Renal Flashcards
Alcoholic presents with Na+ - 110 plasma osmolarity - 265 Cortisol - WNL No edema, cyanosis etc. dx?
SIADH
High ADH causes water retention leading to hyponatremia and decreased plasma osmolarity
Causes - pulm dz, malignancy, CNS disorders (meningitis, brain ascess, trauma)
In an alcoholic - aspiration pneumo
A pt with a hx of recurrent calcium stones (seen on XR, and elevated urine Ca2+ but NL serum Ca2+). What should be done to prevent stone formation?
HCTZ
Lowers calcium excretion by inhibiting NaCl reabsorption in the DCT. The mild volume depletion leads to increased proximal sodium reabsorption which secondarily increases passive reabsorption of Calcium
What are the effects of an ACEI?
Angiotensin II regulates vasoconstriction and release of aldosterone. It also increases GFR by constricting the efferent arteriole. This also allows for reabsorption of bicarbonate and secretion of acid
A homeless alcoholic man presents unresponsive and dry mucus membranes. Following IV fluids he has decreased urine output and flank pain. On bx - ballooning and vacuolar degeneration of proximal renal tubules, multiple oxalate crystals in tubular lumen. Pathogenesis?
Toxic renal injury proximal tubular cell ballooning and vacuolar degeneration = Acute tubular necrosis. Oxalate crystals (envelopes) = ethylene glycol poisoning (antifreeze, coolant, brake fluid) High anion gap and metabolic acidosis, tubular cats, oxalate crystals.
What is observer bias?
When investigator’s choices are affected by prior knowledge of the exposure status (ie more likely to dx diabetec nephropathy when they know a bx came from a DM pt)
How does a beta blocker affect the RAAS system?
Renin, Ag1, AgII, aldosterone, bradykinin
Decreased renin, AgI, AgII, Aldosterone
No change - bradykinin
Beta blockers block the beta 1 mediated regulation of RAAS and reduces renin activity (and therefore everything else is decreased)
At 18 wks gestation fetal U/S demonstrates unilateral hydronephrosis in a male. Where is the site of the obstruction?
Ureteropelvic junction (connection b/w kidney and ureter).
Caused by narrowing or inking of the proximal ureter
Newborns present with palpable abdominal mass
Can be due to failure of canalization or abnormal development of cirucular musculature
Which artery feeds the proximal ureter (close to its exit from the kidney)?
Renal a.
Which artery feeds the distal ureter?
Superior vesicular a.
A healthy volunteer is found to have decreased intestinal absorption of lysine, arginine, ornithine, and cysteine. If untreated, what is he at risk of developing?
Cystine Kidney stones
Cystinuria is an ar disorder that causes reduced absorption of Cysteine, ornithine, lysine, and arginine (Cola) aa’s in the intestine and kidneys (b/c they share the same transporter).
the kidneys aren’t able to reabsorb these amino acids.
RFs include low urine pH, preexisting crystal nidus, and urine supersaturation
A pt on furosemide takes high dose ibuprofen for joint pain. Blunting of the diuretic response is due to decreased production of?
Prostaglandins
Loop diuretics stimulate prostaglandin release for their vasodilatory effects (increased RBF = increased GFR which enhances drug delivery)
NSAIDs inhibit prostaglandin synthesis
What is the action of high dose IL-2 in its ability to regress malignancy?
Enhanced activity of natural killer cells
iL-2 is produced by Cd4+ to stimulate growth of CD4+, CD8+, and B cells. Also activates NK’s and monocytes. Increased activity of T cells and NK cells is responsible for IL-2’s anticancer activity
Which cytokine increases expression of MHC I and II on APC’s?
IFN-gamma
If reabsorption of a molecule is blocked in the PCT, the clearance of that molecule will be approximately be equal to the clearance of?
Inulin
During a U/S midline cystostomy which structures (besides the bladder) could be pentrated?
Anterior abdominal aponeurosis
The bladder is extraperitoneal
Which kidney structures arise from the metanephric mesoderm?
DCT Glomeruli Bowman's space, PCT Loop of Henle
What are the 3 sheets of primitive nephrotic tissues?
Pronephros
Mesonephros
Metanephros
Which kidney structures arise from the pronephros?
None. it regresses
Which kidney structures arise from the mesanephros?
Reproductive structures (Wolffian ducts, Gartners ducts)
A sexually active female presents with frequent UTI’s, cystitis, and pyelo. What is predisposing her to the pyelo?
Vesicoureteral urin reflux
Presents pathogens to the bladder due to urine returning into the ureter due to anatomic abnormality
A 7 y/o was given epi for a bee stink 2 weeks ago and is presenting with nephrotic symptoms. Dx?
Minimal change dz Inciting event can be due to infection, ummunization, or insect bite Normal LM, IF See diffuse podocyte effacement on EM Tx - corticosteroids
A pt tries to OD on diuretics. She presents with: Na - 122 K - 2.8 Cl - 84 Bicarb - 28 BUN - 22 Cr - 1.4 Ca2+ - 11.4 Albumin 3.9 What did she take?
