Behçet disease (CNS manifestations)

CNS manifestations of Behçet disease, also known as neuro-Behçet disease, corresponds to the neurological involvement of the systemic vasculitis Behçet disease and has a variety of manifestations. 

For a discussion of the disease, in general, please refer to Behçet disease article. 

Epidemiology

CNS involvement is seen in 4-49% of patients with systemic Behçet disease and has the same predilection of patients of middle eastern and Japanese descent ¹. 

Clinical presentation

In the vast majority of cases, ulcerative lesions preceded neurological involvement, aiding in the diagnosis. In 3% of cases, central nervous system manifestations occur first, making diagnosis significantly more challenging ¹. Signs and symptoms include ¹:

• headaches
• sensory disturbances
• personality changes
• dysarthria
• cerebellar signs

Pathology

Neuro-Behçet disease, depending on the stage or degree of the inflammation, shows perivascular infiltration of leukocytes and microglia, degeneration of oligodendroglia, and perivascular softening or necrosis ³.

Radiographic features

Unfortunately, neuro-Behçet disease has a wide variety of manifestations in the central nervous system, including ¹: 

• focal or multifocal lesions
• meningoencephalitis 
• cerebral vein thrombosis

Meningoencephalitis and cerebral vein thrombosis are discussed separately in general articles related to these conditions. 

MRI

Lesions in neuro-Behçet disease typically involve ^1,3, in order of preference: 

• brainstem: most common
• basal ganglia: bilateral in a third of cases
• thalamus
• subcortical white matter: less common
• spinal cord: less common

Lesions in neuro-Behçet disease typically demonstrate the following signal characteristics ¹:

• T1: usually hypointense
• T2:
  • usually hyperintense
  • associated with vasogenic oedema
  • in acute phase, lesions cause mass effect 
• T1 C+ (Gd): typically moderate patchy enhancement
• DWI: isointense to slightly hyperintense [Ed: T2 shine through or true restricted diffusion?]
• MRS: drop in NAA, with elevated lipid and choline/creatine ratio⁴

Treatment and prognosis

• corticosteroids: i.v. methylprednisolone infusion then oral prednisone 
• immunosuppression: azathioprine, methotrexate, and anti-TNFα ²

Differential diagnosis

General imaging differential considerations include

• multiple sclerosis
• neurosarcoidosis
• primary CNS lymphoma
• gliomatosis cerebri 
• antiphospholipid syndrome
• Sweet syndrome

Consider other causes of T2 hyperintensity of the basal ganglia.