Intracranial structural lesions

Absolute contraindications to fibrinolytic therapy include (1) active internal bleeding (2) previous ICH at anytime (3) ischemic stroke within 3 months (4) known intracranial neoplasm (5) known structural vascular lesion (6) suspected aortic dissection and (7) significant closed head or facial trauma within 3 months. Primary PCI is preferred in these situations. 

Structural intracranial lesions tumor, chronic subdural hematoma, vascular malformation, giant aneurysm Multiple sclerosis... 

Gradual onset of stroke over hours or days, rather than seconds or minutes, is unusual and is much more likely to occur in ischemic than in hemorrhagic stroke. If the onset is gradual, and not Ukely to be caused by low flow or migraine (Ch. 8), then a structural intracranial lesion must be excluded. In younger patients, multiple sclerosis should also be considered. However, focal neurological deficits that develop over hours, or up to two days, in elderly patients are still most likely to have a vascular cause since vascular disease is so common in older patients. 

Giant cell arteritis (or other inflammatory vascular disorders) (Ch. 6) Structural intracranial lesion (Chs. 8 and 9) intracranial venous thrombosis (Ch. 29)... 

Two different methods have been used to determine the structure-activity relations of the neurotoxic action of the excitatory amino acids. With the first, the amino acids are administered by peripheral injection, which produces neuronal damage in areas of the brain to which the excitotoxins gain access. The second approach involves direct intracranial injection with analysis of the affected area to determine the scope and specificity of the lesion. While the latter method allows for more precise definition of toxic potencies and avoids variables such as metabolism and penetration of the blood-brain barrier, the systemic administration of these compounds was exploited first and continues to be used. 

When systemic or topical pharmacotherapy and other non-invasive approaches provide inadequate relief in patients with NP, interventional approaches may be used, including sympathetic blockade with local anesthetics, intraspinal drug delivery, spinal cord stimulation, peripheral subcutaneous nerve stimulation, or stimulation of specific central nervous system structures, and various neuroablative procedures (e.g. dorsal rhizotomy, neurolytic nerve block, intracranial lesioning). Neuroablative procedures are not reversible and should be reserved for carefully and properly selected patients with intractable pain. 

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