Acute Kidney Injury (AKI)

Clinical Description

Acute Kidney Injury (AKI) is a term that has now replaced the term Acute Renal Failure (ARF). It describes a sudden decrease in renal function occurring over a period of hours to days resulting in accumulation of nitrogenous waste products and disruption of blood volume, electrolyte and acid-base balance. Patients with acute kidney injury should be referred to a hospital. Carefully check the use of any drug in renal failure and reduce drug doses where required, see below

Diagnosis in children

• Anuria (urine output <0,2 ml/kg/hr) or Oliguria (<0.5ml/kg/hr for 6 hours)

OR

• increasing creatinine (>0.3mg/dL above baseline)

Causes of AKI

Prerenal AKI

• • Dehydration, Bleeding, Burns, Nephrotic syndrome, Septic shock, Anaphylaxis, Heart failure

Intrinsic AKI, Tubular injury (often acute tubular necrosis (ATN)), Nephrotoxins, Infections (Malaria), Rhabdomyolysis, severe hemolysis, Vascular, Hemolytic uremic syndrome (recent bloody diarrhea), Vasculitidies (symptoms from other systems - lungs, brain, joints, skin), Congenitalanomalies of kidneys, Glomerulonephritis

Postrenal AKI

• Bilateral urinary tract obstruction
• Renal calculi
• neurogenic bladder
• posterior urethral valves
• spinal trauma/ tumours

Signs and Symptoms

• Oliguria/anuria
• Nausea, vomiting
• Altered level of consciousness
• Tachypnoea
• Hypertension
• Oedema
• Pulmonary oedema
• Look for clues for the cause of renal failure, which include:
• Shock
• Acute glomerulonephritis
• Use of herbal remedies containing nephrotoxins

Investigations

• Urine dipstick,microscopy and culture
• FBC
• urea, electrolyes and Creatinine
• blood gases
• malaria test
• HIV
• Hepatitis B and C
• Renal ultrasound
• Investigate underlying cause

TREATMENT IN CHILDREN

• Monitoring of blood pressure, urine output, fluid balance (input and
• output), daily weight
• Avoid nephrotoxins (NSAIDs, gentamycin, tenofovir)
• Treat the underlying cause

Pre-renal AKI

• If the child is in hypovolaemic shock and /or severely dehydrated, treat according to protocol refer

Renal AKI

• Treat hypertension with Calcium channel blockers: Nifedipine initial dose 0.25- 0.5mg/kg/day divided in 2 to 4 doses/day, titrate upwards up to 1mg/kg and if needed with Betablockers: Atenolol initial dose 0.5-1mg/kg 12 to 24 hourly
• Treat fluid overload:
• salt restriction
• Frusemide 1-2 mg/kgIV 2- 4 times a day

Refer patient

Post-renal AKI

• Urgent catheterization
• Refer to tertiary facility

Non-pharmacological

• Avoid nephrotoxins
• Adjust the doses of renally excreted drugs (penicillin, amoxicillin, cotrimoxazole,ciprofloxacin)
• Nutrition
• Low salt diet
• Low potassium diet (no bananas, tomatoes, unboiled potatoes, citrus fruits)
• High caloric diet
• Breastfeeding can be continued

Complications

• Chronic kidney disease
• Pulmonary oedema
• Uraemic encephalopathy
• Bleeding diapthesis

Complications and Referral Criteria

All patients with AKI

TREATMENT IN ADULTS

Objectives

• Assess the hydration status of the patient
• Patients who are dehydrated will need fluid resuscitation
• Avoid Ringer's Lactate fluids (has high potassium content)
• Patients who are fluid overloaded will need fluid restriction and/or diuretics
• Restrict salt intake
• Weigh the patient daily
• Carefully monitor fluid intake and output on a chart
• Medical rehabilitation for cardiorespiratory rehabilitation.
• Reduce the rate of rise of urea:
• Give adequate calories
• Restrict protein in the diet
• Treat hyperkalaemia:
• Restrict potassium intake by restricting fruits, vegetables, meat and feezy drinks
• If potassium is > 6.5mmol/l give Insulin 10 Units in 50ml of 50%

Dextrose infusion over 30 minutes

• Give a Potassium Binding Resin 30-60g orally
• Refer patient to Central Hospital for further management and consideration for dialysis if not responding to measures above

Indications for dialysis include:

• Hyperkalaemia refractory to insulin shifting
• Fluid overload not responsive to diuresis
• Metabolic acidosis
• Pericarditis
• Uremic symptoms and signs (encephalopathy, haemorrhagic pericardial effusion bleeding)
• Lithium and theophylline overdose

Note:

• Treat complications of renal failure such as convulsions, hypertension
• Do an HIV and Hepatitis B test before referral for dialysis.