Fatal systemic nocardia infection revealed by cardiac tamponade

A case report of Nocardia asiatica constrictive pericarditis in a patient with Human Immunodeficiency Virus

Nocardiosis commonly affects the respiratory system and is a rare cause of purulent pericarditis. Invasive nocardial infections occur more frequently in patients with immunosuppression. A misdiagnosis as tuberculosis infection is not uncommon, especially in the context of immunosuppression in high burden tuberculosis settings. The risk factors and clinical features of the two disease entities overlap substantially. Misdiagnosis may lead to a delay in appropriate treatment and may result in poor outcomes. It is important to note that these conditions may also co-exist in the same patient. We describe, to the best of our knowledge, the first case of Nocardia asiatica pericarditis in a 32-year-old man with Human Immunodeficiency Virus infection. The patient was initially diagnosed in September 2020 with a lower respiratory tract infection and pulmonary tuberculosis was suspected. A chest radiograph, performed at admission, revealed a pericardial effusion and N. asiatica was cultured from a pericardial fluid specimen that was collected 5 days following admission. Despite a good initial clinical response to a combination of trimethoprim/sulfamethoxazole and imipenem/cilastatin, the patient demised after 16 weeks of treatment. Previous reports of laboratory confirmed nocardial pericarditis are also reviewed and summarized.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

First Report of Nocardia asiatica Presenting as an Anterior Mediastinal Mass in a Patient with Myasthenia Gravis: A Case Report and Review of the Literature

The spectrum of infections with Nocardia spp. is heterogeneous. It has classically been associated with lung, brain, or skin involvement. We describe an unusual presentation of Nocardia asiatica (N. asiatica) in an Iraqi patient with myasthenia gravis suffering from a disseminated infection and presenting with an anterior mediastinal cystic mass. N. asiatica has only been three times described outside Japan and Thailand, and the rarity of this entity deserves this communication.