154 Infectious Disease and Foreign Travel Emergencies
HUMAN IMMUNODEFICIENCY VIRUS INFECTION(ii) Group 2 – Asymptomatic infection:
(a) the acute infection symptoms usually resolve by 3 weeks
(b) infected patients seroconvert to HIV-positive over the next 4
months, most within 2–12 weeks of exposure
(c) 50% of these patients will have fully developed AIDS by
10 years, with a near 100% mortality, although disease
progression is slowing almost to a preserved life expectancy
with modern highly active anti-retroviral therapy (HAART).
(iii) Group 3 – Persistent generalized lymphadenopathy:
(a) enlarged nodes in two or more non-contiguous extra-inguinal
sites for at least 3 months and not due to a disease other than
HIV
(b) the patient is otherwise relatively well and enters a latency
period of 2–10 years or more.
(iv) Group 4 – Symptomatic infection:
(a) subgroup A: constitutional disease with persistent fever,
unexplained weight loss of 10% body mass or diarrhoea for
over 1 month
(b) subgroup B: neurological disease, including encephalopathy,
myelopathy and peripheral neuropathy
(c) subgroup C: secondary infectious diseases due to opportunistic
infections occur as the CD4+ count drops usually below
200/mm^3. These include Pneumocystis jiroveci pneumonia,
recurrent pneumonia, Mycobacterium tuberculosis, atypical
mycobacteria, toxoplasmosis, cryptosporidiosis, isosporiasis,
strongyloidosis, cytomegalovirus, systemic candidiasis,
cryptococcosis and many others
(d) subgroup D: secondary cancers including Kaposi’s sarcoma,
high-grade non-Hodgkin’s lymphoma, primary lymphoma of
the brain and invasive cervical cancer
(e) subgroup E: other conditions such as the HIV-wasting
syndrome and chronic lymphoid interstitial pneumonitis.
5 AIDS-defining illnesses in an HIV-positive patient are in subgroups B to E,
most commonly P. jiroveci pneumonia and Cryptococcus neoformans menin-
gitis.
6 Thus, patients encountered in the ED infected with HIV range from the
asymptomatic carrier state in the majority to non-specific illness or to acute
problems as varied as collapse, respiratory failure, gastrointestinal bleeding,
skin disorders, depression, dementia, stroke and coma.
7 Always maintain a high index of suspicion to identif y an HIV-risk patient, if
necessary by direct questioning.
8 Send blood preferably for HIV antigen if the patient is acutely unwell with a
possible new HIV illness, requesting nucleic acid amplification (NAA)