Acute kidney injury (AKI) in children is a serious medical condition that can lead to life-threatening complications if not promptly identified and treated. While AKI is more commonly associated with adults, paediatric AKI is on the rise and represents a major cause of morbidity and mortality among children.

The condition can be triggered by a variety of factors, including infections, medications, and pre-existing medical conditions. Understanding the causes, symptoms, and treatment options for acute kidney injury in children is crucial for healthcare providers and caregivers alike.

In this article, we will explore the causes, symptoms, treatment options, and long-term outcomes of acute kidney injury in children. We’ll also highlight the importance of early diagnosis and discuss how advancements in medical science are improving recovery rates for paediatric patients.

Causes of Acute Kidney Injury in Children

The causes of acute kidney injury in children are diverse and can range from relatively benign to life-threatening conditions. Some of the most common causes include:

• Dehydration: One of the most common triggers of pre-renal AKI in children, especially in developing countries, is severe dehydration, often resulting from diarrhoea, vomiting, or fever.
• Sepsis: Infections that spread throughout the body (sepsis) can lead to significant damage to the kidneys. Sepsis-related AKI is often associated with a higher risk of mortality and long-term complications.
• Medications and Nephrotoxins: Certain medications (e.g., nonsteroidal anti-inflammatory drugs (NSAIDs), some antibiotics, and chemotherapy drugs) can cause kidney damage in children, leading to intrinsic AKI.
• Glomerulonephritis: This condition, characterised by inflammation of the kidney’s filtering units, can lead to AKI in children. It can result from infections like streptococcus or autoimmune diseases.
• Haemolytic Uremic Syndrome (HUS): HUS is a condition that causes the destruction of red blood cells, which leads to kidney failure. It is often associated with bacterial infections such as E. coli and is one of the leading causes of AKI in young children.
• Congenital or Structural Abnormalities: Children born with abnormalities in the urinary tract (such as posterior urethral valves or vesicoureteral reflux) are at increased risk of post-renal AKI.
• Trauma and Surgery: Severe trauma, burns, or major surgery can reduce blood flow to the kidneys, leading to AKI.
• Multisystem Inflammatory Syndrome in Children (MIS-C): Recently, there has been an increase in paediatric AKI cases due to MIS-C, a condition linked to COVID-19.

Acute Kidney Failure in Children: Symptoms

The symptoms of acute kidney injury in children can vary widely depending on the underlying cause and the severity of the kidney damage. Some children may exhibit obvious signs of AKI, while others may present with subtle or non-specific symptoms. Common symptoms include:

• Decreased urine output (oliguria): A noticeable reduction in the amount of urine produced by the child.
• Swelling (edema): Accumulation of fluid in tissues, particularly around the eyes, hands, feet, and legs.
• Fatigue and lethargy: Children with AKI often feel excessively tired and weak due to the buildup of toxins in the blood.
• Nausea and vomiting: A common symptom resulting from the body’s inability to excrete waste products.
• Loss of appetite: Children with AKI may experience a sudden reduction in their desire to eat.
• High blood pressure (hypertension): AKI can cause increased blood pressure due to fluid retention and disrupted hormone regulation.
• Pale skin or a yellowish tint: As toxins accumulate, some children may develop a pallor or jaundice.
• Breathing difficulties: Accumulation of fluids in the lungs can lead to difficulty breathing or shortness of breath.
• Seizures or confusion: In severe cases, AKI can lead to neurological symptoms such as confusion or seizures due to electrolyte imbalances.

Diagnosing Acute Kidney Injury in Children

Early diagnosis of AKI is critical to prevent long-term complications and improve outcomes. Diagnosis typically involves a combination of clinical assessment, laboratory tests, and imaging studies.

• Blood Tests: Measuring blood levels of creatinine and blood urea nitrogen (BUN) provides insights into kidney function. Elevated levels of these waste products indicate reduced kidney function.
• Urine Tests: A urine test may be conducted to check for abnormalities such as proteinuria (excess protein in urine), haematuria (blood in urine), or the presence of casts, which indicate kidney damage.
• Ultrasound: Renal ultrasound is a non-invasive imaging technique commonly used to assess kidney size, structure, and the presence of obstructions or abnormalities.
• Kidney Biopsy: In some cases, a kidney biopsy may be needed to determine the exact cause of AKI, especially if intrinsic kidney disease is suspected.
• Electrolyte and Acid-Base Balance: Children with AKI often have imbalances in potassium, sodium, and bicarbonate levels, which require careful monitoring.

Acute Kidney Injury Paediatric Treatment

Treatment for acute kidney injury in children varies based on the cause, severity, and the child’s general health. The primary goal of treatment is to restore normal kidney function, manage the underlying cause, and prevent complications.

