case 5 Flashcards
Innate immune
Produces non specific immune response ● Does not use antibodies ● Examples are Skin, Hair, Stomach Acid, and Inflammatory response ● First line of defense
inflammation response
Inflammation Mechanism 1) Injury occurs 2) Signaling molecules cause vasodilation 3) Increased diameter allows for increased permeability of immune cells
cells of innate 5
Leukocytes: white blood cells (Ex. Neutrophils, Lymphocytes, Monocytes, Eosinophils,
and Basophils)
● Dendritic Cells: present antigens and attack pathogens
● Macrophages: present antigens and attack pathogens
● Interferons: secreted by infected cells in order to signal nearby cells of danger
● Natural Killer Cells: activated by interferons and attack cells
adaptive immune system
Uses antibodies ● Initiates specific immune responses ● Uses B cells and T cells ● Uses major histocompatibility complex I & II to identify cells and antigens ○ MHC I= all nucleated cells ○ MHC II= antigen presenting cells
B cells adaptive
Plasma Cell: Create antibodies
2. Memory B Cell: Stored by body for future immune response
5 types of antibodies
● IgM - Made first and is replaced later by IgG
● IgA - Found in secretions (Ex. Breastmilk)
● IgG - Most abundant
● IgE - Cause allergic responses
● IgD - Unknown function and made in small
amounts
antibodies
Antibodies: glycoproteins that recognize a specific antigen ● Mark pathogen for destruction by other immune cells ● Are presented to T Cells ● In some cases can lyse cells or neutralize toxins ● Activates complement system ○ Complement system: enhances immune response by phagocytizing pathogens with a group of proteins
adaptive T helper cells
(CD4) ● Stimulate release of antibodies in B cells ● Increase innate and adaptive immunity ● Can become T memory cells that are used for future immune response ● Serve as a precursor to Cytotoxic T cells
adaptive cytotoxic t cells
(CD8)
● Attack specific antigen
● Use perforins and granzymes to cause apoptosis in cells
● Can become T suppressor cells to provide negative feedback on the immune system
● Antigens are presented by macrophages, B cells, and dendritic cells
Require an antigen presenting cell
○ Macrophages, B cells, and
Dendritic cells
● MHC I = CD8 cells
● MHC II = CD4 cells
● After being presented with an antigen, T cell recognizes only that specific antigen
HIV aids`
HIV: Human Immunodeficiency Virus that leads to a weakened immune system
● AIDS: Acquired immunodeficiency syndrome that leads to many life-threatening
conditions and illness as a result of HIV
● HIV leads to AIDS
HIV I
Common form & easy to transmit
● Develops into AIDS quicker
● 4 groups
4 Groups of HIV I
- M group
a. Makes up 90% of cases
b. 9 strains (A, B, C, D, F, G, H, J, & K) - N group
a. Rare and only found in Cameroon - O group
a. Very rare - P group
a. Newest group
HIV II
Rare ● Harder to transmit ● Takes longer to develop AIDS ● Mostly in West Africa ● Makes up 0.01% of cases in the USA ● No subgroups or strains
HIV structure 6
Capsid: holds RNA
● Enzymes: performs steps of the life cycle
● RNA: holds genetic material
● Envelope: outer surface that protects virus
● Glycoproteins: found on surface of virus
● Retrovirus (uses reverse
transcriptase)
conversion from mature to immature HIV
Done by viral proteases cleaving a long protein chain ● Cleaving of chain makes virus infectious and mature ● Mature virus is able to continue life cycle and replicate
life cycle of HIV
Binding to CD4 receptor
- Fusion through membrane
- Reverse Transcription
- Integration into cell genome
- Replication via cell machinery
- Assembly & creation of more HIV
- Budding of HIV
Acute infection
(2-4 weeks) ● Virus count is high ● Patient has flu like symptoms ● Life cycle repeats quickly and CD4 cells are being attacked ● Easy to transmit Fever, rash, sores, fatigue, swelling, and weight loss ● Lasts for a couple weeks
