**4.2 Chronic progressive disseminated histoplasmosis**

It is a severe form, which occurs in immunosuppressed people, for example, patients with HIV, in the AIDS stage with CD4 below 150 cells/μL, and transplant

*Pulmonary Histoplasmosis: Clinical and Imagistic Characteristics DOI: http://dx.doi.org/10.5772/intechopen.110006*

#### **Figure 4.**

*CT image in the axial plane demonstrates a generalized miliary pattern in both lung fields, with associated ground-glass areas showing a tendency to multifocal condensations.*

patients, with malignant hematological pathology. Also, patients who follow various immunosuppressive therapies, such as systemic corticosteroids, tumor necrosis factor antagonists (infliximab, etanercept), or patients exposed to fungi in childhood, are more prone to this severe form. *H. Capsulatum* can remain latent after the initial exposure, and the reactivation can occur years after the initial exposure. The organism can even be transmitted through donated organs [12].

The *disseminated progressive form* presents the following CT characteristics (see **Figure 4**): diffuse pulmonary infiltrates in both lung fields, nodular miliary pattern, or aspect of acute respiratory distress syndrome (ARDS) representing the consequence of uncontrolled fungal proliferation at the level of the reticuloendothelial system with secondary dissemination at the pulmonary, hepato-splenic, gastrointestinal tract and at the hematogenous bone marrow level [9].
