Methamphetamine May Trigger Ischemic Stroke

IRVINE, Calif., Dec. 26-- Methamphetamine users may develop carotid artery dissections, leading to a severe stroke, an effect also seen in cocaine users, according to researchers here.

Two women, one 36 years old and the other 29, arrived separately at a tertiary emergency department with stroke symptoms that turned out to have been caused by dissection of the carotid artery and ischemia in the middle cerebral artery on the same side of the head, related Andrew McIntosh, M.D., at the University of California at Irvine, and colleagues.

Neither patient had a history of recent trauma, infection, connective tissue disorders or miscarriages, and neither had used an illegal drug other than methamphetamine, the investigators reported in the Dec. 25 issue of Neurology.

"Methamphetamine may induce vasospasm, hypertension, vasculitis, or direct vascular toxicity," they wrote. "Methamphetamine abuse has been associated with aortic dissection. Carotid artery occlusion or segmental narrowing, described in a previous case report, appeared to be consistent with carotid artery dissection."

The 36-year-old presented to the emergency department with 30 minutes of the onset of speech difficulty and right-sided weakness, which occurred while she was eating lunch.

She had a history of migraine, used oral contraceptives, and reported having smoked methamphetamine over the two previous nights, during which time she had experienced some left neck pain.

On initial examination, she was found to have global aphasia, left gaze preference, and right hemiplegia without Horner syndrome (oculosympatheic paralysis, which can be a sign of a dissecting carotid aneurysm).

She had an NIH Stroke Scale (NIHSS) score of 21 (severe). This patient was started on intravenous tissue plasminogen activator (tPA) within 80 minutes of symptom onset. She improved significantly, and eight hours after tPA therapy, had only moderate expressive speech difficulties and mild hemiparesis on the right (dominant hand) side.

On follow-up MRI and magnetic resonance angiography studies she was found to have a small infarct in the left frontal lobe, and a focal narrowing in the left internal carotid artery. Carotid ultrasound studies showed that she had an intimal flap, and fat-saturation T1 MRI revealed an intramural thrombus, which is indicative of dissection, the author noted.

"Extensive workup, including fasting lipid panel and transesophageal echocardiogram, was only significant for methamphetamine in the urine," they wrote. "No cocaine or other illicit drugs were detected."

This patient was treated with IV heparin, and a cerebral angiography performed three days later showed only minimal irregularity in the left internal carotid artery, suggesting that the dissection was resolving dissection.

She was discharged on Coumadin (warfarin) five days after the onset of stroke, recovered with only mild expressive aphasia, and returned to work within four months, on a course of Coumadin, which was later switched to 81 mg aspirin daily.

The 29-year-old, a 10-year methamphetamine user, also developed right-side weakness and speech problems, in this case four days after last using the drug. An MRI taken at a local hospital showed a large left middle-cerebral-artery infarct, and she was discharged home on aspirin four days after her stroke. But due to worsening deficits she was brought to UC Irvine on the fifth day.

Studies there showed that she too had global aphasia and right hemiparesis without Horner syndrome, and had an NIHSS score of 17.

Various other studies, including transesophageal echocardiography and tests for hypercoagulability state were all unremarkable, the investigators wrote. They did not perform a urine toxicology screen, however.

This woman was seen on MR angiography to have significant narrowing of the left proximal common carotid artery, and diagnostic cerebral angiography demonstrated a large intimal flap and severe stenosis with a filling defect (clot) underneath the flap, also indicative of dissection.

Because of the size of the middle-cerebral-artery infarct with hemorrhagic transformation, this patient was treated with angiography and a carotid artery stent rather than anticoagulation. She was discharged home on full-dose (325 mg) aspirin and Plavix (clopidogrel) at 75 mg daily. She recovered with only moderate expressive aphasia and mild right hand weakness within four months, and had no evidence of restenosis on follow-up at seven months

The investigators noted that cocaine abuse has been shown to have similar effects to those seen in the two cases, and that cocaine has also been implicated in carotid artery dissection.

"Therefore, it is likely that cervicocephalic dissections may be secondary to a drug class effect rather than a specific drug," they concluded.