24 radman acute renal failure
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Transcript of 24 radman acute renal failure
DR. SAMI ABDO RADMAN
Acute Renal Failure
Acute Renal Failure Definition Acute renal failure (ARF) is a syndrome defined as an abrupt decrease in glomerular filtration rate sufficient to result in retention of nitrogenous waste products (blood urea nitrogen [BUN] and creatinine) and perturbation of extracellular fluid volume and electrolyte and acid-base homeostasis
Usually, but not invariably, reversible over a period of days or weeks.
Detsufficiently severe to result in uraemia
Oliguria is usually, but not invariably, a feature.
Cause sudden, life-threatening biochemical erioration in renal function is disturbances
Is a medical emergency..
Causes ARF can result from (1) diseases that cause a decrease of
renal blood flow (prerenal azotemia ( (2diseases that directly involve renal
parenchyma (renal azotemia) (3) diseases associated with urinary
tract obstruction (postrenal azotemia)
Prerenal uraemia
Is the most common form of ARF There is impaired perfusion of the kidneys
with blood. Hypovolaemia, Hypotension, Impaired cardiac pump efficiency or Vascular disease limiting renal blood flow, Or combinations of these factorsExcretory function in prerenal uraemia
improves once normal renal perfusion has been restored.
CLINICAL MANIFESTATIONS
Thirst, dizziness Hypotension and tachycardia, Reduced jugular venous pressure,Decreased skin turgor, Dry mucous membranes,Reduced axillary sweating.History of intake of hypotensive drugs
Management
Correction of hypovolaemia and hypotension,
Treatment of the undelying cause
recovery typically takes 1 to 2 weeks after normalization of renal perfusion
Postrenal uraemia
Obstruction of the urinary tract at any point from the calyces to the external urethral orifice.
Clinical exam:Tenderness on the suprabubic region or renal
angle History of stones History of Prostatic diseaseTreatment Removal of the obstruction
Renal AzotemiaAcute uraemia due to renal parenchymal disease (Acute tubular necrosis, ATN)
This is most commonly due to acute renal tubular necrosis (Due to acute ischemic or nephrotoxic insult)
Causes HaemorrhageBurnsDiarrhoea and vomitingDiureticsMyocardial infarction
Congestive cardiac failureSnake biteMyoglobinaemia Haemoglobinaemia (due to haemolysis, e.g. in falciparum malaria, 'blackwater fever)
Hepatorenal syndrome Drugs, e.g. aminoglycosides, NSAIDs, ACE inhibitors
N.B:In liver failure, acute renal result from rapidly
reversible vasomotor abnormalities within the kidney.
A kidney removed from a patient with hepatic cirrhosis and liver failure dying with oliguric renal failure may function normally immediately after transplantation into a normal individual
Pathogenesis Intrarenal microvascular vasoconstriction:
Tubular cell injury Ischaemic injury results in rapid depletion of intracellular ATP stores resulting in cell death
Glomerular contraction reducing the surface area available for filtration
Obstruction of the tubule by debris shed from ischaemic tubular cells
Clinical Course Depending on the severity and duration
of the renal insult. Oliguria is common in the early stages:
non-oliguric renal failure is usually a result of a less severe renal insult.
Recovery of renal function typically occurs after 7-21 days,
ATN may last for up to 6 weeks, even after a relatively short-lived initial insult
Clinical and biochemical featuresThe features of the causal condition together with features of rapidly progressive uraemia
serum urea and creatinine concentrations depend upon the rate of tissue breakdown(trauma, sepsis and surgery)
Pulmonary oedema
Symptoms of uraemia such as anorexia, nausea, vomiting pruritus develop, drowsiness, fits, coma and haemorrhagic
episodes. Epistaxes and gastrointestinal
haemorrhage Severe infection may have initiated the
acute renal failure or have complicated it owing to the ( impaired immune defences)
URINALYSIS in ARFAnuria suggests complete urinary tract
obstruction OR severe cases of prerenal or intrinsic renal ARF
Wide fluctuations in urine output raise the possibility of intermittent obstruction,
Polyuria in partial urinary tract obstructionTransparent hyaline casts In prerenal ARF, (secreted by epithelial cells of the loop of
Henle)
Hematuria and pyuria are common in patients with intraluminal obstruction or prostatic disease.
Epithelial casts present in ATN (ischemic or nephrotoxic ARF)
Red blood cell casts indicate glomerular injury
Eosinophiluria is common in antibiotic-induced allergic interstitial nephritis
Bilirubinuria may provide a clue to the presence of hepatorenal syndrome.
Urine should be tested for free haemoglobin and myoglobin,
Laboratory findings in ARFBlood tests include measurement of
serum urea, electrolytes, creatinine, calcium, phosphate, albumin,
Increase serum Creatinin Hyperkalemia, hyperphosphatemia,
hypocalcemiaSevere anemia in the absence of
hemorrhage indicates hemolysisSystemic eosinophilia suggests
allergic interstitial nephritis
RADIOLOGICAL INVESTIGATIONSA plain film of the abdomen UltrasonographyPelvicalyceal dilatation is usual with urinary tract obstruction
Retrograde or anterograde pyelography
ManagementGeneral measures
Consistent documentation of fluid intake and output,
Measurement of daily bodyweightEmergency measures
Correction of acidosis with intravenous sodium bicarbonate
Pulmonary oedema DuireticsTreatment of sepsis
Fluid and electrolyte balance Diet
Protien restriction (40 gm daily)sodium and potassium restriction
Management …contDialysis is indicated in
Symptoms of uraemia Complications of uraemia, such as
pericarditis Hyperkalaemia not controlled by
conservative measures Pulmonary oedema Severe acidosis For removal of drugs causing the acute renal
failure, e.g. Gentamicin, lithium, severe aspirin overdose.