Cramps and spasms of the musculature (ICD-10-GM R25.2: Cramps and spasms of the musculature) can occur from many different causes.
A cramp is an involuntary and painful muscle contraction (spasm). It is accompanied by a hardening of the affected muscle. The skeletal muscles are predominantly affected by cramps. Muscle cramp often occurs at night and at rest (rest cramp) and mainly affects the lower extremity. The cause of a cramp at rest is usually a calcium deficiency.
Cramps in the leg muscles (leg cramps; calf cramps) occur more frequently during the summer months than during the longer winter nights.
Fasciculations are to be differentiated from cramps. These are irregular and involuntary contractions of muscle fiber bundles that are macroscopically visible.
Cramps (crampi/cramps) can be a symptom of many diseases (see under “Differential diagnoses”).
Spasm is a cramping contraction of individual muscles or muscle groups repeated at time intervals.
The different types of spasm are subdivided according to the type of contraction:
- Tonic spasm: Uniform and static contractions that usually persist over a relatively long interval of time.
- Clonic spasm (clonus): involuntary, rhythmic contractions of muscles or muscle groups, i.e., alternating contraction and relaxation of muscle fibers. This often occurs in short temporal succession.
- Mixed spasm
According to the duration of clonus, two forms of clonic spasm can be distinguished:
- Inexhaustible clonus
- Exhaustible clonus (pathological only in case of side difference).
Clonus is a pyramidal sign, that is, the control by the fibers of the pyramidal tract is defective, so that instead of the brief excitation of the muscle that occurs in the physiological intrinsic reflex, there is a continuous excitation.
Spasticity refers to an “increased, velocity-dependent resistance to stretching of the skeletal muscles.” Spasticity often occurs as a symptom of damage to the nervous system.
The following forms of spasticity can be distinguished:
- Generalized spasticity
- Regional spasticity
- Focal spasticity (this spasticity is due to a focus of disease).
Spasticity can be a symptom of many diseases (see under “Differential diagnoses”).
Course and prognosis: muscle spasm usually lasts only a short time (seconds to a few minutes). It is self-limiting, meaning that it stops spontaneously (by itself). In spasticity, the prognosis depends on how severe it is and which parts of the body are affected. Furthermore, the cause of the spasticity and the age of the affected person influence the degree of impairment.
