Background: We present two cases of children who were diagnosed with cerebellitis with acute cerebellar swelling. This rare pathology is potentially fatal, and no clear treatment guidelines are described in the literature. Discussion: Considering our experience, we discuss the different therapeutic strategies and propose aggressive surgical measures consisting of external ventricular drainage and posterior fossa decompression in case of failure of early response to medical treatment to limit secondary cerebellar and brainstem lesion

Bloch, J.

Cotting, J.

de Ribaupierre, S.

Jeannet, P.

Meagher-Villemure, K.

Porchet, F.

Roulet, E.

Villemure, J.

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Childs Nerv Syst (2005) 21: 970–974DOI 10.1007/s00381-005-1176-7 ORIGINAL PAPERS. de RibaupierreK. Meagher-VillemureJ. G. VillemureJ. CottingP. Y. JeannetF. PorchetE. RouletJ. BlochReceived: 3 May 2004Published online: 1 June 2005# Springer-Verlag 2005The role of posterior fossa decompressionin acute cerebellitisAbstract Background: We presenttwo cases of children who werediagnosed with cerebellitis with acutecerebellar swelling. This rare patholo-gy is potentially fatal, and no cleartreatment guidelines are described inthe literature. Discussion: Consider-ing our experience, we discuss thedifferent therapeutic strategies andpropose aggressive surgical measuresconsisting of external ventriculardrainage and posterior fossa decom-pression in case of failure of earlyresponse to medical treatment to limitsecondary cerebellar and brainstemlesions.Keywords Cerebellitis . CNSinfection . Posterior fossadecompression . HydrocephalusIntroductionPara-infectious involvement of the central nervous systemis rare, but para-infectious cerebellitis with acute cerebellarswelling is exceptional and deserves special attentionbecause the treatment modalities can diverge from medicalcare to aggressive surgical decompression. We report heretwo cases of children who presented with acute cerebellitisand brainstem involvement, and whose outcome was goodwith ventricular drainage and posterior fossa decompres-sion. Treatment options are discussed in this potentiallyfatal pathology.Case reportsCase 1A 6 1/2-year-old girl, with known migraine disorder, pre-sented with a 2-day history of pulsating headache, pho-tophobia, nausea and onset of vomiting that morning. Herneurological and fundoscopic exams were normal, and shewas admitted for observation with a diagnosis of severemigraine. On day 2, her headache increased despite painmedication, and she developed meningeal signs, upper limbdysmetria, and a temperature of 37.8°C. A cerebral CTscanshowed posterior fossa meningeal enhancement and dif-fuse cerebellar swelling, with a slight upward trans-ten-torial and downward trans-foramen magnum herniation.Cisternae were still visible, and there was no hydroceph-alus (Fig. 1a). The child was admitted to the intensive careunit with a diagnosis of cerebellitis with acute cerebellarswelling, and dexamethasone treatment (0.5 mg/kg q6)was started. On admission, white blood count was 6,000.By day 3, cerebral MRI confirmed the diffuse cerebellarswelling, with T2-hyperintense lesions of both cerebellarhemispheres predominantly on the right side (Fig. 2a, b),without venous or arterial abnormalities. She worsenedprogressively during the fourth day with a decreased levelof consciousness. Ocular bobbing and bradycardia wereobserved, and brainstem involvement was suspected. Arepeated cerebral CT scan showed increased cerebellarswelling with disappearance of basal cisterns, a deformedfourth ventricle and moderate tri-ventricular hydrocepha-lus without trans-ependymal resorption (Fig. 1b). An ex-ternal ventricular drainage was inserted in the right frontalS. de Ribaupierre (*) . J. G. Villemure .F. Porchet . J. BlochDépartement de Neurochirurgie,CHUV, Rue du Bugnon,1011 Lausanne, Switzerlande-mail: s_derib@hotmail.comTel.: +41-21-3142626Fax: +41-21-3142595K. Meagher-VillemurePathology Department, CHUV,Lausanne, SwitzerlandJ. CottingPediatric Intensive Care Unit, CHUV,Lausanne, SwitzerlandP. Y. Jeannet . E. RouletPediatric Neurology Department,CHUV,Lausanne, Switzerlandhorn with an opening pressure of 15 cm H2O. The drainwas collecting around 