Kidney/Urinary: Congenital and Acute renal failure Flashcards
What is the most common congenital renal anomaly
horseshoe kidney
What is horseshoe kidney
conjoined kidney usually at lower pole
where is horseshoe kidney abnormally located
lower abdomen
where do normal kidneys develop
pelvis
what problem occurs when horseshoe kidney ascends from pelvis to lower abdomen
get caught on inferior mesenteric artery
what is renal agenesis?
absent kidney formation
- may be unilateral or bilateral
renal agenesis unilateral leads to what consequence?
hypertrophy of existing kidney
- hyperfiltration increases risk of renal failure later in life
renal agenesis bilateral leads to what consequence?
oligohydramnios with lung hypoplasia
Potter’s sequence
What are the symptoms for Potter’s sequence? Is it compatible with life?
flat face
low set ears
developmental defects of extremities
- incompatible with life
what is dysplastic kidney disease
- inherited, congenital malformation of renal parenchyma characterized by cysts and abnormal tissue (cartilage)
what is polycystic kidney disease
- inherited defect leading to bilateral enlarged kidneys with cysts in renal cortex and medulla
what are two forms of polycystic kidney disease (PKD)
Autosomal recessive
Autosomal dominant
autosomal recessive polycystic kidney disease presents in who? How does it present
infants
- worsening kidney failure and hypertension
- newborns present with Potter sequence
autosomal recessive polycystic kidney disease is associated with what congenital abnormality
congenital hepatic fibrosis (leads to portal hypertension)
hepatic cysts
Autosomal dominant polycystic kidney disease presents in who and clinical features
young adults
- hypertension ( due to increase renin)
- hematuria
- worsening renal failure
autosomal dominant polycystic kidney disease is due to what mutation which causes what
APKD1 and APKD2
cysts develop over time
autosomal dominant polycystic kidney disease is associated with what health problems
- berry aneurysm
- hepatic cysts
- mitral valve prolapse
Which congenital kidney problem is not inherited
dysplastic kidney
What happens to the size of kidneys in polycystic kidney disease
enlarged
what is medullary cystic kidney disease inherited
autosomal dominant
what is medullary cystic kidney disease
cysts in medullary collecting ducts
- parenchymal fibrosis results in shrunken kidneys and worsening renal failure
oliguira
low production of urine
azotemia? what lab values are associated with it
increase nitrogen-containing waste products in blood
- increased BUN and creatinine [Cr]
what is a common cause of acute renal failure
prerenal azotemia
what causes prerenal azotemia
decreased blood flow to kidneys
how does prerenal azotemia impact the kidney, blood, and urine
decreases GF
azotemia
oliguria
what is the BUN: Cr ration in prerenal azotemia and why?
greater than 15
- reabsorption of fluid and BUN back into system
what is the tubular function of prerenal azotemia? lab value?
remain intact
- fractional excretion of sodium [FENa] less than 1%
what is the urine osmolality in prerenal azotemia
[osm] greater than 500 mOsm/kg
what is postrenal azotemia
obstruction of urinary tract downstream from kidney
how does postrenal azotemia impact the kidney, blood, and urine
- decrease GFR
- azotemia
- oliguria
what happens during the early stages of postrenal azotemia? lab values?
- increased tubular pressure ‘forces’ BUN into blood; BUN:Cr greater than 15
- tubular function remains intact; FENa less than 1%
- urine osmolality; osm greater than 500 mOsm/kg
what happens during the later stages of postrenal azotemia? lab values
- tubular damage , decrease absorption of BUN; BUN: Cr less than 15
- decreased reabsorption of sodium; FENa greater than 2%
- inability to concentrate urine; less than 500
What is the MOST common cause of acute renal failure
acute tubular necrosis
What is acute tubular necrosis
injury and necrosis of tubular epithelial cells
- necrotic cells plug tubules
necrotic cells plug tubule in acute tubular necrosis, which causes what
- decrease GFR
- brown, granular casts seen in urine
dysfunctional tubular epithelial cells in acute tubular necrosis results in
- decreased reabsorption of BUN (serum BUN:Cr greater than 15)
- decreased reabsorption of sodium ( FENa less than 2%)
- inability to concentrate urine ( urine osm less than 500 )
what are etiologies of acute tubular necrosis
ischemia and nephrotoxic
what is ischemia of acute tubular necrosis
- decreased blood supply results in necrosis of tubules
what usually precedes ischemia of acute tubular necrosis
prerenal azotemia
what parts of the kidney are susceptible in ischemia acute tubular necrosis
proximal tubule and medullary segment of thick ascending limb
what causes nephrotoxic acute tubular necrosis
toxic agents resulting in necrosis of tubules
what part of the kidney is susceptible to nephrotoxic acute tubular necrosis?
proxmial tubule
nephrotoxic acute tubular necrosis can be caused by
- aminoglycosides
- heavy metals ( lead)
- myoglobinuria ( from crush injury to muscle)
- ethylene glycol ( associated with oxalate crystals in urine)
- radiocontrast dye
- urate ( tumor lysis syndrome)
what is ethylene glycol? characteristics
anti-freeze
blue and sweet
what is used prior to initiation of chemotherapy of acute tubular necrosis?
this whole processes decreases what?
hydration and allopurinol
decrease risk of urate-induced ATN
what are clinical features of acute tubular necrosis
- oliguria with brown, granular casts
- elevated BUN and creatinine
- hyperkalemia ( due to decreased renal excretion) with metabolic acidosis
Can you treat acute tubular necrosis
reversible, requires supportive dialysis, electrolyte imbalance can be fatal
what happens in oliguria and tubular cells during recovery of acute tubular necrosis
- oliguria persists for 2-3 weeks before recovery
- tubular cells ( stable cells) take time to reenter the cell cycle and regenerate
what is acute interstitial nephritis ? what causes it? what does it lead to?
- drug-induced hypersensitivity involving the interstitium and tubules
- acute renal failure ( intrarenal azotemia)
what are some causes of acute interstitial nephritis
NSAIDS
penicillin
diuretics
clinically how does acute interstitial nephritis present
oliguria
fever
rash days to weeks after starting drug
EOSINOPHILS may be present in urine
how do you treat acute interstitial nephritis
stop taking drug
what can acute interstitial nephritis progress to
renal papillary necrosis
what is renal papillary necrosis
necrosis of renal papillae
how does renal papillary necrosis present
gross hematuria and flank pain
what are 4 causes of renal papillary necrosis
- chronic analgesic abuse
- diabetes mellitus
- sickle cell trait/disease
- severe acute pyelonephritis
what can cause chronic analgesic abuse
long-term phenacetin or aspirin use
