Scrub Typhus in Northeastern Thailand: Eschar Distribution, Abnormal Electrocardiographic Findings, and Predictors of Fatal Outcome

Abstract

Abstract. Scrub typhus is endemic in Thailand. Of the 495 patients with acute undifferentiated fever studied in Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand, from June 1, 2011, to December 31, 2012, 146 patients (29.5%) had confirmed scrub typhus. The majority of cases were male, farmers, with the mean (±standard deviation) age of 54.1 ± 15.2 years. A total of 59 patients (40.4%) had eschar lesion. The commonest sites for an eschar in male patients were the perineum, inguinal, and buttock area; whereas in females, it was the head and neck area. Abnormal electrocardiogram was found in 39 of 79 patients (49.4%) with sinus tachycardia being the most frequent finding (17, 21.5%). A total of 73 patients (50%) had at least one complication. Myocarditis was the cause of complete heart block in a scrub typhus patient, and he fully recovered after receiving intravenous chloramphenicol treatment. The case fatality rate was 6.2% (nine deaths).The independent predictors for fatal outcome were age over 65 years (odds ratio [OR] = 14.49, 95% confidence interval [CI] = 1.26-166.44, P = 0.03), acute kidney injury (OR = 12.75, 95% CI = 1.77-92.07, P = 0.01), and hyperbilirubinemia (OR = 24.82, 95% CI = 2.12-286.61, P = 0.01). Early diagnosis and prompt appropriate treatment can improve the patient's outcome.

Scrub Typhus and Abnormal Electrocardiography

“…In another Thailand study, abnormal ECG was found in 39 of 79 patients (49.4%), including sinus tachycardia (17 patients, 21.5%), new onset AFib (nine patients, 11.3%). 8 In a Papua New Guinea study conducted in 1945, no significant ECG changes were observed in patients with scrub typhus 9 ; a study conducted in Thailand in 2002 revealed that mild ECG changes (e.g., ST-T change, U wave, VPB) were observed in only 24% of patients. 10 However, in this study, ECG abnormalities were observed in 72 (43.6%) of 165 scrub typhus patients and this result is higher than previous report by Kim et al, 11 where ECG abnormalities were observed in about one-third of scrub typhus patients.…”

Complex Cytokine Responses in Imported Scrub Typhus Cases, Germany, 2010–2018

“…Most patients in our study presented with nonspecific symptoms such as fever (91%), exanthema (55%), and headache (45%). Prevalence of the characteristic eschar in scrub typhus patients can vary greatly [13][14][15] and might depend on the O. tsutsugamushi genotype. 16 In our study, nearly half of the patients presented with an eschar.…”

Time spent in an endemic area is a crucial clue to diagnose scrub typhus without eschar

“…The bacterium is passed on via Trombiculidae mites (chiggers); 1–2 days after a chigger bite, an erythematous papule develops at the bite site and gradually turns into a painless eschar lesion . There is a difference in predominant sites of eschar between men (the perineal, inguinal and buttock areas) and women (trunk, especially front above the umbilicus) . Multiple eschars can be seen in some patients.…”

“…Despite the absence of eschar lesion, rickettsial infection was strongly suspected, as Thailand, especially Chiang-Mai, is known to be an endemic area for scrub typhus. 1 Consequently, azithromycin for empirical treatment of scrub typhus and Mycoplasma pneumonia was initiated while serological diagnosis was awaited. The following day (day 7 of the illness), tests for M. pneumoniae antibodies came back negative.…”

“…2,4 There is a difference in predominant sites of eschar between men (the perineal, inguinal and buttock areas) and women (trunk, especially front above the umbilicus). 1 Multiple eschars can be seen in some patients. Although eschar is a cardinal sign of scrub typhus, it is not specific, and can also be seen in other infections such as Mediterranean spotted fever, rickettsial pox, cutaneous anthrax, tularaemia, trypanosomiasis and poxvirus, as well as with the bite of the brown recluse spider.…”