ABSTRACT
Purpose of Study: In areas endemic for murine typhus, it can be difficult to distinguish from other febrile syndromes. During COVID-19 surges, we identified several cases of typhus. Presenting symptoms and quantitative lab values at and during admission were compared between patients who were diagnosed with murine typhus or multisystem-inflammatory syndrome in children (MIS-C). Methods Used: Retrospective data was collected at a tertiary care center from July 2020 to March 2022. Inclusion criteria were patients under 21 years of age diagnosed at discharge with murine typhus or MIS-C based on clinical and laboratory evidence, serologic data, and expert consultation. Patients found to have an alternate diagnosis, and those without serologic testing were excluded. Subjects were grouped as either MIS-C or typhus based final diagnosis. Categorical data included headache, fatigue, mucocutaneous changes, rash, con-junctival injection, sore throat, rhinorrhea, palpitations, shortness of breath, chest pain, abdominal pain, nausea/vomiting, diarrhea, myalgia, and appetite change at initial presentation. The categorical data were compared using chi-square test. Quantitative data included age, maximum temperature in first 24 hours of hospitalization, duration of symptoms prior to admission, C-reactive protein, erythrocyte sedimentation rate, platelet count, white blood cell count (WBC), absolute neutrophil count (ANC), absolute lymphocyte count, serum sodium, alanine aminotransferase, hemoglobin (Hgb), and albumin (Alb). Means of the quantitative data were compared with a one-tailed 2- Sample T-Test. The maximum and minimum laboratory values during admission were also compared. Additional demographic data including gender and date of initial presentation was also collected. Summary of Results: There were 7 patients in the MIS-C group and 19 in the typhus group. The average age of MIS-C patients, 6.5 years of age vs. 11.5,was significantly lower (p < 0.5) than the typhus group. Initial mean WBC (cells x 103/mm3) was higher in MIS-C than typhus (12.21, SD = 3.52, vs. 7.85, SD = 3.52, p < 0.05), as was ANC (8.9, SD = 3.7vs. 5.12, SD = 2.05, p < 0.05). During hospitalization, minimum Hgb (g/dL) was 9.3, SD = 2.07, and11.49, SD = 1.67, in MIS-C and typhus respectively (p < 0.05). Minimum albumin (g/dL) was also lower in MIS-C than typhus (2.32, SD = 0.86 vs. 2.8, SD = 0.45, p < 0.05). There were no other statistically significant differences in categorical or quantitative data. Typhus cases typically occurred in the summer and fall months. There was no clear seasonality of MIS-C, but occurred during local COVID-19 surges. Conclusion(s): The initial presenting symptoms of typhus and MIS-C were similar. WBC and ANC were higher in MIS-C, while age, Hgb and Alb were lower. These parameters may aid in distinguishing the diseases. A high clinical suspicion for both typhus and MIS-C in endemic areas for typhus is crucial. A rapid detection for typhus would aid in distinguishing these diseases and allow prompt treatment interventions. Copyright © 2023 Southern Society for Clinical Investigation.
ABSTRACT
CASE: 66yo woman with a past medical history of hypertension and monoclonal gammopathy of undetermined significance was sent from clinic in winter for 4 days of worsening fevers and sinus congestion unrelieved by over-the- counter medications. COVID and flu negative. Patient has had no sick contacts or recent travel and has pet cats but no recent scratches. Initial chest x-ray showed no acute processes, but patient was continuing to have fevers up to 103 with mild dyspnea and chills so a CT chest was completed which showed ground glass opacities in the right middle lobe. Blood and sputum cultures were obtained, and patient was started on ceftriaxone and azithromycin for community acquired pneumonia. Urine strep and legionella antigens were also acquired, both negative. Over the next two days, she continued to have high fevers and chills at nights with leukocytosis, thrombocytopenia, hyponatremia, and notable worsening of mild elevation of liver enzymes on admission. Cultures were negative and patient had no other indication of an infection aside from the cyclical fevers therefore empiric doxycycline was added for coverage of atypical infections. Over the next two days, she continued to have nightly fevers up to 103 so ID was consulted for fever of unknown origin. On repeat exposure assessment, patient revealed that she lived with multiple animals including cats, dogs, parakeets, chickens, geese and a pony. Patient was continued on doxycycline while additional lab tests were sent for atypical infections including Rickettsia typhi, Coxiella brunetti (Q fever), and Brucella spp given patient's history of exposure to multiple animals at home. Patient was discharged on doxycycline after being afebrile for 48hrs with declining white count and liver enzymes. Lab results confirmed the diagnosis with high titers for Rickettsia typhi IgG and IgM. IMPACT/DISCUSSION: This case illustrates an atypical presentation of murine typhus with pneumonia in winter. There are several key teaching points in this case: 1. Ricketssia typhi infections have largely nonspecific symptoms therefore it should should be included in differential diagnoses of febrile illnesses with thrombocytopenia and elevated liver enzymes 2. Although a complete history is acquired on admission, it is important to revisit and review information again when a clinical diagnosis has not been established 3. Defeverscence after starting doxycycline can take anywhere from 4 to 66hrs so fevers during this timeframe is not an indication of failure of therapy CONCLUSION: Murine typhus presents with non-specific symptoms so it should be included in the differential diagnosis of patients with fevers of unknown origin with potential exposure to flea-bearing animals. The optimal therapy is doxycycline 100mg twice a day for seven days. Patients should also be advised to treat their animals for fleas to prevent recurrent infections.
ABSTRACT
Rickettsiosis is an important cause of febrile illness among travellers visiting Southeast Asia (SEA). The true incidence of rickettsiosis is underestimated; however, murine typhus and scrub typhus are widely distributed across SEA. Among travellers visiting SEA, scrub typhus was mostly reported from Thailand, whereas murine typhus was frequently found in Indonesia. Although most cases are self-limited or present with mild symptoms, a few cases with severe clinical manifestations have been reported. Doxycycline remains the key treatment of rickettsiosis. Some travellers, such as backpackers, trekkers, or cave explorers, are at a higher risk for rickettsiosis than others. Therefore, in resource-limited conditions, empirical treatment should be considered in these travellers. The coronavirus disease 2019 (COVID-19) pandemic has contributed to difficulty in the diagnosis of rickettsiosis because of the clinical similarities between these diseases. In addition, physical distancing mandated by COVID-19 management guidelines limits accurate physical examination, resulting in misdiagnosis and delayed treatment of rickettsiosis. This review summarises the characteristics of murine typhus and scrub typhus, describes travel-associated rickettsiosis, and discusses the impact of the COVID-19 pandemic on rickettsiosis.