Cerebrovascular Disease - Prince of Songkla University

58kB Size 3 Downloads 9 Views

Cerebrovascular Disease. I. ... is the abrupt onset of symptoms and neurologic deficits that correspond to interruption of vascular supply to a ... Vital signs ...
Cerebrovascular Disease I. The hallmark of stroke is the abrupt onset of symptoms and neurologic deficits that correspond to interruption of vascular supply to a specific brain region. Although stroke is synonymous with cerebral infarction, fluctuation of functional deficits after stroke onset and reversible deficits known as transient ischemic attacks (TIAs) (deficits resolve within 24 hours) and reversible ischemic neurologic deficits (deficits resolve within a week) suggest that tissue at risk for infarction can be rescued by re-establishing perfusion. Currently, the most important aspect of stroke management is consideration of stroke as a medical emergency that requires rapid diagnosis and treatment. Recombinant tissue plasminogen activator (rt-PA) is the only proven therapy for acute stroke, but patients must be selected carefully, and administration of rt-PA must commence within 3 hours of stroke onset. Other treatments, including intra-arterial thrombolysis, are available at some centers under research protocols. | |A. Important historical information includes the onset and | | |progression of symptoms and contributory events (e.g., head | | |trauma or seizure). Prior TIA symptoms (e.g., transient | | |monocular loss of vision, aphasia, dysarthria, paresis, or | | |sensory disturbance) are often associated with atherosclerotic| | |vascular disease, the most common cause for stroke. A history | | |of trauma, even minimal, is important, as extracerebral | | |arterial dissections may cause ischemic strokes. Other medical| | |conditions associated with stroke, such as cardiac arrhythmia | | |or valvular disease, connective tissue disease, and sickle | | |cell anemia, should be identified. Classic migraine can mimic | | |stroke and is a risk factor for stroke. In epileptic patients,| | |ictal paralysis is rare, but postictal paralysis (Todd's | | |paralysis) is common after a focal seizure. The diagnosis may | | |be suggested by stroke risk factors such as hypertension, | | |diabetes, smoking, postpartum state, illicit IV drug use, and | | |medications such as oral contraceptives, and management is | | |influenced by these factors. |

| |B. Physical examination should provide clues that indicate | | |specific diagnostic tests and therapy. Cardiogenic embolism | | |accounts for about 20% of strokes; physical examination should| | |focus on findings of mitral or aortic stenosis and murmur. | | |Embolic disease affects fundi, conjunctivae, nail beds, | | |fingers, and palms. Urinalysis should be performed to evaluate| | |for hematuria. Fever raises concern for infectious etiologies.| | |Meningismus, seizures, or altered mental status suggest | | |meningitis or encephalitis. Septic emboli from bacterial | | |endocarditis can cause meningitis or cerebral or parameningeal| | |abscess. The patient should be examined for evidence of | | |neurocutaneous disease (neurofibromatosis and tuberous | | |sclerosis) and vasculitis (e.g., systemic lupus | | |erythematosus). |

| |C. A careful neurologic examination reliably establishes the | | |anatomic location of a stroke, which is typically confirmed by| | |neuroimaging. In general, carotid artery distribution strokes | | |(anterior circulation) produce combinations of functional | | |deficits (hemiparesis, hemianopsia, cortical sensory loss, | | |often with aphasias or agnosias) contralateral to the affected| | |hemisphere, whereas vertebral-basilar strokes (posterior | | |circulation) produce unilateral or bilateral motor/sensory | | |deficits, usually accompanied by cranial nerve and brain stem | | |signs. Horner's syndrome (ptosis, miosis, anhidrosis) | | |contralateral to an acute hemiparesis suggests carotid | | |dissection. |

