The significance of head tilt in a patient with rotatory vertigo
Carsten Finke, MD and
Christoph J. Ploner, MD
From the Department of Neurology, Charité-Universitätsmedizin Berlin, Germany.
Address correspondence and reprint requests to Dr. Carsten Finke, Department of Neurology, Charité-Universitätsmedizin Berlin, Campus Charité Mitte, Charitéplatz 1, D-10117 Berlin, Germany carsten.finke{at}charite.de
As the OTR frequently shows an incomplete manifestation, a headtilt can be the only apparent clinical sign of significant brainstemdisorders. Hence, even a slight head tilt should be thoroughlyinvestigated.
A 48-year-old man presented after sudden onset of a severe,persistent rotatory vertigo associated with nausea, vomiting,and postural imbalance. Examination revealed a horizontal-torsionalspontaneous nystagmus with the quick phases beating to the rightear. The nystagmus was attenuated by fixation as examined byFrenzel goggles. Head impulse test was positive to the left.When attempting to walk and during Romberg testing he fell tohis left side. Except for a head tilt to the right (see videoon the Neurology® Web site at www.neurology.org), no otherneurologic deficit was observed. The patient's medical historyrevealed no neurologic disorders. Quantitative caloric testingshowed a canal paresis of the left vestibular organ. Taken together,the initial clinical presentation was highly suggestive of aleft vestibular neuritis.
However, due to the head tilt, an extended neuroophthalmologicexamination was performed that revealed a discrete but completeOTR to the right with head tilt, mild skew deviation (2°left hypertropia), ocular torsion (right eye excyclotropia 4°,left eye no cyclotropia), and a tilt of the subjective visualvertical to the right (right eye 7° to the right, left eye4° to the right).
In contrast to the sparse clinical signs, cerebrospinal MRIshowed multiple T2-hyperintense lesions of the right dorsolateralmedulla oblongata, left mesencephalon, right medial cerebellarpeduncle, corpus callosum, pericallosal white matter, and threelesions in the spinal cord. Reconstruction of the lesion ofthe dorsolateral medulla oblongata according to the atlas ofPaxinos and Huang1 revealed damage to the right spinal, medial,superior, and lateral vestibular nuclei. Reconstruction of themesencephalic lesion showed involvement of the left interstitialnucleus of Cajal (INC) (figure). No further brainstem lesionswere observed. No enhancement of the eighth cranial nerve, asoccasionally described for vestibular neuritis,2 was seen. CSFanalysis revealed no pleocytosis and normal protein, glucose,and lactate, but oligoclonal bands in CSF only. Visual evokedpotentials (VEP) showed a delayed P100 on the left.
Figure Cerebral MRI revealing (A) a left mesencephalic lesion affecting the interstitial nucleus of Cajal and (B) T2-hyperintense lesions of the right dorsolateral medulla oblongata affecting the spinal, medial, superior, and lateral vestibular nuclei
The cerebrospinal lesion pattern, the inflammatory CSF changes,and the abnormal VEP were suggestive of a demyelinating process.According to the revised McDonald Criteria, a clinically isolatedsyndrome (CIS) was diagnosed and treatment with IV steroidswas initiated. On follow-up 4 weeks later, the patient had recoveredfrom vertigo and nausea and had no nystagmus on examination.However, the head tilt to the right persisted. MRI showed nonew lesions. Seven months later, the head tilt was still detectable,but neuroophthalmologic examination showed only a slight tiltof the subjective visual vertical to the right (both eyes 2°)and no skew deviation or ocular torsion. Cerebrospinal MRI showedno new lesions.
The clinical presentation comprised a left peripheral vestibularsyndrome suggestive of vestibular neuritis and a right centralvestibular syndrome manifesting as OTR. The latter is characterizedby the triad of head tilt, skew deviation, and ocular torsion.3Additionally, a tilt of subjective visual vertical (SVV) isobserved. The head is tilted toward the lower eye. Ocular torsionmanifests as incyclotropia of the upper eye and excyclotropiaof the lower eye, i.e., the upper poles of the eyes rotate towardthe lower ear. Pathogenetic substrate is a vestibular tone imbalancecaused by unilateral lesions of the graviceptive vestibularpathways that run from the otoliths and the vertical semicircularcanals to the ocular motor nuclei and the rostral integrationcenters for vertical and torsional eye movements (INC and riMLF).They also provide input to vestibular thalamic nuclei and corticalareas involved in perception of verticality.4 Altogether, lesionsof these projections lead to the clinical syndrome involvingocular motor (ocular torsion, skew deviation), perceptual (SVVtilt), and postural (head tilt) dysfunction. As the graviceptivevestibular pathways cross at a lower pontine level, directionof the ocular tilt reaction holds a clinically relevant topographicvalue: with peripheral and pontomedullary lesions below thecrossing all tilt effects (ocular motor, perceptual, and postural)are ipsiversive, i.e., the ipsilateral eye is undermost. Withpontomesencephalic lesions all tilt effects are contraversive,i.e., the contralateral eye is undermost. Hence, the OTR tothe right in our patient cannot be explained by a left-sidedperipheral vestibular syndrome but must rather be attributedto the lesion of the vestibular nuclei in the right dorsolateralmedulla or to the lesion of the INC in the left mesencephalon.As pontomedullary lesions typically cause a disconjugated oculartorsion and pontomesencephalic lesions, a conjugated oculartorsion,5 damage to the vestibular nuclei appears to be thecause of OTR in our patient.
The two vestibular syndromes that differ in localization (peripheralvs central) and side (right vs left) could point to separatepathogenetic mechanisms, i.e., an inflammatory brainstem lesionand an incidental left peripheral vestibular neuritis. Alternatively,the peripheral vestibular syndrome may have resulted from aMRI-negative plaque at the root entry zone of the left eighthnerve causing a vestibular pseudoneuritis.6 Such a strategicallylocalized lesion causes a vestibular syndrome mimicking vestibularneuritis in clinical presentation and calorimetric testing.However, there is no means to reliably differentiate betweenthese two possibilities.
Recently, the reliability of clinical examination in the differentiationof vestibular neuritis from vestibular pseudoneuritis was investigated.7It was shown that single clinical signs provide only limitedsensitivity and specificity, except for skew deviation thatindicated a vestibular pseudoneuritis with a high specificity.In our case, the key for the diagnosis of a central vestibularsyndrome in addition to the obvious peripheral vestibular syndromelay in recognizing the head tilt to the right side as an incompatiblecomponent of a left peripheral vestibular syndrome. Recognizingthis incompatibility and consequently assuming an additionalvestibular disease called for further investigations that finallyled to the correct diagnosis.
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