| Description |
The patient is a 50 year old woman who presented in November 1977 with a transient facial droop, nystagmus, diplopia, dysarthria and vertigo. She was admitted to New England Tufts Medical Center and had an extensive workup including an electroencephalogram, first generation CT brain scan, angiogram and spinal tap. The CT scan suggested a pontine lesion and she received a brief course of steroids. Her symptoms resolved fully in approximately six week's without recurrence. She remained well until August 1991, when she developed sinusitis and bilateral head pressure. She was seen at the Massachusetts Eye and Ear Infirmary and a brain MRI scheduled. Five days prior to her MRI appointment, she developed intractable hiccups. Nevertheless, she was able to go ahead with the scan. Brain MRI on 8/26/91: A T1 - T2 signal intensity in the posterior midline of the left side of the medulla with an area of surrounding decreased density. The images suggested possible extension of a non-hemorrhagic component rostrally into the pons. Following the reading of the MRI as indicative of a medullary hemorrhage, the patient was admitted to the Massachusetts General Hospital. Diagnosis: Left medullary hemorrhage Past History: Mild hypertension for 15 years treated with hydrochlorothiazide. Family History: Negative for brain hemorrhage Neurological Examination: BP 132/78, pulse regular Persistent hiccups No cranial or carotid bruits Alert and oriented Speech normal Pupils equal, normal reflexes Funduscopic examination normal Extraocular movements full, no nystagmus No facial weakness Normal gag and palatal movement Motor System: Strength 5/5 throughout Reflexes 2+ symmetric, plantar flexor responses Sensory System: Normal Co-ordination: No ataxia Blood Studies: Normal electrolytes Platelet count 264,000 PT and PTT normal Hospital Course: The patient's hiccups persisted, although somewhat decreased, on thorazine 25 mg p.o., t.i.d. Neurosurgery Consult: The neurosurgeon considered the hemorrhage was due to either an arteriovenous malformation or cavernous angioma. 9/16/91 A left and right vertebral arteriogram showed no evidence of an arteriovenous malformation. Brain MRI 12/12/91: Showed a region of hypointense T1 signal with a hyperintense margin anterior to the foramen of Magendi at the level of the medulla approximately in the region of the obex. Axial images showed the lesion was at the level of the left restiform body. The hyperintense rim represented fresh blood with intra methemoglobin, hemosiderin and additional hemoglobin products. Diagnosis: Medullary cavernous angioma 12/20/91 Suboccipital craniotomy and laminectomy to the level of C1 with resection of the cavernous angioma Pathology: Cavernous angioma with closely packed vessels of varied wall thickness and diameter. (Figure 1) Hospital Course: Post operatively, the patient complained of movement of the visual world up and down (oscillopsia). She no longer had hiccups Neuro-ophthalmic Consult: Visual acuity J2 OU Pupils 4 mm OU sluggish to light, brisker to near Ocular Motility: Upbeat nystagmus in primary gaze Lid nystagmus Vertical gaze full with upbeat nystagmus Convergence normal Vertical and horizontal saccadic pursuit Vertical and horizontal saccadic hypermetria. Horizontal vestibular ocular reflex suppressed (tested by rotating the patient in the chair and asking them to fix on a target moving with them) Brain MRI post-op: Within the posterior aspect of the pontomedullary junction at the midline and slightly to the left, just below the level of the middle cerebellar peduncles, there was an area of slightly decreased signal on T1 WI measuring 6 mm in diameter. T2 WI showed apparent enlargement of the area of hemorrhage on the graded echo sequence, described as "blooming" and consistent with old blood products. A central nodule was not identified. Electronystagmogram: Abnormal study consistent with a brainstem lesion because of 1.Torsional nystagmus with the eyes open in the light which stopped with eye closure 2.Impaired pursuit with saccadic corrections for leftward tracking. Consult Dr. David Zee, Johns Hopkins I reviewed the vestibular tests, eye movement recordings and brain MRI findings with Dr. David Zee. He suspected that the patient might have a lesion of the nucleus propositus hypoglossi (NPH) with possible damage to the velocity storage mechanism of the vestibular system. Vestibular Symptoms: Post-operatively she had to turn and move slowly to prevent vertigo with head movement. Marking time in place or nodding her head vertically up and down and then stopping resulted in a time lag of 30 seconds before she could focus and read the 20/30 line. Dr. Zee commented that "the post-operative head movement vertigo suggested head shaking nystagmus which would of course mean that velocity storage is working and possibly too much". The patient was discharged home with persistent oscillopsia. In Sept 1992 she was readmitted with vertical double vision. Brain MRI 1992: She had a repeat MRI which revealed a change in signal characteristic of resolving blood and no new bleed. Ocular Motility: Upbeat nystagmus in primary gaze Lid nystagmus Skew deviation and right ocular tilt reaction with right hypotropia and right head tilt. Occasional square wave jerks Horizontal gaze nystagmus with a torsional component only on gaze left. Horizontal saccadic hypermetria Full vertical gaze, no dysmetria or nystagmus. I again consulted Dr. David Zee who suggested seeing the patient and recording her eye movements if she was willing to go to Johns Hopkins. The patient agreed to make the trip and we went together in October 1992. Fortunately for the patient, the routine testing and recording of her eye movements by Dr. Zee, in an attempt to prove her lesion impaired the velocity storage mechanism failed. She showed normal horizontal OKN, horizontal saccades and pursuit, normal optokinetic after nystagmus (OKAN) and normal time constant and gains. Medication: Klonopin 0.5 mg. t.i.d. To localize the lesion as precisely as possible we consulted Professor Jean Buttner-Ennever in Munich. Jean reviewed all the imaging studies in April 1993 and noted: "The lesion lies mainly caudal to the abducens nucleus, has bilateral involvement of the PPH nucleus and the right (plus left in 1991) medial vestibular nucleus (MVN), and compromises the subjacent region where fibers essential for velocity storage cross the midline. The involvement of these areas looks to be at its worst in the images of 1991. The lesion has shrunken since 1991 and in the more recent images of April 1992, the lesion appears unilateral (right), in MVN and PPH and the subjacent medullary retricular formation". Conclusion: "At present I consider the anatomic basis for the velocity storage integrator to involve a bilateral interplay between areas of the peripheral AVN, MVN and PPH nuclei, which are interconnected bilaterally via a system of fibre pathways that cross the midline in the dorsal rostral medulla - PPH lying on the output pathway. This region is certainly affected by the medullary lesion but I would guess (since you ask) not enough to knock out the velocity storage. It looks as if the crossing fibres which we showed to be essential for the velocity storage in monkey are damaged. So, I expect that here the velocity storage has gone. I expect that saccadic integrator crossing fibres (which cross at the level of abducens nucleus) are spared. It will be interesting to see if I am right, or is it all wrong? I have never had to estimate lesions so exactly from MRI scans." The patient steadily improved and by 1994 she no longer had oscillopsia and upbeat nystagmus was only visualized with the ophthalmoscope. The right ocular tilt reaction with skew deviation, right eye hypotropic persisted unchanged. Horizontal gaze was full with gaze evoked nystagmus with a torsional component both to the right and to the left. Vertical gaze full with no nystagmus Medication: The patient had been on Klonopin since surgery. Following this visit the drug was stopped. Her follow-up continued until January 1995 with no new symptoms and no change on examination. See also: http://content.lib.utah.edu/cdm/ref/collection/ehsl-shw/id/239 |
