Acute renal failure

Acute Renal Failure

Dr.Nariman Fahmi

Clinical Scenario

History: A five years old male presents to emergency with a 5 day history of diarrhoea and vomiting. he has been unable to keep anything down including water and now lethargic and the mother noticed no urine output for the last 12 hours . O/E: he has dyspnea and has reduced skin turgor. BP is 70/50 and HR 95. Examination is otherwise unremarkable Ix: normal FBC, Na 149meq/l, K 6.7meq/l, Urea 17.0 mmol/l and Creatinine 258mmol/l

Acute kidney injury

By the end of the lecture the student can -Describe the etiology &categories of AKI -Understand principles of management of AKI -Identification of appropriate investigations - Knowledge of indications for dialysis -Awareness of complications and management of hyperkalemia (common complication)

Renal system

2 Kidneys 2 Ureters Bladder Urethra

Kidney Function

Detoxify blood Regulate blood pressure , electrolyte and fluid balance Increase calcium absorption calcitriol Stimulate RBC production erythropoietin

To function properly kidneys require:

Normal renal blood flow Functioning glomeruli and tubules Clear urinary outflow tract for drainage and elimination of formed urine from the body.

Acute renal failure

Acute sudden onset rapid reduction in urine output Usually reversible

Classifications

Pre-renal (55%) renal(40%) post-renal(5-15%)

Causes of ARF

Pre-renal = vomiting, diarrhea, cardiac failure, septic shock ,others Intrinsic Interstitial nephritis, acute glomerulonephritis, tubular necrosis, toxins Post-renal -prostatic hypertrophy, bilateral renal calculi, bladder carcinoma

Generalized or localized reduction in RBF

Hypovolaemia Haemorrhage Volume depletion ( vomiting, diarrhoea, burns)
Hypotension Cardiogenicshock (sepsis, anaphylaxis)
Oedema states Cardiac failure Hepatic cirrhosis Nephrotic syndrome
Renal Hypoperfusion NSAIDs ACEI / ARBs RAS /occlusion Hepatorenal syndrome
Reduced GFR
PRE-RENAL (Hemodynamic) AKI
PRERENAL AKI

Symptoms of ARF

Decrease urine output (70%) Edema, esp. lower extremity Mental changes Nausea, vomiting Tachypenia

Management

Think about the diagnosis Maintenance of -volume homeostasis (Assess fluid status, Fluid resuscitation) -Stop Nephrotoxic drugs -correction of biochemical abnormalities Treat reversible elements Hydrate -Relieve obstruction

Management

Treat the Treat reversible causesInfection – give antibiotics, renal dosesIntrinsic renal disease – R/v medicationObstructionExample (calculus obstruction either surgical removal or nephrectomy)

Hyperkalemia Symptoms

Weakness Lethargy Dysrhythmias

Hyperkalaemia

Potassium range is 3.5 – 5mmol/LRise in serum K+ >5mmol/lSigns/symptoms: muscle weaknessECG changes:Flattened P wavesBroad QRS complexSlurring of ST segmentTall tented T waves http://www.aafp.org/afp/2006/0115/p283.html



Hyperkalemia
Potassium >6.0 mmol/LCalcium resonium 15g QDS POIf septic or rising quickly treat as though K+ 6.5Potassium >6.5 mmol/LDextrose-insulin (50ml 50% Dextrose with 10units Actrapid insulin, IV over 5mins) –Calcium resonium 15g QDS PO

Hyperkalemia

Potassium >7 mmol/L Calcium gluconate (10ml of 10% solution into central vein or diluted into 40ml 0.9% saline into peripheral vein over 10mins, with cardiac monitor) Dextrose insulin Nebulised salbutamol 5mg IV sodium bicarbonate (50ml 8.4% over 5mins centrally or 500mls 1.26% over 30mins peripherally Calcium resonium

Dialysis

Dialysis


Diffuse harmful waste out of body Control BP Keep safe level of electrolytes and acid base level in body 2 types Hemodialysis Peritoneal dialysis

Peritoneal Dialysis

Abdominal lining filters blood

INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE

PERICARDITIS MENTAL STATUS CHANGE SEIZURES Uncontrollable hypertension , hyperkalemia or acidosis Toxins

summary

Acute renal failure is defined as an abrupt or rapid decline in renal filtration function. It is the clinical manifestation of several disorders that affect the kidney acutely treatment is supportive

References

http://www.umm.edu/ency/article/000471.htm http://www.fpnotebook.com/REN38.htm http://www.paems.org/eWebquiz/renal%20failure/Dialysis%20CEU.pdf http://www.loyolaems.com/sop/4med.htm#med8 http://www.chpnet.org/BIEM_Res/lectures.asp

Davidson's Principles and Practice of Medicine Edited by Brian R. Walker, BSc MD FRCPE FRSE, Nicki R Colledge, BSc (Hons) FRCPE, Stuart H. Ralston, MD FRCP FMedSci FRSE and Ian Penman, BSc MD FRCPE Harrisons Principles of Internal Medicine,



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