Oculomotor palsy
| Classification according to ICD-10 | |
|---|---|
| H49.0 | Paralysis of the oculomotor nerve [III. Cranial nerve] |
| ICD-10 online (WHO version 2019) | |
As a third nerve palsy a is the lesion of the oculomotor nerve (III. Cranial nerve hereinafter). Since this nerve innervates the greatest number of the external eye muscles via motor fibers and parasympathetically two out of three internal eye muscles, a disorder can, depending on its location and extent, cause extremely complex impairments of eye mobility and perception. Depending on which muscles are affected by a paresis, one differentiates the inner from the outer third nerve palsy. This can be present as unilateral or bilateral paralysis, be located centrally in the core area or peripherally, present partially or completely and occur in combination with other eye muscle paralysis.
External oculomotor palsy
An external oculomotor paresis results in the complete or partial loss of function of the following motor-supplied eye muscles:
- Medial rectus muscle
- Superior rectus muscle
- Inferior rectus muscle
- Inferior obliquus muscle
- Levator palpebrae superioris muscle
Symptoms
The affection of the first four muscles mentioned leads to a squint position corresponding to their function and a restriction of movement with possibly horizontal, vertical and rotational double image perception, the distance between which increases when looking into the respective muscle pulling direction. Not all muscles have to be affected by the lesion to the same extent, which means that the functional components of the muscles may be affected differently or not at all. In addition, the extent of the squint deviation is usually inconsistent , and therefore different in size depending on the viewing direction. As with all ocular muscle paresis, there is a fixation-dependent primary and secondary angle . If the levator palpebrae superioris muscle is affected, drooping of the upper eyelid ( ptosis ) usually occurs .
A typical appearance is, for example, a depression of the affected eye with a slight outward rotation and incomplete ptosis. Depending on the situation, there may also be a forced head posture to maintain binocular simple vision .
Internal oculomotor palsy
| Classification according to ICD-10 | |
|---|---|
| H52.5 | Accommodation disorders - internal ophthalmoplegia (totalis) |
| ICD-10 online (WHO version 2019) | |
An internal oculomotor paresis is present when the following parasympathetically supplied muscles are affected:
Symptoms
The core symptoms in this case are a wide, light- rigid pupil ( absolute pupil rigidity ), as well as a restriction of the optical ability to focus close ( accommodation ). An isolated internal oculomotor paralysis without involvement of the external eye muscles is also called an internal ophthalmoplegia .
causes
Damage to the oculomotor nerve can have very different causes. In affections in the area of the nucleus ( nucleus nervi oculomotorii ), supranuclear disorders often come into consideration, such as B. brain stem tumors or circulatory disorders, as well as aneurysms . Lesions in the peripheral course can also be triggered by space-occupying processes, trauma or compression mechanisms, e.g. B. Clivuskanten syndrome . Oculomotor paresis is often an accompanying symptom of a more pronounced disease complex (e.g. Nothnagel syndrome , Benedict syndrome , Weber syndrome ). Combination disorders with simultaneous involvement of other cranial nerves that are responsible for the innervation of the external eye muscles are also not uncommon, e.g. B. in cavernous sinus syndrome or Godtfredsen syndrome . Combined paralysis of the oculomotor nerve and abducens nerve can be diagnosed relatively reliably, while a simultaneous disruption of the trochlear nerve is easier to overlook. Oculomotor palsy is also often associated with diabetes mellitus .
Diagnosis
There are a number of diagnostic tools available for assessing eye muscle paralysis. Despite the many variations and forms of oculomotor paresis, a precise strabological examination and diagnosis is almost always possible in addition to the neurological evaluation, if the patient's condition permits. Complex movement analyzes, double image schemes and time-consuming squint angle measurements in different viewing directions help in making the diagnosis, also as a demarcation or, if necessary, evidence of combined paralysis. In contrast, the assessment of pupillary motor skills and accommodation is much easier. In principle, possible accompanying symptoms such as headache, neck pain or ataxia are to be included .
therapy
As with all neurological disorders, once the cause has been clarified, treatment is primarily in the hands of a neurologist. The prognosis for oculomotor paresis caused by trauma, tumors, or aneurysms is often unfavorable, as faulty innervations often occur during the regeneration process . In the case of causal circulatory disorders, on the other hand, the chances of recovery are significantly better. If the situation has not improved significantly after about a year, a squint operation may be indicated. The aim of this is to shift the field of binocular simple vision into the primary position, i.e. without adopting a forced head posture, and, if necessary, to enlarge it. Depending on the available findings, interventions are primarily carried out on the affected muscles. In the case of very minor paresis, the adjustment of prismatic lenses can also help to improve the situation.
Differential diagnosis
In terms of differential diagnosis , the respective symptoms and findings are to be distinguished from one another by supplementing and completing all necessary examinations in order not to lead to a wrong assessment. Restriction of movement when looking down does not necessarily have to go hand in hand with a loss of function of the inferior rectus muscle. An affection of the trochlear nerve or the superior oblique muscle could also be considered for this. Nor does ptosis always mean a lesion of the levator palpebrae superioris muscle , but can also be an expression of Horner's syndrome . Paralysis of the medial rectus muscle must also be differentiated from internuclear ophthalmoplegia , in which the adduction induced by subsequent movements is sometimes severely restricted, but the movement of convergence is still intact.
See also
swell
- Guideline 27 of BVA and DOG: Paretic strabismus
- Guideline 27a of BVA and DOG: Eye muscle surgery for paretic squint
literature
- Herbert Kaufmann (Ed.): Strabismus. With the collaboration of Wilfried de Decker et al. Enke, Stuttgart 1986, ISBN 3-432-95391-7 .
Individual evidence
- ↑ Commission "Guidelines of the German Society for Neurology" (Ed.): Guidelines for Diagnostics and Therapy in Neurology. 3rd, revised edition. Georg Thieme, Stuttgart et al. 2005, ISBN 3-13-132413-9 , keyword: Peripheral eye muscle and nerve paresis; AWMF guidelines register: No. 030/033.
