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Q. How do you investigate and manage a patient with renal failure? (both acute & chronic)?

A. Investigations in a case of ARF is done on emergency basis to detect life threatening situations like hyperkalemia, pulmonary edema, acidosis. BUN, serum creatinine , serum sodium, potassium, blood pH, bicarbonate, serum calcium, phosphorus, alkaline phosphatase, urine examination, ECG to detect cardiac arrhythmia due to hyperkalemia, x-ray chest for diagnosis of pulmonary edema and cardiomegaly are needed. Although oliguria i.e. urine output less than 1ml/kg/day with increase in level of BUN > 20 mg/dl and serum creatinine > 1.5 mg/dl are hallmarks of diagnosis of ARF, before starting the treatment the above mentioned investigations are necessary for diagnosis of complications and to decide the indications of dialysis if conservative treatment fails. For the diagnosis of cause of ARF, clinical manifestations combined with special tests like ASO titer and serum C3 levels(for diagnosis of acute poststreptococcal glomerulonephritis); ANA, anti-dss DNA(for lupus); peripheral smear for burr cells &platelet count and coagulation studies (for diagnosis of HUS/TTP) and G-6-PD level are required. Rarely kidney biopsy may be indicated for final diagnosis of ARF to diagnose crescentic glomerulonephritis, MPGN, IgA nephropathy or lupus nephritis.

Management of ARF consists of maintenance of fluid and electrolyte balance (strictly according to urine output, weight, presence of sodium and water retention), control of hypertension, treatment of hyperkalemia (with I. V. calcium gluconate + I.V. sodium bicarbonate + glucose insulin drip and use of ion exchange resin like kayexalate which exchanges potassium for sodium in G.I. tract and reduces blood levels of potassium. Albuterol inhalation is used for hyperkalemia recently.)

Dietetic restriction of protein, potassium, sodium and water is the backbone of conservative management of ARF. If these measures fail, peritoneal dialysis is the treatment of choice as renal replacement therapy (RRT). The main indications of peritoneal dialysis are emergency situations like:

• CNS manifestations of drowsiness/seizures
 
• Respiratory failure with pulmonary edema/CCF
 
• Bleeding from G. I. tract due to uremia.

Dialysis is advised if conservative therapy fails to control

• Hyperkalemia with ECG changes of cardiotoxicity
 
• uncontrolled hypertension
 
• severe acidosis
 
• Anuria of more than one week
 
• Early dialysis in HUS, Crush injuries, myoglobinuria and in neonatal ARF (since normal neonates kidneys are immature).

As regards chronic renal failure, the same tests are recommended. Ultrasonography is used to assess the size of kidney (small kidney- poor outcome). In addition x-ray of hands for diagnosis of renal bone disease and hematological investigations including serum ferritin levels for diagnosis of anemia due to erythropoietin deficiency are required. GFR estimation using standard endogenous creatinine clearance test or Schwartz's formula

'k' is a constant which differs with age. The above formula gives accurate measurement of renal function.

Treatment of CRF includes :

• Diet
 
• Conservative therapy to reduce phosphorus, use of calcitriol, erythropoietin in appropriate cases. Conservative management can maintain good health for a few months to years.

If GFR falls below 10 ml/ min/ 1.73 sq.metre, renal replacement therapy (RRT) needs to be initiated. RRT consists of (1) chronic maintenance hemodialysis (2) chronic ambulatory peritoneal dialysis (CAPD) (3) Renal transplantation which is a preferred mode of therapy.

Q. How is a patient with renal failure followed up?

A. A patient with acute renal failure needs frequent follow up with renal biochemistry, urine examination, BP monitoring at least once a week till all parameters normalise. Complete recovery may take few months to 1 year.

Chronic renal failure should be followed with growth monitoring, BP recording and renal function tests every 1-3 months to evaluate efficacy of conservative therapy, till the renal function stabilises or GFR falls to a level when renal replacement therapy needs to be initiated.

Q. What is the prognosis of a patient with renal failure?

A. Prognosis of ARF depends on (a) underlying cause e.g. Acute poststreptococcal glomerulonephritis and ATN (Acute tubular necrosis)can recover fully if early diagnosis and treatment are offered. (b) Severe crescentic glomerulonephritis and HUS are associated with mortality (c) Anuria lasting for more than 3 weeks, young age, multiorgan failure, cortical necrosis, late referral are associated with high mortality (d) pre-existing renal disease like lupus, MPGN etc. are likely to progress to end stage renal disease years after the initial presentation as ARF.

Prognosis in a case with CRF depends on the cause e.g.congenital obstructive anomalies, congenital nephrotic syndrome, polycystic kidney disease, oxalosis, cystinosis progress to ESRD requiring RRT by 5-6 years of age, whilst chronic glomerulonephritis, chronic pyelonephritis, Alport's disease go into ESRD during adolescence and young adulthood.

There are some cases of CRF who remain with stable renal function with proteinuria and hypertension for years. They usually suffer from short stature. Growth hormone therapy is additional treatment for short stature due to CRF. It is very expensive.