Pseudomyotonia

Description

The term pseudomyotonia (slow relaxation of muscles after voluntary contraction) describes the clinical appearance of myotonia in the absence of myotonic discharges on the electromyography. Pseudomyotonia is most commonly observed as the slow-relaxing or “hung-up” tendon reflexes of hypothyroidism, although other causes are described. Pseudomyotonia is seen in about one-third of patients with Isaacs syndrome, particularly with handgrip, but also after eye and jaw closure; rarely, this can be the first symptom.

Index terms

Pseudomyotonia

Excludes

http://id.who.int/icd/entity/1159616108 – Secondary myopathies
http://id.who.int/icd/entity/1425591047 – Myasthenia gravis or certain specified neuromuscular junction disorders

Exclusions from above levels

http://id.who.int/icd/entity/155258022 – Metabolic disorders
LD26.41 – Arthrogryposis multiplex congenita
05 – Endocrine, nutritional or metabolic diseases

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18 – Complications of pregnancy, childbirth and the puerperium
19 – Certain conditions originating in the perinatal period
22 – Injury, poisoning or certain other consequences of external causes

Sibling codes

8C71.0 – Myotonic dystrophy
8C71.1 – Chondrodystrophic myotonia
8C71.2 – Myotonia congenita
8C71.3 – Drug-induced myotonia
8C71.4 – Neuromyotonia
8C71.Y – Other specified myotonic disorders
8C71.Z – Myotonic disorders, unspecified

Foundation entity

Pseudomyotonia – http://id.who.int/icd/entity/715714152

Part of: 8C71: Myotonic disorders › 08: Diseases of the nervous system