Thursday, 14 July 2016
Histo pathological Differential Diagnosis of Neuro sarciodosis
Involvement of the nervous system is reported in 5 to 15% of patients with sarcoidosis, although autopsy series indicate that the frequency of lesions in the nervous system may be higher.
A 32-year-old man presented with a 1-year history of olfactory hallucinations and a 6-week history of intermittent numbness and paresthesias on the left side. MRI revealed a nodular focus of enhancement in the medial right temporal lobe. A diagnostic procedure was performed. A new Case Records of the Massachusetts General Hospital summarizes.
• What is the most common abnormality reported in cases of neurosarcoidosis?
Basilar meningeal involvement with an associated cranial neuropathy (usually involving the facial nerve) is the most common abnormality reported. Involvement of the facial nerve can be either unilateral or bilateral, and bilateral involvement can be simultaneous or sequential.
• What are some of the other clinical manifestations of neurosarcoidosis?
Optic nerve involvement may occur alone or in association with other lesions. Leptomeningeal involvement, either focal or diffuse, may be observed in association with cranial neuropathies or in isolation. Disease in the region of the infundibular stalk may result in endocrinopathies caused by alteration of the hypothalamic–pituitary axis. Dural involvement may be manifested by a discrete mass that may mimic meningioma. Neurosarcoidosis with parenchymal involvement is less frequent than neurosarcoidosis with meningeal involvement.
Figure 1. MRI of the Head.
Q: What is the prognosis of neurosarcoidosis?
A: Clinical experience and a few long-term studies have shown that the response to therapy and the prognosis depend on the clinical syndrome. Lymphocytic meningitis, mononeuropathies of the facial nerves, multiple cranial neuropathies, and polyradiculoneuropathies respond to relatively short courses of glucocorticoids, are associated with a good long-term prognosis, and are generally not debilitating. In contrast, patients with sarcoidosis affecting the parenchyma of the brain, the spinal cord, or the conus medullaris and cauda equina or with granulomatous involvement of the optic nerves and hypothalamic and pituitary regions often have a protracted and progressive course over a period of years. Such patients respond partially to glucocorticoids and glucocorticoid-sparing immunosuppressive medications, such as methotrexate, azathioprine, and mycophenolate, but they require treatment for years.
Q: How is neurosarcoidosis treated?
A: Immunosuppressive drugs, predominantly glucocorticoids, are the backbone of therapy for neurosarcoidosis in all its forms, but biologics such as TNF-α inhibitors are now an important part of the treatment. TNF-α inhibitors may be useful when the usual immunosuppressive therapy is inadequate or is associated with an unacceptable side-effect profile. The rationale for the use of TNF-α inhibitors is evidence of the role of the cytokine TNF-α, which is generated in granulomas, in causing tissue damage and perpetuating the granulomatous process. The most commonly used TNF-α inhibitor is infliximab, which is a chimeric monoclonal antibody that inhibits both soluble and membrane-bound TNF-α.