II. Initial assessment and management | |A. Vital signs, including oximetry and continuous ECG, should | | |be monitored. Administration of oxygen, placement of IV | | |access, and checking of blood glucose should be done | | |immediately. Laboratory analysis should include CBC with | | |differential and platelet count, PT, activated PTT, and | | |electrolyte panel. ECG (for atrial fibrillation) and a chest | | |radiograph should be obtained. |

| |B. Immediately after initial assessment and stabilization, a | | |noncontrast head CT scan should be performed to identify | | |various hemorrhagic lesions that influence specific management| | |decisions. The CT scan often confirms a suspected ischemic | | |infarct, unless it is very early after onset (hours) or if the| | |stroke is very small (particularly in the brain stem), in | | |which case MRI is more sensitive. A mass lesion may preclude a| | |diagnostic lumbar puncture for meningitis/encephalitis because| | |it may precipitate brain herniation (see Alterations in | | |Consciousness, sec. III.F). Appropriate antimicrobial and | | |antiviral drugs should still be administered. |

| |C. rt-PA therapy should be considered when a nonhemorrhagic | | |ischemic infarct has been demonstrated and infectious | | |etiologies are excluded, while one continues to pursue a | | |specific diagnosis. Hemorrhagic transformation of infarcts | | |accompanied by higher mortality was observed with rt-PA; | | |therefore, strict adherence to the American Academy of | | |Neurology/American Heart Association guidelines is recommended| | |(Neurology 47:835, 1996). Exclusion criteria include stroke | | |onset longer than 3 hours; extensive infarction evident on CT | | |scan; recent surgery, head trauma, or GI or urinary | | |hemorrhage; seizure at stroke onset; bleeding disorder or | | |anticoagulation with prolonged PT/PTT; and severe uncontrolled| | |hypertension (systolic >185, diastolic >110 mm Hg). The rt-PA | | |dose is 0.9 mg/kg up to a maximum of 90 mg, with the first 10%| | |(maximum, 9 mg) given IV over 1 minute, then the remaining 90%| | |(maximum, 81 mg) given by infusion pump over 1 hour. Aspirin, | | |heparin, and warfarin are not given during the first 24 hours.| | |Systolic BP should be maintained at less than 185 and | | |diastolic BP at less than 110 mm Hg to reduce the patient's | | |risk for hemorrhagic transformation. |

III. Diagnosis and management of specific etiologies | |A| | | |.| | | |A| | | |d| | | |d| | | |i| | | |t| | | |i| | | |o| | | |n| | | |a| | | |l| | | |d| | | |i| | | |a| | | |g| | | |n| | | |o| | | |s| | | |t| | | |i| | | |c| | | |t| | | |e| | | |s| | | |t| | | |s| | | |m| | | |a| | | |y| | | |b| | | |e| | | |r| | | |e| | | |q| | | |u| | | |i| | | |r| | | |e| | | |d| | | |t| | | |o| | | |e| | | |s| | | |t| | | |a| | | |b| | | |l| | | |i| | | |s| | | |h| | | |a| | | |s| | | |p| | | |e| | | |c| | | |i| | | |f| | | |i| | | |c| | | |d| | | |i| | | |a| | | |g| | | |n| | | |o| | | |s| | | |i| | | |s| | | |.| | | | |1. MRI scan is more sensitive and accurate than CT in | | | |narrowing the differential diagnosis of cerebral lesions, | | | |and MR angiography is a useful noninvasive method to | | | |evaluate large arteries and veins. | | | |2. Carotid Doppler studies enable noninvasive estimation of | | | |carotid stenosis. Conventional iodine contrast angiography | | | |may be required to diagnose cerebral aneurysm or isolated | | | |CNS angiitis and is usually required when carotid | | | |endarterectomy is considered (see sec. III.B.2). | | | |3. Transthoracic two-dimensional echocardiography is helpful| | | |to demonstrate intracardiac thrombi, valve vegetations, | | | |valvular stenosis or insufficiency, and right-to-left | | | |shunting (contrast echocardiogram). In some patients, | | | |transesophageal echocardiography is necessary to evaluate | | | |the left atrium for thrombi. | | | |4. CSF analysis for malignant cells, special cultures, preps| | | |(e.g., acid-fast bacilli stain, India ink preparation), or | | | |antibody titers (e.g., VDRL) is helpful in the | | | |identification of carcinomatous or less common infectious | | | |etiologies. | | | |5. Erythrocyte sedimentation rate, antinuclear antibody, | | | |anticardiolipin antibody, hemoglobin electrophoresis, lipid | | | |profile, or other specific tests may be required as | | | |indicated to establish a specific diagnosis. |

