Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Sarcoidosis
- Radiologic Findings
- Simple chest radiograph shows bulging shadow in bilateral hilum and AP window. Brain MRI (precontrast T1 and postcontrast T1-weighted) sagittal images show enhanced mass in pituitary galnd and suprasellar area. Chest CT shows multiple lymph node enlargement in paratracheal, subcarinal, bilateral hilar, and bilateral interlobar area.
- Brief Review
- Sarcoidosis is a systemic disorder of unknown cause with a wide variety of clinical and radiologic manifestations. Thoracic involvement is reported in up to 90% of patients with sarcoidosis and bilateral hilar lymphadenopathy is the most common radiologic finding frequently with associated pulmonary infiltrates and typically has a characteristic perivascular distribution at high-resolution chest computed tomography. There are five radiologic stages of intrathoracic changes: Stage 0, normal chest radiograph; stage 1, lymphadenopathy only; stage 2, lymphadenopathy with parenchymal infiltration; stage 3, parenchymal disease only; and stage 4, pulmonary fibrosis. One-half of patients present with stage 1 disease.
Asymptomatic involvement of the CNS is present in up to 25% of patients at autopsy, whereas clinically recognizable involvement is seen in less than 10% of patients. Manifestations of neurosarcoidosis are variable and depend on the site and extent of involvement. The prognosis is also variable, ranging from a self-limiting process to a progressive course. Although the radiologic features of CNS sarcoidosis may simulate those of infectious or metastatic disease, mild clinical manifestations and laboratory data from cerebrospinal fluid analysis, such as increased ACE titer and CD4:CD8 ratio, may be useful in differentiating CNS sarcoidosis from other disease entities.
Neurosarcoidosis has a strong predilection for the base of the brain. Neuroendocrine disorders such as diabetes insipidus that arise owing to involvement of the pituitary gland and hypothalamus are relatively common, although the anterior pituitary gland is rarely involved. By facial and optic nerve involvement, bilateral facial nerve palsy and decreased visual acuity can occur. These palsies often demonstrate rapid onset with spontaneous resolution. Periventricular and deep white matter lesions are commonly seen and are typically hyperintense on T2-weighted images. Leptomeningeal involvement, which is most commonly observed at the base of the brain, is also a frequent manifestation of CNS sarcoidosis and causes aseptic meningitis. Contrast-enhanced T1-weighted imaging can accurately depict diffuse enhancement in these lesions. These radiologic appearances may occasionally mimic those of granulomatous meningitis, including tuberculosis or carcinomatous meningitis.
Decreased secretion or action of argininevasopressin (AVP) usually manifests as diabetes insipidus (DI), a syndrome characterized by the production of abnormally large volumes of dilute urine. The 24-h urine volume is >50 mL/kg body weight and the osmolarity is <300 mosmol/L. Deficient secretion of AVP can be primary or secondary. The primary form usually results from agenesis or irreversible destruction of the neurohypophysis and is variously referred to as neurohypophyseal DI, pituitary DI, or central DI. Secondary deficiencies of AVP result from inhibition of secretion by excessive intake of fluids. They are referred to as primary polydipsia. Neurosarcoidosis is one of causes of central DI.
- References
- 1. Koyama T, Ueda H, Togashi K, Umeoka S, Kataoka M, Nagai S. Radiologic manifestations of sarcoidosis in various organs. Radiographics. 2004;24:87-104.
2. Diabetes insipidus. in Harrison's online. (www.accessmedicine.com)
3. Nishimura K, Itoh H, Kitaichi M, Nagai S, Izumi T. Pulmonary sarcoidosis: correlation of CT and histopathologic findings. Radiology 1993; 189:105-109.
4. Muller NL, Kullnig P, Miller RR. The CT findings of pulmonary sarcoidosis: analysis of 25 patients. AJR Am J Roentgenol 1989; 152:1179-1182.
5. Brauner MW, Grenier P, Mompoint D, Lenoir S, de Cremoux H. Pulmonary sarcoidosis: evaluation with high-resolution CT. Radiology 1989; 172:467-471.
6. Mana J. Magnetic resonance imaging and nuclear imaging in sarcoidosis. Curr Opin Pulm Med 2002; 8:457-463.
7. Manz HJ. Pathobiology of neurosarcoidosis and clinicopathologic correlation. Can J Neurol Sci 1983; 10:50-55.
8. Chapelon C, Ziza JM, Piette JC, et al. Neurosarcoidosis: signs, course and treatment in 35 confirmed cases. Medicine (Baltimore) 1990; 69:261-276.
9. Sharma OP. Neurosarcoidosis: a personal perspective based on the study of 37 patients. Chest 1997; 112:220-228.
10. Zajicek JP, Scolding NJ, Foster O, et al. Central nervous system sarcoidosis: diagnosis and management. QJM 1999; 92:103-117.
11. Sherman JL, Stern BJ. Sarcoidosis of the CNS: comparison of unenhanced and enhanced MR images. AJNR Am J Neuroradiol 1990; 11:915-923.
12. Lexa FJ, Grossman RI. MR of sarcoidosis in the head and spine: spectrum of manifestations and radiographic response to steroid therapy. AJNR Am J Neuroradiol 1994; 15:973-982.
- Keywords
- Multiple organ, Connective tissue diseases, Sarcoidosis ,