Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (797 page)

   Increased eosinophils: parasitic infection of the CNS, fungal infection of the CNS, viral infection of the CNS, CNS syphilis, allergic reaction

   Increased basophils: chronic myelogenous leukemia

   Tumor cells: primary or metastatic tumors of the CNS

   Xanthochromia (yellowish discoloration): marker of previous intracerebral bleeding

OTHER BODY FLUIDS: PLEURAL, PERICARDIAL, AND PERITONEAL SPACES

   Definition

   Under normal conditions, a very small amount of fluid (up to 50 mL) is present. This facilitates movement of membranes against each other. Abnormal fluid accumulation is called a serous effusion. In the presence of effusions, fluid can be aspirated from the affected cavity, either for diagnosis or for relief of pressure, commonly both. Finding substantial amounts of fluid always reflects a pathologic process.

   Interpretation

   Pleural fluid

   Appearance

   Cloudiness: neutrophils present, indicating infection

   Milkiness: chylous effusion

   Bloody: traumatic tap, malignancy, pneumonia, trauma, status post-myocardial infarction, or pulmonary infarction

   Cell counts and differentials