Chapter 12 ( Kideny And Urinary Tract ) Flashcards
The most common renal anomaly ?
Horseshoe kidney
Kidneys site in horseshoe kidney ? Why ?
In the lower abdomen
As the horseshoe kidney gets caught on the Inferior mesenteric artery root during its ascent from the pelvis to the abdomen
Unilateral renal agenesis results in ?
Hypertrophy of the existing kidney , hyperfiltration increases risk for renal failure later in life
Bilateral renal agenesis results in ?
Oligohydraminos
Potter Sequence
Incompatible with life
Potter sequence ?
Developmental events occurs in Oligohyraminos due to absence of amniotic fluid bubble and pressure against wall of the uterus , consists of : Lung hypoplasia Flat face Low set ears Developmental defects of the extremities
Dysplastic kidney defect ?
Noninherited congenital malformation of the renal parenchyma characterized by cysts and abnormal tissue
Mechanism of polycystic kidney ?
Inherited defect leading to bilateral enlarged kidneys with cysts in the RENAL CORTEX and MEDULA
Autosomal recessive form of PKD presents in who ? Presentation ? Associations ?
Infants
Presents as worsening renal failure and hypertension , newborns may present with Potter sequence
Associated with : congenital hepatic fibrosis that leads to portal hypertension , hepatic cysts
Autosomal dominant form of PKD presents in who ? Defect ? Presentation ? Associations ?
Young adults
Mutation in APKD1 or APKD2 gene
Presents as hypertension ( due to increased renin ) , hematuria and worsening renal failure
Associated with :
Berry aneurysm
Hepatic cysts
Mitral valve prolapse
Medullary cystic kidney disease defect ? Presentation ?
Inherited autosomal dominant defect leading to cysts in the medullary collecting ducts
Presents as shrunken kidney and worsening renal failure ( due to Parenchymal fibrosis )
Azotemia ?
Increased serum BUN and Creatinine
Prerenal azotemia lab findings ?
Serum BUN : Cr ratio > 15 ( because of increased reabsorption of fluid and BUN )
FENa < 1%
Urine osmolality > 500 mOsm/kg
Early stage of postrenal azotemia lab findings ?
Serum BUN:Cr ratio > 15
Normal tubular function
Long standing postrenal azotemia lab findings ?
Serum BUN:Cr ratio < 15
FENa > 2%
Urine osm < 500 mOsm/kg
Most common cause of acute renal failure ?
Acute tubular necrosis
Mechanism of acute tubular necrosis in causing acute renal failure ?
1- necrotic cells plug tubules —> obstruction —> ⬇️ GFR
2- dysfunctional tubular epithelium results in :
Decreased reabsorption of BUN ( serum BUN:Cr ratio < 15 )
Decreased reabsorption of Na ( FENa > 2% )
Inability to concentrate urine ( urine osm < 500 mOsm/kg )
Urine casts in acute tubular necrosis ?
Brown granular casts
Which parts of renal tubule are particularly susceptible to ischemic damage ?
Proximal tubule
Medullary segment of thick ascending limb
Which part of renal tubule is particularly susceptible to toxic agents ?
Proximal tubule
Toxic agents that cause nephrotoxic ATN ?
1- Aminoglycosides ( most common ) 2- Heavy metals as lead 3- Myoglobinuria 4- Ethylene glycol ( associated with OXALATE CRYSTALS in urine ) 5- Radiocontrast dye 6- Urate ( as in tumor lysis syndrome )
How to decrease risk of urate induced ATN with chemotherapy ?
Hydration and Allopurinol before initiation of chemotherapy
Clinical features of ATN ?
Oliguria with brown granular casts
Elevated BUN and Cr
Hyperkalemia with metabolic acidosis
Why oliguria can persists foe 2-3 weeks before recovery from ATN ?
As tubular cells ( stable cells ) take time to reenter the cell cycle and regenerate
Acute interstitial nephritis mechanism ? Causes ? Presentation ?
Drug induced hypersensitivity involving the interstitium and tubules
Causes :
NSADs
Penicillin
Diuretics
Presents as : oliguria , fever and rash days to weeks after stating drug , eosinophilia may be seen in urine
Renal papillary necrosis causes ? Presentation ?
Causes : 1- Chronic analgesic abuse 2- DM 3- Sickle cell trait or disease 4- Sever acute pyelonephritis
Presents as Gross hematuria and Flank pain
Nephrotic syndrome ?
Proteinuria > 3.5 gm/day
Most common cause of nephrotic syndrome in children ?
Minimal change disease
MCD is associated with ? On H and E stain , EM and IF ?
Hodgkin lymphoma
On H and E : normal glomeruli , lipid may be seen in proximal tubule cells
On EM : effacement of foot processes
On IF : negative
Why there is excellent response to steroids in MCD ?
As the damage is mediated by cytokines from T cells
Most common couse of nephrotic syndrome in Hispanics and African Americans ?
Focal segmental glomerulosclerosis
FSG is associated with ? On H and E stain , EM and IF ?
HIV , Heroin use , sickle cell disease
On H and E stain : focal and segmental sclerosis
On EM : effacement of foot processes
On IF : negative
Most common cause of nephrotic syndrome in Caucasian adults ?
Membranous nephropathy