2 ml/h at +15 cm. CSF showed lessthan one cell, with 35 mg/l for proteins and 7 mmol/l forglucose. White blood count increased to 18,000, and CRPwas 58 mg/l. On day 5, her clinical exam had not im-proved, and a repeated cerebral CT scan showed an en-largement of the ventricles despite good positioning andfunctioning of the drain (Fig. 1c). Since posterior fossawas very full with herniation and brainstem compression,a posterior fossa decompression with resection of thecerebellar tonsils was then performed to avoid secondarybrainstem lesions. Material from surgical biopsies con-sisted of fragments of cerebellar cortex with granular celllayer. There was a mixed chronic inflammatory infiltratefocally in the arachnoid and few perivascular cuffing ofthe same type of infiltrate in the white matter. An immuno-histochemistry study of the type of inflammatory infiltratewas positive for T lymphocytes (CD3), B lypmhocytes(CD20) and numerous macrophages (CD68) (Fig. 3). Thebiopsy PCR [Lyme, Epstein–Barr virus (EBV) and vari-cella] remained negative. Different etiologieswere searched,but Lyme and EBV serologies were negative, and IgG forvaricella were detected but compatible with the primo-infection at the age of three.By day 6 the patient clinically started to improve andwas extubated, and dexamethasone was decreased progres-sively. Cerebral MRI showed a slight decrease in ventric-ular size. Cerebellar lesions were demarcated, and pinpointbulbar lesions appeared, which confirmed the suspicionof brainstem involvement (Fig. 4). CRP and leukocytesdecreased as well. The external ventricular drainage waswithdrawn on day 13. The child started rehabilitation withdaily progress, but had persistence of ataxia and hypopho-Fig. 2 Case 1: sagittal T2-weighted MRI (day 1) showing fullness ofthe posterior fossa with upward trans-tentorial and downward trans-foramen magnum herniationFig. 1 Case 1: axial cerebral CTscan, through the lateral and thethird ventricles showing a day 1,normal ventricular size; b day 3,enlargement of the ventricularsystem; c day 4, increased hy-drocephalus despite externalventricular drain (in place andfunctioning)Fig. 3 Case 1: chronic inflammatory infiltrate in the arachnoid overthe cerebellar cortex. HE ×100. Cerebellar granular layer and whitematter with perivascular cuffing by lymphocytes and plasma cells.HE ×100971nia. Before being discharged home (day 28), a repeatedcerebral CT scan showed a slight decrease in ventricularsize, but a large subdural or subarachnoid posterior fossacollection without mass effect, which was interpreted assecondary to cerebellar atrophy (Fig. 5). Nineteen monthslater, the child showed no neurological deficits, and hervoice was back to normal.Case 2A previously healthy 14-year-old girl, with a childhoodhistory of varicella, mumps and measles without any com-plications, and immediate past history of aphthous ulcersfollowed by sinusitis treated with Augmentin (amoxicillinand clavulanate potassium) and Klacid (Clarithromycin),was admitted to the hospital with acute pulsating head-aches, photophobia and nausea. The family had noticed achange in her voice in the last few days. On physical exam,she was afebrile with a heart rate down to 35 beats/min; herneurological and fundoscopic exams were normal. The ce-rebral CT scan showed fullness of the posterior fossa and aslight upward trans-tentorial and downward trans-foramenmagnum herniation, as well as hydrocephalus. MRI showedbilateral cerebellar hemisphere hyperintensities on fluid-attenuated conversion recovery (FLAIR) sequences (Fig. 6).White blood count was 9,000, and CRP was 13 mg/l. Shewas diagnosed with acute cerebellitis and received a treat-ment of dexamethasone (0.5 mg/kg) every 4 h. On day 1her clinical status worsened, and she underwent placementof an external ventricular drainage, with an opening pres-sure lower than 15 cm H2O, and posterior fossa decompres-sion, with resection of the cerebellar tonsils and cerebellarbiopsies. The sample collected from the surgery showedfoci of inflammatory reaction at every level from thearachnoid to the deep white matter as well as significantmicroglial cells activation within the cerebellar cortex.Immunohistochemistry results confirmed the mixed typeof inflammatory