Altered Mental Status

Although the majority of alterations in sensorium in cancer patients are caused by endogenous or exogenous intoxication, the clinician must be alert to the possibility of structural disease in any patient who experiences a change in mental status. Accurate diagnosis of structural disease and prompt intervention can significantly improve the outcome of cancer treatments. Mogami et al. (1983) note five causes of increased intracranial pressure due to structural lesions in cancer patients: (1) intracranial space-occupying lesions, especially malignant tumors; (2) leptomeningeal tumors; (3) hemorrhage into brain tumors; (4) intracranial hemorrhage due to hemorrhagic diathesis related to malignant tumors; and (5) cerebral thrombosis or embolism due to an increase in blood coagulability caused by malignancy. Raised intracranial pressure may also occur as a complication of nonstructural conditions such as chronic infectious meningitis (Wilhelm and Ellner, 1986) the encephalitides, and severe metabolic disturbances such as hepatic encephalopathy, respiratory failure, and exogenous intoxications. Ironically, severe intracranial hypertension may accompany treatment of intracranial metastases, especially tumors that are sensitive to therapy. This commonly occurs with radiotherapy, including radioisotope therapy (Datz, 1986) for sensitive tumors. Cerebral herniation, which leads to increased intracranial pressure, is a possible, but uncommon complication of systemic chemotherapy (Walker et al., 1988) and cytokine treatment (Goey et al., 1988). Herniation has also been described as a complication of photodynamic therapy (Ji et al., 1992) for experimental gliomas. Patients with occult brain metastasis are in particular danger during the initiation of cytoreductive therapy. When the malignant cells are injured by therapy, they swell and induce edema in the surrounding tissues, thereby increasing intracranial pressure.