Renal Flashcards
“Lumpy Bumpy/Starry Sky” Immunofluorescence, subepithelial humps. What is the cause, and what are other classic findings?
This is acute poststreptococcal glomerulonephritis. It usually occurs in children a few weeks after a Group A strep infection (throat or skin). Type III hypersensitivity, decreased complement, lumpy-bumpy due to IgG, IgM, and C3. Coca-cola urine, facial puffiness.
IgA deposits in mesangium with painless hematuria following a URI in an older child/young adult. What is it? What is it called if accompanied by extrarenal symptoms? (ie abdominal pain, arthralgias, skin lesions)
IgA nephropathy (Berger disease). It’s the MOST COMMON type of glomerulonephritis. Look for MESANGIAL HYPERCELLULARITY/DEPOSITS. If extrarenal symptoms, it’s called Henoch Schonlein purpura.
A patient comes in with obvious signs of DKA. What would you expect the pH, HCO2, and PO4 levels to be? Hint: For PO4, remember that it would be in the form of H2PO4 in the kidneys.
pH=low. Bicarb=low (causing the metabolic acidosis). PO4=high (this is because the kidneys would be trying to get rid of the hydrogen ions so that it would be a less acidic environment.)
In the setting of dehydration (high ADH), what part of the kidney has the most concentrated and most dilute urine?
Most concentrated=Collecting duct Most dilute=Distal convoluted tubule (followed by thick ascending loop of Henle)
What is the filtration fraction, and what happens to it in the setting of severe dehydration?
Filtration Fraction (FF)=Glomerular Filtration Rate (GFR)/Renal Plasma Flow (RPF)
In dehydration, the renin-angiotensin system is activated, causing efferent arteriole constriction and afferent arteriole dilation (to try to preserve GFR).
So when BP is really low, the RPF is really low, and while the GFR is lower than normal, it doesn’t decrease as much, and so the FF actually increases
Dehydration: RPF decreases, GFR decreases, FF increases.
Light microscopy shows necrosis and crescent formation in the kidney. What is the type of glomerulonephritis, what would the crescent consist of, and name a syndrome associated with it.
Rapidly Progressive Glomerulonephritis.
Crescents consist of ABUNDANT FIBRIN, monocytes, macrophages, and glomerular parietal cells. They cause irreversible injury.
Goodpasture Syndrome is one type, you would find linear depositon of C3 and IgG.
What’s the most common cancer in the kidney, how is it described histologically, and from what type of cells does the cancer originate?
Renal Cell Carcinoma (70% of renal cancers)
Cuboidal or polygonal cells with clear abundant cytoplasm and eccentric nuclei, yellow macroscopic appearance.
Originate from the epithelium of PROXIMAL RENAL TUBULES.
What causes ANP (Atrial natriuretic peptide) and BNP (Brain natriuretic peptide) to be released, and what effect do they have?
ANP (released from atrium) and BNP (released from ventricles) are released in response to myocardial wall stretch.
They ultimately cause increased GFR, decreased Na reabsorption, and decreased renin secretion.
Net effect is Diuresis.
A patient who is currently on chemo for breast cancer comes in with hemorrhagic cystitis. What should the patient have taken concurrently with their chemo?
Mesna.
What is the net effect of a ureteral obstruction on the GFR and FF of the kidney on that side?
The GFR and FF are both decreased.
The obstruction causes the pressure in Bowman’s space to be INCREASED which results in a lower GFR.
For the first few hours the FF may increase, but once there is efferent constriction the FF will decrease.
