Small Vessel Vasculitis of the Central Nervous System – A Rare Disease with Unique Presentation

Background: Small vessel vasculitis of the central nervous system (CNS), also referred as angiography negative primary angiitis of the CNS (PACNS), is a rare inflammatory disease that causes severe neurological deficits and deterioration in previously healthy children.

Case presentation: A healthy, adequately developed 17-year-old male presented with sudden paraplegia, leg pain, numbness, areflexia and urinary retention. He was admitted to the pediatric intensive care unit (PICU) and underwent cranial as well as spinal magnetic resonance imaging (MRI), which demonstrated hyperintense lesions in different regions of the brain and spinal cord, without pathological enhancement. He was diagnosed with acute transverse myelitis. Subsequently he was treated with pulse steroids and intravenous immunoglobulins (IVIg) - following which he clinically improved and was transferred to rehabilitation. Two months later, he had a relapse in which he presented with paraplegia, urinary retention, fever, acute confusional state, headache and anisocoria with left ptosis. During that hospitalization, given severe decline in consciousness, he was intubated and underwent plasmapheresis. The differential diagnosis was expanded, and included acute disseminating encephalopathy (ADEM) and seronegative Neuromyelitis optica (NMO). During the following months, he had five similar relapses, which ultimately required a more definite diagnosis. Consequently, a brain biopsy was performed and showed small-vessel CNS vasculitis.

Discussion: Small vessel vasculitis of the CNS can clinically and radiologically mimic other more common pediatric neurological diseases such as transverse myelitis, ADEM and NMO. Although it is a very rare situation, when angiography is negative, a brain biopsy is required to confirm the diagnosis.