3. HIV and AIDS Flashcards
What type of virus is HIV?
Retrovirus
How many types of HIV are there?
HIV1 and HIV2
What is the counterpart of HIV2 called?
SIV- species of retrovirus found in non-human primates, found in sooty mangabey animals
What is the evidence that HIV causes AIDS?
HIV fulfils Koch’s postulates for infectious disease as a cause of AIDS.
- you can isolate the agent
- there is an epidemiological association between the infection and development of AIDS
- transmission pathogenesis- you can transmit the infection by injecting it into another organism
Which group of people have the highest risk of HIV?
Sex workers, gay men, people injecting drugs
What does a HIV molecule contain?
gp120, gp41, p24, p17, 2 copies RNA, integrase. reverse transcriptase
What is the mechanism of infection of HIV?
- gP120 attaches to chemokine of CD4 cells
- This causes the virus to merge its envelope with the cellular membrane which will enter the CD4 cell
- The virus will disassemble and RNA will be converted to DNA by reverse transcriptase
- Integration of viral DNA into host DNA by integrase
- Transcription by host RNA polymerase
- Assembly
- Viral budding
What are examples of HIV treatment?
Entry inhibitors
Integrase inhibitors
Protease inhibitors
Portmanteau inhibitors- both RT and integrase inhibitors
Reverse transcriptase inhibitors- nucleoside-analog RTI’s, nucleotide analogue RTI’s, non-nucleoside RTI’s
How is HIV transmitted?
Through exchange of blood or bodily fluids, sexual contact, injection, perinatally
What is the first stage of HIV infection?
Primary HIV infection
What is the second stage of HIV infection?
Occurs 3-6 weeks after primary HIV infection
- Includes acute HIV syndrome mononucleosis-like, plasma viremia
What is the third stage of HIV infection?
Occurs 1 week to 3 months after plasma viremia
HIV-specific immune response, seroconversion
Seroconversion is when the antibodies start appearing in the blood.
What is the fourth stage of HIV infection?
Occurs 1-2 weeks after seroconversion
Clinical latency, decline in CD4 cell count, PGL
What is PGL?
Persistent generalised lymphadenopathy- if there is no treatment for this, after 10 years you will get AIDS, then 2 years later will die.
What is the 5th stage of infection?
Occurs 10 years after PGL
Get clinically apparent disease, AIDS-defining illness, Aids-related complex
What is the final stage of infection?
Occurs 2 years after ARC
You get death from AIDS.
What is the normal CD4 T-cell count?
800-1050/mm3 with a range of 2 standard deviations of approximately 500-1400mm3
What is the normal total blood lymphocyte count?
530-2780
What is the normal CD8 cell count?
320-690
What is the normal CD4 to CD8 cell ratio?
0.9-3.2
What is the CD4 cell count to suffer from AIDS-related complex?
200-400/mm3
What are the constitutional symptoms of AIDS-related complex?
Fever, weight loss, diarrhoea, fatigue, night sweats, PGL
200-400/mm3
What infections can you get in AIDS-related complex?
Listeria, Herpes zoster, oral/vaginal candidosis, oral hairy leukoplakia
200-400/mm3
What CD4 count do you need for AIDS defining conditions?
Below 200/mm3
What are some opportunistic infections of AIDS defining conditions?
Mycobacterium turberculosis, pneumocystis carinii pneumonia, candidiasis of trachea, bronchi, lungs and oesophagus, herpes simplex, cryptococosis, cytomegalovirus, histoplasmosis, salmonella
What are examples of AIDS defining conditions of neoplastic disease?
Kaposi sarcoma, cervical carcinoma, Non-Hodgkin lymphoma
What are other diseases seen in AIDS defining conditions?
Thrombocytopenic purpura, HIV encephalopathy, wasting syndrome due to HIV, progressive multifocal leukoencephalopathy
What are associated oral manifestations of HIV/AIDS?
Hairy leukoplakia, ANUG, oral candidosis, Kaposi’s sarcoma, AIDS related gingivitis and periodontitis, recurrent herpetic infections
What are the candidal infections in HIV like?
Erythematous on palate and tongue
Pseudomembranous in any site
Median rhomboid glossitis
Can also see CHC in cheeks, commissures are rarely involved, unlike HIV seronegative
What is hairy leukoplakia?
Hair-like corrugated appearance of tongue, often seen bilaterally on lateral border of tongue, might contain candida but it is secondary
Not premalignant
What is the histology of hairy leukoplakia?
Depletion of Langerhan’s cells
No associated inflammatory cells
EBV identifiable in epithelial cells nuclei- stain brown
Increase in thickness of the epithelium
Parakeratinised epithelium
What is Kapsoi sarcoma caused by?
Kaposi sarcoma virus/HHV 8
Where is Kaposi sarcoma most commonly found?
On the face it is found on the tip of the nose
Orally it is most common on palate>gingiva>tongue
It looks red to violet in colour
What is the histology of Kaposi sarcoma?
Endothelial proliferation, cleft like vascular channels, erythrocytes, haemosiderin, inflammatory cells, atypical spindle cells
What can be used to stain endothelial cells?
CD31- stains endothelial cells brown
Can also do an antibody test against HHV8 or Kaposi sarcoma virus
What are AIDS related periodontal diseases?
Some association between HIV and severe PD
Increased attachment loss in HIV positive patients when CD4 is less than 200/mm3
Linear gingival erythema- at the margin of the gingiva there is redness
Acute necrotising stomatitis
Chronic adult periodontitis
What are the risk factors for ANUG?
Immunosuppression, deficiency, stress, bad diet, bad hygiene, smoking
What are the 3 things making up the fusospirochetal complex?
Spirochetes, pleomorphic rods, fusiform organisms
What are the 6 fusiform organisms?
- Treponema vincentii
- prevotella intermedia
- porphyromonas gingivalis
- selenomonas sputigena
- fusobacterium fusiformis
- leptotrichia buccalis
What does ANUG present like?
Halitosis, necrosis of interdental papilla with grey sloughing, pain, bleeding, metallic taste. Healing with disappearance of interdental papilla.
Malaise, fever, cervical adenopathy.
What is recurrent herpetic infection caused by?
HSV 1 (mostly oral) and HSV 2 (mostly genital)
What is the infection period of recurrent herpetic infection like?
Primary infection is subclinical
Prodromal period is 5 days- then start showing prodromal symptoms
Numerous vesicles ulcerate
Perioral lesions are seen due to serum coagulation
Herpetic whitlow
Herpetic keratitis in the eyes
What is the histology of herpetic infections?
Intraepithelial blister, ballooning degeneration
How do recurrent infections of Herpes occur?
The virus resides in the trigeminal ganglia and in mild infections, uv light, trauma, stress, menstruation, immune suppression/deficiency, the virus can infect again.
Associations of Herpes to other malignant diseases?
- Kaposi’s sarcoma
- squamous cell carcinoma (tongue)
- ano-rectal carcinoma (HPV)
- malignant transformation may be due to a transformation in cell membrane antigens such as CEA, alpha-fetoprotein, PSA
What are examples of HAART?
Reverse transcriptase inhibitors, eg. AZT prevent RNA reverse transcription
Protease inhibitors prevent cleavage of newly synthesised HIV proteins
What are side effects of HAART?
Perioral dysesthesia, dry mouth, oral melanosis
