AUGUST 8, 2017 GRAND ROUNDS

CASE 1: DISSEMINATED HISTOPLASMOSIS

43/M with rheumatoid arthritis (receiving methotrexate and etanercept), p/w chronic pneumonia; additional studies showed an elevated urine Histoplasma antigen and a GMS stain of a bronchoalveolar lavage that demonstrated numerous yeasts forms consistent with Histoplasma

1. Histoplasmosis is the most common invasive fungal infection among people receiving anti-TNF therapy.

2. Anti-TNF therapy should be discontinued in patients who develop histoplasmosis.

3. Be aware of immune reconstitution syndrome (IRIS) in patients with histoplasmosis while receiving effective antifungal therapy (in 9% of cases). This occurs after anti-TNF medication is discontinued.

CASE 2: DISSEMINATED PARVOVIRUS B19 INFECTION

57/M w/ primary biliary cirrhosis s/p liver transplantation 11 years prior (receiving tacrolimus and mycophenolate), p/w chronic fatigue and new-onset pancytopenia (Hgb 6.6, WBC 1.9, platelet 65); additional studies showed low reticulocyte count and a positive blood parvovirus B19 PCR test

1. Suspect parvovirus B19 in immunocompromised patients with:

·         Unexplained anemia (seen in 99% of patients) or pancytopenia

·         Clinical syndromes: fever (25% of patients), rash, arthralgia

·         Others: hepatitis, myocarditis, pneumonitis, neurologic manifestations, vasculitis

2. Two-thirds of infection occurs within 3 months after transplantation (can be late as well).

3. The diagnosis commonly rests on detecting a positive serum parvovirus Ig M (in 75% of transplant patients) or PCR. If both tests are negative but the suspicion remains, a bone marrow biopsy can be done and this normally shows characteristic giant pronormoblasts.

4. IVIG 400 mg/kg/day for 5 days is the treatment of choice. It can recur in 28% of transplant patients even after therapy.