Cytochrome C Oxidase Negative Muscle Fibers C4021724
A muscle condition where certain fibers lack an important enzyme needed for energy production. It may cause muscle weakness. Management involves supportive care and monitoring for associated symptoms.
Key facts at a glance
- ICD-10
- M79.9
- ICD-11
- FA00.0
- Body system
- musculoskeletal
- Severity
- moderate
- Chronic
- false
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Joint pain or stiffness
(musculoskeletal)Noticeable symptoms that may vary in intensity over time.
Frequency: Varies
Proximal muscle weakness
(musculoskeletal)Exercise intolerance
(musculoskeletal)Muscle pain after exercise
(musculoskeletal)Elevated serum creatine kinase
(musculoskeletal)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Coenzyme Q10 (CoQ10) supplementation
CoQ10 acts as an electron carrier in the mitochondrial respiratory chain and may help improve energy production in muscle fibers with cytochrome c oxidase deficiency.
Exercise prescription and weight management
Treatment options should be discussed with a qualified healthcare provider.
Tailored exercise program
Low-impact aerobic exercise and resistance training designed to maintain muscle strength and function while avoiding overexertion that could worsen mitochondrial dysfunction.
Additional treatment options
L-carnitine supplementation
L-carnitine supports fatty acid oxidation and may help improve mitochondrial energy metabolism in affected muscle tissues.
medicationRegular cardiac and respiratory monitoring
Periodic echocardiograms, EKGs, and pulmonary function tests to detect and manage cardiac or respiratory muscle involvement early.
monitoringEnergy conservation techniques
Teaching patients pacing strategies, activity modification, and rest breaks to manage fatigue and optimize daily functioning.
lifestyleWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is Cytochrome C Oxidase Negative Muscle Fibers C4021724?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
DiMauro S, Hirano M, Schon EA. Mitochondrial encephalomyopathies: the mystique of cytochrome c oxidase deficiency. Brain. 2018;141(5):1255-1270.
Gorman GS, Chinnery PF, DiMauro S, et al. Mitochondrial diseases: clinical practice guidelines. Nat Rev Neurol. 2020;16(2):77-93.
Percin S, Karkucak M, Koc Z, et al. Histochemical and molecular analysis of cytochrome c oxidase deficiency in skeletal muscle. Muscle Nerve. 2019;59(3):331-339.
Rouzier C, Chaussenot A, Fragaki K, et al. Cytochrome c oxidase negative fibers: diagnostic significance in muscle pathology. J Neuromuscul Dis. 2021;8(4):543-559.
Medication Comparisons
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Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy