Pharmacological and nutritional treatment for McArdle's disease (Glycogen Storage Disease type V)

  • Review
  • Intervention

Authors

  • R Quinlivan,

  • RJ Beynon


Dr Rosaline Quinlivan, Consultant Paediatrician, Muscle Clinic, Robert Jones and Agnes Hunt District and Orthopaedic Hospital, Gobowen, Oswestry, Shropshire, SY10 7AG, UK. Ros.Quinlivan@rjah.nhs.uk.

Abstract

Background

McArdle's disease (Glycogen Storage Disease type V) is caused by the absence of the glycolytic enzyme, muscle phosphorylase. Patients present with exercise-induced pain, cramps, fatigue, myoglobinuria and acute renal failure, which can ensue if the myoglobinuria is severe.

Objectives

To systematically review the evidence from randomised controlled trials of pharmacological or nutritional treatments in improving exercise performance and quality of life in McArdle's disease.

Search strategy

We searched the Cochrane Neuromuscular Disease Group register (September 2005), Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), MEDLINE (January 1966 to September 2005) and EMBASE (January 1980 to September 2005) using the search term 'McArdle's disease and it's synonym 'glycogen storage disease type V'.

Selection criteria

We included randomised controlled trials (including crossover studies) and quasi-randomised trials. Open trials and individual patient studies with no patient or observer blinding were included in the discussion but not the review. Types of interventions included any pharmacological agent or micronutrient or macronutrient supplementation. Primary outcome measures included any objective assessment of exercise endurance (VO2 max, walking speed, muscle force/power and improvement in fatiguability). Secondary outcome measures included metabolic changes (such as reduced plasma creatine kinase activity and a reduction in the frequency of myoglobinuria); subjective measures (including quality of life scores and indices of disability); and serious adverse events.

Data collection and analysis

Two authors checked the titles and abstracts identified by the search, independently assessed methodological quality of the full text of potentially relevant studies and extracted data.

Main results

We reviewed 20 trials. Ten trials fulfilled the criteria for inclusion and ten trials were included in the discussion. The largest treatment trial included 19 cases, the other trials included fewer than 12 cases. As there were only single trials for a given intervention we were unable to undertake a meta-analysis.

Authors' conclusions

It is not yet possible to recommend any specific treatment for McArdle's disease. Low dose creatine supplementation was shown to demonstrate a statistically significant benefit, albeit modest, in ischaemic exercise in a small number of patients. Ingestion of oral sucrose immediately prior to exercise reduces perceived ratings of exertion and heart rate and improves exercise tolerance. This treatment will not influence sustained or unexpected exercise and may cause significant weight gain. Because of the rarity of McArdle's disease, there is a need to develop multicentre collaboration and standardised assessment protocols for future treatment trials.

Plain language summary

Plain language summary

Low-dose creatine supplementation and taking sucrose by mouth prior to exercise have been shown to benefit a small number of people with McArdle's disease. Further research with larger numbers of participants is required to confirm the findings and to determine whether the benefit improves quality of life as well as improving laboratory based measures

McArdle's disease (also known as glycogen storage disease type V) is a metabolic muscle disorder, caused by the absence of an enzyme called muscle phosphorylase. The absence of this enzyme causes an inability to utilise glycogen stores (or 'fuel') needed by the muscles for exercise. This results in pain and fatigue on starting exercise. If exercise continues, severe muscle damage may develop and in some cases, acute renal failure. Low dose creatine supplementation has been shown to have a modest benefit in improving exercise tolerance in a small number of people with McArdle's disease, but further trials are needed. Oral ingestion of sucrose prior to exercise reduces ratings of perceived exertion and heart rate but this treatment is not practical for day to day living and may result in weight gain. Sucrose ingestion will be contraindicated in people with diabetes.