What is the cause of this disease?

Whether one believes it or not, the disease in question is caused as a result of a sore throat. It may be tonsillitis/pharyngitis, or both. However, not all cases of sore throat cause this serious disease of the kidneys. It only occurs when the sore throat takes place due to the invasion of a specific bacteria called group A beta-haemolytc streptococcus. This bacteria does not directly involve the kidneys, but it remains confined in the throat, and the disease manifests itself after 1-3 weeks after the subsiding of the sore throat. It is said to be an allergic manifestation, as a result of streptococcal infection in the throat. Hence the disease may be labelled as post-streptococcal glomerulonephritis (PSGN).

What are the symptoms of GN?

The disease may be acute, subacute or chronic. The acute manifestation of the disease is very troublesome. It commonly occurs in children, and is called acute GN. This condition subsides in about 7-10 days, but in some cases, the disease may be so serious that a sudden kidney failure may occur, requiring urgent dialysis. In other cases, after the disease has subsided with treatment, or in some mild cases, even without treatment, being self-limited in nature, it may pass on to the subacute, or directly into the chronic phase, called subacute GN and chronic GN respectively.

Although patients of acute GN report to the physician/ hospital immediately, as the symptoms are of an emergency nature, yet the cases of subacute GN remain so concealed that sometimes the patient is diagnosed in a normal medical examination. Chronic GN is the terminal stage of the disease, and it is one of the important causes of chronic renal failure. And, interestingly, the patient may directly /suddenly report to the physician with the symptoms of chronic GN, without passing through either the acute/subacute phase of the disease. Further, most of the time, a previous history of sore throat may also not be available. Therefore, the occult nature of the disease is clear both in the subacute and chronic stages of this ailment.

Acute Glomerulonephritis GN

A child may suddenly report the passing of a large amount of blood in the urine (as the blood leaks into the urine due to the involvement of the blood vessel walls of several glomeruli in the kidneys), which looks a dark-brown/coca-cola colour, and the urine passed is also small in quantity. There may be pain in both the flanks due to the pathology in the kidneys, which get enlarged/swollen. As a result of haemorrhage, the whole surface of the kidney shows tiny haemorrhagic spots, and are hence called 'flea-bitten kidneys'. Such kidneys are only seen in the museums of medical colleges where they are kept/ preserved for the study of medical students. Besides blood in urine, there is puffiness / swelling of the face of the child as well. A sudden rise of blood pressure in the child is also noted.

A urine examination shows marked red blood cells (RBC), there may be a small amount of albumin in the urine and the blood urea will be slightly raised. There will be no pus cells in the urine, and the urine culture will be sterile as there is no direct invasion of bacteria, and hence no infection/pus formation.

The child should be given bed rest till all signs and symptoms disappear. If RBC or albumin persists in the urine, rest may be prolonged, or the child may be temporarily mobilised, and if RBC or albumin increases, rest should be again advised. Proper follow-up / treatment of all these cases is important so that they may not pass on to the subacute/ chronic GN, silently.

In view of sudden hypertension, a salt-restricted diet is also recommended.

With usual supportive therapy and rest, most children recover in about a fortnight. The patient, especially when the disease appears in adulthood, may pass on to the subacute / chronic stage, after remaining asymptomatic for a long period. Hence a prolonged follow-up of such a case is required, and a periodic examination of urine, especially for albumin, should be the rule, so that as soon as the patient shows the earliest sign of the, disease, it can be treated.