprinting
Presentation of primary hyperparathyroidism
- THINK: Stones, thrones, bones, groans, psychiatric overtones
- Hypercalcemia, increased PTH
- Renal stones
- Polyuria (thrones)
- Osteitis fibrosa cystica (cystic bone spaces filled with brown fibrous tissue)
- Weakness and constipation (groans)
- Depression (psychiatric overtones)
Mutation in neurophysin can lead to what disease
- Neurophysin = carrier protein for oxytocin and vasopressin from hypothalamus to posterior pituitary
- Mutation in neurophysin can lead to defective transport of vasopressin = Central diabetes insipidus
Treatment of pituitary apoplexy
- Acute hemorrhage into the pituitary gland
- Occurs most often in patients with preexisting pituitary adenoma
- Cardiac collapse caused by ACTH deficiency and subsequent adrenocortical insufficiency
- Treatment – Medical emergency
- Glucocorticoid replacement (to prevent life-threatening hypotension)
- Surgical decompression
What type of collagen makes up granulation tissue
Type III
Which vasculitides are associated with granulomas?
Giant cell (large-vessel)
Takayasu (large-vessel)
Granulomatosis with polyangiits (small-vessel)
Churg-Strauss (small-vessel)
What is Werdnig-Hoffman disease
- Damage to anterior motor horn secondary to inherited autosomal recessive disease
- LMN lesion – flaccid paralysis with SYMMETRIC weakness
- Floppy baby
- THINK: Hoff = hop, so you know it is associated with polio (hopping on one leg)
What is the V/Q ratio at the apex and the base of the lung
- Zone 1 = apex
- High V/Q (> 1)
- Low perfusion (gravity pulls down)
- Wasted ventilation (physiologic dead space)
- High V/Q (> 1)
- Zone 3 = base
- Low V/Q (< 1)
- High perfusion (gravity pulls down)
- Wasted perfusion (shunting)
- Low V/Q (< 1)
In which V/Q mismatch will giving 100% O2 improve paO2
In blood flow obstruction (V/Q = infinity)
100% O2 will not improve paO2 in airway obstruction
What are the ways in which CO2 can be transported from tissues to lungs
- (1) HCO3- (via carbonic anhydrase)
- 90% of CO2 travels in this form
- (2) Carbaminohemoglobin – CO2 bound to Hb and N terminus of globin (not heme)
- CO2 binding favors taut form (O2 unloaded)
- (3) Dissolved in blood
- Presentation of acute mountain sickness:
- Headache, fatigue, cerebral edema, pulmonary edema
- Cerebral edema due to hypoxia-induced vasodilation
- Pulmonary edema due to hypoxia-induced local vasoconstriction
- Physiological changes in chronic mountain sickness:
- Increased RBC mass and hematocrit
- Increased blood viscosity and decreased tissue blood flow
- Elevated pulmonary artery pressure – due to hypoxic pulmonary vasoconstriction
- Right-sided heart enlargement
- Peripheral artery pressure falls
- Congestive heart failure
Treatment of altitude sickness
Acetazolamide
- High elevation leads to hyperventilation = blowing off CO2 = respiratory alkalosis = can treat with acetazolamide to decrease bicarb
Presentation of Decompression sickness / “The bends” / Caisson disease
- Presentation:
- Pain in joints and muscles of arms and legs
- Neurologic problems (dizziness, paralysis, syncope)
- “Chokes” (SOB, pulmonary edema, death)
- Cause:
- At deep pressures, nitrogen dissolves in blood
- As you ascend, nitrogen escapes dissolved state and forms bubbles that can occlude blood vessels
- Tx:
- Hyperbaric therapy = High pressure room that will re-dissolve the nitrogen in blood
In what thyroiditis will you see painless vs. painful goiter
- Hashimoto = painless
- Autoimmune destruction due to lymphocyte infiltration
- Subacute (granulomatous/de Quervain) = painful
- Self-limited disease following flu-like viral illness due to granulomatous infiltration
