Neuro-Behçet's disease
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Neuro-Behçet's disease | |
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Specialty | Neurology |
Behçet's disease with neurological involvement, neuro-Behçet's disease (NBD), involves central nervous system damage in 5–50% of cases.[3] The high variation in the range is due to study design, definition of neurological involvement, ethnic or geographic variation, availability of neurological expertise and investigations, and treatment protocols.
Signs and symptoms
The initial signs and symptoms of NBD are usually very general. This makes NBD hard to diagnose until the patients experience a severe neurological damage. In addition, the combination of symptoms varies among patients.
Parenchymal neuro-Behçet's disease
The main symptom is meningoencephalitis which happens in ~75% of NBD patients. Other general symptoms of Behçet's disease are also present among parenchymal NBD patients such as fever, headache, genital ulcers, genital scars, and skin lesions. When the brainstem is affected, ophthalmoparesis, cranial neuropathy, and cerebellar or pyramidal dysfunction may be observed. Cerebral hemispheric involvement may result in encephalopathy, hemiparesis, hemisensory loss, seizures, dysphasia, and mental changes including cognitive dysfunction and psychosis. As for the spinal cord involvement, pyramidal signs in the limbs, sensory level dysfunction, and, commonly, sphincter dysfunction may be observed.
Some of the symptoms are less common such as stroke (1.5%), epilepsy (2.2–5%), brain tumor, movement disorder, acute meningeal syndrome, and optic neuropathy.
Non-parenchymal neuro-Behçet's disease
Because Non-parenchymal NBD targets vascular structures, the symptoms arise in the same area. The main clinical characteristic is the
Some of the less common symptoms include intracranial hypertension and intracranial aneurysms.
Causes
Because the cause of Behçet's disease is unknown, the cause responsible for neuro-Behçet's disease is unknown as well. Inflammation starts mainly due to immune system failure. However, no one knows what factors trigger the initiation of auto-immune disease like inflammation. Because the cause is unknown, it is impossible to eliminate or prevent the source that causes the disease. Therefore, treatments are focused on how to suppress the symptoms that hinder daily life activities.[4]
Diagnosis
Although there is a diagnostic criterion for Behçet's disease, one for neuro-Behçet's disease does not exist. Three diagnostic tools are mainly used.
Blood test
60–70% of Japanese and Turkish patients were tested to possess HLA-B51, HLA-B serotype. These patients showed 6 times risk of getting BD. However, the same criteria are not ideal to be applied for Europeans because only 10–20% of European patients showed to possess HLA-B51.
Cerebrospinal fluid level
Cerebrospinal fluid is a clear bodily fluid that occupies the subarachnoid space and the ventricular system around and inside the brain. It is revealed that 70–80% of Parenchymal NBD patients show altered CSF constituents. The observed different is 1) Elevated CSF protein concentration (1 g/dL), 2) Absence of oligoclonal band, and 3) elevated CSF cell count (0–400×106 cells/L) in the body.
Others
"...Despite its rarity, the patient's ethnic background and the typical radiographic findings should prompt the clinicians to include NBD in the differential diagnosis of optic neuritis and demyelinating disease in the young..."[5][citation needed]. This quote indicates that even common symptoms such as headache should be recognized as the sign for possible NBD considering the patient's ethnic background.
Types
There are two types of neuro-Behçet's disease: parenchymal and non-parenchymal. The two types of neuro-Behçet's disease rarely occur in the same person. It is suggested that the pathogenesis of the two types are probably different.[3] Statistics indicate that approximately 75% (772 of 1031) BD patients advanced to parenchymal NBD while 17.7% (183 of 1031) of BD patients advanced to non-parenchymal NBD. The remaining 7.3% were not able to be categorized.
Parenchymal
If one experiences parenchymal neuro-Behçet's disease, meningoencephalitis, inflammation of brain, primarily occurs. The target areas of parenchymal NBD include brainstem, spinal cord, and cerebral regions. Sometimes it is hard to determine the affected area because patients are asymptomatic.[5]
Non-parenchymal
In non-parenchymal NBD, vascular complications such as
Others
Peripheral nervous system involvement is rarely reported (~0.8%). In this case,
Some of the syndromes are not common but recognized for the relation to NBD such as acute meningeal syndrome, tumor-like neuro-Behçet's disease, psychiatric symptoms and optic neuropathy.
Treatment
No definite standard treatment have been set. This is because treatments of the disease has been poorly studied as of 2014.[7] Often in cases of inflammatory parenchymal disease, "corticosteroids should be given as infusions of intravenous methylprednisolone followed by a slowly tapering course of oral steroids". It is suggested that therapy should be continued for a period of time even when the symptoms get suppressed because early relapse may occur. Sometimes, the medical doctors may suggest a different steroid depending on the nature of the disease, the severity, and the response to steroids. According to several studies, parenchymal NBD patients successfully suppress the symptoms with the prescribed steroids. As for non-parenchymal patients, there is no general consensus on how to treat the disease. The reason is that the mechanisms of cerebral venous thrombosis in BD are still poorly understood. Some doctors use anti-coagulants to prevent a clot. On the other hand, some doctors only give steroids and immunosuppressants alone.[8][9]
Epidemiology
In one study of 387 Behçet's disease (BD) patients that has been done for 20 years, 13% of men with BD developed to NBD and 5.6% of women developed to NBD. Combining all statistical reports, approximately 9.4% (43 of 459) BD patients advanced to NBD. In addition, men were 2.8 times more likely to experience NBD than women. This fact indicates possible gender-based pathology.[10][11][12] In speaking about age of NBD patients, the general range was between 20 and 40. NBD patients with age less than 10 or more than 50 were very uncommon.
Spectrum disorders
A related disorder to Neuro-Behçet's disease is neuro-Sweet disease.
References
- PMID 2919979.
- S2CID 21869670.
- PMID 9527155.
- PMID 10545401.
- PMID 10545402.
- ^ Tunc R, Saip S, Siva A, Yazici H. Cerebral venous thrombosis is associated with major vessel disease in Behçet's syndrome. Ann Rheum Dis 2004; 63: 1693–94.
- PMID 25521793.
- PMID 10545401.
- S2CID 24943648.
- PMID 30308139.
- PMID 12645628.
- PMID 12700303.
- S2CID 20773636.
- S2CID 53772268.
- PMID 34615825.
Further reading
- Al-Araji, A; Kidd, DP (February 2009). "Neuro-Behçet's disease: epidemiology, clinical characteristics, and management". Lancet Neurology. 8 (2): 192–204. S2CID 16483117.
- Koçer, N; Islak, C; Siva, A; Saip, S; Akman, C; Kantarci, O; Hamuryudan, V (Jun–Jul 1999). "CNS involvement in neuro-Behçet syndrome: an MR study". AJNR. American Journal of Neuroradiology. 20 (6): 1015–24. PMID 10445437.
- Borhani Haghighi, A (April 2009). "Treatment of neuro-Behçet's disease: an update". Expert Review of Neurotherapeutics. 9 (4): 565–74. S2CID 136810719.