| |B| | | |.| | | |T| | | |r| | | |e| | | |a| | | |t| | | |m| | | |e| | | |n| | | |t| | | |o| | | |f| | | |a| | | |t| | | |h| | | |e| | | |r| | | |o| | | |s| | | |c| | | |l| | | |e| | | |r| | | |o| | | |t| | | |i| | | |c| | | |s| | | |t| | | |r| | | |o| | | |k| | | |e| | | | |1. Aspirin reduces the incidence of stroke and vascular | | | |mortality. A common aspirin dose is 325 mg/day, but lower | | | |and higher doses are effective. The combination of aspirin | | | |(25 mg bid) and extended-release dipyridamole (200 mg bid) | | | |may be more effective in stroke prevention after TIA or | | | |ischemic stroke (J Neurol Sci 143:1, 1996). Clopidogrel (75 | | | |mg qd) and ticlopidine (250 mg bid) are alternatives to | | | |aspirin for patients who cannot tolerate or have not | | | |responded to aspirin therapy (Chest 114:683S, 1998). | | | |2. Carotid endarterectomy decreases the risk of stroke and | | | |death in patients with recent TIAs or nondisabling strokes | | | |and ipsilateral high-grade (70–99%) carotid stenosis (N Engl| | | |J Med 325:445, 1991). Carotid endarterectomy for | | | |asymptomatic high-grade carotid stenosis (>60%) reduces the | | | |relative risk of stroke provided that the | | | |surgical/angiography complication rate is less than 3% (JAMA| | | |273:1421, 1995). Stroke risk factor reduction and | | | |antiplatelet therapy are important components of | | | |postoperative management (Stroke 29:554, 1998). | | | |3. Heparin and warfarin treatment for atherosclerotic | | | |cerebrovascular disease is controversial; use must be | | | |individualized, with potential benefits considered with | | | |risks for hemorrhagic complications. |

| |C. Treatment of cardiogenic embolus. Anticoagulation is | | |indicated to prevent recurrent embolic strokes (see Chap. 19).| | |Anticoagulation with heparin should be initiated. Warfarin is | | |used for chronic anticoagulation with a target international | | |normalized ratio of 2–3 for embolic infarcts, the exception | | |being mechanical heart valves, for which an international | | |normalized ratio of between 2.5 and 3.5 is recommended. | | |Systemic hypertension is a relative contraindication to | | |long-term anticoagulation because of increased risk for | | |intracranial hemorrhage. |

| |D. Modification of risk factors, including systemic | | |hypertension, diabetes, smoking, illicit IV drug use, and | | |possibly elevated lipids and cholesterol, reduce risk for | | |stroke. Oral contraceptives may need to be discontinued in | | |women with stroke. |

