Shunt-Associated Migraines Respond Favorably to Changes in Work Conditions
To the Editor:
In their case-control study on shunt-associated migraines, Anzola and colleagues convincingly show that atrial septal repair induces a favorable modification of the natural history of the disease.1 Nearly half of their consecutive patients had a history of cerebrovascular disease, and it is plausible that the vast majority of them were active workers, because the mean age of these subjects was <40 years. Because the degree of right-to-left shunt is strongly influenced by activities requiring an increase of intra-abdominal pressure, it is possible that working conditions associated with such efforts may represent a risk factor for both migraine and cerebrovascular disease, in subjects with right-to-left shunt. We wish to report about a young patient with severe migraine and crebrovascular disease in whom changes in working conditions determined a dramatic decrease in migraine attacks and prevented further ischemic episodes. A 29-year-old nurse, attending the care of hospitalized non–self-sufficient patients, was seen at the service of Occupational Medicine for periodic routine evaluation. She reported a history of chronic daily migraine and of repeated lateralizing neurologic signs (3 episodes during the last year) with complete clinical recovery. During hospitalization for these symptoms, she had performed an encefalic MRI showing multiple defects, compatible with small infarcts, and a transesophageal echocardiography, showing no clear interatrial defect, but a mild right-to-left shunt, elicited by the Valsalva maneuver. On this basis, she had undergone an invasive procedure for transcatheter closure of the possible interatrial defect. During the procedure, a minimal interatrial defect, not amenable to surgical repair, was detected. Other risk factors for ischemic stroke, including the search for coagulation abnormalities, had been unremarkable. She was treated with daily low-dose aspirin, and with analgesics or triptans during attacks. Previous attempts of withdrawal from acute-headache medication had failed. At the visit, the physical examination and routine laboratory findings were normal. Bilateral transcranial Doppler contrast monitoring of both middle cerebral arteries during normal ventilation, and during Valsalva maneuvers2 showed no emboli during normal breathing, and 4 emboli during the Valsalva maneuver. Because the care of non–self-sufficient patients requires frequent increases of intra-abdominal pressure, we speculated that the working conditions of the nurse might represent a risk factor for both the migraine attacks and ischemic strokes. Therefore, we recommended to shift the nurse to an ambulatory service, with reduction to a minimum of maneuvers requiring an increase of intra-abdominal pressure. After about 2 months, the frequency of migraine attacks dropped to <10 days per month and remained stable at 2-year follow-up. More important, no further neurologic signs were observed during this period. Furthermore, a substantial decrease in the intake of acute-headache medication was observed. We feel that changes in working conditions should be considered in migraineurs patients with right to left shunt engaged in activities requiring frequent increases of intra-abdominal pressure. This approach may be useful even in patients undergoing atrial septal repair, because, as shown by Anzola and colleagues,1 a residual shunt is still detectable after the procedure in about 15% of them.