2. 2
Learning Outcomes
• By the end of this session, you will be
expected to be able to:
• Discuss disease staging and AIDS-defining
illness based on WHO guidelines
3. 3
What is Staging?
• Classification of the particular stage reached
by a progressive disease
4. 4
Why is Staging Important in HIV?
• Tracking and monitoring the HIV
epidemic
• Providing clinicians and patients with
important information about HIV disease
stage and clinical management
5. 5
What are the Staging Systems in use?
(1) U.S. Centers for Disease Control and
Prevention (CDC) classification system
(2) World Health Organization (WHO)
Clinical Staging and Disease
Classification System
8. 8
Three Phases of HIV Infection
• Course taken by HIV is understood in terms of
interplay between HIV and the immune system.
9. 9
Phase I-The early, acute phase
• Initial response of an immunocompetent adult to HIV
infection
• High level of virus production and viraemia
widespread viral seeding of the lymphoid tissues and
1-2 billion CD4+ T-cells die each day
• Clinically characterized by infectious mononucleosis-
like features of sore throat, myalgias, fever, weight
loss, and fatigue
10. 10
Phase II-The middle, Chronic Phase
• Relative containment of the virus and clinical latency
• Virus replication continues for several years,
• predominantly in the lymphoid tissues
• Immune system largely intact
• Clinically, patients are either asymptomatic or
develop persistent generalized lymphadenopathy
(PGL).
• Many patients have herpes zoster, oral thrush
21
11. 11
Phase III-The Final Phase
• Breakdown of host defense
• CD4 count usually < 200 cells/mm3
• Sudden and rapid viraemia
• Clinically, the patient presents with marked weight
loss,
• Chronic diarrhoea, and fever lasting more than 1
month
• Opportunistic infections (OI) occur
• The clinical picture of AIDS will depend on the type
of OI
22
12. 12
Phase of HIV and AIDS
• Four phases emerge from day zero
–Infection
–Window period
–Seroconversion
–Asymptomatic period
–HIV/AIDS - related illness
• AIDS
13. 13
CD4 Counts
• Number of CD4 cells in blood provides a
measure of immune system damage
• CD4 count reflects phase of disease
• CD4 count:
–500 – 1200: Normal
–200 – 500: Beginning of HIV illness
–< 200: AIDS
14. 14
Window Period
• Time between infection & enough
antibodies for a positive HIV test
• Duration: approximately 3 months
• No symptoms or signs of illness
• HIV test is negative
• Virus is multiplying rapidly - viral load is
high
• Person is very infectious
15. 15
Seroconversion
• Point at which HIV test becomes positive
• Body starts making antibodies to HIV a few
weeks after infection
• HIV test becomes positive when antibody
levels are high enough to be measured
• Happens about 3 months after infection
• Person may have a mild flu-like illness,
lasting a week or two then the person is well
again
16. 16
Asymptomatic Periodic
• Time period between seroconversion and
onset of HIV/AIDS-related illness
• Duration variable: < 1 year to > 15 years
• Most people remain healthy
(asymptomatic) for about three years
• Duration may depend on socio-economic
factors
• The CD4 count is above 500 cells/ml
17. 17
HIV-Related Illnesses & AIDS
• Time period between onset of illness &
diagnosis of AIDS
• Duration is variable: average about 5
years
• Illnesses initially mild, with gradual
increase in frequency and severity
• CD4 count is between 500 & 200 cells/ml
18. 18
AIDS
• Final phase of HIV/AIDS
• Duration: without antiretroviral drugs, less
than 2 years with and with antiretrovirals,
many many years
• CD4 count is below 200 cells/ml
• Viral loads are high & the person is very
infectious
• HIV test may become negative
20. 20
WHO Clinical Staging in Adults
Adults with HIV infection are classified into 4
clinical stages depending on the presence of
HIV-related conditions
21. 21
WHO Clinical Staging Criteria?
Classification WHO clinical stage
Asymptomatic 1
Mild 2
Advanced 3
Severe 4
22. WHO Clinical Stage 1- Primary HIV
Infection
• Asymptomatic
• Persistent Generalized
Lymphadenopathy (PGL)
• Performance scale 1: asymptomatic,
normal activity
23. WHO Clinical Stage II-Asymptomatic
• Weight loss, <10% of body weight
• Minor mucocutaneous manifestations (seborrheic
dermatitis, prurigo,
• Fungal nail infections, recurrent oral ulcerations,
angular cheilitis
• Herpes zoster within the last five years
• Recurrent upper respiratory tract infections
• And/or performance scale 2: symptomatic, normal
activity.
25. WHO Clinical Stage IV-(HIV to AIDS)
• HIV wasting syndrome, as defined by the
Centers for Disease Control and Prevention
• Pneumocystis carinii pneumonia
• Toxoplasmosis of the brain
• Cryptosporidiosis with diarrhoea >1 month
• Cryptococcosis, extrapulmonary
• Cytomegalovirus disease of an organ other than
liver, spleen or lymph nodes
• Herpes simplex virus infection, mucocutaneous
>1 month, or visceral any duration
• Progressive multifocal leukoencephalopathy
26. 26
WHO Clinical Stage IV- (HIV to AIDS)
• Any disseminated endemic mycosis
(i.e.histoplasmosis, coccidioidomycosis)
• Candidiasis of the oesophagus, trachea, bronchi or
lungs
• Atypical mycobacteriosis, disseminated
• Non-typhoid Salmonella septicaemia
• Extrapulmonary tuberculosis
• Lymphoma
• Kaposi’s sarcoma
• HIV encephalopathy, as defined by the Centers for
Disease Control and Prevention.
• And/or performance scale 4: bedridden >50% of the
day during the last month 32
27. 27
References Cited
• WHO Case Definitions of HIV for Surveillance and
Revised Clinical Staging and Immunological
Classification of HIV-Related Disease in Adults and
Children; 2007.
• 1993 revised classification system for HIV infection and
expanded surveillance case definition for AIDS among
adolescents and adults. MMWR Recomm Rep. 1992 Dec
18;41(RR-17):1-19.
• Guidelines for national human immunodeficiency virus
case surveillance, including monitoring for human
immunodeficiency virus infection and acquired
immunodeficiency syndrome. MMWR Recomm Rep.
1999 Dec 10;48(RR-13):1-27, 29-31.