IV. Intracerebral hemorrhage and SAH | |A| | | | |.| | | | |I| | | | |n| | | | |t| | | | |r| | | | |a| | | | |c| | | | |e| | | | |r| | | | |e| | | | |b| | | | |r| | | | |a| | | | |l| | | | |h| | | | |e| | | | |m| | | | |o| | | | |r| | | | |r| | | | |h| | | | |a| | | | |g| | | | |e| | | | |u| | | | |s| | | | |u| | | | |a| | | | |l| | | | |l| | | | |y| | | | |p| | | | |r| | | | |e| | | | |s| | | | |e| | | | |n| | | | |t| | | | |s| | | | |w| | | | |i| | | | |t| | | | |h| | | | |a| | | | |c| | | | |u| | | | |t| | | | |e| | | | |o| | | | |n| | | | |s| | | | |e| | | | |t| | | | |o| | | | |f| | | | |f| | | | |o| | | | |c| | | | |a| | | | |l| | | | |n| | | | |e| | | | |u| | | | |r| | | | |o| | | | |l| | | | |o| | | | |g| | | | |i| | | | |c| | | | |d| | | | |e| | | | |f| | | | |i| | | | |c| | | | |i| | | | |t| | | | |s| | | | |t| | | | |h| | | | |a| | | | |t| | | | |r| | | | |e| | | | |f| | | | |l| | | | |e| | | | |c| | | | |t| | | | |t| | | | |h| | | | |e| | | | |l| | | | |o| | | | |c| | | | |a| | | | |t| | | | |i| | | | |o| | | | |n| | | | |a| | | | |n| | | | |d| | | | |s| | | | |i| | | | |z| | | | |e| | | | |o| | | | |f| | | | |t| | | | |h| | | | |e| | | | |h| | | | |e| | | | |m| | | | |o| | | | |r| | | | |r| | | | |h| | | | |a| | | | |g| | | | |e| | | | |.| | | | |H| | | | |e| | | | |a| | | | |d| | | | |a| | | | |c| | | | |h| | | | |e| | | | |,| | | | |v| | | | |o| | | | |m| | | | |i| | | | |t| | | | |i| | | | |n| | | | |g| | | | |,| | | | |a| | | | |n| | | | |d| | | | |a| | | | |l| | | | |t| | | | |e| | | | |r| | | | |e| | | | |d| | | | |m| | | | |e| | | | |n| | | | |t| | | | |a| | | | |l| | | | |s| | | | |t| | | | |a| | | | |t| | | | |u| | | | |s| | | | |r| | | | |e| | | | |f| | | | |l| | | | |e| | | | |c| | | | |t| | | | |i| | | | |n| | | | |c| | | | |r| | | | |e| | | | |a| | | | |s| | | | |e| | | | |d| | | | |i| | | | |n| | | | |t| | | | |r| | | | |a| | | | |c| | | | |r| | | | |a| | | | |n| | | | |i| | | | |a| | | | |l| | | | |p| | | | |r| | | | |e| | | | |s| | | | |s| | | | |u| | | | |r| | | | |e| | | | |a| | | | |n| | | | |d| | | | |o| | | | |f| | | | |t| | | | |e| | | | |n| | | | |i| | | | |n| | | | |d| | | | |i| | | | |c| | | | |a| | | | |t| | | | |e| | | | |e| | | | |x| | | | |t| | | | |e| | | | |n| | | | |s| | | | |i| | | | |v| | | | |e| | | | |h| | | | |e| | | | |m| | | | |o| | | | |r| | | | |r| | | | |h| | | | |a| | | | |g| | | | |e| | | | |.| | | | |B| | | | |r| | | | |a| | | | |i| | | | |n| | | | |h| | | | |e| | | | |r| | | | |n| | | | |i| | | | |a| | | | |t| | | | |i| | | | |o| | | | |n| | | | |a| | | | |n| | | | |d| | | | |d| | | | |e| | | | |a| | | | |t| | | | |h| | | | |m| | | | |a| | | | |y| | | | |o| | | | |c| | | | |c| | | | |u| | | | |r| | | | |r| | | | |a| | | | |p| | | | |i| | | | |d| | | | |l| | | | |y| | | | |.