Horners syndrom

Horner's syndrom er en kombination af symptomer der skyldes påvirkning af grænsestrengen (truncus sympaticus) sympathetic trunk is damaged.

Symptomer

Horners syndrom er karakteriseret af ensidige fund og symptomer i form af:

• Miosis (pupil kontraktion)
• Ptose partiel (hængende øjenlåg)
• Anhidrose (nedsat svedproduktion lokalt)
• Enoftalmus (indsunket øje - ikke et obligatorisk fund)

Anatomi

Den sympatiske innervation af øjet er en 3-neuron kæde startende:

• 1. Centrale sympatiske fibre fra del posterolaterale del af hypothalamus descenderer ukrydset til C8-Th2 niveau i medulla spinalis
• 2. Præganglionære fibre træder ud fra Th1 niveau træder ind i grænsestrengen og askenderer til ganglion cervikale på niveau C3-4 ud for carotis bifurkaturen
• 3. Postganglionære fibre fra ganglion cervikale danner netværk omkring a. carotis interna og fortsætter med denne gennem sinus cavernosus

Årsager

Horners syndrom er oftest erhvervet men kan også være medfødt (kongenit). De fleste årsager til Horners syndrom er relativt benigne så bør en af de mere alvorlige årsager altid overvejes = Pancoast tumor som er lokaliseret i lungeapeks og vokser ud og beskadiger græsnsestrengen

Årsager kan inddeles anatomisk efter om der er anhidrose og lokalisationen af denne:

• Central (+anhidrose lokaliseret til ansigt,arm, trunkus)
  • Syringomyeli
  • Multiple sklerose
  • Encephalitis
  • Hjerne tumor
  • Lateralt medullært syndrom
• Præganglionært (+anhidrosis lokaliseret til ansigt)
  • Cervikalt ribben træk på ganglion stellatum
  • Thyroidea cancer
  • Thyroidectomi (Iatrogen)
  • Struma
  • Pancoast tumor
  • Klumpke paralyse (skade på plexus brachialis typisk traktions skade under fødsel)
  • Traume
  • Iatrogen ved thorax kirurgi
  • Thorakalt aorta aneurysme
• Postganglionær uden anhidrose
  • Horton's hovedpine
  • Migræne
  • Carotis dissektion
  • Sinus Cavernosus Thrombose
  • Otitis Media
• Sympathectomi
• Nerve blokader

Pathophysiology

Horner syndrome is due to a deficiency of sympathetic activity. The site of lesion to the sympathetic outflow is on the ipsilateral side of the symptoms. The following are examples of conditions that cause the clinical appearance of Horner's syndrome:

• First-order neuron disorder: Central lesions that involve the hypothalamospinal tract (e.g. transection of the cervical spinal cord).
• Second-order neuron disorder: Preganglionic lesions (e.g. compression of the sympathetic chain by a lung tumor) that releases acetylcholine.
• Third-order neuron disorder: Postganglionic lesions at the level of the internal carotid artery (e.g. a tumor in the cavernous sinus or a carotid artery dissection) that releases norepinephrine.
• Partial Horner's syndrome: In case of a third-neuron disorder, anhidrosis is limited to the middle part of the forehead or can be absent, resulting in a partial Horner's syndrome.<ref name="Lee">Skabelon:Cite journal</ref>

If someone has impaired sweating above the waist affecting only one side of the body, yet they do not have a clinically apparent Horner's syndrome, then the lesion is just below the stellate ganglion in the sympathetic chain.

Diagnosis

Fil:Example of Horner's syndrome in a cat.jpg

Left-sided Horner's syndrome in a cat as a result of trauma, demonstrating miosis in left pupil.

Three tests are useful in confirming the presence and severity of Horner syndrome:

• Cocaine drop test: Cocaine eyedrops block the reuptake of post-ganglionic norepinephrine resulting in the dilation of a normal pupil from retention of norepinephrine in the synapse. However, in Horner's syndrome the lack of norepinephrine in the synaptic cleft causes mydriatic failure. A more recently introduced approach that is more dependable and obviates the difficulties in obtaining cocaine is to apply the alpha-agonist apraclonidine to both eyes and observe the increased mydriatic effect (due to hypersensitivity) on the affected side of Horner syndrome (the opposite effect to what the cocaine test would produce in the presence of Horner's).Skabelon:Citation needed
• Paredrine test: This test helps to localize the cause of the miosis. If the third order neuron (the last of three neurons in the pathway which ultimately discharges norepinephrine into the synaptic cleft) is intact, then the amphetamine causes neurotransmitter vesicle release, thus releasing norepinephrine into the synaptic cleft and resulting in robust mydriasis of the affected pupil. If the lesion itself is of the third order neuron, then the amphetamine will have no effect and the pupil remains constricted. There is no pharmacological test to differentiate between a first and second order neuron lesion.<ref name="Lee"/>
• Dilation lag testSkabelon:Clarify

It is important to distinguish the ptosis caused by Horner's syndrome from the ptosis caused by a lesion to the oculomotor nerve. In the former, the ptosis occurs with a constricted pupil (due to a loss of sympathetics to the eye), whereas in the latter, the ptosis occurs with a dilated pupil (due to a loss of innervation to the sphincter pupillae). In a clinical setting, these two ptoses are fairly easy to distinguish. In addition to the blown pupil in a CNIII (oculomotor nerve) lesion, this ptosis is much more severe, occasionally occluding the whole eye. The ptosis of Horner syndrome can be quite mild or barely noticeable (partial ptosis).Skabelon:Citation needed

When anisocoria occurs and the examiner is unsure whether the abnormal pupil is the constricted or dilated one, if a one-sided ptosis is present then the abnormally sized pupil can be presumed to be on the side of the ptosis.Skabelon:Citation needed

In children

The most common causes in young children are birth trauma and a type of cancer called neuroblastoma.<ref name=":0">Skabelon:Cite book</ref> The cause of about a third of cases in children is unknown.<ref name=":0" />

History

It is named after Johann Friedrich Horner, the Swiss ophthalmologist who first described the syndrome in 1869.<ref>Skabelon:Cite journal</ref><ref>Skabelon:WhoNamedIt</ref> Several others had previously described cases, but "Horner's syndrome" is most prevalent. In France and Italy, Claude Bernard is also eponymized with the condition ("Claude Bernard-Horner syndrome").

See also

• Anisocoria
• Harlequin syndrome

Video om Horners syndrom

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