What is eGFR?
The estimated glomerular filtration rate (
eGFR) is a key indicator of kidney function. It measures how well the kidneys filter blood, specifically how many milliliters of blood are filtered by the glomeruli per minute. In pediatrics, eGFR is essential for diagnosing and managing
kidney diseases in children.
Why is eGFR Important in Pediatrics?
Children are not just small adults; their bodies and organs, including kidneys, are still developing. Accurate assessment of
kidney function in children is crucial for early diagnosis and timely intervention of kidney-related issues. eGFR helps in the early detection of
chronic kidney disease (CKD), monitoring of disease progression, and adjustment of medications that are cleared by the kidneys.
How is eGFR Calculated in Children?
In pediatrics, eGFR is typically calculated using the
Schwartz formula. This formula considers the child's height and serum creatinine levels. The equation is:
eGFR = (k x height) / serum creatinine
Where k is a constant that varies by age and sex. This formula is preferred because it accounts for the physiological differences in children compared to adults.
What is a Normal eGFR in Children?
Normal eGFR values vary with age. For
newborns, normal eGFR is lower and gradually increases as the child grows. Generally, a normal range for children is considered to be between 90-120 mL/min/1.73m². Values below this range might indicate impaired kidney function and warrant further investigation.
Interpreting eGFR Results
eGFR results should be interpreted in the context of the child's overall health, symptoms, and other diagnostic tests. A single abnormal eGFR value does not necessarily indicate
kidney disease; it could be influenced by transient conditions such as dehydration or acute illness. Persistent low eGFR values over time are more indicative of chronic kidney issues.
Factors Affecting eGFR in Children
Several factors can affect eGFR in children: Age: Younger children typically have lower eGFR values.
Body size: Height is a crucial factor in the Schwartz formula.
Serum creatinine levels: These can be influenced by muscle mass, diet, and hydration status.
Medications: Some drugs can affect kidney function and thus eGFR.
Management of Abnormal eGFR in Children
If a child has an abnormal eGFR, further evaluation is necessary. This may include additional blood tests, urine tests, and imaging studies. Management strategies depend on the underlying cause but may include:
Conclusion
eGFR is an invaluable tool in pediatric nephrology, providing critical information about kidney health in children. Accurate calculation and interpretation of eGFR can lead to early diagnosis and effective management of kidney diseases, ultimately improving health outcomes for pediatric patients.