infiltrate and negativity for herpes virus,cytomegalovirus, and EBV by in situ hybridization. Onultrastructure study, no viral particle could be identified(Fig. 7). The serologies (Lyme, EBVand varicella) remainednegative. The maximum white blood count during hospi-talization was 13,000 and CRP was 14 mg/l.On day 2 the patient gradually improved clinically. Arepeated cerebral CT scan showed no decrease in the hy-Fig. 4 Case 1: axial T2-weighted MRI (day 1) showing hyperinten-sities in the cerebellar hemispheres (large arrows), and involvementof the bulbar region (thin arrow)Fig. 6 Case 2: axial T2-FLAIRMRI (day 1) showing hypersignals inboth cerebellar hemispheresFig. 5 Case 1: enhanced axial cerebral CT scan (1 month later)showing cerebellar atrophy972drocephalus despite good positioning (confirmed by theCT scan) and functioning of the drain (5–10 ml/h).By day 9 the cerebral CT scan showed a slight decreasein the ventricular size, with a posterior fossa subdural col-lection having the same density as CSF. She continued toimprove clinically with a rapidly decreasing ataxia and hadno complications. The clinical follow-up at 13 months re-vealed a normal neurological exam, and the patient washeadache-free.DiscussionCerebellitis with acute cerebellar swelling in children hasrarely been reported in the literature. In all of the cases wehave reviewed, the pathology seemed to be limited to thecerebellum. The involvement of the brainstem observed inour first case is exceptional and underlines the severity ofthe process without necessarily being a factor of poorprognosis. Typically, there are bilateral hemispheric cere-bellar T2-weighted hyperintensities and cerebellar swellingon MRI, with or without gadolinium enhancement [1, 2].The etiology is thought to be para-infectious (after var-icella, EBV or enteric fever [3–7]), but in most cases nospecific agent is found, as observed in our patients.Considering the management of this condition, there areno established rules, and we believe that every case shouldbe considered individually. Therapeutic options are eithermedical with high dose steroids and close monitoring, orsurgical with either external ventricular drainage, posteriorfossa decompression, or both. Medical management is prob-ably sufficient in milder cases of non-progressive cerebel-litis with no clinical or radiological progression [8, 9].However, if the disease is severe with hydrocephalus and/or threat of brainstem compression, this approach is notsufficient, and surgical options have to be considered.Most of the authors consider hydrocephalus associatedwith cerebellar swelling as purely obstructive at the level ofthe fourth ventricle. This is probably the case when theopening ventricular pressure is high, and drainage may bethe adequate treatment [4, 10]. However, in the presenceof obstructive hydrocephalus, there is a risk of upwardherniation with ventricular drainage if the drain is too lowor if the patient is not carefully monitored. There are casesof unexpected low opening pressure, as presented here, andas reported by Asenbauer et al. [11]. In the latter, hydro-cephalus may result from a combination of CSF flow ob-struction and mal-resorption. Hydrocephalus, in such cases,is possibly associated with a gradual inflammatory sub-arachnoid space obstruction which leads to a progressiveventricular size enlargement with regulation of the intra-cranial pressure, as observed in the adult normotensivehydrocephalus, even though the situation is relatively acute.The absence of trans-ependymal resorption seen in ourpatient, as well as in the two cases reported by Roulet Perezet al. [12], is another argument in favor of this theory.Moreover, ventricular size enlargement, despite posteriorfossa decompression, as seen in our patients, reinforces ourhypothesis.External ventricular drainage associated with cortico-steroids can be efficient; unfortunately, a few patients donot respond to this treatment. There are reported casesof fatal issues despite efficient drainage [12, 13]. In thelatter, neurological deterioration is likely secondary to di-rect brainstem compression from the cerebellar swelling.Posterior fossa decompression therefore appears to be in-dicated in some cases of acute cerebellitis.In