대한흉부영상의학회 Weekly Chest Cases

Case No : 1409 Date 2024-10-21

Courtesy of Ji Young Lee, Jiyoung Song, Woo Hyeon Lim / Seoul National University Hospital
Age/Sex 83 / M
Chief ComplaintChief complaint: fever (onset: 3 weeks ago), dyspnea (onset: 3 days ago), skin rash - - Brief history: doing farming work 3 weeks ago

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Diagnosis With Brief Discussion

Diagnosis: Acute respiratory distress syndrome associated with Scrub typhus (tsutsugamushi disease)
Radiologic Findings: Fig 1. Chest AP shows patchy bilateral ground-glass opacities, predominantly lower zone distribution.
Fig 2-5. CT scans reveals bilateral diffuse ground-glass opacification and mild interlobular septal thickening with underlying emphysema. Enlarged mediastinal lymph nodes, bilateral pleural effusion, and pericardial effusion are seen.
Brief Review: Scrub typhus, also known as tsutsugamushi disease, is an acute febrile illness caused by infection with Orientia tsutsugamushi and characterized by focal or disseminated vasculitis and perivasculitis, which may involve the lungs, heart, liver, spleen, and central nervous system. The diagnosis of scrub typhus is based on the patient’s history of exposure, the clinical features, and the results of serologic testing. The classic case description includes an eschar at the site of chigger feeding, regional lymphadenopathy, and a maculopapular rash. An eschar at the wound site is the single most useful diagnostic clue. A diagnosis can be made in the presence of a significant increase in the serum antibody titer measured either with the Weil-Felix agglutination test or with indirect immunofluorescence.
Pulmonary involvement is a well-documented complication of scrub typhus infection. The basic pathologic process in pulmonary involvement of scrub typhus is interstitial pneumonia with or without vasculitis. At microscopy, blood vessels in specimens from the interlobular septa and alveolar walls appear congested and surrounded by a mononuclear cellular infiltrate. In addition, the nonvascular tissues of the interlobular septa and alveolar walls show edema and infiltration by mononuclear cells. The reported incidence of chest radiographic abnormalities in patients with scrub typhus varies from 59% to 72%. Bilateral diffuse areas of reticulonodular opacity, hilar lymph node enlargement, and septal lines are the most common findings. Airspace consolidation is relatively uncommon and generally appears in the lower zone of both lungs. Unilateral or bilateral hilar enlargement and pleural effusion are common radiographic features. CT also depicts bilateral abnormalities, predominantly in the lower zone of the lung. Common findings include interlobular septal thickening, axial interstitial thickening, ground-glass opacity, and centrilobular nodules. Consolidation and large nodules are less common findings. CT findings of scrub typhus may reflect cellular infiltration, edema, and hemorrhage caused by vasculitis or may be due to interstitial edema secondary to cardiac involvement. Contrast-enhanced chest CT images in most cases depicted mediastinal and axillary lymphadenopathy.
Acute respiratory distress syndrome may develop in scrub typhus. This is a rarely reported but serious complication. Older age, thrombocytopenia, and the presence of early pneumonitis (defined as evidence of infiltrates on chest radiographs at least 2 days before the development of respiratory distress) have been suggested as risk factors for the development of acute respiratory distress syndrome. With appropriate antibiotic therapy, patients usually recover without serious sequelae. The major cause of mortality is a delay in diagnosis. Although the radiologic findings of scrub typhus are nonspecific, an awareness of the related findings at imaging, especially at CT, may facilitate accurate diagnosis.
References: 1. Jeong YJ, Kim S, Wook YD, Lee JW, Kim KI, Lee SH. Scrub typhus: clinical, pathologic, and imaging findings. Radiographics. 2007 Jan-Feb;27(1):161-72.
Keywords

No. of Applicants : 59

▶ Correct Answer : 24/59, 40.7%

- Ishikawa Matto Central Hospital , Japan MANABU AKIMOTO
- medical scanning , Japan HIROAKI ARAKAWA
- Shiga University of Medical Science , Japan AKITOSHI INOUE
- Kyoto City Hospital , Japan YUSUKE UTSUNOMIYA
- , Korea (South) DONG-HO BANG
- Healthy Longevity Medical Center , Japan SHIN-ICHI CHO
- Other , Korea (South) SEONGSU KANG
- , Korea (South) JIN YOUNG LEE
- Secomedic Hospital , Japan FUMINORI MIYOSHI
- university of montreal , Canada Andrei Bogdan Gorgos I
- Osaka University , Japan AKINORI HATA
- The University of Tokyo Hospital , Japan TOSHIHIRO FURUTA
- , Japan YOSHIKI ISHII
- , Japan SHUNJIRO NOGUCHI
- University of Tsukuba, Dept of Radiology , Japan MANABU MINAMI
- Osaka metropolitan university Hospital , Japan TATSUSHI OURA
- Mie university , Japan SHIKO OKABE
- Dokkyo Medical University , Japan HIROAKI ARAKAWA
- Paras hospital, Panchkula , India SHALEEN RANA
- Yonsei University,Severance Hospital , Korea (South) SEO BUM CHO
- Kantou Rousai Hospital , Japan KAORU SUMIDA
- , Japan YUMI MAEHARA
- Toyota Kosei Hospital , Japan YUKI HAYASHI
- the first affiliatited hospital of nanjing medical univercity , China HAI XU

▶ Correct Answer as Differential Diagnosis : 8/59, 13.6%

- Vita Hospital , Brazil DIOGO LAGO PINHEIRO
- Oita University, Faculty of Medicine , Japan FUMITO OKADA
- Seoul Medical Center , Korea (South) HYUK GI HONG
- , Japan KENTARO KOTANI
- Korea University Anam Hospital , Korea (South) KYU-CHONG LEE
- Kyoto University , Japan SHO KOYASU
- The Catholic University of Korea Yoeuido St. Mary , Korea (South) CHAWOONG JEON
- University of Yamanashi , Japan KOJIRO ONOHARA

▶ Semi-Correct Answer : 2/59, 3.4%

- IRSA LA ROCHELLE , France JEAN LUC BIGOT
- Other , Korea (South) DOWOO KIM

대한흉부영상의학회 Korean Society of Thoracic Radiology

Archive of Old Cases

Case No : 1409 Date 2024-10-21

Discussion

No. of Applicants : 59