C Laboratory and Other Studies in Objective-C

Maker Quick Response Code in Objective-C C Laboratory and Other Studies

The electroencephalogram provides supporting information concerning cerebral function and may show either a focal disturbance due to the neoplasm or a more diffuse change reflecting altered mental status Lumbar puncture is rarely necessary; the findings are seldom diagnostic, and the procedure carries the risk of causing a herniation syndrome

Treatment depends on the type and site of the tumor (Table 24 5) and the condition of the patient Complete surgical removal may be possible if the tumor is extra-axial (eg, meningioma, acoustic neuroma) or is not in a critical or inaccessible region of the brain (eg, cerebellar hemangioblastoma) Surgery also permits the diagnosis to be verified and may be beneficial in reducing intracranial pressure and relieving symptoms even if the neoplasm cannot be completely removed Clinical deficits are sometimes due in part to obstructive hydrocephalus, in which case simple surgical shunting procedures often produce dramatic benefit In patients with malignant gliomas, radiation therapy increases median survival rates regardless of any preceding surgery, and its combination with chemotherapy provides additional benefit Indications for irradiation in the treatment of patients with other primary intracranial neoplasms depend on tumor type and accessibility and the feasibility of complete surgical removal Corticosteroids help reduce cerebral edema and are usually started before surgery Herniation is treated with intravenous dexamethasone (10 20 mg as a bolus, followed by 4 mg every 6 hours) and intravenous mannitol (20% solution given in a dose of 15 g/kg over about 30 minutes) Anticonvulsants are also commonly administered in standard doses (see Table 24 3) but are not indicated for prophylaxis in patients who have no history of seizures Long-term neurocognitive deficits may complicate radiation therapy For those patients whose disease deteriorates despite treatment, palliative care is important (see 5)

Byrne TN Cognitive sequelae of brain tumor treatment Curr Opin Neurol 2005 Dec;18(6):662 6 [PMID: 16280677] Gonzalez J et al Treatment of astrocytomas Curr Opin Neurol 2005 Dec;18(6):632 8 [PMID: 16280673] Henson JW Treatment of glioblastoma multiforme Arch Neurol 2006 Mar;63(3):337 41 [PMID: 16533960]

CT scanning or MRI with gadolinium enhancement may detect the lesion and may also define its location, shape, and size; the extent to which normal anatomy is distorted; and the degree of any associated cerebral edema or mass effect CT scanning is less helpful with tumors in the posterior fossa, but

Taillibert S et al Palliative care in patients with primary brain tumors Curr Opin Oncol 2004 Nov;16(6):587 92 [PMID: 15627022] Tam Truong M Current role of radiation therapy in the management of malignant brain tumors Hematol Oncol Clin North Am 2006 Apr;20(2):431 53 [PMID: 16730301] Wen PY et al Malignant gliomas Curr Neurol Neurosci Rep 2004 May;4(3):218 27 [PMID: 15102348]

Metastatic brain tumors present in the same way as other cerebral neoplasms, ie, with increased intracranial pressure, with focal or diffuse disturbance of cerebral function, or with both of these manifestations Indeed, in patients with a single cerebral lesion, the metastatic nature of the lesion may only become evident on histopathologic examination In other patients, there is evidence of widespread metastatic disease, or an isolated cerebral metastasis develops during treatment of the primary neoplasm The most common source of intracranial metastasis is carcinoma of the lung; other primary sites are the breast, kidney, and gastrointestinal tract Most cerebral metastases are located supratentorially Laboratory and radiologic studies used to evaluate patients with metastases are those described for primary neoplasms They include MRI and CT scanning performed both with and without contrast material Lumbar puncture is necessary only in patients with suspected carcinomatous meningitis (see below) In patients with verified cerebral metastasis from an unknown primary, investigation is guided by symptoms and signs In women, mammography is indicated; in men under 50, germ cell origin is sought since both have therapeutic implications In patients with only a single cerebral metastasis who are otherwise well, it may be possible to remove the lesion and then treat with irradiation; the latter may also be selected as the sole treatment In patients with multiple metastases or widespread systemic disease, the prognosis is poor; stereotactic radiosurgery, whole-brain radiotherapy, or both, may help in some instances, but in others treatment is palliative only

Kaal EC et al Therapeutic management of brain metastases Lancet Neurol 2005 May;4(5):289 98 [PMID: 15847842] Stafinski T et al Effectiveness of stereotactic radiosurgery alone or in combination with whole brain radiotherapy compared to conventional surgery and/or whole brain radiotherapy for the treatment of one or more brain metastases: a systematic review and meta-analysis Cancer Treat Rev 2006 May;32(3): 203 13 [PMID: 16472924]

The diagnosis is confirmed by examination of the cerebrospinal fluid Findings may include elevated cerebrospinal fluid pressure, pleocytosis, increased protein concentration, and decreased glucose concentration Cytologic studies may indicate that malignant cells are present; if not, spinal tap should be repeated at least twice to obtain further samples for analysis CT scans showing contrast enhancement in the basal cisterns or showing hydrocephalus without any evidence of a mass lesion support the diagnosis Gadolinium-enhanced MRI frequently shows enhancing foci in the leptomeninges Myelography may show deposits on multiple nerve roots Treatment is by irradiation to symptomatic areas, combined with intrathecal methotrexate The long-term prognosis is poor only about 10% of patients survive for 1 year and palliative care is therefore important (see 5)