1. Dr. muntader E. Alkhirsan Senior Lecturer College Of Medicine Kufa University M.B.CH.B F.I.B.M.S

2. EXCRETORY FUNCTION …..maintains homeostasis Urea Sodium Water Potassium Phosphate Acids

3. ENDOCRINE FUNCTION Renin-angiotensin Vitamin D Erythropoietin

4. Acute Renal Failure Clinical syndrome Abrupt decline in GFR (days to weeks) Upset of ECF volume, electrolyte and acid/base homeostasis Accumulation of nitrogenous waste products ARF increases morbidity and mortality

5. Detect acute kidney injury, by using any of the following criteria: a rise in serum creatinine of 26 micromol/L or greater within 48 hours a 50% or greater rise in serum creatinine known or presumed to have occurred within the past 7 days a fall in urine output to less than 0.5 ml/kg/hour for more than 6 hours in adults and more than 8 hours in children and young people a 25% or greater fall in eGFR in children and young people within the past 7 days

6. Oliguria (“little urine”) is defined as less than 500 ml of urine per day or less than 20 ml per hour. Anuria (“no urine”) is defined as less than 100 ml of urine per day.

7. Acute Renal Failure Incidence difficult to assess -variable criteria approximately 200pmp/yr 7% of hospitalised patients 25 -30% of patients admitted to intensive care units

8. Causes of acute renal failure Pre-renal failure Intrinsic renal failure Post-renal failure (obstruction)

9. Pre-renal Volume depletion heart failure cirrhosis

10. Renal causes Renal artery occlusion Intrarenal vascular Glomerulonephritis IschaemicATN Toxic ATN Interstitial disease Intrarenalobstruction

11. Post-renal Urinary tract obstruction

12. Pre-renal acute renal failure Caused by a reduction in renal perfusion Unless the cause of poor renal perfusion is recognised and promptly treated then acute tubular necrosis will develop

13. Causes of prerenal failure Reduced effective extracellular fluid volume Hypovolaemia Blood loss,Fluid loss,Third spacing Systemic vasodilatation Sepsis, Cirrhosis, Anaphylaxis Cardiac failure

17. Intrinsic acute renal failure Acute tubular necrosis Glomerular and arteriolar disease Acute tubulo-interstitial nephritis

18. Acute tubular necrosis Severe acute ischemia -If the fall in renal perfusion is not treated promptly tubular necrosis results Toxic acute tubular necrosis Nephrotoxins damage the epithelial cells lining the tubules, and cause cell death and shedding into the lumen Nephrotoxins can be endogenous or exogenous [e.g. drugs] ATN is much more likely if there is reduced perfusion and a nephrotoxin Treat every drug that the patient is taking as a potential nephrotoxin until proved otherwise If in doubt look it up

19. The three commonest drugs which contribute to ARF…..… These are all excellent drugs when used in the right dose for the right indication ate acute renal dysfunction GENTAMICIN ACE INHIBITORS NSAIDs

20. Glomerular and arteriolar disease Acute glomerulonephritis -immune disease affecting the glomeruli Can be - Primary: The disease only affects the kidneys Secondary: The kidneys are involved as part of a systemic process [e.g. SLE, vasculitis]

22. Other causes of acute glomerular / small vessel damage Haemolytic uraemic syndrome Malignant hypertension Pre-eclampsia Caused by endothelial damage → platelet thrombi → partial obstruction of small arteries, → destruction of RBC’s Microangiopathic haemolytic anaemia

23. Acute tubulo-interstitial nephritis Infection Acute pyelonephritis Toxin induced -many drugs -but commonest are: Antibiotics, NSAID’s

24. Post-renal failure Accounts for 10% of Acute Renal Failure cases More common in elderly

26. Post-renal Causes can be grouped into: Within the lumen Within the wall Pressure from outside

27. Within the lumen Calculi (stones) Blood clot Papillary necrosis Sloughed papillae –following infection and ischemia Tumour of renal pelvis, ureter, bladder

28. Within the wall Congenital causes: –Pelviureteric neuromuscular dysfunction –Megaureter –Neurogenic bladder Ureteric stricture (e.g. post-TB) These usually cause CRF not ARF

29. Pressure from outside Prostatic hypertrophy Tumours Aortic Aneurysm Diverticulitis Accidental ligation of ureter

30. Examination and further analysis What is the patient’s volume status? Are the kidneys under perfused? Is the patient volume depleted? Cool peripheries Increased pulse Low BP Postural hypotension Low JVP Increased skin turgor Dry axillae

31. Examination and further analysis What is the patient’s volume status ?Are the kidneys under perfused ? Is patient volume overloaded ? [a] in cardiac failure -a cause of renal under perfusion [b] as a result of ARF Gallop rhythm Raised BP Raised JVP Pulmonary oedema –basal crackles and dyspnoea, Peripheral oedema (sacral or ankle)

32. Severe infection may have initiated the acute renal failure Are there signs of sepsis? Pyrexia and rigors Vasodilatation, warm peripheries Bounding pulse Rapid capillary refill Hypotension

33. Has the patient got urinary tract obstruction? NB If patient has a bladder catheter.. make sure that it is not blocked History: Suspect obstruction in patients with: Anuria Single functioning kidney History of renal stones History of prostatism or previous pelvic or abdominal surgery Examine for: Palpable bladder Pelvic or abdominal masses Enlarged prostate in men –rectal examination

34. Serum Biochemistry ↑ Urea, ↑ creatinine in all causes of ARF Hyperkalaemia Hyponatraemia Hypocalcaemia and hyperphosphataemia

36. Imaging Ultrasound scan renal size and presence of obstruction CXR–pulmonary oedema

40. Renal Histology Obtained when: Pre-renal and post-renal ARF ruled out A confident diagnosis of ATN cannot be made Systemic inflammatory symptoms/ signs are present.

44. Indications for dialysis Usually haemodialysis in acute renal failure setting Hyperkaemia Volume overload with pulmonary oedema Pericardial rub (uraemic pericarditis) Uraemic symptoms (altered mental state, nausea, neuropathy) Metabolic acidosis Azotaemia(urea >30mmol/L)