Canadian Family Physician • Le Médecin de famille canadien : •
: • Canadian Family Physician • Le Médecin de famille canadien
Stroke following an airline fl ight
irline passengers have been reported to be at risk of thromboembolic complications, including deep vein thrombosis (DVT), pul- monary embolism (PE),1-5 femoral arterial throm- bosis,6 and sudden cardiac death.7 Internet and MEDLINE searches revealed only one previous medi- cal case report of stroke occurring in association with an airline fl ight. Beighton and Richards8 described three patients who collapsed during or immediately after a fl ight and were subsequently diagnosed with nonhemorrhagic stroke. One had a patent foramen ovale and DVT, from which a detached clot was pre- sumed to have occluded the brain.
Case report
e patient was a 76-year-old woman who presented to a hospital in Newfoundland with right hemipare- sis and hemisensory loss without aphasia. e symp- toms began a few hours after a fl ight from Ontario.
Her history included hypertension, which was treated with enalapril. Blood pressure on admission was 190/110. Family history revealed two sisters who had suff ered strokes. Results of a computed tomog- raphy scan of her head were normal. A carotid ultra- sound scan showed slight atheromatous changes but no critical lesions. Her serum cholesterol level was 5.63 (low-density lipoprotein 3.25, high-density lipo- protein 1.08, triglycerides 2.87). One week later she
fl ew back to Ontario and was admitted to a rehabili- tation unit. A transesophageal echocardiogram and bubble study showed no evidence of intracardiac thrombosis or right-to-left shunt. Her hemiparesis slowly improved. She was discharged home to con- tinue outpatient therapy.
Discussion
Stroke is a common illness, and its occurrence following an airline flight could be coincidental.
A review of 149 patients with nonhemorrhagic stroke, consecutively discharged from the Freeport Rehabilitation Unit, revealed four additional patients (two men and two women, ranging in age from 40 to 75) with an association between non- hemorrhagic stroke and medium- to long-haul airline fl ights. Two patients had strokes within 48 hours of fl ight. Another patient had symptoms of vertebro-basilar insuffi ciency that began while on board a plane. e symptoms resolved, but a stroke with the same symptom complex occurred 2 weeks later. The final patient had a history of previous stroke, which occurred 2 days after a fl ight. A sec- ond stroke occurred after a long car journey. ese cases suggest that the association between fl ying and stroke is worthy of further investigation.
e health risks associated with fl ying are low.
The International Air Transport Association7 reported an in-fl ight death rate of about 125 deaths per billion km flown, or 25.1 deaths per million flights. Most were classified as sudden cardiac death, mainly occurring among passengers with no reported health problems. Complications might not appear for hours after a fl ight, however, so the incidence of events during fl ights underestimates the risks of fl ying.
Flying is known to increase risk of lower limb thromboembolism. A case-control study found
Case report:
Stroke following an airline fl ight
Anne R. Crowe, MD, CCFP, FCFP, MBA
Dr Crowe practises family medicine in Kitchener- Waterloo, Ont. She is attending physician for the Inpatient Rehabilitation Unit in the Freeport Health Centre and Medical Director of Complex Continuing Care and Rehabilitation at Grand River Hospital.
This article has been peer reviewed.
Cet article a fait l’objet d’une évaluation externe.
Can Fam Physician 2004;50:76-77.
irline passengers have been reported to be at risk of thromboembolic complications, including deep vein thrombosis (DVT), pul- monary embolism (PE),
A
Canadian Family Physician • Le Médecin de famille canadien : •
: • Canadian Family Physician • Le Médecin de famille canadien
Stroke following an airline fl ight
that patients with DVT or PE were signifi cantly more likely to have had a recent journey of 4 hours or greater (by airplane, car, or train) than controls.9 e condition of DVT, with or without associated PE, was dubbed “economy class syn- drome” by Symingtom and Stack,2 based on the theory that tightly packed seating puts passen- gers at risk. It is postulated that precipitating fac- tors include venous stasis from prolonged sitting, pressure from the aircraft seat on the back of the legs, and hemoconcentration due to diminished fl uid intake and water loss in the dry atmosphere of airplane cabins.4,10
It is generally assumed that PE results from DVT, not from generalized hypercoagulability.
Only five of 15 patients with PE who developed symptoms within 4 days of a flight, however, had demonstrable venous thrombosis.10 None had any pre-existing clotting abnormalities.
With the availability of newer, more sensitive measures of clotting activity, further study of the effect of airline travel on blood coagulability is warranted.
If flying increases the risk of stroke and other thromboembolic complications, what should passengers do? Common sense recommenda- tions to prevent DVT, which might also prevent other thromboembolic complications, include drinking adequate fluids, refraining from ciga- rette smoking and alcohol consumption, chang- ing position frequently, exercising the lower limbs, and getting up and moving around.10 For patients at high risk, wearing support hose3,11-14 or taking acetylsalicylic acid10,12,15 has been rec- ommended. This makes empirical sense and is unlikely to cause harm, but no scientific evi- dence supports these recommendations.13
Conclusion
A relationship between long-distance air travel and DVT has been previously demonstrated.
Passengers tightly squeezed into economy class seats might be at particular risk because of cramped conditions, in addition to decreased barometric pressure and low humidity. is case
report suggests that flying might also result in stroke. Given the popularity of long-distance travel among aging baby boomers and the increas- ing age-related risks of stroke, the relationship between thromboembolic stroke and air travel requires further study.
Competing interests None declared
Correspondence to:Dr Anne R. Crowe, 41 High St, Waterloo, ON N2L 3X7; telephone (519) 574-1558; fax
(519)745-1881; e-mail [email protected] References
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3. Levy Y, George J, Shoenfeld Y. e occurrence of thromboembolic events following air- plane fl ights—“the economy class syndrome.” Isr J Med Sci 1995;31:621-3.
4. Sahiar F, Mohler SR. Economy class syndrome. Aviat Space Environ Med 1994;65(10 Pt 1):
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5. Milne R. Venous thromboembolism and travel: is there an association? J R Coll Physicians Lond 1992;26:47-9.
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a survey of 19 cases. Vasa 1999;28:199-203.
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12. Rayman RB. Passenger safety, health, and comfort: a review. Aviat Space Environ Med 1997;68:432-40.
13. Kaplan NM, Palmer BF, Nassar NN, Keiser P, Gregg CR. Southwestern Internal Medicine Conference. Keeping travelers healthy. Am J Med Sci 1998;315:327-36.
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EDITOR’S KEY POINTS
• A relationship has been established between air travel and deep vein thrombosis.
• This case report raises the possibility that incidence of stroke increases following a flight and suggests further study into this relationship.
POINTS DE REPÈRE DU RÉDACTEUR
• L’existence d’une relation entre les voyages en avion et les throm- boses profondes des veines est maintenant établie.
• Cette étude de cas émet l’hypothèse que l’incidence des accidents vasculaires cérébraux augmente après un vol et suggère que cette relation fasse l’objet d’études additionnelles.
