Q. What is renal failure ?

A. Renal functions include excretory, metabolic and endocrinal functions. Renal failure is a clinical condition when kidneys fail to perform the function adequately as a result of which there is breakdown of homeostatic balance of fluid, electrolytes and acid-base with accumulation of nitrogenous waste products like BUN; creatinine and acid metabolites in blood resulting in uremia. In Chronic renal failure, deficiency of Vit. D, hyperparathyroidism and erythropoietin deficiency cause renal bone disease and renal anemia.

Q. How does a patient with renal failure present ?

A. A renal failure patient can present with salt and water retention, high BP, reduced urine output and in severe cases breathlessness(due to acidosis/pulmonary edema/CCF), convulsions and unconsciousness due to hypertensive encephalopathy or uremic toxins.

Q. What are the different types of renal failure? How do you distinguish between them?

A. Renal failure are of 3 types viz. acute renal failure, chronic renal failure and acute on chronic renal failure. Acute renal failure is characterized by sudden deterioration of renal function commonly associated with oligo-anuria which is a hallmark of ARF; whilst CRF presents insidiously with failure to thrive, short stature, anemia resistant to hematinics, resistant rickets- a clinical picture which can be confused with chronic malnutrition. Acute on chronic renal failure present like ARF and on investigations a preexisting renal disease is found viz. membranoproliferative glomerulonephritis, lupus nephritis etc.

Q. Why does renal failure occur? What are the causes?

A. Causes of ARF- At any age, the basic mechanisms leading to ARF are:

• Prerenal ARF-Due to reduced blood volume as a result of dehydration, shock, hemorrhage, cardiac failure, hypoxia, nephrotic syndrome etc.
 
• Intrinsic renal failure due to acute tubular necrosis which follows prolonged prerenal failure resulting in renal ischemia following acute gastroenteritis commonly. Other causes in bigger children can be acute post streptococcal glomerulonephritis or pyelonephritis, hemolytic uremic syndrome, drugs and toxins causing tubulointerstitial injury, G-6-PD deficiency, malaria, vasculitis, bilateral renal vein thrombosis, uric acid nephropathy, sepsis or hypoxic-ischemic injury (as in asphyxia or renal artery obstruction), acute renal failure on preexisting renal disease like lupus nephritis, IgA nephropathy or membrano-proliferative G.N.
 
• Post renal ARF whenever there is obstruction at the level of bladder neck or urethra due to posterior urethral valves, calculi or obstruction in ureter of a single kidney or pelviureteric junction obstruction in a single kidney.

Chronic renal failure is caused broadly by chronic glomerulonephritis , chronic pyelonephritis with reflux nephropathy, obstructive uropathy, congenital anomalies of kidney like hypoplastic kidney , bilateral cystic dysplasia, infantile polycystic kidney disease, inherited diseases like Alport's disease, juvenile nephronophthisis, oxalosis, cystinosis and systemic diseases like lupus nephritis, polyarteritis nodosa etc. The common pathology in all these diseases is a relentlessly progressive destruction of nephrons as a result of a variety of diseases of kidney and urinary tract which may culminate in end stage renal disease over a period of months or years.