Symptoms of Acute Nephritis in Children: What Parents Need to Know

Acute nephritis in children is a sudden inflammation of the kidneys that can affect normal kidney function and requires prompt medical attention. Recognizing the early signs is crucial for timely diagnosis and effective treatment. This condition often develops after a bacterial or viral infection, particularly streptococcal infections, and primarily impacts school-aged children.

Common Signs and Symptoms of Pediatric Acute Nephritis

When a child develops acute nephritis, several physical and clinical symptoms may appear within days or weeks following an infection. These symptoms vary in severity but typically include fluid retention, changes in urination, and systemic complications.

1. Swelling (Edema)

One of the most noticeable early signs is swelling, which usually begins around the eyelids upon waking and may gradually spread to the face, limbs, and eventually the entire body. As the condition progresses, excess fluid can accumulate in body cavities—leading to pleural effusion (fluid around the lungs), ascites (abdominal fluid buildup), and even pericardial effusion (fluid around the heart). This generalized edema results from the kidneys' reduced ability to excrete water and sodium.

2. Hematuria (Blood in the Urine)

Blood in the urine is a hallmark symptom of acute nephritis and can present in two forms. Microscopic hematuria means red blood cells are only visible under a microscope during a urinalysis, with no visible change in urine color. In contrast, gross hematuria causes the urine to appear visibly discolored—often resembling tea, cola, or wash water due to a high concentration of red blood cells. This discoloration usually alarms parents and prompts immediate medical consultation.

3. High Blood Pressure (Hypertension)

Elevated blood pressure is another critical feature of acute nephritis in children. The kidneys' impaired function disrupts fluid and electrolyte balance, leading to hypertension. Affected children may experience headaches, nausea, vomiting, irritability, or even vision disturbances. In severe cases, uncontrolled hypertension can lead to hypertensive encephalopathy, a serious neurological complication requiring emergency care.

4. Decreased Urine Output (Oliguria)

A significant reduction in daily urine volume—known as oliguria—is commonly observed. Some children may pass very little urine over 24 hours, indicating declining kidney filtration capacity. Monitoring urine output is essential in assessing disease progression and response to treatment.

5. Proteinuria (Excess Protein in the Urine)

Another key diagnostic clue is proteinuria, where large amounts of protein leak into the urine due to damaged glomeruli—the filtering units of the kidneys. This often manifests as persistently frothy or foamy urine. While mild proteinuria might go unnoticed, severe cases contribute to low blood protein levels and worsen edema.

In addition to these primary symptoms, children may also show signs of general illness such as fatigue, poor appetite, abdominal discomfort, or fever. Early detection and proper management—including rest, dietary adjustments, and prescribed medications—can significantly improve outcomes. If you suspect your child may have acute nephritis, seek pediatric evaluation promptly to prevent complications and support a full recovery.