Severe scrub typhus confirmed early via immunohistochemical staining

Area of Science:

• Infectious Diseases
• Pathology
• Pulmonology

Background:

• Interstitial pneumonia presents a diagnostic challenge, particularly when associated with generalized lymphadenopathy.
• Scrub typhus, a zoonotic disease caused by Orientia tsutsugamushi, is endemic in many parts of Asia and the Pacific.
• Early and accurate diagnosis of scrub typhus is crucial for timely treatment and improved patient outcomes.

Observation:

• A case of interstitial pneumonia with generalized lymphadenopathy was investigated.
• The patient had a travel history to a known scrub typhus-endemic region.
• An eschar, a characteristic skin lesion, was present and available for examination.

Findings:

• Immunohistochemical (IHC) staining of the eschar confirmed scrub typhus.
• The IHC staining revealed the presence of Orientia tsutsugamushi within the sweat ducts, glands, and vascular endothelium.
• This histological evidence directly linked the observed symptoms to the causative agent of scrub typhus.

Implications:

• Clinicians should consider scrub typhus in patients with interstitial pneumonia and lymphadenopathy, especially with relevant travel history.
• IHC staining of an eschar provides a rapid and reliable method for early confirmation of scrub typhus.
• This diagnostic approach can facilitate prompt initiation of appropriate antimicrobial therapy, potentially reducing morbidity and mortality.