Quiz Form

Question Date: 10/09/2023

Question: Myokymia is not seen in which of these disorders?

Options:

• Acid maltase deficiency
• Pontine glioma
• Radiation plexopathy
• Guillain Barre syndrome

Correct Answer: Acid maltase deficiency

Explaination: Myokymia is derived from the Greek myo-muscle and kymia-wave. It arises from continuous irregular discharges from motor units. It arises from distal segment of the peripheral nerve and hence is blocked by curare but not by nerve blockade. On EMG, it consists of bursts of motor units (doublets or triplets) which occur regularly but with varying number of units in each discharge and is likened to a marching band. Generalized myokymia is classically seen in neuromyotonia. It has also been described in Guillain barre syndrome, thyrotoxicosis, gold neuropathy and Episodic ataxia-1. Focal myokymia is seen in radiation plexopathy, radiculopathy, focal nerve injury like carpal tunnel syndrome. Facial myokymia is seen in pontine glioma and multiple sclerosis. Myotonic discharges may be seen in acid maltase deficiency

Reference: Sawlani K et al. Peripheral Nerve Hyperexcitability Syndromes. Continuum 201723(5)1437-1450.