Differentials

Tuberculosis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical differentiation is difficult. In immunocompetent patients, cavities are more frequently related to tuberculosis. In immunocompromised patients, particularly patients with AIDS, cavities are less frequently associated with tuberculosis and very common in nocardiosis.[30]

INVESTIGATIONS

Mycobacterium can be differentiated from Nocardia in clinical samples, because mycobacteria do not stain well with Gram stain and modified acid-fast stain. They are also microscopically different from Nocardia.[7]

Actinomycosis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical differentiation is difficult.

INVESTIGATIONS

Actinomyces can be differentiated from Nocardia in clinical samples, because Actinomyces is not stained by modified acid-fast stain.[7]

Lung abscess

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical differentiation is difficult.

INVESTIGATIONS

Evidence of Nocardia species in sputum or other specimens allows differentiation.

Brain abscess

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical differentiation is difficult.

INVESTIGATIONS

Evidence of Nocardia species in clinical specimens allows differentiation of these organisms from others in the differential diagnosis, but sometimes invasive procedures (e.g., brain biopsy) are necessary to confirm or rule out disseminated nocardiosis.[54][56][57]

Pulmonary and disseminated opportunistic fungal infections

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical differentiation is difficult.

INVESTIGATIONS

Evidence of filaments, detection of fungal antigens or nucleic acids, and fungal cultures in sputum or other specimens allow differentiation.

Toxoplasmosis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical differentiation is difficult.

INVESTIGATIONS

Evidence of Nocardia in other clinical specimens, Toxoplasma serology, cerebrospinal fluid Toxoplasma polymerase chain reaction.

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