Hyperintensity in Diffusion-Weighted Imaging is not Necessarily a Sign of Ischemic Stroke

Sir, We read with interest the article by Xiao et al.[1] about a 15-year-old boy with SARS-CoV-2 infection (SC2I) who had also developed limb weakness eight days before admission, which was attributed to ischemic stroke of the brainstem and spinal cord. After 45 days of hospitalization, the patient was cured of SC2I but was still paraplegic.[1] The study is excellent, but several points should be discussed. The first point is that the diagnosis of ischemic stroke in the index patient is not convincing.[1] Ischemic stroke shows up on multimodal MRI as a diffusion-weighted (DWI) hyperintense and an apparent diffusion-coefficient (ADC) hypointense lesion in a vascular territory if the lesion occurs <8 hours after onset. If the lesion is older, it may also be hyperintense on T2/FLAIR.[2] However, no ADC maps have been presented or described, so all differential diagnoses that demonstrate DWI hyperintensity must be considered and ruled out before cytotoxic edema characteristic of ischemic stroke can be diagnosed. The second point is that no CSF tests were performed on the patient. Since SC2I can be complicated by infectious or immunologic encephalitis or myelitis, it would have been imperative to determine whether the index patient had pleocytosis and whether superficial or intracellular antibodies associated with immunologic encephalitis were elevated. A CSF examination would also have been necessary to rule out the possibility that the patient had Guillain–Barre syndrome, in addition to the central nervous system lesions. The third point is that the description of the neurological examination is inadequate. The first sentence mentions that the patient suffered from limb weakness.[1] Was it one, two, three, or four limbs? At the end of the case description, it is mentioned that the patient still had paraplegia.[1] Was it paraplegia of the upper or lower limbs? There is also no description of the tendon reflexes and pyramidal signs.[1] To assess whether the clinical presentation correlates with the imaging findings, it is essential to describe the clinical presentation in more detail. The fourth point is that the patient had elevated D-dimer and that venous sinus thrombosis was not adequately ruled out. Although elevated D-dimers could be related to SC2I, it would have been necessary to rule out venous sinus thrombosis as well. The fifth point is that the clinical presentation is not consistent with the imaging findings.[1] Given the brainstem and spinal cord lesions, the patient should have been quadriplegic and not paraplegic. The sixth point is that no imaging follow-up was presented. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.