Renal Flashcards
What is another name for post-streptococcal glomerulonephritis?
Acute proliferative glomerulonephritis
How can one determine if pleural effusion in a pt is related to co-morbid nephrotic syndrome or an infection?
Nephrotic syndrome → transudate
Infection → exudate (elevated protein, LDH
Excess production of aldosterone (i.e. Conn’s syndrome) leads to what GI and urinary findings?
constipation, polyuria
What is the pronephros?
A transient collection of cells that disappears during the fourth week of development. It does NOT form the permanent kidney.
In a patient with a severe UTI and bacteremia, what empiric therapy should be started? What kind of drugs should not be used?
IV ampicillin and gentamicin, ciprofloxacin, olfloxacin, or ceftriaxone (i.e. bactericidal agents that kill gram-negatives); do not use bacteriostatic agents such as tetracycline, erythromycin, and nitrofurantoin in severe cases
What is a normal range for urine potassium? A high value can indicate abuse of what drug?
25-125 mEq/d; diuretics (e.g. an athlete trying to lose weight)
What is an oncocytoma?
Oncocytoma is an uncommon epithelial tumor thought to arise from the intercalated cells of the collecting tubules.
Gross: Well-encapsulated tumors with a homogenous, tan or mahogany brown cut surface
Histologic: large eosinophilic cells w/ small round nuclei and prominent mitochondria
What is bumetadine?
A loop diuretic
What type of cells predominantly make up the DCT and what is one area of exception?
Most of the distal convoluted tubules is lined by simple cuboidal epithelium with a modest apical brush border of microvilli. The macula densa is a discoid patch of tall columnar cells in the wall of the distal convoluted tubule.
What is the equation for plasma osmolality?
(total body osmoles - urine osmoles) / (TBW - urine volume)
How do you calculate TBW?
weight (kg) x % of body composed of H2O (~60%)
How do you calculate total body osmoles?
plasma osmolarity x TBW
What is the most common form of the nephrotic syndrome?
FSGS (Kaplan)
Membranous (Firecracker)
In organisms that colonize the urinary tract causing UTI, what is the most important pathogenic factor?
P-pilli (pyelonephritis-associated pilli): mediates attachment to urinary tract mucosa
What category of drug is indomethacin? As such, what is its effect on the kidney?
NSAID - decreases prostaglandin synthesis → afferent arteriole constriction
What effect do ACE inhibitors have in the treatment of patients with the nephrotic syndrome?
Improved symptoms, ↓ protein and lipid excretion, but ↑ plasma K+
What class of drug is enalapril?
ACE inhibitor
How can ECF volume be estimated?
Inulin: (amount administered - excreted)/ plasma [inulin]
What effect can ACE inhibitors have in patients at risk for acute renal failure?
↓ ATII → ↓ efferent arteriole constriction → ↓ GFR → ↑ serum creatinine → ARF (especially if co-morbid with vascular dz s.a. athero)
What effect does sickle cell disease have on the kidney?
sickle cell crisis affecting vasa recta of renal medulla → ischemia → patchy papillary necrosis
The antibodies in Goodpasture syndrome can also affect which part of the eye?
lens (contains Type IV collagen)
How does Wilms tumor present histologically?
Islands of stromal or epithelial cells which may organize into recognizable glomerular or tubular structures; may also contain muscle, bone, cartilage, fat, and fibrous tissue.
As the plasma concentration of a secreted substance increases, how is clearance of the substance affected?
Clearance is maintained until saturation of secretory transporters leads to a decrease in clearance (clearance = urinary excretion/plasma conc. & both rise proportionally)
What is tolterodine and what is it indicated for?
competitive muscarinic receptor antagonist used to treat urinary incontinence, urgency, and frequency
What is a cause of hypernatremia (↑ osm) with a continued ADH-refractory polyuria?
T2DM
What is the equation for anion gap?
[Na+] - ([Cl-] + [HCO3-])
How can GFR be calculated from lab measurements of creatinine?
For creatinine, excretion rate = filtration rate (roughly)
Excretion rate = Ucr x V
Filtration rate = Pcr x GFR
GFR = Ucr x V / Pcr
What dietary recommendations should be made for a patient with chronic renal failure?
High carb, moderate fat, low protein, low fluid intake
Which drug class decreases Na+ reabsorption while decreasing K+ excretion?
ACE inhibitors through ↓ ATII → ↓ aldosterone and corresponding ↑K+
In a patient with renal insufficiency, does FENa+ ↑ or ↓ ? How about K+?
It will initially increase to maintain normal plasma levels since GFR is ↓ until the patient becomes substantially oliguric
Where is most water reabsorbed in the kidney?
60% in the proximal tubule
What is the main side effect of cyclosporin?
nephrotoxicity – the mechanism is believed to include intense vasoconstriction → ↓ GFR; affects ppl >50 y.o. and transplant patients (6-8 wks post)
What pathology does DIC cause in the kidney?
diffuse cortical necrosis
Do loop diuretics lead to ↑ NaCl delivery to the macula densa? What is the result?
Yes, but the MD has the same NKCC transporter that furosemide acts on, so less NaCl is detected → ↑ renin secretion, efferent arteriole constriction, ↑ GFR
Is mannitol contraindicated in oliguria?
No, it is contraindicated in aneuria
Which diuretic class of drugs is contraindicated in crush injury patients with renal failure?
potassium sparing, s.a. spinonolactone and eplernone → hyperkalemia → arrhthmias → possible death
What would happen to bicarb levels immediately after 2 minutes of not breathing?
slightly increase
Is E. coli lactose fermenting?
yes
What gram negative rod that causes UTIs is lactose non-fermenting?
P. aeruginosa
How do you calculate renal plasma flow?
RPF = PAH clearance = urine [PAH]*urine flow rate / plasma [PAH]
How do you calculate renal blood flow?
RBF = PAH clearance / 1 - hematocrit
What are the 2 titratable acids that can be found in the urine in metabolic acidosis (e.g. DKA)?
NH4+, H2PO4-
How body fluid volume affected in SIADH?
It transiently increases → ↑ ANP → ↑ sodium excretion → normal body fluid volume
(euvolemic hyponatremia)
