Scrub typhus associated with hemophagocytic lymphohistiocytosis: A report of six pediatric patients

Hemophagocytic Lymphohistiocytosis secondary to Rickettsial infection: A case report

Hemophagocytic Lymphohistiocytosis (HLH) is a rare life-threatening condition characterized by widespread activation of the immune system leading to tissue damage all over the body. It is divided into primary HLH due to inborn error in lymphocytes, T cells, and macrophages and secondary HLH which is mostly due to infections, systemic connective tissue diseases, and lymphoid malignancies. Here, we report a 34-year-old man with a history of high-grade fever, chills, and rigor, eschar, splenomegaly with the laboratory findings of thrombocytopenia, hypochromic RBCs with anisocytosis and basophilic stippling, elevated transaminases, and a positive Weil Felix test along with positive PCR results for Orientia tsutsugamushi and the presence of IgG and IgM antibodies. A detailed workup was done to rule out other etiology for fever. Diagnosis of HLH secondary to Rickettsia infection was made with a thorough history, clinical evaluation, and a variety of investigations. The patient was treated with Doxycycline, Ciprofloxacin, Etoposide, and Dexamethasone but unfortunately, the patient died during treatment due to multiorgan failure. Patients with scrub typhus typically respond well to therapy; therefore, early detection and antibiotic treatment can help avoid serious complications. Scrub typhus with the hemophagocytic syndrome can result in DIC and multiorgan failure. Despite its rarity, scrub typhus may be lethal; as a result, practitioners must be aware of the necessity of detecting and treating suspected cases as soon as possible. We learned that a systematic diagnostic approach, use of diagnostic criteria, and prompt treatment are very crucial in this disease.

Predictors of Severity of Scrub Typhus in Children Requiring Pediatric Intensive Care Admission

Objective of our study was to determine the clinical characteristics and laboratory profile of scrub typhus patients requiring pediatric intensive care admission and to find out risk factors for the severity of illness. This was a cross-sectional observational study conducted on 1-month to 12-year-old children admitted with scrub typhus in a tertiary care pediatric intensive care unit (PICU). Relevant demographic, clinical, laboratory, treatment, and outcome-related data were documented. The severity of the disease was measured in the form of multiple organ dysfunction syndrome (MODS). With further correlation, and univariate and multivariate analyses, factors associated with severe disease were identified. During the study period, out of 586 PICU admission, 62 patients (10.6%) were diagnosed with scrub typhus. The mean age was 63.85 ± 52.78 months, where infants constituted 32.3% of the total population. Fever was present in 100% of the cases. Common indications of PICU admission were: respiratory distress 42 (67.7%), altered sensorium 41 (66.1%), convulsion 37 (59.7%), and shock 31 (50%). Total number of patients with MODS was 40 (64.5%). The case fatality rate was 8%. On multivariate analysis, infant age group (p = 0.02), altered sensorium (p = 0.001), reduced urine output (p = 0.02), thrombocytopenia (p = 0.001), raised C-reactive protein (p = 0.004), hyponatremia (p = 0.005), hypoalbuminemia (p = 0.01), deranged international normalized ratio (p = 0.02), and hyperferritinemia (p = 0.02) came out to be independent factors in predictability for development of MODS. Multiorgan dysfunction is a life-threatening manifestation of scrub typus in children, which necessitates PICU admission. Infant age group, presence of altered sensorium, reduced urine output, thrombocytopenia, elevated inflammatory markers, coagulopathy, hypoalbuminemia, and hyponatremia predict risk for MODS.

Scrub Typhus-Associated Hemophagocytic Lymphohistiocytosis: Not a Rare Entity in Pediatric Age Group

BACKGROUND

Our goal was to study the demographic, clinical and laboratory profile and outcome of scrub typhus-associated hemophagocytic lymphohistiocytosis (HLH) in the pediatric age group.

METHODS

We conducted a prospective observational study in a tertiary care teaching hospital over a period of 1 year. Children in the age group of 1 month to 12 years with IgM ELISA positive for scrub typhus were included in the study. HLH was diagnosed using HLH-2004 criteria. Demographic, clinical and laboratory profile, treatment and outcome of HLH patients were noted and also compared with non-HLH scrub typhus patients.

