35 - HIV-Associated Respiratory Infections

Summary

INTRODUCTION

Shortness of breath is a common presenting complaint in human immunodeficiency virus (HIV)–infected patients, and the relevant differential diagnosis is broad. Etiologies include both infectious and noninfectious causes related and unrelated to underlying HIV infection and range from the minor (e.g., viral upper respiratory infection) to the life-threatening (e.g., Pneumocystis pneumonia [PCP]). Although the list of potential diseases may seem overwhelming, an understanding of the most commonly encountered pulmonary complications and their characteristic presentations will help narrow the differential diagnosis.

EPIDEMIOLOGY

The rate of bacterial pneumonia is between 5- and 25-fold higher in HIV-infected patients than in the non-HIV infected population. Although its prevalence has declined after the introduction of highly active anti-retroviral therapy (HAART), PCP is still a common acquired immunodeficiency syndrome (AIDS)-defining illness and is seen almost exclusively in immunocompromised persons. Globally, Mycobacterium tuberculosis (TB) pneumonia is the major pulmonary infection complicating the HIV epidemic. HIV-infected patients who have latent TB infection face a 10% annual risk of progressing from latent to active tuberculous disease compared to an approximately 10% lifetime risk in non-HIV-infected individuals. (See Chapter 33, Tuberculosis.)

CLINICAL FEATURES

The clinical presentations of common HIV-associated pulmonary infections often overlap. The goal of a thorough history and physical is to narrow the differential diagnosis, recognize constellations of particular symptoms and signs, and guide diagnostic testing and therapy.