| | | | |H| | | | |e| | | | |a| | | | |d| | | | |C| | | | |T| | | | |s| | | | |c| | | | |a| | | | |n| | | | |i| | | | |s| | | | |n| | | | |e| | | | |c| | | | |e| | | | |s| | | | |s| | | | |a| | | | |r| | | | |y| | | | |t| | | | |o| | | | |d| | | | |i| | | | |f| | | | |f| | | | |e| | | | |r| | | | |e| | | | |n| | | | |t| | | | |i| | | | |a| | | | |t| | | | |e| | | | |i| | | | |n| | | | |t| | | | |r| | | | |a| | | | |c| | | | |e| | | | |r| | | | |e| | | | |b| | | | |r| | | | |a| | | | |l| | | | |h| | | | |e| | | | |m| | | | |o| | | | |r| | | | |r| | | | |h| | | | |a| | | | |g| | | | |e| | | | |f| | | | |r| | | | |o| | | | |m| | | | |i| | | | |s| | | | |c| | | | |h| | | | |e| | | | |m| | | | |i| | | | |c| | | | |s| | | | |t| | | | |r| | | | |o| | | | |k| | | | |e| | | | |.| | | | | |1| | | | |.| | | | |T| | | | |h| | | | |e| | | | |e| | | | |t| | | | |i| | | | |o| | | | |l| | | | |o| | | | |g| | | | |y| | | | |i| | | | |s| | | | |u| | | | |s| | | | |u| | | | |a| | | | |l| | | | |l| | | | |y| | | | |c| | | | |h| | | | |r| | | | |o| | | | |n| | | | |i| | | | |c| | | | |s| | | | |y| | | | |s| | | | |t| | | | |e| | | | |m| | | | |i| | | | |c| | | | |h| | | | |y| | | | |p| | | | |e| | | | |r| | | | |t| | | | |e| | | | |n| | | | |s| | | | |i| | | | |o| | | | |n| | | | |.| | | | |T| | | | |h| | | | |e| | | | |l| | | | |o| | | | |c| | | | |a| | | | |t| | | | |i| | | | |o| | | | |n| | | | |s| | | | |o| | | | |f| | | | |h| | | | |y| | | | |p| | | | |e| | | | |r| | | | |t| | | | |e| | | | |n| | | | |s| | | | |i| | | | |v| | | | |e| | | | |i| | | | |n| | | | |t| | | | |r| | | | |a| | | | |c| | | | |e| | | | |r| | | | |e| | | | |b| | | | |r| | | | |a| | | | |l| | | | |h| | | | |e| | | | |m| | | | |o| | | | |r| | | | |r| | | | |h| | | | |a| | | | |g| | | | |e| | | | |a| | | | |r| | | | |e| | | | |p| | | | |u| | | | |t| | | | |a| | | | |m| | | | |e| | | | |n| | | | |/| | | | |t| | | | |h| | | | |a| | | | |l| | | | |a| | | | |m| | | | |u| | | | |s| | | | |(| | | | |7| | | | |0| | | | |%| | | | |)| | | | |,| | | | |p| | | | |o| | | | |n| | | | |s| | | | |(| | | | |1| | | | |0| | | | |%| | | | |)| | | | |,| | | | |c| | | | |e| | | | |r| | | | |e| | | | |b| | | | |e| | | | |l| | | | |l| | | | |u| | | | |m| | | | |(| | | | |1| | | | |0| | | | |%| | | | |)| | | | |,| | | | |a| | | | |n| | | | |d| | | | |c| | | | |e| | | | |r| | | | |e| | | | |b| | | | |r| | | | |a| | | | |l| | | | |w| | | | |h| | | | |i| | | | |t| | | | |e| | | | |m| | | | |a| | | | |t| | | | |t| | | | |e| | | | |r| | | | |(| | | | |1| | | | |0| | | | |%| | | | |)| | | | |.