Antibody & Biopsy
Pathology is often
Type II muscle fiber atrophy
Cachexia (weight loss > 15%)
Other disorders with prominent wasting associated with weakness
Congenital myasthenic syndromes
METABOLIC CHANGES IN SYSTEMIC DISORDERS WITH MUSCLE WASTING
Metabolic changes (Low CG syndrome)
Low plasma cystine & glutamine
High plasma glutamate
Low intracellular glutathione
High urea production
Selectively in skeletal muscle
Not prevented by aggressive nutrition
Natural killer cell function: Reduced
Syndromes with low plasma cystine & glutamine levels
HIV: Late asymptomatic stage
Sepsis & trauma
Bowel disease: Crohn's; Ulcerative colitis
Chronic fatigue syndrome
Changes may be reversed by N-acetyl-cystine (NAC) treatment
Differs from starvation which has
Low urea production
Weight loss in most organs
Severe wasting involves the distal arms & legs.
The most distal regions, the hands & feet, are relatively spared
Chronic denervation: Severe
Severe wasting involves the distal arms & legs including the most distal regions, the hands & feet.
Note atrophy of median (thenar) and ulnar innervated muscles in the hands.
Severe trophic skin changes are present on the legs.
Hereditary Distal Motor Neuropathy
Myopathy & NMJ Index
Neuromuscular home page