Question

A young boy presents to the OPD with hypoglycemia and muscle cramps, on exertion or while playing. Then he becomes normal after resting for a while. These episodes are recurrent after a period of activity. He has decreased serum lactate and glucose levels. Which of the following diseases is he most likely to be suffering from?

• A. McArdle disease
• B. Hers disease
• C. Cori's disease
• D. Andersen disease

Answer 1

The Correct Option is A

The clinical presentation described in the question is indicative of McArdle disease, which is also known as Glycogen Storage Disease type V. This condition is an inherited disorder caused by a deficiency of the enzyme muscle phosphorylase (myophosphorylase), which is essential for glycogen breakdown in muscle cells.

Symptoms include:

• Muscle cramps and pain during exertion or physical activity.
• Temporary relief upon rest.
• Recurrent episodes of muscle fatigue and weakness following exertion.

Biochemical findings associated with McArdle disease include:

• Decreased serum lactate levels post-exercise due to impaired glycolysis as glycogen cannot be broken down effectively.
• Hypoglycemia can occur as glucose is not readily available from muscle glycogen stores.

Based on these symptoms and biochemical abnormalities, McArdle disease is the most likely diagnosis.