| | | | |L| | | | |e| | | | |s| | | | |s| | | | |c| | | | |o| | | | |m| | | | |m| | | | |o| | | | |n| | | | |l| | | | |y| | | | |,| | | | |i| | | | |n| | | | |t| | | | |r| | | | |a| | | | |c| | | | |e| | | | |r| | | | |e| | | | |b| | | | |r| | | | |a| | | | |l| | | | |h| | | | |e| | | | |m| | | | |o| | | | |r| | | | |r| | | | |h| | | | |a| | | | |g| | | | |e| | | | |r| | | | |e| | | | |s| | | | |u| | | | |l| | | | |t| | | | |s| | | | |f| | | | |r| | | | |o| | | | |m| | | | |t| | | | |r| | | | |a| | | | |u| | | | |m| | | | |a| | | | |,| | | | |a| | | | |n| | | | |t| | | | |i| | | | |c| | | | |o| | | | |a| | | | |g| | | | |u| | | | |l| | | | |a| | | | |n| | | | |t| | | | |t| | | | |h| | | | |e| | | | |r| | | | |a| | | | |p| | | | |y| | | | |,| | | | |s| | | | |a| | | | |c| | | | |c| | | | |u| | | | |l| | | | |a| | | | |r| | | | |a| | | | |n| | | | |e| | | | |u| | | | |r| | | | |y| | | | |s| | | | |m| | | | |,| | | | |a| | | | |r| | | | |t| | | | |e| | | | |r| | | | |i| | | | |o| | | | |v| | | | |e| | | | |n| | | | |o| | | | |u| | | | |s| | | | |m| | | | |a| | | | |l| | | | |f| | | | |o| | | | |r| | | | |m| | | | |a| | | | |t| | | | |i| | | | |o| | | | |n| | | | |,| | | | |t| | | | |u| | | | |m| | | | |o| | | | |r| | | | |,| | | | |b| | | | |l| | | | |o| | | | |o| | | | |d| | | | |d| | | | |y| | | | |s| | | | |c| | | | |r| | | | |a| | | | |s| | | | |i| | | | |a| | | | |,| | | | |a| | | | |n| | | | |g| | | | |i| | | | |o| | | | |p| | | | |a| | | | |t| | | | |h| | | | |y| | | | |,| | | | |o| | | | |r| | | | |v| | | | |a| | | | |s| | | | |c| | | | |u| | | | |l| | | | |i| | | | |t| | | | |i| | | | |s| | | | |.| | | | |2| | | | |.| | | | |T| | | | |r| | | | |e| | | | |a| | | | |t| | | | |m| | | | |e| | | | |n| | | | |t| | | | |c| | | | |o| | | | |n| | | | |s| | | | |i| | | | |s| | | | |t| | | | |s| | | | |o| | | | |f| | | | |s| | | | |u| | | | |p| | | | |p| | | | |o| | | | |r| | | | |t| | | | |i| | | | |v| | | | |e| | | | |c| | | | |a| | | | |r| | | | |e| | | | |a| | | | |n| | | | |d| | | | |g| | | | |r| | | | |a| | | | |d| | | | |u| | | | |a| | | | |l| | | | |r| | | | |e| | | | |d| | | | |u| | | | |c| | | | |t| | | | |i| | | | |o| | | | |n| | | | |i| | | | |n| | | | |B| | | | |P| | | | |.| | | | | |a. Vascular autoregulation is unpredictably impaired in | | | | |patients with chronic hypertension and intracerebral | | | | |hemorrhage. Higher than normal systemic BP may be required| | | | |to maintain cerebral perfusion. Therefore, BP is gradually| | | | |reduced over days, with careful observation for worsening | | | | |neurologic deficits, which may reflect cerebral ischemia. | | | | |b. Surgical consultation is indicated for cerebellar | | | | |hematomas, because brain stem compression or obstructive | | | | |hydrocephalus may develop, and immediate hematoma | | | | |evacuation or ventricular shunting is lifesaving. | | | | |Evacuation of deep cerebral hematomas is rarely | | | | |beneficial. |

