|Description:||This image depicts an anteroposterior radiograph of a patient’s right arm revealing the boney involvement of the distal humerus in a case of actinomycotic mycetoma that had been caused by the Gram-positive bacterium, Nocardia asteroides.|
It is only rarely that N. asteroids bacteria cause mycetoma formation in the cutaneous or skeletal system. Overall, 80% of nocardiosis cases present as invasive pulmonary infection, disseminated infection, or brain abscess; 20% present as cellulitis. Pulmonary infection commonly presents with fever, cough, or chest pain. Central nervous system (CNS) symptoms include headache, lethargy, confusion, seizures, or sudden onset of neurologic deficit.
Severely immunocompromised persons are at greatest risk for nocardiosis. These include persons with connective tissue disorders, malignancy, HIV infection, pulmonary alveolar proteinosis, alcoholism, or high-dose corticosteroid use.