Wasting refers to a thinning of the musculature, also known as atrophy or, if of neurogenic origin, amyotrophy.
Wasting may be a consequence of disorders of:
- Muscle (myopathies, dystrophies)
- Peripheral nerve (more so in axonal than demyelinating peripheral neuropathies)
- Anterior horn cells (e.g., motor neurone disease).
Wasting may occur in chronic upper motor neurone syndromes (e.g., chronic hemiplegia) but is not as evident as in lower motor neurone syndromes where wasting may appear subacutely (over a few weeks).
Wasting may also be seen in general medical disorders associated with a profound catabolic state, e.g., cancer cachexia, uncontrolled heart failure, liver cirrhosis, renal failure.