5. All the above

Rocky mountain spotted fever (RMSF) is endemic in eastern Arizona, and is a tick-borne disease characterized by an acute febrile illness that can result in multisystem organ failure. 90% of cases manifest a petechial macular/popular rash with predilection for the palms and soles. Our patient did not visit parts of the state where RMSF has been reported, did not have recognizable risk factors for tick bite and did not have the typical rash of RMSF, however empirical doxycycline was started pending results of RMSF (which were negative). Most patients are asymptomatic at the onset of HIV infection, but a minority manifest the acute retroviral syndrome (ARS), with fever, lymphadenopathy, sore throat, myalgia, arthralgia and rash – typically small erythematous macules on the face and upper trunk. ARS has rarely been associated with pneumonitis, rhabdomyolysis and opportunistic infections that occur during the transient CD4 lymphopenia that can occur years before the patient would be expected to manifest AIDS.

Still’s disease is a seronegative rheumatic disease characterized by quotidian (daily) fevers, arthralgia, myalgia, splenomegaly and an evanescent “salmon-colored” macular rash similar to the one we observed in our patient. Still’s disease does not cause multisystem organ failure unless it triggers secondary hemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome as some have called it.
Systemic lupus erythematosus can present with the same set of constitutional symptoms, lymphadenopathy, splenomegaly and multisystem organ failure including glomerulonephritis, pneumonitis, and pancytopenia. Multiple rashes can be seen including malar, discoid, photosensitivity and palpable purpura (in patients with cutaneous vasculitis associated with SLE)

Antibiotics were broadened to meropenem, vancomycin and doxycycline. HIV, EBV, CMV, hepatitis serology, ANA and rheumatoid factor were ordered.

Which laboratory tests is most likely to suggest a specific diagnosis? (Click on the correct answer to be directed to the third of six pages)

  1. Anti-nuclear antibody (ANA)
  2. Erythrocyte sedimentation rate (ESR)
  3. Ferritin
  4. Procalcitonin
  5. Rheumatoid factor

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