Supportive Care

Supportive care is often the first step in managing paediatric AKI. This may include:

• Fluid Management: Fluid balance is crucial. In cases of dehydration, careful rehydration with intravenous fluids can help restore kidney function. Conversely, in cases where fluid overload occurs, diuretics may be administered to help remove excess fluid.
• Electrolyte and Acid-Base Correction: Children with AKI often experience imbalances in potassium, sodium, and other electrolytes, which can lead to life-threatening complications such as cardiac arrhythmias. Electrolyte levels must be carefully monitored and corrected using medications or intravenous fluids.
• Nutritional Support: Adequate nutrition is essential for children with AKI. In some cases, a low-protein diet may be recommended to reduce the burden on the kidneys, while ensuring that the child receives sufficient calories and nutrients to support growth and healing.

Medications

• Antibiotics: If the AKI is caused by an infection, such as sepsis, appropriate antibiotics or antiviral medications will be administered to target the infection.
• Diuretics: In cases where the child is retaining too much fluid, diuretics (e.g., furosemide) may be given to encourage urine production and reduce fluid accumulation.
• Blood Pressure Control: Hypertension is common in paediatric AKI, and medications such as angiotensin-converting enzyme (ACE) inhibitors or beta-blockers may be prescribed to help control blood pressure.
• Dialysis: In severe cases of AKI where the kidneys are not functioning adequately, dialysis may be necessary to perform the functions of the kidneys. This may be temporary until the kidneys recover, or in rare cases, may become a long-term solution.

Renal Replacement Therapy

Renal replacement therapy (RRT), including dialysis, may be needed for children with severe AKI who do not respond to supportive measures. RRT options include:

• Haemodialysis: A machine filters the child’s blood, removing waste products and excess fluids. Haemodialysis is usually performed in a hospital setting.
• Peritoneal Dialysis: This method uses the lining of the abdomen (the peritoneum) to filter waste products from the blood. It can be performed at home or in a hospital.
• Continuous Renal Replacement Therapy (CRRT): This is a slower form of dialysis that is often used in critically ill children in the intensive care unit (ICU).

Long-Term Outcomes of Acute Kidney Injury in Children

While many children recover fully from AKI, there is a growing concern about the long-term effects of the condition. The severity of AKI and the child’s underlying health condition play a critical role in determining long-term outcomes.

Chronic Kidney Disease (CKD)

Children who experience AKI are at increased risk of developing chronic kidney disease later in life. CKD is a long-term condition characterised by gradual loss of kidney function over time.

Hypertension

Children who recover from AKI may have an increased risk of developing high blood pressure, which requires long-term monitoring and management.

Proteinuria

Some children may develop persistent proteinuria (protein in the urine), which is a marker of ongoing kidney damage and may require ongoing treatment.

Growth and Developmental Delays

Severe AKI can lead to growth delays in children, especially if the condition occurs during infancy or early childhood. This is often due to malnutrition, electrolyte imbalances, and the body’s stress response to illness.

Recurrence of AKI

Some children may be more prone to recurring episodes of AKI, particularly if they have underlying medical conditions or structural abnormalities in their kidneys.

Preventing Acute Kidney Injury in Children

Preventing AKI in children is challenging due to the variety of potential causes, but some strategies can reduce the risk:

• Early Diagnosis and Treatment of Infections: Timely treatment of infections, especially sepsis and urinary tract infections (UTIs), can help prevent AKI.
• Avoidance of Nephrotoxic Medications: Medications known to cause kidney damage should be used cautiously in children, especially those with pre-existing kidney conditions.
• Hydration: Ensuring that children remain adequately hydrated during illness, especially when experiencing diarrhoea or vomiting, can help prevent pre-renal AKI due to dehydration.
• Regular Monitoring: Children with congenital kidney abnormalities or those who have had a previous episode of AKI should be regularly monitored by a paediatric nephrologist to detect early signs of kidney damage.

A Final Word

Acute kidney injury in children is a serious condition that requires prompt medical attention and careful management. While many children recover fully, others may experience long-term consequences, including chronic kidney disease and hypertension. Early diagnosis, appropriate treatment, and ongoing monitoring are essential to improving outcomes for children with AKI.

Advances in medical care, including the use of renal replacement therapy and improvements in supportive care, have improved the prognosis for children with AKI. By understanding the causes, symptoms, and treatment options for acute kidney injury in children, healthcare providers and caregivers can work together to ensure that children receive the best possible care and support during their recovery journey.

Sources:

• https://www.ncbi.nlm.nih.gov/pmc
• https://www.childrenshospital.org/conditions/acute-kidney-injury
• https://www.ncbi.nlm.nih.gov/books/NBK441896/
• https://www.mayoclinic.org/diseases-conditions/kidney-failure/symptoms-causes
• https://www.aafp.org/pubs/afp/issues