Do metabolic myopathies cause elevation of both creatine phosphokinase (CK) and aldolase, or only CK?

Metabolic Myopathies and Enzyme Elevation Pattern

Metabolic myopathies typically elevate CK (creatine phosphokinase) but not aldolase, making isolated aldolase elevation with normal CK highly atypical for this group of disorders.

Key Enzyme Pattern in Metabolic Myopathies

Metabolic myopathies—including glycogen storage diseases (GSD), fatty acid oxidation defects, and mitochondrial myopathies—characteristically present with elevated CK levels as the primary biomarker of muscle injury 1, 2, 3. The guidelines on GSD III and GSD I specifically mention CK elevation as a diagnostic feature, particularly in GSD IIIa where muscle involvement causes increased CK concentrations 4, 5.

Why This Matters Clinically

• CK is the standard biomarker: When evaluating suspected metabolic myopathy, CK elevation (hyperCKemia) is the expected finding and serves as the biological marker for these conditions 1, 2
• Aldolase elevation with normal CK suggests different pathology: Recent evidence demonstrates that isolated aldolase elevation with normal CK is actually characteristic of inflammatory myopathies, not metabolic ones 6

The Aldolase-Normal CK Pattern: What It Actually Indicates

A 2024 study specifically investigated myopathies with elevated aldolase and normal CK, finding 6:

• Dermatomyositis was the most common cause (8/34 patients)
• Overlap myositis and inflammatory conditions predominated
• Perimysial pathology was present in 50% of cases
• Metabolic myopathies were notably absent from this cohort

Clinical Algorithm

When you encounter elevated muscle enzymes:

1. Elevated CK (with or without aldolase) → Consider metabolic myopathy along with other causes of muscle damage

   • Glycogen storage diseases show CK elevation, especially with muscle involvement 4, 5
   • Fatty acid oxidation defects cause CK elevation during metabolic stress 2, 3
   • Mitochondrial myopathies demonstrate variable CK elevation 2

2. Elevated aldolase with normal CK → Think inflammatory/immune-mediated myopathy, NOT metabolic myopathy 6

   • Dermatomyositis is the leading diagnosis
   • Consider overlap syndromes
   • Look for perimysial pathology on biopsy

Important Caveats

CK can be normal between episodes: In metabolic myopathies presenting with episodic symptoms (exercise intolerance, recurrent rhabdomyolysis), CK may normalize between attacks 7. This doesn't mean aldolase becomes the marker—it means both may be normal interictally.

GSD III specifics: The guidelines note that normal CK does not rule out muscle involvement in GSD IIIa, but when muscle is affected, CK is typically elevated 4. The point is that CK lacks perfect sensitivity, not that aldolase replaces it as the marker.