Cryptococcal intracerebral mass lesions: CT-pathologic considerations.

Two patients with cryptococcal intracerebral disease showed CT evidence of multiple round hypodense nonenhancing lesions in the gray matter. These lesions proved to be gelatinous pseudocysts rather than granulomas or abscesses. Pseudocysts may occur alone or with meningitis or granulomas. Recognition of these will avoid confusion with other infectious, vascular, or neoplastic conditions.

Gentamicin, tobramycin, amikacin, and netilmicin levels in tears following intravenous administration.

Peak and trough tear and serum concentrations were determined in 27 human volunteers undergoing intravenous (IV) gentamicin sulfate, tobramycin sulfate, amikacin sulfate, and netilmicin sulfate therapy. Although effective serum concentrations were achieved, tear levels were subtherapeutic. The mean peak tear concentrations were 0.4 microgram/mL, 0.5 microgram/mL, 1.7 micrograms/mL, and 0.3 microgram/mL for gentamicin, tobramycin, amikacin, and netilmicin, respectively. These levels did not approach the minimum inhibitory concentrations for Pseudomonas and raise some concern regarding the risk-benefit ratio of IV antibiotics for bacterial keratitis.

Abnormal splenic uptake of gallium-67 citrate in a case of infectious mononucleosis.

A case of fever of undetermined origin (FUO) demonstrated abnormal intense concentration of Ga-67 citrate in the spleen. Initial workup demonstrated two negative mono spot tests for infectious mononucleosis (IM) but, on hospital day 2, a repeat mono test was positive. The diagnosis was subsequently confirmed by rising heterophilic antibody titers. Six weeks after hospital discharge, repeat Ga-67 citrate imaging demonstrated absence of abnormal splenic activity. To our knowledge, this phenomenon has not been previously described in IM. In the appropriate clinical setting, intense splenic uptake of Ga-67 should alert the clinician to include the possibility of IM in the differential diagnosis.

Computerized tomographic abnormalities in patients with transient episodes of focal neurological dysfunction.

Forty patients with episodes of transient neurological dysfunction lasting less than 24 hr had abnormal CT scan findings. Eight patients had intracranial mass lesions and 32 had vascular lesions i.e. ischemic, infarction, hematoma. Seventeen patients had hypodense lesions consistent with tissue infarction; whereas 12 patients had isodense enhancing lesions consisting with tissue ischemia. In eight patients with isodense enhancing lesions, this was no neurological deterioration following carotid endarterectomy. In 3 patients who had transient ischemic attacks with CT evidence of hypodense lesions there was clinical and CT deterioration following carotid surgery.

Enhancing cerebellar infarction.

Five patients with CT evidence of enhancing cerebellar infarcts are analyzed. This represented 12% of cerebellar infarcts diagnosed by CT scan. The pattern of cerebellar linear enhancing bands which are contiguous with a hypo- or isodense lesion is quite characteristic of cerebellar infarction. In two cases, the lesion appeared isodense on the plain scan and therefore the enhanced scan was crucial to establishing the diagnosis of a cerebellar infarction. The presence of nodular or ring enhancement is sometimes seen with cerebellar infarction but is more common of neoplastic disorders, vascular malformations, or infectious-inflammatory disorders. The enhancement pattern of the cerebellar infarctions developed within the initial seven days after the onset of neurological deficit, and this is earlier than the enhancement pattern of supratentorial ischemic vascular lesions.