Xerostomia in a patient with scrub typhus

Scrub typhus is an acute febrile disease caused by the intracellular organism Orientia tsutsugamushi. The main pathogenesis is focal or disseminated multi-organ vasculitis caused by the infection of endothelial cells and the perivascular infiltration of leukocytes. Many studies have reported interstitial pneumonia, cholecystitis, pancreatitis, and meningoencephalitis in scrub typhus. However, there is no report about sialoadenitis in a patient with scrub typhus. A 79-year-old man was admitted to the emergency room due to a high fever, headache, and myalgia. Scrub typhus was confirmed based on the indirect immunofluorescence assay and the nested polymerase chain reaction. He suffered from severe dry mouth and underwent Tc-99m pertechnetate salivary scintigraphy. While the radiopharmeceutical uptake of the bilateral parotid and submandibular glands was within normal range, salivary excretion into the oral cavity was markedly decreased. After the proper antibiotic treatment, salivary scintigraphy was performed again. Radioactivity in the oral cavity was increased and the ejection fraction (%) after using sialogogue was also improved to the normal range. As far as we know, this is the first report to show salivary scintigraphy of a patient with scrub typhus. By using a Tc-99m pertechnetate salivary scintigraphy, we found that the excretory function of salivary glands was markedly decreased, while the uptake ability was preserved in scrub typhus, unlike Sjögren's syndrome and radiation-induced xerostomia. Salivary scintigraphy presents dry mouth objectively and provides quantitative values as well. Salivary scintigraphy could contribute to the assessment of sialoadenitis before and after treatment of scrub typhus.