Keywords
síndrome de Horner central - spinal cord lesion - cervical disc herniation
Palavras-chave
síndrome de Horner central - lesão medular - hérnia de disco cervical
Introduction
Horner syndrome, or oculosympathetic dysfunction, was described by the Swiss ophthalmologist
Friedrich Horner in 1869,[1] and represents the interruption of the cervical sympathetic nervous system. It is
characterized by a symptom triad: ptosis (upside down ptosis), pupillary miosis and
facial anhidrosis, although some authors associate a fourth symptom to the syndrome,
facial hyperemia.[2] It is an unusual entity that has no relation to age, gender or race. The syndrome
prognosis depends on the etiology, and underlying patient condition. This case report
refers to a rare cause for this entity, which resulted from the compression of the
cervical sympathetic preganglionic nuclei by cervical disc core herniation.[3]
[4]
Case Report
A fifty-five years-old patient with complaints of neck and shoulder pain for a week,
without reference to a triggering factor, namely exercise or a traumatic event. The
symptoms had increased in the 24 hours previous to the hospital observation, without
any relief with immobilization or postural correction. Four hours after pain exacerbation,
he described motor deficit of right side limbs, without other neurological disorder.
Physical examination showed decreased muscle strength on the right arm and leg, grade
4 on Medical Research Council (MRC) scale, impairment of sensory function below C6-C7
dermatome level, increased deep tendon reflex at upper and lower right limbs, and
positive Babinski sign. The cranial nerves exam showed anisocoria, with right pupil
miosis and slowed photo-motor response, combined with upper right eyelid ptosis and
elevation of the lower eyelid ([Fig. 1]). The patient presented facial anhidrosis, but he refused starch-iodine test. The
ciliospinal reflex was absent on the right side, and no other abnormal finding was
detected through cranial nerves exam. Brain computed tomography (CT) was normal, but
cervical CT and cervical magnetic resonance imaging (MRI) showed a stenotic cervical
spinal canal with disc protrusions at C3-C4 (major) and C5-C6, with evident spinal
cord compression. Magnetic resonance imaging (T2 sequence) revealed spinal cord hyperintensity
on the described levels; however, it had been conditioned by motion artifact ([Fig. 2]).
Fig. 1 Preoperative photo. Right upside down ptosis and miosis.
Fig. 2 Preoperative MRI - C3–4 and C5–6 disc herniation with T2/FLAIR hyperintense spinal
cord.
Patient was submitted to anterior cervical discectomy and fusion of C3-C4 and C5-C6,
with placement of intervertebral polyetheretherketone (PEEK) cages on both levels
([Fig. 3]). He presented postoperative motor recovery, but sustained right pupil miosis and
upside down ptosis ([Fig. 4]). On the first month evaluation, patient showed clear recovery, without motor or
sensory deficit, and no evidence of oculosympathetic dysfunction ([Fig. 5]). Due to the progressive improvement of all the deficits, and the absence of identifiable
lesions on brain CT, we decided not to conduct postoperative brain MRI.
Fig. 3 Postoperative X-ray - C3–4 and C5–6 intersomatic PEEK cages.
Fig. 4 Immediate postoperative photo. Right upside down ptosis and miosis.
Fig. 5 First month follow-up photo. Oculosympathetic recovery.
Discussion
Horner Syndrome etiology is diverse, from congenital, hereditary to acquired causes,
which highlights the trauma.[5]
[6] It may arise from brachial plexus lesions, chest, cervical or thoracic spine injury,
tumor lesions, such as Pancoast, or carotid dissecting aneurysms. It is an entity
repeatedly associated with thoracic, throat and neurological surgical procedures.
A concern on anterior cervical discectomy, related to longus colli sympathetic chain
retraction injury.[7]
[8]
The sympathetic chain is a three-neuron pathway that originates in the hypothalamus.
