Is an alkaline phosphatase (ALP) level of 1342 normal in a 10-month-old with a viral illness?

Elevated Alkaline Phosphatase of 1342 in a 10-Month-Old with Viral Illness

An alkaline phosphatase (ALP) level of 1342 is likely benign transient hyperphosphatasemia, a common and self-resolving condition in infants with viral illnesses, and does not require extensive workup beyond follow-up ALP testing in 2-3 months to confirm resolution.

Understanding Benign Transient Hyperphosphatasemia

Benign transient hyperphosphatasemia is a well-documented condition in infants and young children characterized by:

• Markedly elevated serum ALP (often >1000 U/L)
• No evidence of bone or liver disease
• Spontaneous resolution within weeks to months
• Common association with viral illnesses

A recent large retrospective study of 382 children with this condition found that:

• 87% of cases occurred in children under 24 months of age
• Median age was 14 months (IQR 10-18 months)
• Mean ALP was 2557 U/L (range 1002-14,589 U/L)
• Many patients had recent viral infections, fever, or gastroenteritis 1

Clinical Approach

Initial Assessment

• Verify that the child appears otherwise healthy with normal growth and development
• Confirm absence of:
  • Jaundice
  • Hepatomegaly
  • Bone pain or deformities
  • Signs of metabolic bone disease

Limited Laboratory Testing

• If the child appears well with isolated ALP elevation:
  • Check AST, ALT, GGT, and bilirubin to rule out liver disease
  • Normal values would support benign transient hyperphosphatasemia

When to Consider Other Diagnoses

Consider further workup only if:

• Abnormal liver enzymes beyond ALP
• Signs of bone disease
• Failure to thrive
• Persistent ALP elevation beyond 3-4 months

Specific Considerations for Viral Illness

Recent evidence specifically links viral illnesses to transient hyperphosphatasemia:

• Case reports have documented severe hyperphosphatasemia in infants with viral infections, including SARS-CoV-2 2
• A seasonal peak in autumn-early winter has been observed, coinciding with common viral illness seasons 1

Management Recommendations

1. Avoid unnecessary testing - Additional laboratory tests and imaging are not indicated if the child is otherwise healthy with isolated ALP elevation
2. Reassure parents - Explain the benign nature of this condition
3. Follow-up testing - Repeat ALP in 2-3 months to confirm resolution
4. No intervention needed - No specific treatment is required

Pitfalls to Avoid

• Ordering extensive bone or liver workups for an otherwise healthy child
• Creating unnecessary parental anxiety
• Pursuing invasive testing like liver biopsy
• Failing to recognize this common and benign condition

While extremely high ALP levels in adults often indicate serious conditions like sepsis, malignant obstruction, or AIDS 3, 4, the pathophysiology in children is distinctly different and typically benign when associated with viral illnesses 5.