Disseminated nocardiosis with thyroid involvement: A case report
Bo-An Su, Wen-Chien Ko, Yin-Ching Chuang, Hung-Jen Tang
Received: July 3, 2009 Revised: October 28, 2009 Accepted: March 2, 2010
Section of Infectious Diseases, Department of Internal Medicine, Chi-Mei Medical Center, 901 Junghua Road, Yungkang City, Tainan, Taiwan 710. E-mail address: firstname.lastname@example.org (H.-J. Tang).
Background and purpose:
Nocrdiae are aerobic, branching, filamentous, Gram-positive actinomycetes that are ubiquitous saprophytes. They are important parts of the normal microflora of soils worldwide. Nocardiosis can occur as a localized or disseminated infection1 and is commonly introduced through the respiratory tract. Nocardiosis occurs in many animals, such as cats, dogs, swines, and guinea pigs. However, there is no evidence of respiratory spread from infected animals to humans or of person-to-person spread.2
In immune-compromised patients, nocardiae are opportunistic pathogens. During the past three decades, 30–85% of Nocardia infections involved immune-compromised patients.1, 5 The incidence of infection has increased recently, probably related to the increasing numbers of moderately or severely immune-compromised patients because of human immunodeficiency virus infection or organ transplantation. Other conditions that are notably associated with Nocardia infection include lymphoreticular neoplasm, solid tumors, chronic alcoholism, diabetic mellitus, systemic lupus erythematosus, chronic granulomatous disease, and intravenous drug abuse.2, 6 However, Nocardia infection can occur in patients without concurrent disease or immunosuppressive therapy.
Although many Nocardia species are known, not all of them are capable of causing diseases in humans.3 In humans, the most frequently encountered species are Nocardia asteroids complex (including its subtypes Nocardia nova and Nocardia farcinica); Nocardiabrasiliensis; and Nocardia otitidiscaviarum.4 Pulmonary infection occurs most frequently, although extrapulmonary infections may occur, especially in the central nervous system (CNS) and soft tissues. The thyroid gland is a rare location for Nocardia infection.