Blood

URATE

• Urate levels are often raised in people with McArdle’s, due to increased purine metabolism [1].

• There is an increased rate of gout amongst McArdle people compared to the rest of the population [2]. (Approx. 10% compared to 3%.)

• Renal stones of uric acid crystals and calcium oxalate can be instigated by raised urate levels [3].

LIVER ENZYMES

• Routine screening for unrelated matters may reveal, in people with McArdle’s, mildly elevated levels of the liver enzymes ALT and AST [4].

• These enzymes are released into the blood when skeletal muscle is damaged [5] and is normally not a matter for concern regarding the liver.

• Further investigation may be indicated if the ALT or AST levels are grossly raised and remain so.

• Further investigation is also indicated if the ALP or bilirubin levels are significantly raised.

[1] See page 7, reference [2].

[2] See page 7, reference [3].

[3] Kidney stones: pathophysiology and medical management. Orson W Moe. (2006) Lancet; 367: 333–44.

[4] McArdle’s disease: case report and review of the literature. Tuzun A et al. (2002) Turk J Gastroenterol 13: 56-59.

[5] Serum Alanine Aminotransferase in Skeletal Muscle Diseases. (2005)
Rahul A et al. Hepatology, Volume 41, Issue 2.

Urine

• If urine test strip shows blood (hemoglobin) or protein, consider whether this is in fact myoglobin which is often present in McArdle’s.