Pericarditis after allogeneic peripheral blood stem cell transplantation caused by Legionella pneumophila (non-serogroup 1)

Legionellosis in Transplantation

Legionella species are emerging opportunistic pathogens in hematopoietic stem cell and solid organ transplant recipients, associated with significant morbidity and mortality. The clinical and radiological features of Legionella infections can mimic other opportunistic pathogens in these profoundly immunocompromised patients. Diagnosis in transplant patients is challenging as non-pneumophila Legionella infections, for which these patients are at risk, cannot be identified using the urinary antigen test. Changes in management of transplant recipients and changes in Legionella epidemiology suggest that the number of transplant patients potentially exposed to Legionella spp. may be on the rise. Yet, evidence-based, transplant-specific guidelines for managing and preventing Legionella infections are not currently available. In this article, we review the epidemiology, clinical features, diagnostic challenges, treatment options, and preventive strategies of Legionella infections in these high-risk patient populations.

Infections in Leukemia and Hematopoietic Stem Cell Transplantation

Infections are one of the most common complications in patients diagnosed with leukemia and serve as a major obstacle to treatment. Through the early 1970s, infections were the most common cause of death in patients diagnosed with acute leukemia, but improvement in treatment and supportive care over the past few decades, coupled with expanded prophylaxis and prevention regimens, have led to reduction in both the frequency and severity of infections. Regardless, due in part to an aging cancer population and the diversity of cancer treatments and procedures, infectious diseases remain a major cause of morbidity and mortality in patients with leukemia.

Bacterial pericarditis: diagnosis and management

Bacterial pericarditis occurs by direct infection during trauma, thoracic surgery, or catheter drainage, by spread from an intrathoracic, myocardial, or subdiaphragmatic focus, and by hematogenous dissemination. The frequent causes are Staphylococcus and Streptococcus (rheumatic pancarditis), Haemophilus, and M. tuberculosis. In AIDS pericarditis, the incidence of bacterial infection is much higher than in the general population, with a high proportion of Mycobacterium avium-intracellulare infection. Purulent pericarditis is the most serious manifestation of bacterial pericarditis, characterized by gross pus in the pericardium or microscopically purulent effusion. It is an acute, fulminant illness with fever in virtually all patients. Chest pain is uncommon. Purulent pericarditis is always fatal if untreated. The mortality rate in treated patients is 40%, and death is mostly due to cardiac tamponade, systemic toxicity, cardiac decompensation, and constriction. Tuberculous infection may present as acute pericarditis, cardiac tamponade, silent (often large) relapsing pericardial effusion, effusive-constrictive pericarditis, toxic symptoms with persistent fever, and acute, subacute, or chronic constriction. The mortality in untreated patients approaches 85%. Urgent pericardial drainage, combined with intravenous antibacterial therapy (e.g. vancomycin 1g twice daily, ceftriaxone 1-2g twice daily, and ciprofloxacin 400 mg/day) is mandatory in purulent pericarditis. Irrigation with urokinase or streptokinase, using large catheters, may liquify the purulent exudate, but open surgical drainage is preferable. The initial treatment of tuberculous pericarditis should include isoniazid 300 mg/day, rifampin 600 mg/day, pyrazinamide 15-30 mg/kg/day, and ethambutol 15-25 mg/kg/day. Prednisone 1-2 mg/kg/day is given for 5-7 days and progressively reduced to discontinuation in 6-8 weeks. Drug sensitivity testing is essential. Pericardiectomy is reserved for recurrent effusions or continued elevation of central venous pressure after 4-6 weeks of antituberculous and corticosteroid therapy.