# APBA Kısa Özet

Post-infectious cerebellitis (PIC) is an immune-mediated cerebellar inflammatory syndrome that follows a preceding infection (or, rarely, vaccination) after a latent interval. It spans a spectrum from benign post-infectious/acute cerebellar ataxia (ACA) through more severe acute cerebellitis (AC) with leptomeningeal enhancement and mass effect, to rare, life-threatening acute fulminant cerebellitis (AFC) with hydrocephalus risk. Evidence is largely limited to individual case reports and small case series, and no prior review has systematically pooled patient-level data across etiologies. A PRISMA-guided systematic review screened 899 records identified through electronic database searches, citation tracking, and supplementary bibliography searches. After duplicate removal and eligibility assessment, 47 studies (case reports, case series, and cohort studies) were included in the qualitative synthesis. Patient-level data from 73 individuals were extracted for quantitative pooling. Pooled patients had a mean age of 24.5 years (range 7 months-74 years; 40 pediatric, 28 adult); of 70 patients with sex reported, 51 (72.9%) were male. Based on neuroimaging findings and the presence of life-threatening features, 34 patients (46.6%) were classified as acute cerebellitis (AC); 15 patients (20.5%) were classified as post-infectious ACA; and 11 patients (15.1%) were classified as acute fulminant cerebellitis (AFC).

# Çalışma neyi araştırdı?

This systematic review aimed to systematically define the etiologies, clinical features, treatments, and outcomes of post-infectious cerebellitis. Specifically, the role of SARS-CoV-2 as a trigger, the frequency of immunomodulatory treatments, and recovery rates were examined. The review followed PRISMA guidelines. A comprehensive search of electronic databases, citation tracking, and supplementary bibliography identified 899 records. Duplicates were removed, and studies were screened for eligibility. Inclusion criteria required a diagnosis of post-infectious cerebellitis with individual patient data available. Case reports, case series, and cohort studies were included. After eligibility assessment, 47 studies were included in the qualitative synthesis, and patient-level data from 73 individuals were extracted for quantitative pooling. Descriptive statistics were calculated for age, sex, etiology, treatment modalities, and outcomes. No comparative analysis or meta-analysis was performed.

# Yöntem

  • Arama Stratejisi: 899 kayıt, elektronik veri tabanları, atıf takibi ve ek bibliyografik taramalarla taranmıştır.
  • Seçim Kriterleri: Post-infectious cerebellitis tanısı konmuş, bireysel hasta verileri sunan vaka raporları, vaka serileri ve kohort çalışmaları dahil edilmiştir. Çiftleme, uygunluk ve kalite değerlendirmeleri PRISMA yönergelerine göre yapılmıştır.
  • Veri Çıkarımı: 47 çalışma (vaka raporu, seri, kohort) üzerinden 73 hastanın demografik, klinik, tedavi ve sonuç verileri çıkarılmıştır.
  • Analiz: Tanımlayıcı istatistikler (ortalama yaş, cinsiyet dağılımı, etiyoloji, tedavi modaliteleri, sonuçlar) raporlanmıştır; karşılaştırmalı analiz veya meta‑analiz yapılmamıştır.

# Temel bulgular

  • Demografi: Ortalama yaş 24,5 yıl (7 ay‑74 yıl). 40 pediatrik, 28 yetişkin; cinsiyet bilgisi 70 hastada mevcut, %72,9 erkek (n=51).
  • Etiyoloji: SARS‑CoV‑2 en sık tetikleyici (n=24, %32,9). Diğer virüsler, bakteriler ve nadir vakalar da rapor edilmiştir.
  • Klinik Sınıflandırma: Neuro‑görüntüleme ve yaşamı tehdit eden bulgulara göre 34 hasta (%46,6) akut serebellit (AC) olarak sınıflandırıldı; 15 hasta (%20,5) post-infectious ACA; 11 hasta (%15,1) akut fulminant serebellit (AFC).
  • Tedavi: Kortikosteroidler en yaygın tedavi (n=54, %74,0). Antiviral ilaçlar %47,9 (n=35), IVIG %26,0 (n=19) uygulanmıştır.
  • Sonuçlar: Tam iyileşme %64,4 (n=47), kısmi iyileşme %20,5 (n=15), sonuç bilinmeyen %13,7 (n=10). Tek ölüm (%1,4) AFC alt grubunda kaydedilmiştir.

# Bulgular ne anlama geliyor?

This review provides a comprehensive overview of the current evidence on post-infectious cerebellitis. It highlights that SARS-CoV-2 is the most frequently identified trigger in the current pandemic context. The predominant use of corticosteroids reflects current clinical practice; however, the lack of comparator groups limits conclusions about treatment efficacy. The overall favorable prognosis—with 64.4% achieving complete recovery—must be balanced against the 20.5% with partial recovery and the 1.4% mortality, which was confined to the acute fulminant cerebellitis subgroup, often associated with COVID-19-associated necrotizing encephalopathy. These findings underscore the importance of early recognition and individualized treatment decisions, while also highlighting the need for higher-quality studies to establish evidence-based protocols.

# Klinik önem

  • Tanı: Post-infectious cerebellitis should be considered in patients developing cerebellar symptoms (ataxia, nausea, headache) following an infection, particularly in those with a recent COVID-19 history.
  • Tedavi Yaklaşımı: Corticosteroids are the most commonly used treatment, reflecting current clinical practice. However, given the low evidence quality, treatment decisions should be based on individual risk‑benefit assessment.
  • Prognostik Beklentiler: The majority of patients (~64%) achieve complete recovery. However, a significant minority (≈20%) experience partial deficits, and mortality, though rare, is concentrated in the acute fulminant subgroup. Early diagnosis and appropriate immunomodulatory therapy, particularly in severe cases, may improve outcomes.
  • Araştırma İhtiyacı: Future research should focus on controlled clinical trials, standardization of treatment protocols, and long-term neurological outcome monitoring to establish more definitive evidence.

# Sınırlılıklar

  • Kanıt Seviyesi: The study relies solely on a dataset of case reports and small case series, resulting in a high risk-of-bias score.
  • Örneklem Büyüklüğü: Pooling 73 patients limits the generalizability of the findings.
  • Kontrol Grubu Yokluğu: The absence of comparator groups prevents differentiation between treatment effects and natural disease course.
  • Veri Eksikliği: Outcomes were not stated for 13.7% of patients, obscuring true recovery rates.
  • Heterogenity: Significant variability exists across mild ACA, typical AC, severe AFC subtypes, age groups, and etiologies, complicating the formulation of a single treatment recommendation.
  • Çıkarım Sınırlamaları: The review identifies correlations but lacks the methodological rigor to establish causality or treatment efficacy.

This review synthesizes the limited available evidence on post-infectious cerebellitis and serves as a foundation for future high-quality research; clinical decisions should rely on individual patient assessment and current guidelines.