The first-order neuron runs from the posterolateral hypothalamus to the midbrain and
pons. It extends to spinal cord intermediate-lateral column, between C8 and T2 (ciliospinal
center of Budge). The second-order neuron consists on preganglionic pupil-motor fibers,
emerging from T1 and extends to the cervical sympathetic chain, in close relation
to the pulmonary apex and subclavian artery. The trunk enters the superior cervical
ganglion where it synapses with postganglionic neurons at the carotid bifurcation
level (C3-C4). It surrounds the internal carotid artery to the distal structures,
covering the cavernous sinus, and follows the VI cranial pair (abducens) and ophthalmic
branch of V cranial pair (trigeminal), innervating the pupillary dilator system, Muller
muscle and the vascular complex of the face.[8]
[9]
[10] The rostral ventrolateral medulla contains premotor neurons controlling cardiovascular
conditions, whereas rostral medullary raphe regions are a candidate source of sympathetic
premotor neurons for thermoregulatory functions
The network interruption can be central, from the hypothalamus to C8-T2 level, or
peripheral, including the cervical sympathetic chain, superior cervical ganglion or
the internal carotid artery, with the classification of pre or postganglionic.[8]
[10]
The occurrence of central Horner syndrome is relatively uncommon, and can usually
be identified by the concomitant presence of hypothalamic, brainstem, or spinal cord
signs and symptoms, which help to localize the lesion.[11]
[12]
This entity is not associated to the so common cervical spondylotic myelopathy. Myelopathy
occurs as result of three important pathophysiological factors. Static mechanical
factors, dynamic-mechanical factors, and spinal cord ischemia.[11]
[13] It damages the posterior columns, spinocerebellar, and corticospinal tracts. Although
as the corticospinal tract is first affected during spinal cord compression because
it has a watershed arterial supply, the first-order neurons of sympathetic chain localized
on Budge center, immediately lateral to the dorsal gray, are preserved by a common
anterior and posterior blood supply. The descending sympathetic tract presents a lateral
location that preserves it from mechanical trauma or compression.
The most typical presentation occurs as part of the lateral medullary syndrome (Wallenberg
syndrome) due to posterior-inferior cerebellar artery or distal vertebral artery stroke.[14]
[15]
[16] It manifests with the common symptom triad, but anhidrosis usually affects ipsilateral
hemibody (not only the face).[3]
[10] Patients with preganglionic lesions may have flush. This symptom, also called harlequin
effect, occurs with exercise in some patients.[5] Patients with postganglionic lesions may report ipsilateral orbital pain or migraine-like
headache.
Differential diagnosis is required in all situations, especially on such unusual clinical
setting, which combines a pyramidal pathway lesion together with the sympathetic nervous
system impairment. It is necessary to consider the hypotheses of ischemic vascular
injury, subarachnoid hemorrhage, epidural hematoma and space occupying lesions.[4]
[6]
[10]
[12]
[13]
[15]
[16] As a complementary diagnostic method, MRI assumed main importance to differential
diagnosis in Horner Syndrome, like in the case of carotid artery dissection, spinal
cord infarction, and cervical or thoracic injury.[10]
[13]
[16]
As shown, the present case constitutes a first-order neuron lesion. It resulted from
the spinal cord compression by a right lateralized disc herniation and narrowing of
the spinal canal, which affected the intermediate-lateral column. Radiographic evaluation
excluded major brain lesions but showed spinal cord hyperintensity on T2/ Fluid-Attenuated
Inversion Recovery (FLAIR), mainly at C3-C4 level, an unusual location to cause Horner
syndrome. Even in a trauma situation this would generally be ascribed to lesions at
C5-C6 and T1-T2.[14]
Neurosurgical intervention was crucial in this case.[4]
[6] Recovery did not happen immediately after surgery, although motor function, pupillary
and eyelid symmetry were restored in the following days.
In our research on PubMed and Google Scholar, we found that only the work of Hyunjin
Ma and Insoo Kim,[3] reports Horner Syndrome due to a large left paramedian disc herniation with cord
compression at the C4–5 level. Similarly to our case, it also presented total recovery
after decompression with cervical discectomy and arthrodesis.
Conclusion
Horner syndrome is a rare clinical entity, even more unusual when related to cervical
disc herniation. This is a case report with fast clinical progression, without previous
symptoms, obvious trauma or cervical spine instability signs. In such cases, clinical
and image findings are paramount, and timely surgery might dictate the patient's prognosis.
