Nephrotic syndrome is a disease where the kidneys are damaged and are unable to hold back proteins. Proteins in variable quantity are passed in urine daily. Protein deficiency commences in the body due to this loss.
It is a non specific disorder which can occur in children as well as adults, though the causes may be different. Both genders are affected.
Damage to the kidneys can lead to loss of more than 3.5 grams of proteins in urine every day. Due to the protein loss, fluid tends to accumulate in the dependant parts of the body. This leads to development of swelling. In nephrotic syndrome, one passes smoky urine due to the presence of proteins and at times microscopic amount of blood.
Though the person may look as if they have gained weight, this appearance is mainly due to the accumulated fluid. In reality the person feels weak because of the protein deficiency.
In case of a child, the diagnosis is often delayed because when he starts swelling in the face, family members mistake it as ‘getting chubby’. It is only when he starts to become weak or develops other problems, that they seek medical treatment.
Along with deficiency of proteins, there is elevation of the fat i.e. lipid levels in the blood. This elevated lipid level can lead to forming and dislodging of blood clots. The dislodged clot can pass on to the heart through circulation causing stroke or it may enter the heart vessels resulting in a heart attack.
Obesity can develop because of high lipid levels in the blood. Some patients also develop hypertension. Long standing damage to kidneys can result in kidney failure with its attendant complications.
In the early stages, the swelling appears first on the face around eyes especially in the morning though later disappears in the course of the day. As the problem increases a person gets breathless while walking and even sleeping because of the fluid accumulated in the lungs. His abdomen looks distended due to the accumulated fluid and he has a sense of persistent bloating of the abdomen. Generalized edema present has to be differentiated from cirrhosis of the liver, protein malnutrition states and cardiac failure.
Nephrotic syndrome can be without a cause i.e. idiopathic. Some cases occur due to a cause in or outside the kidney. Diseases of the renal filtering apparatus like membranous or minimal change glomerulonephritis, can lead to nephrotic syndrome.
Among extra renal causes, multisystem diseases like SLE (systemic lupus erythematosis), sjogren’s syndrome, amyloidosis and others can cause nephrotic syndrome. Drugs like pain killers, interferon, gold and penicillamine can damage the glomerular membrane leading to nephrotic syndrome.
Malignancy particularly of the breast, colon, stomach, leukemia and lymphomas, are known to cause nephrotic syndrome. Infections like malaria, filarial, syphilis and schistosomiasis can also cause nephrotic syndrome.
These infections are responsible for causing nephrotic syndrome in large number of people in tropical climates. Other infections which cause nephrotic syndrome as a complication are hepatitis B and C. Insect bites or allergy to poison ivy is yet another cause for nephrotic syndrome. Long standing diabetes is known to damage kidneys and lead to nephrotic syndrome.
Diagnosis is very easy. The puffiness over the face is typical. Diagnosis is confirmed by blood tests revealing low levels of proteins and high lipid levels. Measurement of proteins in a 24 hour collection of urine sample also helps in confirming the diagnosis.
Once nephrotic syndrome develops, the possible cause should be identified and treated. Drugs increasing urine quantity like frusemide are given to increase the urine volume. Along with this, salt is restricted in the diet. Corticosteroids are also used routinely. Before, proteins were also restricted but as no beneficial effects were demonstrated, protein restriction is no longer part of therapy. Lipid lowering drugs are used to reduce high blood lipid levels. Depending on the condition of the patient, other drugs like ace inhibitors and anticoagulants are used.
If the cause is treated in time, like if causative pain killers are stopped, there is very good recovery otherwise one can develop a chronic disease and its related complications.
Dr Rachna Pande, Specialist, internal medicine