Minimal Change Disease is most common in very young children but can occur in older children and adults. It is by far the most common cause of nephrotic syndrome (NS) in children between the ages of 1 and 7, accounting for the majority (about 90%) of these diagnoses.^[2] Among teenagers who develop NS, it is caused by minimal change disease about half the time. It can also occur in adults but accounts for less than 20% of adults diagnosed with NS. Among children less than 10 years of age, boys seem to be more likely to develop minimal change disease than girls.

People with 1 or more autoimmune disorders are at increased risk of developing minimal change disease. Having minimal change disease also increases the chances of developing other autoimmune disorders.

Most cases of MCD are idiopathic, however there have been causes of secondary MCD identifed, including medications, immunizations, neoplasm, and infection. Case reports and literature reviews have shown an association between MCD and malignancies, particularly hematologic malignancies, such as Hodgkin’s disease, non-Hodgkin lymphomas, or leukemias. Colorectal cancer-associated MCD is uncommon and has been reported in only a few cases to date.^[3]

Symptoms

The symptoms are proteinuria (leakage of protein into the urine) and edema (water retention). Nephrotic syndrome (NS) is a general term that refers to the loss of protein in the urine, hypoalbuminemia, and edema. Many conditions are categorized as nephrotic syndromes—minimal change disease is unique, because it is the only one lacking any evidence of pathology on light microscopy (hence the name).

When protein is lost in the urine, the concentration of protein in the blood decreases, thereby reducing the intravascular Oncotic pressurerelative to the interstitial tissue. The subsequent movement of fluid from the vascular compartment to the interstitial compartment manifests as the swelling known as edema. Edema is commonly observed in the feet and legs, particularly in individuals with poorly functioning venous valves, and in the belly or abdomen (ascites), and around the eyes, but can occur anywhere, especially in response to gravity. Additionally, because of this extra fluid that stays in the body, individuals often gain weight and experience fatigue—in many patients, for example, clothes and shoes no longer fit. Some people notice that their urine becomes more frothy or foamy from the excess protein in the urine, and may find that they urinate less often.