Superior oblique myokymia
| Classification according to ICD-10 | |
|---|---|
| H55 | [...] other abnormal eye movements |
| ICD-10 online (WHO version 2019) | |
The superior oblique myokymia (from myos , μῦς, Greek: "muscle" and kyma , κύµα, Greek: "wave") is a very rare form of eye tremor . It is an episodic, unilateral microtremor of the upper oblique eye muscle ( musculus obliquus superior ). This is triggered by uncontrolled activities of individual fibers of the IV cranial nerve supplying it , the trochlear nerve . Superior oblique myokymia should not be confused with another pathological form of eye tremors, nystagmus .
Symptoms
The affected eye has a very fine, vertical or rotating tremor depending on the direction of view. These attacks last for a few seconds, can occur several times a day and are usually clearly felt by the patients themselves. At the same time they perceive apparent movements ( oscillopsia ) and tilted double images ( diplopia ). The symptoms are therefore sometimes felt very intensely. However, the findings are usually completely normal between the attacks.
Sometimes the tremor can be provoked by looking down and inhibited by looking up. It is true that the examiner can hardly see it during the look-out, since it is drowned in the activities of the normally innervated muscle fibers; However, if the patient looks straight ahead again, the affected nerve fibers are still excited by the previous lowering of their gaze and the chances of noticing the tremor increase. Nevertheless, due to their low amplitude and high frequency , the movements can often only be made out with the help of a special ophthalmic apparatus ( slit lamp ).
Although the affected muscle can rarely show signs of paralysis , no other neurological disorders usually occur.
The patients usually describe symptoms that are very typical and characteristic of the disease. Nevertheless, they are not infrequently mistaken for hysterics . A correct diagnosis could easily be made by thinking of them.
causes
| Classification according to ICD-10 | |
|---|---|
| G52.8 | Diseases of other specified cranial nerves |
| ICD-10 online (WHO version 2019) | |
The superior oblique myokymia is a benign disease, the cause of which has not yet been clarified with certainty. It is probably triggered by pressure from the posterior cerebral artery ( arteria cerebri posterior ) on the trochlear nerve.
In addition, one simultaneous case of lead poisoning and adrenoleukodystrophy were described. The coincidence of these diseases could also have been purely coincidental. A simultaneous case of epilepsy was also documented.
The result of a special series of neurological examinations using magnetic resonance imaging (MRI) confirmed the assumption that the disorder could be caused by pressure on the nerve. Since then there has been discussion about classifying superior oblique myokymia as a so-called neurovascular compression syndrome .
Therapy and prognosis
Although superior oblique myokymia can resolve on its own in many cases, the rate of spontaneous healing is considered to be low. In the case of pronounced subjective complaints, drug treatment with membrane-stabilizing carbamazepine (Tegretal) or with beta-blockers ( propranolol , betaxolol) can be considered. The relationship between effect and side effect of these drugs is rather unfavorable in the present case. If there is no improvement even after months of therapy, surgical transection and excision of the tendon of the superior oblique muscle may help . The resulting paralysis can then usually be satisfactorily compensated for by further interventions on the other eye muscles . The result, however, remains defect healing . This comparatively radical treatment seems necessary because, according to experience, a half-hearted weakening of the affected muscle easily leads to a recurrence ( relapse ) of the disease.
The neurosurgical relief ( microvascular decompression ) of the trochlear can be an alternative in some cases. Corresponding successes have already been achieved with this, which also supports the hypothesis according to which superior oblique myokymia is caused by pressure on the nerve.
See also
literature
- Herbert Kaufmann (Ed.): Strabismus. 3rd, fundamentally revised and expanded edition. Georg Thieme, Stuttgart et al. 2004, ISBN 3-13-129723-9 , p. 456.
- Peter P. Urban (Ed.): Diseases of the brain stem. Clinic - diagnostics - therapy. Schattauer, Stuttgart et al. 2009, ISBN 978-3-7945-2478-5 , p. 312: Trochlearis compression.
Individual evidence
- ^ Eckbert S. Schnitzler, Gabriele C. Gusek-Schneider, Christoph JG Lang: Myokymia of the Musculus obliquus superior and cryptogenic epilepsy. In: Clinical monthly sheets for ophthalmology. Vol. 220, No. 1/2, 2003, ISSN 0023-2165 , pp. 54-56, doi : 10.1055 / s-2003-37580 .
- ^ A b Indra Yousry, Marianne Dieterich, Thomas P. Naidich, Urs D. Schmid, Tarek A. Yousry: Superior oblique myokymia: Magnetic resonance imaging support for the neurovascular compression hypothesis. In: Annals of Neurology. Vol. 51, No. 3, March 2002, ISSN 0364-5134 , pp. 361-368, doi : 10.1002 / ana.10118 .
- ↑ Peter Berlit (Ed.): Therapielexikon Neurologie. = Neurology. Springer, Berlin et al. 2005, ISBN 3-540-67137-4 , pp. 933-953, doi : 10.1007 / 3-540-26367-5_15 .
- ^ S1 guideline for vertigo therapy of the German Society for Neurology , accessed on August 19, 2019
