Parainfectious acute cerebellitis as a possible adverse effect to the COVID 19 vaccine (mRNA)

We reported a 14-year-old male patient admitted to our Hospital due to a mild fever, headache, disconnection with the environment and dystonic crisis. After initiating symptomatic and anticonvulsant treatment, a MRI was performed where hyperintense bilateral cortico-subcortical cerebellar lesions were observed in T2 and FLAIR sequences with a RT-PCR SARS-Cov-2 negative.

During the second day of hospitalization, after presenting neurological symptoms, the MRI showed the following findings. In both cerebellar hemispheres, MRI found cortico-subcortical hyperintense lesions in T2 and FLAIR sequences, and hypointense in T1, with subtle gadolinium uptake in 3 areas. These lesions produce increase in the size of the cerebellar hemispheres with minimal mass effect on the upper third of the IV ventricle. The rest of the ventricular system and cisterns shown a normal caliber and morphology. Neither were lesions that restrict DWI-ADC sequences, nor signal alteration in the rest of the sequences in the cerebral parenchyma or leptomeningeal enhancement. 8 days after, a MRI control was performed, finding radiological improvement of the lesions by showing: absence of gadolinium enhance and decreased mass effect on the IV ventricle, but the bilateral cerebellar cortico-subcortical lesions persisted. 2 weeks after the MRI was normal

Background

The COVID19 produced by SARS-CoV-2, develops an acute respiratory condition with mild symptoms in the majority of cases (1). In addition, Central Nervous System (CNS) has been affected, producing mild symptoms such as headache, anosmia, and dysgeusia, to more serious conditions such as cerebrovascular disease, necrotizing encephalopathy, encephalitis and Acute Cerebellitis (AC) (1,2).

Given the negativity of microbiological studies, it´s important to suspect a parainfectious aetiology of AC, putting the post-vaccination cause at the fore (3,10). Autoimmunity is a possible explanation, since antibodies against Purkinje cells, centrosome, ganglioside, among others, had been found in these patients (4,11) . Vaccines against varicella and influenza have been reported with AC, if exists a recent vaccine history (3,7,10), but none of the vaccines designed against SARS-CoV-2 has been described as a cause of AC, but recently another case has also been reported as a possible asociation (17).

Clinical perspective

Gait instability and ataxia are symptoms closely related to cerebellar pathology, and the sum of these with others such as headache, vomiting, meningeal signs, seizures and even decreased consciousness allow us to suspect AC. The evolution of AC is favourable in the majority of cases since it is self-limited (4,7,16).

Imaging perspective

Magnetic Resonance Imaging (MRI) is the gold standard for AC diagnosis (3–5). Radiological findings related to AC can range from unilateral or bilateral cerebellar cortex hyperintensity in T2 and FLAIR sequences and hypointense in T1, possible enlargement of the cerebellum due to oedema, enhancement of parenchymal and meningeal lesions after gadolinium administration; as well as signs related to infratentorial intracranial hypertension such as compression of brainstem, IV ventricle or Silvio´s aqueduct with retrograde triventricular dilation and/or tonsillar herniation (5–7). Diffusion sequences (DWI - ADC) could be useful for showing signal restriction in acute lesions (6,8 ).

Outcome

Our patient meets the criteria with the clinical-radiological picture of an AC, whose only relevant antecedent was the recent COVID19 vaccination with a negative microbiological study, so it´s important to suspect this vaccine as a possible aetiology of AC. To support our etiological suspicion, we have found reports of cases that have developed optic neuromyelitis, transverse myelitis, multiple sclerosis and Guillain Barré syndrome after vaccination against SARS-CoV-2 (12,13), which would support the parainfectious aetiology AC in our case (3).

Conclusion

The objective of this work is descriptive, showing the possible association of AC in our patient with the COVID 19 vaccine and propose studies with an adequate design to investigate a possible correlation between AC and COVID19 vaccine.