Iatrogenic vertebral arteriovenous fistula treated with a hemobahn stent-graft.

PURPOSE: To illustrate the utility of color flow duplex ultrasound (CFDU) in the diagnosis and stent-graft treatment of a rare arteriovenous fistula (AVF) involving the vertebral artery and vein. CASE REPORT: An iatrogenic AVF involving the right vertebral artery and vein was diagnosed in a 45-year-old man using CFDU. Treatment was recommended due to the large volume of blood shunted through the fistula and the associated loud bruit. Endoluminal treatment involved deployment of a covered stent within the vertebral artery to exclude the fistula. Postoperative CFDU confirmed the success of the treatment. CONCLUSIONS: CFDU can be utilized to accurately diagnose unusual lesions, such as AVFs involving the vertebral artery. The technique is also useful in planning treatment and monitoring the durability of stent-grafts implanted to obliterate this type of defect.

Synergism between allergens and viruses and risk of hospital admission with asthma: case-control study.

OBJECTIVE: To investigate the importance of sensitisation and exposure to allergens and viral infection in precipitating acute asthma in adults resulting in admission to hospital. DESIGN: Case-control study. SETTING: Large district general hospital. PARTICIPANTS: 60 patients aged 17-50 admitted to hospital over a year with acute asthma, matched with two controls: patients with stable asthma recruited from the outpatient department and patients admitted to hospital with non-respiratory conditions (inpatient controls). MAIN OUTCOME MEASURES: Atopic status (skin testing and total and specific IgE), presence of common respiratory viruses and atypical bacteria (polymerase chain reaction), dust samples from homes, and exposure to allergens (enzyme linked immunosorbent assay (ELISA): Der p 1, Fel d 1, Can f 1, and Bla g 2). RESULTS: Viruses were detected in 31 of 177 patients. The difference in the frequency of viruses detected between the groups was significant (admitted with asthma 26%, stable asthma 18%, inpatient controls 9%; P=0.04). A significantly higher proportion of patients admitted with asthma (66%) were sensitised and exposed to either mite, cat, or dog allergen than patients with stable asthma (37%) and inpatient controls (15%; P<0.001). Being sensitised and exposed to allergens was an independent associate of the group admitted to hospital (odds ratio 2.3, 95% confidence interval 1.0 to 5.4; P=0.05), whereas the combination of sensitisation, high exposure to one or more allergens, and viral detection considerably increased the risk of being admitted with asthma (8.4, 2.1 to 32.8; P=0.002). CONCLUSIONS: Allergens and viruses may act together to exacerbate asthma.