title: Injections of Intravenous Contrast for Computerized Tomography Scans Precipitate Migraines in Hereditary Hemorrhagic Telangiectasia Subjects at Risk of Paradoxical Emboli: Implications for Right-to-Left Shunt Risks.
abstract: OBJECTIVE
  To evaluate if injection of intravenous particles may provoke migraines in subjects with right-to-left shunts due to pulmonary arteriovenous malformations (AVMs).
  
  
  BACKGROUND
  Migraine headaches commonly affect people with hereditary hemorrhagic telangiectasia (HHT), especially those with pulmonary AVMs that provide right-to-left shunts. In our clinical practice, patients occasionally reported acute precipitation of migraine headaches following injection of technetium-labeled albumin macroaggregates for nuclear medicine scans.
  
  
  METHODS
  Self-reported migraine features and exacerbations were examined in HHT subjects with and without pulmonary AVMs, for a series of noninvasive and invasive investigations, using an unbiased online survey.
  
  
  RESULTS
  One hundred and sixty-six subjects were classified as having both HHT and migraines. HHT subjects with migraines were more likely to have pulmonary AVMs (P < .0001). HHT subjects with pulmonary AVMs were more likely to report photophobia (P = .010), "flashes of light" (P = .011), or transient visual loss (P = .040). Pulse oximetry, x-rays, ultrasound, and computerized tomography (CT) scans without intravenous contrast medium rarely, if ever, provoked migraines, but unenhanced magnetic resonance imaging (MRI) was reported to exacerbate migraines by 14/124 (11.2%) subjects. One hundred and fourteen subjects had both enhanced and unenhanced CT examinations: studies with contrast media were more commonly reported to start (9/114 [7.8%]), and/or worsen migraines (18/114 [15.7%]), compared to those undertaken without contrast medium (P < .01), or after simple blood tests (P < .05). Additionally, migraine exacerbation was reported by 9/90 (10%) after contrast echocardiography, 2/44 (4.5%) after nuclear medicine scans, and 10/154 (6.5%) after blood tests.
  
  
  CONCLUSIONS
  HHT subjects frequently report migraine exacerbation following blood tests, contrast echocardiograms, MRI imaging, and CT studies performed with intravenous contrast medium. Since air emboli are recognized to complicate intravenous injections, particularly those given by a pressurized pump during contrast enhanced CT, future studies should re-evaluate whether particulate emboli provoke migraines.
authors.affiliation: Imperial College School of Medicine, London, UK.|NHLI Cardiovascular Sciences, Imperial College London, UK.
authors.forename: Trishan
authors.initials: T
authors.lastname: Patel
authors.affiliation: NHLI Cardiovascular Sciences, Imperial College London, UK.
authors.forename: Amy
authors.initials: A
authors.lastname: Elphick
authors.affiliation: Department of Imaging, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: James E
authors.initials: JE
authors.lastname: Jackson
authors.affiliation: NHLI Cardiovascular Sciences, Imperial College London, UK.|HHTIC London, Respiratory Medicine, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Shovlin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D016208:Databases, Factual / Q000706:statistics & numerical data; D004452:Echocardiography; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000000981:diagnostic imaging* / Q000209:etiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013683:Telangiectasia, Hereditary Hemorrhagic / Q000150:complications*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: computerized tomography (CT); contrast injection; hereditary hemorrhagic telangiectasia (HHT); magnetic resonance imaging (MRI); pulmonary arteriovenous malformations (PAVMs); right-to-left shunt