Definition
- A granulomatous disease that is usually systemic that involves the CNS
Numbers
- Only 1–3% of cases have CNS findings without systemic manifestations Aka Neurosarcoidosis
Aetiology
- Unknown.
Pathology
- An exaggerated cellular immune response for unknown reasons is the currently favoured hypothesis.
- Primarily involves the leptomeninges
- Parenchymal invasion often occurs
- Adhesive arachnoiditis with nodule formation may also occur (nodules have a predilection for the posterior fossa).
- Diffuse meningitis or meningoencephalitis may occur, and may be most pronounced at the
- Base of the brain (basal meningitis)
- In the subependymal region of the third ventricle (including the hypothalamus).
- Spinal involvement may include arachnoiditis
- Lesions that may be intramedullary, extramedullary intradural and extramedullary extradural
Clinical features
- Cranial mononeuropathy: facial, vestibulocochlear, optic
- Multiple cranial nerve palsies in 50–70%
- Esp CN7
- Neuroendocrine dysfunction due to
- Hypothalamic inflammation
- Polyuria
- Can have many causes therefore need water restriction to find out source of issue
- Hypervitaminosis D in sarcoidosis → hypercalcemia → nephrogenic diabetes insipidus
- Direct hypothalamus involvement → Reduce vasopressin → central diabetes insipidus
- Sleep disturbances
- Appetite
- Temperature
- Libido
- Lesions (in both hypothalamus or pituitary)
- Thyroid abnormalities
- Gonadal abnormalities
- Adrenal abnormalities
- Perivascular distribution of granulomatous inflammation in brain can cause
- Generalised seizures
- Seizures occur in 15%.
- Restricted/generalised encephalopathy
- Cognitive or behavioural problems
- Focal neurological deficits
- May produce mass effect
- Hydrocephalus
- Sudden death from raised ICP can occur
- Both types
- Communicating
- Non communicating
- Hydrocephalus may result from adhesive basal arachnoiditis
- Meningeal involvement
- Acute aseptic meningitis
- Chronic meningitis
- Meninges mass lesion
- Myelopathy/radiculopathy: if spinal cord affected
- Can be both extra or intramedullary
- Peripheral neuropathic presentations (can be mono/poly, sensory/motor/autonomic)
- Axonal injury
- Demyelination (like GBS)
- Carpal tunnel common
Investigation
- Serum angiotensin-converting enzyme (ACE)
- Abnormally elevated in 83% of patients with active pulmonary sarcoidosis
- But in only 11% with inactive disease
- Biopsy
- Indicated in uncertain cases
- Target
- Mass lesion
- Meningeal biopsy may be done and should include all layers of meninges and cerebral cortex.
- Cultures and stains for fungus and acid-fast bacteria (TB) should be sent for
- LP
- Increased pressure
- Mononuclear cell pleocytosis (mostly lymphocytes)
- Oligoclonal bands might be present
- Elevated protein (up to 2,000 mg/dl)
- Mild hypoglycorrhachia (15–40 mg/dl),
- CSF ACE is elevated in ≈ 55% of cases with neurosarcoidosis
- Normal in patients with sarcoidosis not involving the CNS
- MRI
- Meningeal or parenchyma enhancement
- Parenchyma nodules following along Virchow robin spaces deep into brain or spinal cord
Diagnosis
- Sarcoidosis diagnosis is straightforward CXR + biopsy of skin/liver nodule/muscle, serum ACE but neurosarcoidosis is much more difficult as a true diagnosis might require a brain biopsy
Treatment
- Corticosteroids
- Other immune modulators
- Infliximab
- Mycophenolate
- Cyclophosphamide
- Refractory cases
- Radiation therapy
- Methotrexate
- Cytoxan
- Cyclophosphamide
- Azathioprine
- Hydroxychloroquine (Plaquenil®)
- VPS
Prognosis
- Usually a benign disease.
- Peripheral and cranial nerve palsies recover slowly
Made with Bullet