Case Presentation: A 86 year-old man with rheumatoid arthritis on methotrexate and prednisone, CAD, HTN, CKD 3 presented with bilateral lower extremity rash for 5 days. He initially had pruritus in the legs, now progressed with redness and pain. He spent most of his days in his backyard during the summertime but did not recall any tick bites and denied recent travels. Initial vitals were significant for fever 102F, tachycardia with HR 116 bpm and hypoxia with SpO2 88% on room air. On exam, he had symmetric, poorly demarcated red scaly patches on the lower pretibial areas bilaterally with scant yellow crusts. Lab results showed pancytopenia with WBC 0.9 k/uL, Hemoglobin 7.4 g/dL, and Platelets 32k/uL. CT chest/abdomen/pelvis demonstrated bibasilar consolidation likely from aspiration but there was no acute intra-abdominal pathology. He was started on IV cefepime for aspiration pneumonia and presumed cellulitis of the legs. Despite the broad-spectrum antibiotic treatment, the patient continued to have persistent fever with worsening pancytopenia. Doxycycline was added as there was concern for rickettsia disease as his rash became more purpuric, yet still confined to the ankles without significant improvement in redness. Rocky Mountain Spotted Fever (RMSF) IgM resulted positive and bone marrow biopsy demonstrated myelodysplastic syndrome. Despite the appropriate treatment with the antibiotic and multiple transfusions, the patient had major complications including gastrointestinal bleeding, pulmonary edema and respiratory failure requiring mechanical ventilation and expired.
Discussion: RMSF is a potentially deadly, tickborne disease caused by Rickettsia rickettsii and endemic in the southeastern and south-central states of the United States. Clinical symptoms can be highly variable ranging from non-specific symptoms to the classic triad of fever, rash, and headaches. Although rash occurs in approximately 88-90 percent of patients, it is uncommonly seen at initial clinical presentation and the appearance as well as the evolution of rash vary widely, often leading to delay in diagnosis and treatment. In our case, the patient lived in suburban area of New York and hence was not from the usual endemic setting. He had no other clear risk factors for acquiring the disease, having no recent travel, hiking, or encounter with dogs. Most patients respond quickly to therapy with rapid improvement in their clinical signs and symptoms especially if treatment is started within five days of the onset of symptoms. Yet, the mortality could be as high as 30% if not promptly treated as in our case.
Conclusions: This case illustrates the importance of keeping RMSF in the differential diagnosis in patient populations outside of the usual geographic areas of incidence in the appropriate clinical setting as delay in appropriate treatment could lead to significant morbidity and mortality.