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INTRODUCTION

Human immunodeficiency virus (HIV) is a cytopathic

retrovirus that attacks the CD4 T-lymphocytes in the

immune system. Acquired immunodeficiency syndrome

(AIDS) occurs when HIV-induced loss of CD4 cells and

the resulting immunosuppression permit infection from

opportunistic pathogens. AIDS is defmed as a CD4

count <200/j..lL, a CD4 percentage < 14%, or the presence of an AIDS-defining illness. AIDS-defining illnesses include Pneumocystis jiroveci pneumonia (PCP),

Mycobacterium tuberculosis (TB), toxoplasmosis, cryptococcosis, cryptosporidiosis, esophageal candidiasis,

disseminated Mycobacterium avium complex (dMAC),

and cytomegalovirus (CMV), among others.

In the United States, approximately 1.2 million persons

are infected with HIV, with up to 50,000 new cases every

year. The estimated prevalence of HN-positive patients

seen in urban emergency departments (EDs) may be as

high as 1 1.4%. Up to 20% of all HN-positive persons in

the United States are unaware of their HN status.

Risk factors for HN acquisition include sexual activity, injection drug use, blood transfusion (particularly

before screening of the donor pool commenced in 1985),

• All patients with H IV and respiratory complaints, especially those with CD4 <200 cells/I-ll should be placed in

negative pressure/airborne isolation until the diagnosis

of tuberculosis can be excluded.

• With appropriate ca re and proper management, people

living with HIV ca n live a normal lifespan.

intrapartum/neonatal exposure to a mother with HIV,

and occupational exposure (break of skin with contarni ­

nated sharps or blood/body fluid splashes onto mucous

membranes/non-intact skin).

Acute retroviral syndrome (ARS) occurs in approximately 50% of acutely infected patients, approximately

2-4 weeks after exposure to HN, and may clinically manifest as a flu-like or mononucleosis-like illness. Regardless of

the presence or absence of ARS, most patients have a high

viral load (> 106 copies/cm3

) during this period, and negative serologic tests. Seroconversion typically occurs 2-6

weeks (though sometimes up to 6 months) after exposure.

An immune response to the virus is then generated, and the

viral load falls to a setpoint with a relatively stable CD4

count.