Neuro Behçet's Disease

Summary

Rare neurological manifestation of Behçet's disease
Characterised by recurrent oral and genital ulcers, uveitis, and neurological symptoms
Imaging typically shows brainstem and diencephalic lesions, with potential for parenchymal and non-parenchymal involvement

Pathophysiology

Multisystem vasculitis affecting small and medium-sized vessels
Neurological involvement due to:
- Direct inflammatory cell infiltration of the nervous system
- Vasculitis of the central nervous system vessels
Two main types:
- Parenchymal: affects brain tissue directly
- Non-parenchymal: involves major blood vessels (cerebral venous thrombosis)

Prevalence highest along the ancient Silk Road (Middle East to East Asia)
Male predominance in Middle Eastern countries, equal gender distribution in Western countries
Typical onset between 20-40 years of age
Neurological involvement occurs in 5-30% of Behçet's disease patients

Based on clinical presentation and imaging findings
International Criteria for Behçet's Disease (ICBD) used for diagnosis
Key features:
- Recurrent oral and genital ulcers
- Ocular lesions (uveitis, retinal vasculitis)
- Skin lesions (erythema nodosum, pseudofolliculitis)
- Positive pathergy test
Neurological symptoms may include:
- Headache
- Cognitive dysfunction
- Pyramidal signs
- Brainstem syndromes
- Psychiatric manifestations

MRI is the modality of choice
Parenchymal involvement:
- Predilection for brainstem, basal ganglia, and diencephalon
- T2/FLAIR hyperintense lesions
- Acute lesions may show contrast enhancement and diffusion restriction
- Chronic lesions may demonstrate atrophy
Non-parenchymal involvement:
- Cerebral venous thrombosis (most common)
- Dural sinus thrombosis
- Arterial involvement (aneurysms, stenosis)
Spinal cord involvement:
- Longitudinally extensive transverse myelitis
Advanced imaging techniques:
- MR spectroscopy: decreased N-acetylaspartate, increased choline and lactate
- Diffusion tensor imaging: reduced fractional anisotropy in affected areas

Case 1

A 20-year-old patient presented with an ophthalmoplegia and confusion.
MRI showed oedema and swelling in the right thalamus and midbrain (cascade/waterfall sign) as well as the optic tract.
Biopsy exlcuded infection but showed macrophages and activated microglia.
Alongside a history of leg and genital ulcers, a diagnosis of neuro-Behçet's was made.

Multidisciplinary approach involving rheumatologists, neurologists, and ophthalmologists
Acute treatment:
- High-dose intravenous corticosteroids (e.g., methylprednisolone)
- Followed by oral corticosteroid taper
Maintenance therapy:
- Immunosuppressants: azathioprine, mycophenolate mofetil, methotrexate
- Biological agents: anti-TNF-α (infliximab, adalimumab) for refractory cases
Anticoagulation for cerebral venous thrombosis
Symptomatic management:
- Antiepileptics for seizures
- Antidepressants for psychiatric manifestations
Regular follow-up and monitoring:
- Clinical assessment
- MRI to evaluate treatment response and disease progression

Differential Diagnosis	Distinguishing Feature
Multiple Sclerosis	Periventricular and calloso-septal ovoid lesions; Dawson's fingers on sagittal FLAIR; no brainstem or diencephalic predilection
Neurosarcoidosis	Leptomeningeal and cranial nerve enhancement; hypothalamic/infundibular thickening; no brainstem tegmentum predilection
CNS Vasculitis	Multifocal cortical and subcortical infarcts; beading on angiography; vessel wall enhancement on high-resolution MRI
Neurosyphilis	Leptomeningeal enhancement; cortical infarcts; mesiotemporal T2 signal; indistinguishable from Behçet's on imaging alone
Viral Encephalitis	Temporal lobe and limbic T2/FLAIR signal; cortical restricted DWI; haemorrhagic foci in herpes encephalitis
Cerebral Venous Thrombosis	Headache more severe; MRV shows venous sinus thrombosis
Vogt-Koyanagi-Harada Disease	Presence of uveitis and dermatological findings; lacks oral/genital ulcers
CADASIL	Family history of stroke; characteristic MRI findings (subcortical infarcts and leukoencephalopathy)