Rickettsia Masquerading as Thrombotic Thrombocytopenic Purpura

Abstract

INTRODUCTION: Rocky Mountain spotted fever (RMSF), a tick-borne illness, and a Spotted fever Rickettsiosis, presents with nonspecific symptoms (e.g., high fever, headache, myalgia) with a high mortality rate in the pre-antibiotic era (20-80%) (1,2). We present a patient who developed thrombotic thrombocytopenic purpura (TTP) with a high PLASMIC SCORE: 6 points. CASE PRESENTATION:A 47-year-old male with no significant past medical history presented to the hospital with altered mental status. His brother reported that the patient's symptoms started 10 days before presentation when the patient chills and shivering. He continued with chills and subsequently developed a severe headache and subsequently reported chest pain, abdominal pain. Physical exam revealed jaundice with scleral icterus. However, with no presence of a rash. The patient lives in a rural area where stray cats, dogs, and cattle were common and allowed inside the house.bLaboratories revealed a white blood cell count (WBC) of 15.4Â 109/L, hemoglobin of 13.4 g/dl, and a platelet count of 20 Â 109/L. A peripheral smear taken upon admission was unremarkable and no evidence of microangiopathic hemolytic anemia. A subsequent peripheral smear showed revealed MAHA with marked thrombocytopenia. The result of immunofluorescence antibody testing for rickettsia immunoglobulin G and M was strongly positive for Rocky Mountain Spotted fever and Flea-borne (murine) typhus.Our patient was treated with doxycycline and admitted to the ICU due to severe illness. Throughout hospitalization, the patient continued to improve, his peripheral smear showed complete resolution of features of disseminated intravascular coagulation and was discharged after 4 days with a course of oral doxycycline DISCUSSION: Rocky Mountain Spotted Fever is an infectious diseasecaused by Rickettsia ricketsii. Tickborne rickettsial diseases in the United States have continued to rise, resulting in severe illness and death in individuals with no prior comorbid conditions, despite the widely available and effective antibacterial therapy. The early signs of tickborne rickettsial illnesses present with nonspecific symptoms; therefore, RMSF can oftentimes be misdiagnosed as an acute viral syndrome, or in our case, as TTP (3). Furthermore, while this disease is often associated with the classic triad of fever, rash, and reported tick bite, only a minority of cases present with these as the initial presentation of symptoms. Clinicians should include rickettsial infection as a diagnostic workup of any patient who presents with a classic pentad of thrombotic thrombocytopenic purpura (TTP).CONCLUSIONS: This case illustrates the importance of rickettsial infections as a differential diagnosis for patients who present with nonspecific febrile illness. With the delay of treatment, this infection can progress rapidly to neurologic manifestations, renal failure, thrombocytopenia, and death.