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Morvan's chorea

Synonyms

Also known as Morvan’s syndrome I or II, Morvan's symptom complex. Synonyms: chorea fibrillaris, chorée fibrillaire, fibrillary chorea, myoclonus multiplex fibrillaris, myoclonus multiplex fibrillaris, myokymia.

Related people

Attacks of chorea affecting muscles at rest.

Description

Attacks of chorea – involuntary fibrillary contraction of muscles at rest – involving the muscles of the calves, the posterior parts of the thighs, seldom involving the trunk.

Walusinski: On 12 April 1890, Morvan published a novel clinical description in Gazette Hebdomadaire de Médecine et de Chirurgie. With his customary modesty, he noted: "I have once again been favoured by chance which, as always, has sown my path with rare, little known cases."

In his observation of the first patient, he wrote: "Paul Ernest de Plabennec, a farmer with a strong constitution, came to my office on 18 July 1885. Eight days prior, he experienced a sort of trembling, specifically fibrillary contractions in his calf muscles. When I examined the patient, this twitching was mainly in the gastrocnemius; however, it also could be seen intermittently in the posterior muscles of the thighs. By 21 July, the twitching had reached other regions of the body, tending to generalise. The fibrillary twitching results in raised points that, in the long muscles of the limbs, only occur at limited locations along the muscle bundles, appearing and disappearing with great irregularity and creating contours similar to those known as "myoïdèmes". The irregularity of the twitching occurring simultaneously at diverse points of the body is such that it is impossible to determine the frequency at a given time; one would have to be watching all points at once. These contractions, despite the pronounced raised points they produce under the skin, do not result in any trembling or movement of any part of the body; they disappear where they began, having no useful effect. The patient is still capable of gripping movements and locomotion.  Furthermore, the twitching stops or at least significantly decreases during voluntary muscle contraction. There are constant, shooting pains throughout the body, but mainly in the muscles where the twitching occurs. These pains are intense enough to disturb sleep. The patient has slept poorly for three days".

Within a few days, the patient's condition worsened: "Due to an unexplained agitation, the patient cannot remain in bed for long periods and is constantly getting up. Excessive perspiration. The patient is drenched with sweat; his shirt is as wet as if he had been in water". In early August, the patient's condition deteriorated rapidly. He could no longer move about and continued to sweat heavily. He became delirious then went into a coma, dying after less than one month of illness. Morvan described four other, less serious cases in which there was a spontaneously favourable progression. These cases were characterised by "fibrillary muscular contractions" that started in the lower limbs, then "moved upwards, without trembling or movement in any part of the body". In three of the cases he noted pains, agitation often associated with insomnia and "generalised excessive perspiration”.

Morvan believed that "fibrillary chorea is caused by damage to the anterior horn of the grey matter.  Initially limited to the columns of motor cells, fbrillary chorea sometimes extends beyond these; it can be seen to go deeper, reaching the excito-sudation and heart acceleration centres, then arriving at the intermedio-lateral tract, where it affects the vasomotor centre, found at this level according to Pierret". (Antoine-Auguste Pierret [1845-1920], interne under Charcot in 1874, spent his career at the Bron asylum).

Morvan went on to compare his observations with the symptoms of Sydenham's chorea, noting that the latter is characterised by uncoordinated movements with an onset that frequently occurs in childhood and is therefore distinct from fibrillary chorea. However, Morvan noted similarities with paramyoclonus multiplex. This term, no longer used today, refers to a pathology described in 1881 in Germany by Nikolaus Friedreich (1825-1882) and analysed by Pierre Marie (1853-1940) in Progrès Médical in 1886. When Morvan published his description, a number of similar clinical pictures had been established in Europe: chorea electrica (Henoch-Bergeron or Dubini or Begdie), myoclonus fibrillaris (Kny), myokymia (Schultze) and familial epileptic myoclonus (Unverricht). Edouard Krebs, an interne under Joseph Babinski (1857-1932), reviewed and compared these clinical descriptions in his remarkable 1922 thesis, establishing a prescient parallel between Morvan's description and the agrypnic forms of encephalitis lethargica (von Economo) (Krebs, 1922). In 1890, Morvan concluded: "I would be rather inclined to accept that fibrillary chorea, despite certain particularities, is only a variety of Friedreich's paramyoclonus, the variety without movements, without shifts in any part of the body and with  sudatory and vasomotor disturbances in some cases".

Morvan also noted the similarity of these sudatory disturbances with the vasomotor disturbances
he described in paretic analgesia, which here he was willing to assimilate with syringomyelia.

Bibliography

  • A. M. Morvan:
    De la chorée fibrillaire. Gazette hebdomadaire de médecine et de chirurgie, Paris, 1890; 27: 173-176, 186-189, 200-202.

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