PAEDIATRIC HIV / AIDS I & II��
Prof. Yakubu Mava. MBBS (ABU), FWACP, FIMC, LMIH (USA)
OUTLINE�
- Introduction
- Historical background
- Aetiology / Pathogenesis / Pathophysiology
- Epidemiology
- Clinical staging
- Diagnosis: clinical and laboratory
- Treatment
- Immune reconstitution syndromes
- Opportunistic infections
- Cotrimoxazole prophylaxis
- Nutrition
- Psychological support
Introduction
To understand what HIV and AIDS are, let’s break it down:
Causative agent:
H – Human – This particular virus can only infect human beings.
I – Immunodeficiency – HIV weakens your immune system by destroying important cells that
fight disease and infection. A "deficient" immune system can't protect you.
V – Virus – A virus can only reproduce itself by taking over a cell in the body of its host.
http://aids.gov/hiv-aids-basics/hiv-aids-101/what-is-hiv-aids/
What is HIV?
Disease:
A – Acquired – AIDS is not something you inherit from your parents like eye color.
You acquire AIDS.
I – Immuno – Your body's immune system includes all the organs and cells that work to
fight off infection or disease.
D – Deficiency – You get AIDS when your immune system is "deficient,"
or isn't working the way it should.
S – Syndrome – A syndrome is a collection of symptoms and signs of disease. AIDS is a syndrome,
rather than a single disease. It is a complex illness with a wide range of symptoms.
http://tcf.epfl.ch/page-20833-en.html
The HIV genome is composed of 9 genes, which encode 15 proteins.
For comparison, the E. Coli bacterium contains around 4,377 genes and the human genome encodes around 21,000 genes.
http://biology.kenyon.edu/slonc/gene-web/Lentiviral/Lentivi2.html
Where did HIV come from?
http://what-when-how.com/medical-microbiology-and-infection/zoonoses-systemic-infection/
Zoonosis = Cross-species transmission event
Phylogeny of lentiviruses.
Sharp P M , and Hahn B H Cold Spring Harb Perspect Med 2011;1:a006841
©2011 by Cold Spring Harbor Laboratory Press
©2011 by Cold Spring Harbor Laboratory Press
Sharp P M , and Hahn B H Cold Spring Harb Perspect Med 2011;1:a006841
Where did HIV come from? Cont.
HIV entered the human population from primates, which harbor a related virus known as SIV (simian immunodeficiency virus). This probably occurred during the butchering and consumption of monkey meat in Africa.
http://www.avert.org/hiv-types.htm
HIV “family tree”
HIV-1 group M, which is the most prevalent HIV strain, jumped from chimpanzees into humans.
http://www.awf.org/content/wildlife/detail/chimpanzee
HIV-2 originated in sooty mangabeys and is responsible for fewer infections than HIV-1
New viruses are still being transferred from primates to humans, and have the potential to cause new diseases and epidemics.
http://pin.primate.wisc.edu/factsheets/entry/sooty_mangabey
Origins of human AIDS viruses.
Sharp P M , and Hahn B H Cold Spring Harb Perspect Med 2011;1:a006841
©2011 by Cold Spring Harbor Laboratory Press
When did HIV first jump into humans?
The strain of HIV responsible for the majority of global infections (HIV-1 Group M) probably jumped into humans in western Africa sometime between 1884 and 1924.
From there it then spread throughout the world.
Origin and Spread of HIV
Historical Background of HIV/AIDS
Historical background cont.
Aetiology and Pathogenesis�
Aetiology and Pathogenesis
PATHOPHYSIOLOGY
THE STRUCTURE OF HIV�
.
Cellular Immune Response to HIV
= CD8 cytotoxic T Lymphocytes (CTL)
. Critical for containment of HIV
. Derived from naïve T8 cells which recognizes viral Ag in
context of MHC class 1 presentation
. Directly destroy infected cells
. Activities augmented by Th1 response
= CD4 Helper T Lymphocytes (Th)
. plays an important role in cell mediated response
. Recognizes viral Ag by an Ag presenting cell (APC)
. Differentiated according to the ‘help’:
-Th1 activates Tc (CD8) lymphocytes promoting cell mediated
immunity
-Th2 activates B lymphocytes promoting Ab mediated immunity
Humoral Immune Response to HIV
. Ab binds to surface of virus to prevent
attachment to target cells
. Fc portion of the Ab binds to NK cells
. Stimulate NK cells to destroy infected cells
HIV Evasion Methods
Epidemiology: Global situation
HIV Epidemiology
HIV Epidemiology cont.
