Renal Flashcards
In horseshoe kidney, 2 kidneys are typically joined at [?] poles
Inferior poles
During embryonic development, kidney develops in pelvis and ascends into upper abdomen.In patients w/ horseshoe kidney, where is kidney located? Why?
Horseshoe kidney abnormally located in lower abdomen b/c inferior mesenteric artery (IMA) impedes its ascent into upper abdomen.
Horseshoe kidney a/w what condition?
Turner syndrome (45 XO)
Unilateral renal agenesis:Existing kidney undergoes?Later-in-life complication?
Existing kidney –> Compensatory hypertrophyLater in life –> Hyperfiltration injury to existing kidney –> Predisposes to renal failure
Bilateral renal agenesis:Embryologic defect?Fetal complication?
Embryologic defect –> Malformation of ureteric budFetal complication –> Oligohydramnios (low amniotic fluid)
Bilateral renal agenesis –> Potter sequence:Clinical presentation (x3)?
Potter sequence:Oligohydramnios –> Pulmonary hypoplasia, flat face w/ low set ears, and developmental defects of limbs/extremities
Cause of death in Potter sequence?
Pulmonary hypoplasia
Potter sequence: 3 causes?
Bilateral renal agenesisARPKDPosterior urethral valves
Renal dysplasia:Inheritance pattern?Embryologic defect?Histologic hallmark on biopsy?
Renal dysplasia = Dysplastic kidney- Non-inherited disorder- Embryologic defect –> Abnormal interaction b/w ureteric bud and metanephric mesoderm(Ureteric bud penetrates into sacral intermediate mesoderm to induce formation of metanephric mesoderm. Reciprocal exchange of inductive signals b/w 2 structures drives their differentiation into structures that form mature kidney.)- Histologic hallmark –> Cysts with abnormal structures (cartilage, immature collecting ductules)
Unilateral renal dysplasia - Clinical presentation analogous to?
Unilateral renal agenesis - Dysplastic kidney –> Cystic with abnormal structures (cartilage, immature collecting ductules) –> Nonfunctional organ- Normal kidney –> Compensatory hyperplasia
DDx of bilateral renal cysts in young child?
ARPKD and b/l renal dysplasia
Site of cysts in medullary cystic disease?
Collecting ducts of medulla
Medullary cystic disease:Cysts in collecting ducts of medulla causes what 2 renal complications?
1) Tubulointerstitial fibrosis –> Shrunken kidney2) Progressive renal insufficiency –> Inability to concentrate urine
Medullary cystic disease:Gross appearance of kidney?
Shrunken kidney 2/2 tubulointerstitial fibrosis Note - Medullary cysts are not grossly visualized
Medullary cystic disease:2 ways to diagnose?
1) Shrunken kidneys on US2) Medullary cysts on intravenous pyelogram (IVP)
Medullary cystic disease v. polycystic kidney disease:- Location of cysts?- Size of kidneys?
Medullary cystic disease –> Cysts in collecting ducts of medulla. Shrunken kidneys 2/2 tubulointerstitial fibrosis.Polycystic kidney disease –> Cysts in cortex and medulla. Enlarged kidneys 2/2 cysts grossly visualized on organ surface
Polycystic kidney disease- Autosomal recessive?- Autosomal dominant?
AR –> ARPKD –> Juvenile polycystic kidney disease –> Seen in childrenAD –> ADPKD –> Seen in adults
ARPKD a/w 1 mutation:Gene?Chromosome?Gene product?Gene product function?
PKHD1 gene on chromosome 6–> Encodes fibrocystinFibrocystin modulates polycystin2 expression and function(Polycystin2 important in renal tubular development)
ADPKD a/w 2 mutations:Genes?Chromosomes?Gene products?
PKD1 gene on chromosome 16 –> Encodes polycystin1PKD2 gene on chromosome 4 –> Encodes polycystin2
ARPKD:Clinical presentation (x4)?
1) Renal cysts –> Bilateral enlarged kidneys 2) Hepatic cysts3) Congenital hepatic fibrosis –> Portal HTN4) Systemic HTN
ARPKD:2 types of HTN?Mechanisms?
1) Portal HTN 2/2 congenital hepatic fibrosis2) Systemic HTN 2/2 elevated renin levels
ADPKD:Clinical presentation (x4)?MCC of death (x2)?
CLINICAL PRESENTATION:1) Renal cysts –> Bilateral enlarged kidneys 2) Hepatic cysts3) Mitral valve prolapse4) Berry aneurysm5) Systemic HTN 2/2 elevated renin levels MCC OF DEATH:1) Chronic renal failure2) Ruptured berry aneurysm 2/2 systemic HTN (2/2 elevated renin levels)
ADPKD a/w what cardiac condition?
Mitral valve prolapse
Renal cyst found in outer cortex filled w/ ultrafiltrate 2/2 tubular obstruction?
Simple renal cyst
Features of complex renal cyst?
Cyst may be septated, slightly calcified, or may have solid component that is non-enhancing or enhancing on CT
Complex renal cyst on CT –> Next step?
Fine needle aspiration (FNA) or surgical removal 2/2 risk of renal cell carcinoma
Clinical picture - Inflammation of connective tissue b/w renal tubules with pyuria (eosinophils in urine)?
Acute interstitial nephritis
AIN may progress to what renal pathology?
Renal papillary necrosis
NSAID-associated renal injury:Early?Chronic NSAID use?
Early: AIN that may progress to renal papillary necrosisChronic: Chronic interstitial nephritis
Muddy brown casts?
Acute tubular necrosis (ATN)Necrosis and sloughing of tubular cells forms cast
Clinical presentation of ATN?
Increased BUN/Cr, hyperK (2/2 decreased K+ excretion), and anion-gap metabolic acidosis (2/2 decreased excretion of organic acids)
ATN - 2 cell types involved? Why?
Tubular cells in:- Proximal tubule- Medullary segment of thick ascending limbBoth susceptible to ischemic injury b/c both located in outer medulla –> Medulla receives only 10% of renal blood flow
Why is ATN reversible?
B/c tubular cells are stable cells that can regenerateTakes some time to re-enter cell cycle though
ATN - 3 stages?
1) Initial stage - Ischemic/toxic “inciting” event2) Maintenance stage - Oliguria3) Recovery phase
ATN - Recovery phase?
Re-epithelialization of tubulesGradual increase in urine output –> High-volume diuresis (polyuria) but b/c tubular function isn’t yet totally recovered still risk of electrolyte imbalances
ATN- Risk of what major electrolyte imbalance in maintenance phase?- In recovery stage?
Maintenance –> Hypokalemia and anion-gap metabolic acidosisRecovery –> Hyperkalemia
Treatment of ATN?
Supportive therapy until tubular cells regenerate. Dialysis may be necessary b/c of danger of electrolyte imbalances
ATN 2/2 ischemia – > Histology?
Flattening of tubular epithelial cells, loss of proximal tubule brush border –> Subsequent necrosis and DETACHMENT OF CELLS FROM BASEMENT MEMBRANE
MCC of ATN 2/2 nephrotoxicity?
AminoglycosidesOthers - Heavy metals, ethylene glycol, radiocontrast dye, myoglobinuria (crush injury), hyperuricemia (tumor lysis), bence jones proteins (multiple myeloma)
Renal papillary necrosis:Macroscopic finding?Microscopic finding?
Macro - Yellow necrosis at tips of renal pyramidsMicro - Coagulative necrosis
