Acute renal failure (ARF)/Acute kidney injury (AKI)## cause and features of ARF___#Treatment of ARF

 Acute renal failure (ARF)/Acute kidney injury (AKI)

      It refers to sudden and usually reversible loss of renal function,which usually develops over days or weeks and accompanied by reduction of urine output.

 

Causes/classification of ARF/AKI 

a)pre renal causes: 

  >Cardiac failure

> Sepsis

>Blood loss 

>Dehydration 

>Vascular occlusion.

b) renal cause: 

>Glomerulonephritis 

>Small vessel vasculitis 

>Acute tubular necroy--drugs,toxin, prolong hypotension 

>Intestinal nephritis. 

c)post renal cause: 

>Urinary calculi 

>Retroperitoneal fibrosis 

>Benign prostatic enlargement 

>Prostatic cancer 

>Cervical cancer 

>Urethral stricture/valve 

>Meatal stenosis/phimosis.

Clinical types of acute renal failure:

  1.reversible pre renal acute renal failure 

 2.established acute renal failure.

Features of ARF/AKI:

1.reduction of urine volume

    . oliguria

   .anuria 

2.disturbness if water & electrolytes,acid base balance

    --hyperkalemia 

   --metabolic acidosis 

    --dilutional hyponatremia 

  --hypocalcaemia 

 

3.others feature: 

 =>uraemic feature- anorexia nausea, vomiting,followed by drowsiness,apathy,confusion,muscle twitching,hiccough,fits and coma.

=>Increased respiratory rate 

=>Anaemia 

=>Severe infection may complicate ARF 

Investigations::

  In all patients:

 1.blood urea and creatinine 

2.serum electrolytes

3.serum calcium and phosphate level 

4.serum albumin 

5.full blood count and clotting screen 

6.C-reactive protein 

7.urinalysis 

8.urine microscopy.

9.renal ultrasound 

10.culture:blood ,urine.

11.chest X-ray 

12.serology:HIV and hepatitis 

13.ecg 

  

In particular circumstances:

1.renal arteriography and Doppler ultrasound of renal vessels.

2.autoantibodies to extractable nuclear antigen 

3.complement level 

4.anti neutrophil cytoplasmic antibody (ANCA) 

5.anti nuclear factor 

7.urgent renal biopsy-if cause unknown.

8.blood and urinary eosinophils 

9.uric acid level 

10.serology-anti streptolysin O titre.

Treatment of ARF/AKI:

a) correction of hyperkalemia:

   =>10 ml 10% calcium gluconate over 10 minutes.

 =>Inhaled B2 agonist--salbutamol 

=>IV glucose(50ml 50%) 

=>Insulin 

=>IV NaHCO3 

b) immediate fluid management 

=>Circulating blood volume should be optimized to ensure adequate renal perfusion.

=>Patients with pulmonary edema /anuria require dialysis.

c) respiratory support.

d) correction of acidosis-with sodium bicarbonate.

e) addressing and treatment of underlying cause of ARF.

 

f)fluid and electrolyte balance

G) protein and energy intake. 

  =>Dietary protein restriction:40gm/day 

f)infection control--broad spectrum antibiotic.

g)drugs to be avoided--NSAIDs and ACE inhibitor.

h)renal replacement therapy-if indicated.

Complications of ARF:

1.hyperkalaemia.

2.metabolic acidosis 

3. Dilutional hyponatremia. 

4. Hypocalcemia.

Causes of anaemia in ARF:

1.blood loss.

2.haemolysis.

3. Decreased erythropoiesis.

4. Uraemic.