the presence of fourth ventricle obliteration, hydro-cephalus, and low intracranial pressure, posterior fossa de-compression should be considered an emergency if thechild does not immediately improve after CSF drainage.This approach was only reported once previously [11] andits aim is to avoid brainstem lesion secondary to posteriorfossa mass effect. The timing of surgical decompression iscrucial, and surgery should be performed early to avoidbrainstem compression and irreversible damage. In both ofour cases, this approach was therapeutic with good clinicalpostoperative outcome.After the acute phase and adequate treatment, recovery isgenerally good; however, it is difficult to predict whichpatient is going to present cerebellar sequellae [1, 14].There must be a correlation between the severity of theprocess and the long-term evolution; nevertheless, we thinkthat early posterior fossa decompression may not only belifesaving, but may also reduce the occurrence of second-ary lesions and thus improve the clinical outcome.Fig. 7 Case 2: numerous microglial cells in the cerebellar cortex.Perivascular cuffing of lymphocytes and plasma cells at the junctionof the granular cells layer and the white matter. HE ×200973ConclusionCerebellitis with acute cerebellar swelling is a rare pathol-ogy that deserves special attention since early recognitionand adequate treatment may change the course of the dis-ease. Progressive cerebellar swelling may lead to hydro-cephalus and/or brainstem compression.In both cases presented here, surgical management wasfollowed by favorable outcome. We are not able to for-mulate therapeutic guidelines on two isolated cases; how-ever, after this experience, we believe that prompt surgicalmanagement should be considered in acute cerebellitis withfailure of medical treatment. In the present cases, externalventricular drainage was not sufficient, and clinical wors-ening led us to proceed to posterior fossa decompressionfollowed by rapid neurological improvement.References1. Bakshi R, Bates VE, Kinkel PR,Mechtler LL, Kinkel WR (1998) Mag-netic resonance imaging findings inacute cerebellitis. Clin Imaging22:79–852. Montenegro MA, Santos SL, Li LM,Cendes F (2002) Neuroimaging of acutecerebellitis. J Neuroimaging 12(1):72–743. de Fraiture DMI, Sie TH, BoezemanEHJF, Haanen HCM (1997) Cerebellitisas a uncommon complication of infec-tious mononucleosis. Neth J Med51:79–824. Hamada H, Kurimoto M, Masuoka T,Hirashima Y, Endo S, Harada J (2001) Acase of surgically treated acute cerebel-litis with hydrocephalus. Childs NervSyst 17:500–5025. Drost G, Verrips A, Thijssen HO,Gabreels (2000) Cerebellar involvementas a rare complication of pneumococcalmeningitis. Neuropediatrics 31(2):97–996. Majda-Stanislawska E (2000) Mumpscerebellitis. Eur Neurol 43(2):1177. Mario-Ubaldo M (1995) Cerebellitisassociated with Lyme disease. Lancet345(8956):10608. Aylett SE, O’Neill KS, De Sousa C,Britton J (1998) Cerebellitis presentingas acute hydrocephalus. Childs NervSyst 14:139–1419. Gohlich-Ratmann G, Wallot M,Baethmann M, Schaper J, RoggendorfM, Roll C et al (1998) Acute cerebellitiswith near-fatal cerebellar swelling andbenign outcome under conservativetreatment with high dose steroids. EurJ Paediatr Neurol 2(3):157–16210. HorowitzMB, PangD, HirschW (1991)Acute cerebellitis: case report and re-view. Pediatr Neurosurg 17(3):142–14511. Asenbauer B, McConachie NS, AllcuttD, Farrell MA, King MD (1997) Acutenear-fatal parainfectious cerebellarswelling with favourable outcome.Neuropediatrics 28(2):122–12512. Roulet Perez E, Maeder P, Cotting J,Eskenazy-Cottier AC, Deonna T (1993)Acute fatal parainfectious cerebellarswelling in two children. A rare or anoverlooked situation? Neuropediatrics24(6):346–35113. Levy EI, Harris AE, Omalu BI,Hamilton RL, Branstetter BF, Pollack IF(2001) Sudden death from fulminantacute cerebellitis. Pediatr Neurosurg 35(1):24–2814. Hayakawa H, Katoh T (1995) Severecerebellar atrophy following acute cer-ebellitis. Pediatr Neurol 12:159–161974

The role of posterior fossa decompression in acute cerebellitis

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The role of posterior fossa decompression in acute cerebellitis

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