HIV Epidemiology
Nigeria: HIV Epidemiology
HIV Epidemiology
HIV Epidemiology by geopolitical zones in Nig.
HIV Epidemiology cont.
MODES OF TRANSMISSION�
1. Intrauterine 25 – 40%
2. Intrapartum (during labour or delivery) 60 –75%
3. Postpartum 15% (through breastfeeding).
4. Breast-feeding thus accounts for the 15%
MODES OF TRANSMISSION Cont.
http://aids.gov
Pediatric HIV Clinical Staging -New WHO
.
STAGE 3 cont.
.
STAGE 4 CONT.
Herpes Zoster (Shingles): varicella zoster virus
Seborrheic Dermatitis: Malassezia fungus
Oral Candidiasis / Thrush (WHO stage III)
HIV wasting syndrome (WHO stage IV)
Karposi Sarcoma: HHV-8
Non-Hodgkin Lymphomas:
INVESTIGATIONS PAEDIATRICS HIV
.
Basic Serologic Testing
More Advanced Serologic Testing
Other HIV testing modalities
WHO Testing Strategy
Window period
Pediatric HIV Diagnosis
Positivity of DNA PCR in HIV-infected infants during the first month of life
Pediatric HIV Diagnosis
Immunologic category | < 1 Year | 1-5 Years | 6-10 Years |
Category I No evidence of suppression | >1500 cells > 25% | >1000 cells > 25% | > 500 cells > 25 % |
Category II Moderate Suppression | 750 – 1499 15 – 24 % | 500 –999 15- 24% | 200- 499 15- 24% |
Category III Severe suppression | <750 cells < 15% | < 500 cells <15 % | < 200 cells < 15 % |
Immune categories by CD4 count and CD4 %
Treatment Modalities
Pediatric HIV Treatment Principles
When to Start ARV Children Age <18 Months
When to Start ARV Children Age >18 Months
WHO Recommended First-line ARV Regimen for Children
First-Line Regimen
NNRTI choice:
Special Considerations for Pediatrics
Special Considerations for Pediatrics cont.
Clinical Assessment of Children on ARV Therapy
Clinical Treatment Failure
Definition of Clinical Treatment Failure
Clinical Treatment Failure cont.
Immunological Treatment Failure
Immune Reconstitution Syndrome (IRS)
IRS: Definition
IRS: Common Pathogens
IRS Management
Antiretrovirus Combinations to Avoid
.Antagonistic and additive side effect of anaemia
.More mitochondrial toxicity, particularly in adults
.May be permissible in children
.Reduced efficacy
.Same action, no additional activity
.Additive toxicity
Opportunistic Infections
Pneumocystis jiroveci, Candidiasis
Mycobacteria tuberculosis
Mycobacterial avium complex
Toxoplasma gondii, Cryptosporidia
Cytomegalovirus, Herpes simplex
Opportunistic Infections (contd)
Pneumocystis jiroveci pneumonia
Opportunistic Infections (contd)
Candidiasis
Opportunistic Infections (contd)
Tuberculosis
HIV and tuberculosis often co-exist.
Pediatric Cotrimoxazole Prophylaxis
recommended for:
- clinical features suggestive of HIV/AIDS and/or
- prior Pneumocystis jiroveci pneumonia and/ or
- evidence of immune dysfunction including:
Nutrition in HIV Children
Nutrition in HIV Children cont.
Psychological Support
PMTCT OF HIV
Factors increases the risk of HIV infections in women.
Comprehensive Approach to Prevention of HIV Infection in Infants and Young children.� Consists of Four elements.
.
1. Primary prevention
2. Prevention of unintended pregnancies among HIV +ve women
3. Prevention of HIV transmission from women infected with HIV to their infants
1.Modification of routine obstetric practices for all women => Accessibility and Affordability of ANC.
All medical persons involved in care management of pregnant women should be trained in VCT.
.
2. Specific modification of obst care for HIV +ve women-Should be given optimal care for safe delivery with focus on HIV related symptoms and illnesses.
.
D. Safer Infant –feeding practices Infant-feeding counseling for safer feeding practices.
4. Provision of treatment, care, and support to women infected with HIV, their infants and their family
Care and support of the infant and child who are HIV- exposed
Thank you for listening!