RESULTS

Among 58 children with scrub typhus infection, 18 had HLH. The mean age of patients with HLH was 35.3 ± 44.8 months and 61% were male. Anemia, thrombocytopenia and hyperferritinemia were seen in all the patients. Hypertriglyceridemia, hypofibrinogenemia and coagulopathy were noted in 78%, 56% and 44%, respectively. All the patients were treated with intravenous doxycycline for an average duration of 9.5 days. Intravenous immunoglobulin and methylprednisolone were given in 33% and 22% cases, respectively. Complications like acute respiratory distress syndrome (ARDS) (p = 0.001) and MODS (p = 0.004) were significantly high in the HLH group. Younger age (<3 years), fever > 7 days, presence of convulsion, ARDS and MODS were the clinical predictors of scrub typhus-associated HLH.

CONCLUSION

HLH in scrub typhus infected children is being increasingly recognized. Younger age, prolonged fever, presence of convulsion, ARDS and MODS should alert clinicians of the risk of HLH. Treating the primary cause usually cures the disease and immunomodulator therapy need not be routinely administered.

Clinical, immunological and genetic findings in patients with UNC13D deficiency (FHL3): A systematic review

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive immune disorder that is caused by mutations in 6 different genes related to the formation and function of secretory lysosomes within cytotoxic T lymphocytes and natural killer (NK) cells. Thus, defect in these genes is associated with the accumulation of antigens due to defective cytotoxic function. FHL type 3 (FHL3) accounts for nearly 30-40% of FHL, and its underlying reason is mutation in UNC13D gene which encodes Munc13-4 protein.

METHODS

For the first time, we aimed to systematically review clinical features, immunologic data, and genetic findings of patients with FHL3. We conducted electronic searches for English-language articles in PubMed, Web of Science, EMBASE, and Scopus databases to collect comprehensive records related to patients with UNC13D mutations.

RESULTS

A total of 279 abstracts were initially reviewed for inclusion. Among them, 57 articles corresponding to 322 individual FHL3 patients fulfilled our selection criteria. Finally, 73 and 249 patients were considered as severe and mild feature groups, respectively. Our results confirmed that fever, hepatosplenomegaly, and hemophagocytosis are common clinical features in the disease. Moreover, reduced fibrinogen and NK cell activity, as well as increased ferritin and triglycerides, are important markers for early diagnosis of the FHL3 disease. Investigation of genotype showed that the most prevalent type and zygosity of UNC13D are splice-site errors and compound heterozygous, respectively.

CONCLUSION

FHL3 patients have a wide range of clinical manifestations, which makes it difficult to diagnose. Therefore, it seems that the sequencing of the entire UNC13D gene (coding and non-coding regions) is the most appropriate way to accurate diagnosis of FHL3 patients.

Hemophagocytic Lymphohistiocytosis: An Unusual Presentation of Scrub Typhus

Scrub typhus is an important etiological cause for acute undifferentiated febrile illness in the Asia-Pacific region, including Sri Lanka. It is a mite-borne disease caused by Orientia tsutsugamushi. Hemophagocytic lymphohistiocytosis (HLH) is a rapidly progressive and potentially life-threatening hyperinflammatory syndrome rarely associated with scrub typhus. We herein describe a rare case of scrub typhus complicated by hemophagocytic lymphohistiocytosis in a 40-year-old previously healthy woman who presented with a history of an acute febrile illness. Following the observation of acute deterioration of hematological parameters despite the nature of the febrile illness, the rare association of hemophagocytic lymphohistiocytosis was considered, and this disease association was confirmed by fulfilling six out of eight of the diagnostic criteria of haemophagocytic lymphohistiocytosis. The patient made an uneventful recovery following treatment for the precipitating illness and with supportive care.

Japanese Spotted Fever with Hemophagocytic Lymphohistiocytosis

Japanese spotted fever (JSF) is an uncommon but potentially fatal infection transmitted by tick bites. We herein report a fulminant case of JSF infection that occurred in an immunocompetent adult that was complicated by disseminated intravascular coagulation and hemophagocytic lymphohistiocytosis (HLH). We discuss the difficulty in making the diagnosis and identifying the complication of HLH in our patient. HLH is a rare complication of rickettsiosis, and this is the first reported case in English of JSF complicated by HLH in an immunocompetent adult. Secondary HLH caused by rickettsiosis requires a different treatment from primary HLH. Rickettsiosis must therefore be considered in patients with HLH.

Clinical Profile and Therapeutic Response of Scrub Typhus in Children: A Recent Trend from Eastern India

OBJECTIVE

The aim of this study was to assess the clinico-laboratory parameters, complications and therapeutic responses in children with scrub typhus in Eastern India.