HCTZ
Inhibits Na/Cl cotransporter in DCT
Causes hyponatremia, hypokalemia, metabolic alkalosis, and hypercalcemia
ONLY diuretic that causes hyponatremia
What would be expected in hyperacute allograft rejection?
min - hours
Recipients blood had preformed Ab against the graft
Histology - gross mottling, cyanosis, arterial fibrinoid necrosis, and capillary thrombotic occlusion
Would would be expected in acute allograft rejection?
What would be expected in chronic allograft rejection?
Months - years
Gradual decrease in allograft function (worsening HTN, progressive rise in serum Cr, proteinuria)
Low grade cellular and humoral response leads to fibrous intimal thickening leading to ischemia, atrophy of the parenchyma and tubules, and intersititial fibrosis
How do you calculate FF?
FF = GFR/RPF
RPF = RBF x (1-Hematocrit)
Because RBC’s are a portion of the RBF that are too large to be filtered
Pt presents with back pain, constipation, fatigability x months. Labs: Hgb - 8.6 MCV - 92 BUN - 68 Cr - 3.8 Total protein - 8.9 Albumin - 4.1 Bx - LM, atrophy of tubules with large obstructing intensely eosinophilic casts. Dx?
Multiple myeloma Suspect in an elderly pt with 1. fatigue (anemia) 2. Constipation (hypercalcemia) 3. Bone pain (lytic lesions) 4. Elevated serum protein (monoclonal) 5. Renal failure Myeloma cast nephropathy due to Bence Jones proteinscausein tubular obstruction and epithelial injury. Deposits = Light chain fragments
A pt on metoprolol is given an ACEI. His HTN improves but see a rise in Serum Cr. Why?
Reduction in renal filtration fraction.
ACEI can cause ARF in susceptible pts because decreased AgII means that there is less efferent arteriole vasoconstriction. This decreases GFR and therefore FF
ACEI can be detrimental in pts that rely on efferent arteriole constriction
An older pt with painless hematuria
Urinary tract cancer (urothelial or RCC)
Bx of RCC?
rounded polygonal cells with abundant clear cytoplasm. Roximal tubular epithelial cells with copious amounts of intracellular glycogen and lipids. Staining usually dissolves glycogen leaving clear psaces on bx.
Where would you expect to see the lower tubular fluid osmolarity in the nephron?
DCT
thick ascending loop
42 y/o man with T1DM presents with frequent involuntary loss of urine, difficulty maintaining stream, and nocturnal enuresis
Overflow incontinence Impaired detrusor contractility or bladder outlet construction. Increased postvoid residual volume T1DM affects detrusor muscle inn Dx with U/s or cath
During surgery a surgeon can palpate the R ureter immediately anterior to the?
internal illiac a., medial to the ovarian a.
but it would be posterior to the uterine a.
A pt recently treated for impetigo is presenting with nephrotic syndrome. What is causing his kidney damage?
Immune complexes Post streptococcal GN Type III HS reaction EM - electron dense sub epithelial humps IF - IgG and C3 +
A pt with anemia due to chronic kidney dz is given a erythropoiesis stimulating agent. What complication is most likely to be seen when this agent is used?
Worsening HTN
Increased risk of thromboemolic events
But, it does allow pts to avoid transfusions
Unilateral kidney atrophy is suggestive of?
Renal a. stenosis
Occurs in elderly with atherosclerotic changes or in women of childbearing age with fibromuscular dysplasia
Often presents with HTN and abdominal bruit
10 y/o presents with tea-colored urine after exercise, HTN, and periorbital edema. Urinalyusis = RBC casts and mild proteinuria. Dx?
Post-infectious GN
Following exercise pt has muscle pain, elevated creatine kinase, myoglobinuria (but not RBC’s). Dx?
Rhabdomyolysis
A young pt presents with recurrent kidney stones and hexagonal crystals are found on urinalysis. Dx?
Cystinuria
Defect in dibasic amino acid transport causes hexagonal cysteine stones.
Sodium cyanide-nitroprusside test can detect excess cystine in the urine
Tx - hydration and alkalinize the urine (acetazolamide)
Differential for a pt with crescent formation on renal bx
- anti-GBM RPGN )Goodpastures)
- Immune complex RPGN - (lympy bumpy, PSGN, SKE, IfA nephropahty, Henoch-Schonlein purpura)
- Pauci-immune RPGN - ANCA (granulomatosis with polyangiitis or microscopic polyangiitis)
A pt presents with heamturia, fatigue, nasal congestion x months. PE = edema. Labs = elevated BUN and serum Cr. Urinalysis = moderate proteinuria, hematuria with RBC casts. Bx = crescentic glomeruli. IF = no immunoglobulin or complement deposits
Crescentic formation with no Ig or complement deposits = pauci-immune GN
Dx - ANCA Abs
Either granulomatosis with polyangiitis or microscopic polyangiitis
Can be idiopathic