Characterization of Iodide-induced Sialadenitis: Meta-analysis of the Published Case Reports in the Medical Literature

Purpose: To evaluate the patient presentation of postcontrast sialadenitis and factors associated with its duration of symptoms through meta-analysis of case reports. Background: Acute iodide sialadenitis, or "iodide mumps," is a rare adverse reaction to iodinated contrast causing salivary gland swelling. The condition may be underdiagnosed, with researchers postulating that its true incidence may be close to 1-2%. Methods and Materials: This study was a meta-analysis performed using PRISMA Reporting Standards. A literature search with no language restriction was performed of the Medline database, primarily through PubMed, using keywords: "iodide mumps," "iodide sialadenitis," "sialadenitis," "salivary enlargement," "contrast reaction," "parotid swelling," and "submandibular swelling." Matching case reports and case series were reviewed, and data regarding the subjects' demographics, renal function, contrast administration, and symptoms were extracted. Uni- and multivariate linear regression analyses were applied to assess the predicting factors of a prolonged symptoms duration. Results: Sixty-five case reports and case series were identified, with 77 cases of iodide-induced sialadenitis. Two cases were unpublished and from the author's institution. Reported subjects' median age was 63 years, and 61% (47/77) were males. Median time to onset was 16 hours, and symptoms resolved in a median of 3 days after the initial onset. Twenty-seven subjects (35%, 27/77) were reported to have an impaired renal function at baseline. Administration of nonionic, low osmolarity contrast medium was reported most frequently (53%, 41/77). There was no difference in resolution of symptoms among subjects with impaired versus normal renal function. Symptoms were resolved in all cases over a median of 3 days with no statistically significant difference between those who received therapeutic intervention and those who did not (p = 0.430). Older age and longer time to onset were significantly associated with longer duration of symptoms in both uni- and multivariate linear regression models, and presence of tenderness demonstrated statistical significance associated with longer duration of symptoms in the univariate model. Conclusion: Postcontrast sialadenitis is a rare reaction to iodinated contrast media. Older age and a longer time to onset of symptoms are associated with longer duration of symptoms.