INTRODUCTION Granulomatous inflammation is a distinctive ...

Tuberculous Meningitis
Tuberous Sclerosis
Wegener Granulomatosis
(Bucurescu, 2006)
Investigations
Sarcoidosis is a diagnosis of exclusion, and establishing evidence for systemic sarcoidosis often
requires an extensive search for the disease in commonly involved organs like the lungs, lymph
nodes, skin, and eyes. The common abnormalities on chest radiograph include bilateral hilar
lymphadenopathy and interstitial infiltrates. If pulmonary involvement is evident, diagnostic
confirmation can be often obtained by transbronchial or mediastinoscopic biopsy or
bronchoalveolar lavage. Also, the clinical evaluation may help in the selection of other sites for
biopsy, including the skin, parotid gland, lymph nodes, liver, or conjunctiva (Rodan and Putman,
1983).
The diagnostic approach for neurosarcoidosis differs depending on the clinical presentation.
Diagnosis is often difficult because of the unknown etiology, diverse clinical manifestations, and
lack of confirmatory diagnostic tests. The diagnosis is particularly difficult if neurological
symptoms are the only presenting features because of the difficulty in obtaining tissue for
histological confirmation. Evidence of systemic disease in this setting is very helpful. The criteria
for diagnosis of neurosarcoidosis include a compatible clinical picture, typical radiological
findings, and histological evidence of noncaseating granulomata in any tissue. A different
diagnostic approach is warranted if patients with known systemic sarcoidosis develop neurological
symptoms. In this group, the diagnosis is relatively easy if the neurological manifestations are
typical of neurosarcoidosis and supported by imaging studies or other laboratory tests. Tissue
diagnosis is not mandatory in these patients; however, not every neurological symptom in
someone with systemic sarcoidosis should be considered caused by neurosarcoidosis (Metwally,
2006-4).
Investigations in systemic sarcoidosis
The Kveim test involves intracutaneous inoculation of a suspension derived from the spleen of
patients with sarcoidosis, when positive, will produce a cutaneous nodule containing noncaseating
granulomata. The Kveim test is reported to be positive in 67% to 92% of patients with sarcoidosis
(Chapelon et al., 1990). Although it is a very specific and sensitive test, the agent for the test is not
widely available. This, with the fact that it takes 4 to 6 weeks to report positive, makes it an
impractical test.
Serum Angiotensin Converting Enzyme (ACE) levels are elevated in 56% to 86% of patients
(Israel et al., 1986). Levels may correlate with the disease activity post-treatment, but they have
little prognostic value in the initial evaluation. Serum ACE levels are also elevated in patients with
liver disease, diabetes mellitus, hyperthyroidism, systemic infection, malignancy, Gaucher's
disease and in normal young individuals, but they are much higher in sarcoidosis (Consensus
Conference, 1994).
Nonspecific laboratory abnormalities in sarcoidosis include anemia, leukopenia,
thrombocytopenia, hypergammaglobulinemia, hypercalcemia, hypercalciuria, elevated liver
enzymes, and elevated blood urea nitrogen (BUN) and creatinine levels (Metwally, 2006-4).