MATERIALS AND METHODS

In this prospective, observational study, all children (age, <12 years) with suspected scrub typhus with a compatible clinical scenario were enrolled consecutively over six months. Cases confirmed by means of a positive IgM serology or a positive Weil-Felix reaction (OXK = 1/80 or above) were administered enteral doxycycline (4.5 mg/kg/day).

RESULTS

Out of 94 recruited children, 61 had confirmed scrub typhus (mean age = 6.1 years, M:F = 1.1:1) with or without complications and having a considerably higher incidence of neurological presentation (meningoencephalistis n = 21, 34.4%). The most frequent manifestations included vomiting (n = 39, 63.9%), abdominal pain (n = 33, 54.1%), lymphadenopathy (n = 36, 59%), hepatosplenomegaly (n = 32, 52.5%), pedal edema (n = 32, 52.5%) and eschar formation (n = 30, 49.2%). Low hemoglobin levels, leukocytosis, thrombocytopenia, hypoalbuminemia, hyponatremia, increased liver enzymes and increased C-reactive protein were associated with delayed defervescence (>48 h).

CONCLUSION

Scrub meningoencephalitis, with a notably higher incidence, showed favorable therapeutic response. Prompt and empiric doxycycline therapy could be lifesaving.

Scrub typhus (Tsutsugamushi disease) in a patient presenting with hemophagocytic syndrome

Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi, which is found mainly in East and Southeast Asia and in Australia. The disease presents with a variety of non-specific symptoms, including fever, headache, cough, myalgia, and rash. Delay in starting appropriate antimicrobial therapy may lead to serious complications and even death. We report the case of an 84-year-old Japanese patient with scrub typhus who developed hemophagocytic syndrome (HPS) and was successfully treated with minocycline in addition to corticosteroids. A pathognomonic skin ulcer on her right buttock, which was initially covered with black eschar, prompted us to consider the possibility of scrub typhus. Blood polymerase chain reaction and antibody assays confirmed the diagnosis. Scrub typhus must be considered as one of the underlying diseases that may cause HPS in patients living in the Asia-Pacific region and in those who have recently returned from endemic areas.

Hemophagocytic Lymphohistiocytosis Associated with Scrub Typhus: Systematic Review and Comparison between Pediatric and Adult Cases

Background: Scrub typhus is a mite-borne bacterial infection caused by Orientia tsutsugamushi. Hemophagocytic lymphohistiocytosis (HLH) is a potential severe complication. Most reported cases of HLH associated with scrub typhus were single cases or case series with a small sample sizes. Thus, no clear consensus exists on clinical manifestations and differences between pediatric and adult cases of this condition. Methods: a systematic search of English and Japanese articles from PubMed, PubMed Central, and Directory of Open Access Journals databases was performed from 3 December 2016 to 28 December 2017. The primary outcome was mortality in patients with HLH associated with scrub typhus; secondary outcomes were differences in clinical symptoms, laboratory findings, and treatment between pediatric and adult patients with HLH associated with scrub typhus. Results: thirty cases of HLH associated with scrub typhus were identified (age range: 2 months to 75 years; median age: 21.5 years, male:female ratio, 1:1). Eschar was frequently observed in the pediatric group (p = 0.017), whereas acute kidney injury was more prevalent in the adult group (p = 0.010). Two patients died of intracranial hemorrhage complicated with multiple organ failure; overall mortality rate was 6.7%. Conclusions: HLH associated with scrub typhus could be cured with remarkable improvement using single antibiotic therapy in approximately half the cases, with the mortality rate being relatively lower than that of HLH associated with other secondary causes.

Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis is a life-threatening disorder characterized by unbridled activation of cytotoxic T lymphocytes, natural killer (NK) cells, and macrophages resulting in hypercytokinemia and immune-mediated injury of multiple organ systems. It is seen in both children and adults and is recognized as primary (driven by underlying genetic mutations that abolish critical proteins required for normal function of cytotoxic T cells and NK cells) or secondary (resulting from a malignant, infectious, or autoimmune stimulus without an identifiable underlying genetic trigger). Clinical and laboratory manifestations include fever, splenomegaly, neurologic dysfunction, coagulopathy, liver dysfunction, cytopenias, hypertriglyceridemia, hyperferritinemia, hemophagocytosis, and diminished NK cell activity. It is treated with immune suppressants, etoposide, and allogeneic hematopoietic stem cell transplantation; more than 50% of children who undergo transplant survive, but adults have quite poor outcomes even with aggressive management. Newer agents directed at subduing the uncontrolled immune response in a targeted fashion offer promise in this highly morbid disease.