Neuromuscular weakness

Research output: Chapter in Book/Report/Conference proceedingChapter


Weakness is defined as a reduced strength in skeletal muscles and it is the most common complaint in patients with neuromuscular disorders, often resulting in disability. Neuromuscular disease is a very broad term that encompasses many different conditions that either directly, via intrinsic muscle pathology, or indirectly, via motor neuron cells, motor nerve, or neuromuscular junction pathology, impair the function of the skeletal muscles. Muscular weakness is therefore the denominator of all neuromuscular diseases in which the motor system is involved. Patients may use the word “weakness” with different meanings. Therefore, such a complaint should be probed unless there is clinical evidence of loss of muscle strength. The terms paralysis or plegia indicate total loss of muscle contractility, whereas paresis refers to mild or moderate weakness. Patients usually do not complain about muscle weakness, but experience diminished function, e.g. difficulty in getting up from a chair, inability to walk on tiptoes, difficulty with washing one’s hair, impaired swallowing, or respiratory insufficiency. Weakness should be distinguished from fatigue. Fatigue, defined as a subjective feeling of excess tiredness or lack of energy, is a common initial complaint in patients with amyotrophic lateral sclerosis (ALS), Pompe disease, and myotonic dystrophy (DM). Fatigue may be a late or residual symptom in patients with postpoliomyelitis syndrome, Guillain-Barré syndrome (GBS), and myositis. If fatigue is the predominant feature, without weakness or elevated serum creatine kinase (CK) activity, a neuromuscular disease is very unlikely. Chronic fatigue syndrome is not a neuromuscular disease. In neuromuscular junction disorders the hallmark of the disease is the fluctuating character of the muscle weakness. If weakness is associated with sensory abnormalities there is likely to be a (poly)neuropathy. However, there exists also a pure motor type of neuropathy, i.e. multifocal motor neuropathy (MMN) which is a treatable condition.

Original languageEnglish
Title of host publicationImaging Acute Neurologic Disease: A Symptom-Based Approach
PublisherCambridge University Press
Number of pages15
ISBN (Print)9781139565653, 9781107035942
Publication statusPublished - Jan 1 2014

ASJC Scopus subject areas

  • Medicine(all)


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