A Case of Hemophagocytic Lymphohistiocytosis Associated With Mediterranean Spotted Fever in a Healthy 29-Year-Old Female

Hemophagocytic Lymphohistiocytosis (HLH) in Patients with Tick-Borne Illness: A Scoping Review of 98 Cases

Hemophagocytic lymphohistiocytosis (HLH) secondary to tick-borne infections is a rare but potentially life-threatening syndrome. We performed a scoping review according to PRISMA guidelines to systematically analyze the existing literature on the topic. A total of 98 patients were included, with a mean age of 43.7 years, of which 64% were men. Most cases, 31%, were reported from the USA. Immunosuppression was present in 21.4%, with the most common cause being previous solid organ transplantation. Constitutional symptoms were the most common, observed in 83.7% of the patients, while fever was reported in 70.4% of cases. Sepsis was present in 27.6%. The most common laboratory abnormalities in this cohort were thrombocytopenia in 81.6% of patients, while anemia, leukopenia, and leukocytosis were observed in 75.5%, 55.1%, and 10.2%, respectively. Liver enzyme elevation was noted in 63.3% of cases. The H-score was analyzed in 64 patients, with the mean value being 209, and bone marrow analysis was performed in 61.2% of patients. Ehrlichia spp. was the main isolated agent associated with HLH in 45.9%, followed by Rickettsia spp. in 14.3% and Anaplasma phagocytophilum in 12.2%. Notably, no patient with Powassan virus infection or Lyme borreliosis developed HLH. The most common complications were acute kidney injury (AKI) in 35.7% of patients, shock with multiple organ dysfunction in 22.5%, encephalopathy/seizure in 20.4%, respiratory failure in 16.3%, and cardiac complications in 7.1% of patients. Treatment included antibiotic therapy alone in 43.9%, while 5.1% of patients were treated with immunosuppressants alone. Treatment with both antibiotics and immunosuppressants was used in 51% of patients. Appropriate empiric antibiotics were used in 62.2%. In 43.9% of cases of HLH due to tick-borne disease, patients received only antimicrobial therapy, and 88.4% of those recovered completely without the need for immunosuppressive therapy. The mortality rate in our review was 16.3%, and patients who received inappropriate or delayed empiric therapy had a worse outcome. Hence, we suggest empiric antibiotic treatment in patients who are suspected of having HLH due to tick-borne disease or in whom diagnostic uncertainty persists due to diagnostic delay in order to minimize mortality.

Flea-Borne Typhus Causing Hemophagocytic Lymphohistiocytosis: An Autopsy Case

Infection with members of the order Rickettsiales (the genera Rickettsia, Anaplasma, Orientia, and Ehrlichia) is known to cause hemophagocytic lymphohistiocytosis (HLH). The literature is scant on flea-borne typhus (FBT) being implicated in this process. We present a case of autopsy-proven HLH caused by FBT in a 71-year-old diabetic female who was initially suspected of having diabetic ketoacidosis who rapidly suffered decompensated multi-organ failure. Although she was suspected of having FBT and HLH pre-mortem, due to her rapid progression to multi-organ failure, she was transitioned to comfort care by her family five days after admission. A literature search yielded five other cases of HLH secondary to FBT, which are analyzed in this review. The literature on HLH occurring with infection due to other members of the order Rickettsiales is also surveyed.

Mediterranean spotted fever with multiorgan involvement

A previously well man in his 50s returned to the UK after a trip to the Mediterranean. The day after returning he developed malaise, fevers, rigors and severe headache. He was hospitalised with sepsis, multiorgan involvement, a maculopapular rash and an eschar on each hip. Serology was positive for Rickettsia spp (spotted fever group) with a rise in titre from 1:64 to 1:1024 eight days later. Blood and tissue PCR were also positive for Rickettsia spp. He had cardiac, pulmonary, renal, ocular and neurological involvement. He completed a 14-day course of doxycycline and recovered well. This is a case of likely Mediterranean spotted fever (MSF) caused by Rickettsia conorii, which is endemic to the Mediterranean basin. We highlight the need for awareness and early treatment to prevent severe complications. This case is also the first to describe Purtscher-like retinopathy in the context of likely MSF.

Haemophagocytic lymphocytic histiocytosis/macrophage activation syndrome with acute inflammatory gastroenteritis

Haemophagocytic lymphocytic histiocytosis (HLH) is a rare, life-threatening condition caused by abnormal activation of cytotoxic T lymphocytes, natural killer cells and macrophages resulting in hypercytokinaemia and immune-mediated injury of multiple organ systems. Secondary HLH occurs in the setting of a malignant, infectious or autoimmune stimulus. Macrophage activation syndrome (MAS) is the term used to describe HLH that develops secondary to rheumatological diseases such as lupus and juvenile idiopathic arthritis, among others. Commonly observed and documented symptoms include fever, organomegaly and lymphadenopathy. Given the potential for multiorgan failure in HLH/MAS, early identification, diagnosis and initiation of treatment is essential. We present a case of secondary HLH/MAS with acute inflammatory gastroenteritis in a middle-aged woman with a history of systemic lupus erythematosus.

Fatal murine typhus with hemophagocytic lymphohistiocytosis in a child

Hemophagocytic lymphohistiocytosis is a rare complication in Rickettsia typhi infections. We report the case of a 2-year-old boy with sudden night-onset fever, pallor, neck adenopathy and erythematous macular rash on the thorax, thighs and buttocks. During admission, he developed hyponatremia, hypoalbuminemia, anemia, thrombocytopenia, leukopenia, neutropenia, liver damage, hemorrhages and persistent fever. No hematological improvement was observed after the initial management, neoplastic diseases were discarded by bone marrow aspiration and lymph node biopsy; hemophagocytic lymphohistiocytosis was diagnosed. By immunohistochemistry and indirect immunofluorescence, murine typhus was also diagnosed and doxycycline was started with transitory recovery. Later, the child developed kidney failure and distributive shock that evolved to cardiac arrest and death. This is the first case report in Mexico on a fatal murine typhus associated with hemophagocytic lymphohistiocytosis in which the etiology was evidenced by histopathology.