Abstract
Acute cerebellitis in children is an inflammatory syndrome with symptoms of cerebellar dysfunction. We describe a 3-year-old boy with acute cerebellitis who had cerebellar tonsillar herniation, hydrocephalus, and transient tonic bilateral upward gaze deviation. Although no etiology for his acute cerebellitis was determined, he fully recovered with high-dose corticosteroids, intravenous immunoglobulin, and antimicrobial therapy. We propose that there was tonic irritation of the upward gaze generator cells in the superior colliculus as an explanation for temporary disturbance of his ocular gaze.
Keywords
Acute cerebellitis, an inflammatory syndrome of the cerebellum, typically presents with clinical cerebellar dysfunction. 1 The severity of symptoms ranges from a relatively benign course with resolution of symptoms to permanent neurological damage and even death. 1,2 Symptoms can result from primary cerebellar disturbance or compression from parenchymal inflammation with regional damage, particularly projections to and from the brain stem. Recently, we evaluated a child who presented with acute cerebellitis with symptoms of cerebellar dysfunction and tonic bilateral upward gaze deviation. We propose, based on experimental monkey studies, that there was tonic irritation of the upward gaze generator cells in the superior colliculus as an explanation for this temporary disturbance of the ocular gaze.
Case Summary
A 3-year-old, previously healthy boy had gait instability and lower extremity weakness for 1 day, with headache, lethargy, and fever for several days. He had truncal ataxia, arm dysmetria, and hypotonia with mild nuchal rigidity but full range of neck movements. Extraocular movements were without limitation, and his fundoscopic examination result was normal.
Laboratory tests indicated mild peripheral leukocytosis and neutrophilia (leukocyte count, 18,900/μL; neutrophils, 79%). Blood chemistry, urinalysis, and blood and urine culture findings were negative. Lumbar puncture showed normal glucose but mildly elevated protein level (49 mg/dL; reference value = 15-45 mg/dL), red blood cells of 130 cells/μL (reference value = 0 cells), and white blood cells of 170 cells/μL (reference value = 0-5 cells) with 81% lymphocytes. Computed tomography (CT) of the brain without contrast medium was within normal limits. Magnetic resonance imaging (MRI) of the brain revealed swelling of the cerebellum with leptomeningeal enhancement and mild cerebellar tonsillar ectopia (Figure 1A and 1B). Neuroimaging and clinical manifestations indicated a diagnosis of acute cerebellitis. The following day, he developed persistent bilateral upward gaze with decreased verbalizations and retroflexion of the neck. He was mildly obtunded with decreased alertness but readily responsive to verbal commands. Urine drug screen results were negative, and the patient had received no medications associated with dystonic reactions. Repeat CT of the head without contrast indicated hydrocephalus. Routine electroencephalography showed occipital slowing without epileptiform discharges. Intravenous methylprednisolone (30 mg/kg/d) was initiated in addition to intravenous immunoglobulins (1 g/kg/d every other day for 3 doses) and empiric antimicrobial therapy (acyclovir, ceftriaxone, ethionamide, isoniazid, pyrazinamide, rifampin, and vancomycin).
(A-D) Magnetic resonance imaging (T1) with gadolinium contrast. (A) Axial image on day 2 of presentation showing leptomeningeal enhancement of the cerebellum that had resolved by day 9 (B). (C) Sagittal image showing swelling of the cerebellum and tonsillar ectopia on day 2 with resolution by day 9 (D).
He was monitored in our intensive care unit for clinical cerebellar herniation and brain stem compromise; however, neither caloric reflexes nor brain stem–evoked responses were performed. Cerebrospinal fluid polymerase chain reactions for herpes simplex virus and enterovirus were negative. Serological test findings for herpes simplex virus 1 and 2, Epstein-Barr virus, cytomegalovirus, West Nile virus, Treponema pallidum, and Bartonella henselae were negative. Stool culture results for adenovirus were negative. Serology findings for Mycoplasma pneumoniae were immunoglobulin M negative and immunoglobulin G equivocal. He continued high-dose corticosteroid therapy for 5 days followed by a corticosteroid taper over 5 days, for a total of 10 days of corticosteroid therapy. By the eighth day of corticosteroid treatment, he had significantly improved with return of function of extraocular movements and normal range of motion at the neck. Repeat MRI at that time showed resolution of swelling and enhancement of the cerebellum and without tonsillar ectopia (Figure 1C and 1D). He had improved vocabulary and gait and continued to improve with rehabilitation.
Discussion
Acute cerebellitis presents with dysmetria, ataxia, and headache. 1 Etiologies range from a primary infectious, postinfectious, or postvaccination condition. Pathogens include multiple infectious agents that produce damage to the cerebellum through direct invasion and/or presumed autoinflammation in reaction to the infectious species. Inflammation leads to swelling and primary dysfunction of the cerebellum. Clinical progression can range from a relatively benign course to severe neurological impairment or death. 1,2 This condition has been shown to be responsive to immunomodulatory therapy, and typically, there is good recovery. 3
Cases have been reported with compressive lesions causing hydrocephalus, tonsillar herniation, and brain stem disturbance. 4,5 The posterior fossa has a relatively small and restrictive volume, and small parenchymal changes may have a profound effect on neighboring structures. Vertical gaze palsy is commonly associated with increased pressure in the posterior fossa. Supranuclear generators for vertical eye movements are located in the rostral midbrain in the vicinity of the mesencephalic pretectum and superior colliculus. 6,7 Parinaud syndrome, a common dorsal midbrain syndrome, is a clinical example of an anatomic lesion that includes selective supranuclear palsy of conjugate upgaze. Our patient had bilateral transient tonic upgaze deviation that suggested an irritative (active) process at the level of the brain stem tectum and superior colliculus. Tonic activity has been seen in other neurological conditions, such as paroxysmal tonic upgaze of childhood in which the pathophysiology is uncertain but has been associated with dorsal lesions in the brain stem. 8,9 Seizures also produce tonic upgaze deviation, 8 but our patient did not have clinical or electrographic evidence of seizure activity. Although a rostral brain stem lesion causing downgaze paresis was an initial consideration, our patient did not have corticospinal long tract findings and recovered rapidly from his bilateral upward gaze deviation without neurological residua. The possibility exists that inflammation of the cerebellum either through direct inflammation or compressive effects caused an irritation of ocular upgaze generators (fixation cells) in the superior colliculus. 6,7 Initially, there was concern that this clinical finding was indicative of brain stem damage and if untreated would have progressed to upgaze paralysis and further symptoms associated with the dorsal midbrain syndrome.
Management of acute cerebellitis is usually directed at a specific organism, if detected, combined with immunomodulation therapy for presumed autoinflammation. The therapeutic goal is to decrease inflammation and swelling to minimize dysfunction of the cerebellum and related structures and pathways. Our report highlights an unusual clinical consequence of cerebellitis in which recognition of the neuro-ophthalmological complications lead to urgent management with intravenous corticosteroids and immunoglobulins. Fortunately, there was excellent recovery in this child with acute cerebellitis of unknown etiology.
Footnotes
Acknowledgments
This work was performed at The University of Texas Health Science Center at Houston by the listed authors.
Author Contributions
JL contributed to the data collection and first draft of the article. IJB contributed equally to the data analysis and critical revisions of the article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.