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Posted by: Mj on 2010-02-02, 10:22:51
CLINICAL EFFECTS OF COCAINE EFFECTS ON SPECIFIC ORGAN SYSTEMS Central nervous system — Cocaine euphoria is associated with transient increases in EEG activity followed by longer-lasting increases in activity [77] . Seizures may occur in persons without a seizure history, even with first time use of cocaine [78-80] . These are usually single, generalized tonic-clonic seizures occurring within 90 minutes of cocaine use. Craving for cocaine is associated with increased activity in the so-called mesocorticolimbic reward circuit in the brain. This includes the inferior frontal-orbitofrontal gyrus, amygdala (thought to mediate stimulus-reward association), anterior cingulate (mediating anticipation of reward), and nucleus accumbens/ subcallosal gyrus (mediating incentive motivation) [81,82] . Cerebral vasoconstriction, cerebrovascular disease, and hemorrhagic and ischemic stroke are increased in cocaine users, even in patients with no other risk factors [78-80,83,84] . Etiologic mechanisms include tachycardia and increased blood pressure from sympathetic activation, vasoconstriction, vasospasm, and intravascular thrombosis due to increased platelet aggregation [85] . MRI, SPECT, and PET imaging in chronic cocaine users demonstrate structural and functional brain abnormalities: cerebral gray matter atrophy and decreased glucose metabolism in the frontal and temporal lobes, small cerebral perfusion defects, increased creatine concentration in parietal white matter (suggesting abnormal energy metabolism), and decreased D2 dopamine receptors in the striatum [82,85,86] . Impairment of behavioral inhibition in cocaine users has been associated with reduced activity in the anterior cingulate and prefrontal cortices [86] . Cocaine use is associated with a variety of movement disorders, including stereotyped behaviors, acute dystonic reactions, choreoathetosis and akathisia (so-called "crack dancers "), buccolingual dyskinesias ( "twisted mouth " or "boca torcida "), and exacerbation of Tourette's syndrome and tardive dyskinesia [49,78,87] . Cocaine users are at increased risk of acute dystonic reactions from neuroleptic (antipsychotic) medications [88] . Cardiovascular system — Cardiopulmonary symptoms are the most frequent complaints in cocaine users who seek medical help, with chest pain the most frequent symptom [89] . Cocaine acutely increases heart rate, blood pressure, and systemic vascular resistance by increasing adrenergic activity in the heart, and indirectly via the CNS [89,90] . The increased myocardial oxygen demand, coupled with decreased coronary blood flow from vasospasm and vasoconstriction, can cause acute myocardial infarction, even in young persons without atherosclerosis. Cocaine use is a factor in about one-quarter of nonfatal heart attacks in persons younger than 45 years [91] . Cocaine use is not usually associated with chronic hypertension [92] , but appears to enhance the progression of renal disease in patients with hypertension (see "Kidneys " below) [93,94] . Cocaine use increases risk for cardiac arrhythmias and sudden death [95,96] . Chronic use is associated with left ventricular hypertrophy, cardiomyopathy, myocardial fibrosis, and myocarditis. (See "Cardiovascular complications of cocaine abuse "). Respiratory system — The effects of cocaine on the respiratory system depend on the route of administration. Intranasal cocaine use ( "snorting ") may cause chronic rhinitis, perforation of the nasal septum, oropharyngeal ulcers, and osteolytic sinusitis, due to vasoconstriction and resulting ischemic necrosis [78,87] . Anosmia is rare. Smoked cocaine use produces acute respiratory symptoms in up to half of users, including productive cough, shortness of breath, wheezing, chest pain, hemoptysis, and exacerbation of asthma [97] . Rarer complications include pulmonary edema, pulmonary hemorrhage, pneumothorax, pneumomediastinum, and thermal airway injury. These effects are probably due to direct damage to the alveolar-capillary membrane by cocaine or inhaled microparticles, damage to the pulmonary vascular bed from vasoconstriction, and/ or interstitial disease. Chronic cocaine smokers generally have normal spirometry tests, but may have increased alveolar epithelial permeability and moderately decreased pulmonary diffusion capacity, even when asymptomatic. (See "Pulmonary complications of cocaine abuse "). Gastrointestinal system — Cocaine use by any route of administration reduces salivary secretions (xerostomia) and causes bruxism [98] . Cocaine reduces gastric motility and delays gastric emptying [78] . Cocaine-induced vasoconstriction and ischemia may result in gastrointestinal ulceration, infarction, perforation, and ischemic colitis [78,87] . Cocaine-associated ulcers are distributed primarily in the greater curvature and prepyloric region of the stomach, pyloric canal, but, similar to peptic ulcers, also occur in the first portion of the duodenum. Liver — |
