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

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 venous thrombosis are discussed separately in general articles related to these conditions. 

MRI

Parenchymal lesions in neuro-Behçet disease typically involve the following sites ^1,3,5,6: 

• mesodiencephalic junction (thalamus, midbrain, and internal capsule): most common, on coronal images appearing as the cascade sign ⁷

• pons: second most common

• basal ganglia: bilateral in one-third of cases

• subcortical white matter: less common

• spinal cord: less common, often as longitudinally extensive transverse myelitis with the bagel sign

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

• T1: usually hypointense

• T2:

  • usually hyperintense

  • associated with vasogenic edema

  • in acute phase, lesions cause mass effect 

• T1 C+ (Gd): typically moderate patchy enhancement

• DWI: isointense to slightly hyperintense

• MRS: drop in NAA, with elevated lipid and choline/creatine ratio ⁴

Treatment and prognosis

• corticosteroids: intravenous methylprednisolone infusion then oral prednisone 

• steroid-sparing immunosuppression: azathioprine, methotrexate, and TNFα inhibitors 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.