Page 25 - Radiology Book

contrast media reactions
The frequency of adverse reaction has decreased with the changes in usage from ionic high-osmolality contrast (HOCM) to nonionic low-osmolality contrast media (LOCM) (2).
Prior to the usage of LOCM, HOCM was responsible for 5-15% of acute adverse reactions. LOCM has a low incidence of acute adverse reactions with reported rates of 0.2-0.7% at multiple institutions (4,5,6).
Pathogenesis of acute adverse events to iodinated contrast media (ICM) is unclear, but appears identical to anaphylactic reactions to a drug or allergen. ICM has been shown to directly cause the release
of histamine from basophils and eosinophils with the belief that a variety of vasoactive substances or mediators are involved (histamine, complement, and the kinin system). The majority of side effect or re- actions to iodinated contrast media are non-life-threatening and mild that only requires reassurance, observation, and support (3).
Mild Contrast Reactions
Mild reactions typically do not require medical treatment, but may evolve into more severe reactions and should be observed for 20-30 minutes with vital signs to ensure clinical stability. Antihistamines may be used, but not required.
Mild Reactions
(physiological response, non-allergic-like) • Nausea
• Vomiting
• Flushing/Warmth
• Pain on injection
Mild Reaction (allergic-like)
• Hives
• Mild angioedema (slight tongue/facial swelling, scratchy throat) • Urticarial
Moderate Contrast Reactions
Moderate reaction often require medical treatment. These reactions are both allergic-like and non-allergic like. Close patient monitoring for all moderate reactions should be done with vital signs, intravenous access, and oxygen until acute events have resolved completely.
Allergic-like
• Severe urticaria
• Bronchospasm
• Moderate tongue/facial swelling
• Transient hypotension with tachycardia
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Reactions