| |B| | | |.| | | |S| | | |A| | | |H| | | |m| | | |a| | | |y| | | |p| | | |r| | | |e| | | |s| | | |e| | | |n| | | |t| | | |w| | | |i| | | |t| | | |h| | | |o| | | |n| | | |l| | | |y| | | |s| | | |u| | | |d| | | |d| | | |e| | | |n| | | |o| | | |n| | | |s| | | |e| | | |t| | | |o| | | |f| | | |s| | | |e| | | |v| | | |e| | | |r| | | |e| | | |h| | | |e| | | |a| | | |d| | | |a| | | |c| | | |h| | | |e| | | |.| | | |L| | | |e| | | |t| | | |h| | | |a| | | |r| | | |g| | | |y| | | |o| | | |r| | | |c| | | |o| | | |m| | | |a| | | |,| | | |f| | | |e| | | |v| | | |e| | | |r| | | |,| | | |v| | | |o| | | |m| | | |i| | | |t| | | |i| | | |n| | | |g| | | |,| | | |s| | | |e| | | |i| | | |z| | | |u| | | |r| | | |e| | | |s| | | |a| | | |n| | | |d| | | |l| | | |o| | | |w| | | |b| | | |a| | | |c| | | |k| | | |p| | | |a| | | |i| | | |n| | | |m| | | |a| | | |y| | | |a| | | |l| | | |s| | | |o| | | |b| | | |e| | | |p| | | |r| | | |e| | | |s| | | |e| | | |n| | | |t| | | |.| | | |F| | | |o| | | |c| | | |a| | | |l| | | |n| | | |e| | | |u| | | |r| | | |o| | | |l| | | |o| | | |g| | | |i| | | |c| | | |d| | | |e| | | |f| | | |i| | | |c| | | |i| | | |t| | | |s| | | |,| | | |n| | | |u| | | |c| | | |h| | | |a| | | |l| | | |r| | | |i| | | |g| | | |i| | | |d| | | |i| | | |t| | | |y| | | |,| | | |a| | | |n| | | |d| | | |r| | | |e| | | |t| | | |i| | | |n| | | |a| | | |l| | | |h| | | |e| | | |m| | | |o| | | |r| | | |r| | | |h| | | |a| | | |g| | | |e| | | |s| | | |(| | | |s| | | |u| | | |b| | | |h| | | |y| | | |a| | | |l| | | |o| | | |i| | | |d| | | |)| | | |s| | | |u| | | |g| | | |g| | | |e| | | |s| | | |t| | | |S| | | |A| | | |H| | | |.| | | |C| | | |o| | | |m| | | |p| | | |l| | | |i| | | |c| | | |a| | | |t| | | |i| | | |o| | | |n| | | |s| | | |o| | | |f| | | |S| | | |A| | | |H| | | |i| | | |n| | | |c| | | |l| | | |u| | | |d| | | |e| | | |r| | | |e| | | |b| | | |l| | | |e| | | |e| | | |d| | | |i| | | |n| | | |g| | | |(| | | |2| | | |0| | | |%| | | |a| | | |t| | | |2| | | |w| | | |e| | | |e| | | |k| | | |s| | | |)| | | |,| | | |v| | | |a| | | |s| | | |o| | | |s| | | |p| | | |a| | | |s| | | |m| | | |w| | | |i| | | |t| | | |h| | | |i| | | |s| | | |c| | | |h| | | |e| | | |m| | | |i| | | |c| | | |d| | | |e| | | |f| | | |i| | | |c| | | |i| | | |t| | | |s| | | |(| | | |d| | | |a| | | |y| | | |s| | | |4| | | |–| | | |1| | | |4| | | |)| | | |,| | | |h| | | |y| | | |d| | | |r| | | |o| | | |c| | | |e| | | |p| | | |h| | | |a| | | |l| | | |u| | | |s| | | |,| | | |s| | | |e| | | |i| | | |z| | | |u| | | |r| | | |e| | | |s| | | |,| | | |a| | | |n| | | |d| | | |h| | | |y| | | |p| | | |o| | | |n| | | |a| | | |t| | | |r| | | |e| | | |m| | | |i| | | |a| | | |.| | | | |1. The most common etiology of SAH is a ruptured saccular or| | | |"berry" aneurysm, which results from defects in the arterial| | | |media and internal elastic lamina of large arteries. Other | | | |types of aneurysms include fusiform aneurysms (probably | | | |secondary to atherosclerosis) and mycotic aneurysms (from | | | |septic embolism). Hypertensive intracerebral hemorrhage, | | | |arteriovenous malformation, blood dyscrasia, head trauma, | | | |cocaine or amphetamine abuse, and tumor are among the other | | | |etiologies. | | | |2. Head CT scan is diagnostic of subarachnoid blood in the | | | |sulci and cisternae in 90% of SAH patients in the first 24 | | | |hours. In some patients, lumbar puncture is necessary to | | | |confirm the diagnosis of SAH. Bloody CSF should be | | | |centrifuged immediately and examined for xanthochromia | | | |(yellow color). Xanthochromia results from RBC lysis and | | | |takes several hours to develop, indicating SAH rather than | | | |traumatic lumbar puncture. Postcontrast head CT or MRI scan | | | |may demonstrate vascular abnormalities, but cerebral | | | |angiography is often necessary for definitive diagnosis. | | | |Angiography is required for presurgical evaluation of | | | |saccular aneurysms. | | | |3. Treatment of SAH depends on etiology. Saccular aneurysms | | | |are usually treated surgically. The timing of surgery after | | | |SAH is controversial and depends on the clinical condition | | | |of the patient. Supportive measures while awaiting surgery | | | |include bed rest, sedation, analgesia, and laxatives to | | | |prevent sudden increases in intracranial pressure or BP. One| | | |should avoid hypotension, as it may worsen ischemic | | | |deficits. Only extreme elevations in BP (diastolic >130 mm | | | |Hg) should be treated, and reduction of BP should be | | | |gradual, with careful monitoring of BP and the neurologic | | | |examination. Nimodipine, a calcium channel blocker, improves| | | |outcome in SAH patients and may reduce the incidence of | | | |associated cerebral infarction with few side effects. | | | |Recommended dosage is 60 mg PO q4h, for 21 days, initiated | | | |within 4 days of presentation. Volume expansion, induced | | | |hypertension, and balloon dilation can occasionally be used | | | |to reverse neurologic deterioration due to vasospasm. |

Comments