Neurologic Diseases: Neurosarcoidosis

Neurosarcoidosis or sarcoidosis of the nervous system is an uncommon condition.

Sarcoidosis is systemic graulomatous inflammatory disease and generally affects the lungs and lymph nodes. Nervous system involvement is rare and only about 5% of the systemic sarcoidosis. Involvement of the nervous system alone is still rare and only about 1% of the all sarcoid cases in the body.

What causes sarcoidosis is still unknown. This disease has certain similarities to TB (tuberculosis) and both are granulomatous conditions, means produce small nodular collection of inflammatory cells called granulomas in the affected organs or tissues. TB is caused by a bacteria called as Mycobacterium tuberculosis and produces a caseating type of necrosis within the granuloma while sarcoidosis produces non caseating necrosis and is not caused by TB bacteria.

Almost any part of the nervous system can be affected by this disease including;

• Cranial nerves
• Brain parenchyma
• Meninges (brain coverings)
• Spinal cord
• Peripheral nerves
• Muscles etc

The manifestations would depend upon the area of involvement. Patients generally present with one or more of these manifestations;

• Facial paralysis
• Seizures
• Headache
• Blurring of vision or blindness
• Limb weakness
• Numbness etc

The following tests are generally required as a work up for sarcoidosis of the nervous system

• CT and/or MRI of brain
• CSF (cerebrospinal fluid) analysis
• Serum ACE (angiotensin converting enzyme) assay
• Serum calcium levels
• EMG/NCS (electromyography and nerve conduction studies)
• Biopsy of the abnormal lesion etc

The following are usually tried to treat the sarcoidosis of the nervous system (decided on case to case basis)

• Steroids e.g. prednisolone
• Other immunosuppressive agents like methotrexate
• Radiotherapy
• Surgical treatment of the lesion etc.

A neurologist is commonly involved in the management of sarcoidosis of the nervous system.