c hronic infection
(many years) ● Also called asymptomatic HIV infection ● HIV continues to repeat life cycle but at a slower rate ● Can take up to several decades ● Patient may not know they are living with HIV Asymptomatic at first, weight loss, prone to infections, fatigue, and swelling (lymph nodes) ● Worsens over time
AIDS progression (stage 3)
Immune system is severely damaged ● Virus is present in large amounts ● Opportunistic infections become extremely dangerous to patients ● CD4 count of less than 200 cells/mm3 Rashes, bumps, persistent fatigue, weight loss, prone to infections, and weakness ● Signs/symptoms are the most severe
Virus transmission
Exit - leaving the infected person 2) Survive - withstand temperature, heat, acidity, and moisture 3) Sufficiency - make enough copies in new host 4) Entry - enter the bloodstream and cause further infection
HIV transmission
Sex
● Sharing Needles
● Bodily fluids (Ex. Blood)
● Pregnancy
RISK Unprotected Sex ● Having other STIʼs ● Sharing needles ● Lack of sterilizing equipment ● Needle stick injuries
Nucleic Acid Tests (NAT):
tests blood for presence of virus by looking for nucleic acids
● Expensive and only used in high-risk exposure scenarios (10-33 days after exposure)
Platelet levels
Platelet levels should be tested for prior to invasive procedures
○ Measured using a platelet count (PC)
○ Platelet count should be above 60,000 cells/mL
■ If below, consult with the patientʼs physician prior to an invasive procedure to
determine the need for a platelet infusion.
treatment
There is currently no cure for HIV
● Treatment is usually done to control HIV and minimize its presence in the body
● Antiretroviral therapy (ART) is used to treat patients
○ Aimed to reduce the viral load, while keeping CD4 T cell levels high.
○ Can reduce transmissibility
○ Administration of ART does not prevent the transmission of other STDʼs.
● Best protection is offered by a combination of 3 ART medications
● Usually taken daily
○ Inconsistently taking medication may lead to drug resistance.
ART
To treat HIV/AIDS, patients are often given a class of antiretroviral drugs called reverse
transcriptase inhibitors
● Targets retroviruses
● Prevents conversion of RNA into DNA
● Prevents proliferation of virus
● Not a cure
● 2 types - Nucleoside/nucleotide and non-nucleoside/nucleotide
NRTI Nucleoside/nucleotide reverse transcriptase
Stop reverse transcription by incorporating with the viral DNA ● abacavir (Ziagen) ● lamivudine (Epivir) ● stavudine (Stavudine) ● zidovudine (Retrovir) ○ Effective at stopping transmission in around 70% of pregnant patients
Non-nucleoside reverse transcriptase inhibitors
NNRTIs
Inhibit reverse transcription by binding directly to the reverse transcriptase enzyme ● doravirine (Pifeltro) ● efavirenz (Sustiva) ● etravirine (Intelence) ● nevirapine (Viramune) ● rilpivirine (Edurant)
Protease inhibnitors + side effects
Bind to the active site of enzymes needed for the maturation of HIV ● Total of 10 FDA approved protease inhibitors ○ Examples are Ritonavir, Nelfinovir, and Amprenavir Side effects of Protease Inhibitors ● Dyslipidemia: elevated levels of cholesterol and triglycerides ● Insulin resistance ● Cardiovascular disease ● Can lead to toxicity
ART and cd4 and viral load
Without ART
● Viral load ultimately exceeds CD4 count
● AIDS can develop much quicker
With ART
● CD4 count remains higher than viral load for
much longer
side effects of art
Nausea and vomiting ● Diarrhea ● Difficulty sleeping ● Dry mouth (Xerostomia) ● Headache ● Nausea ● Rash ● Dizziness ● Fatigue
Post-Exposure Prophylaxis
Taken after an exposure to HIV in order to prevent its transmission ● Must be taken within 72 hours of exposure ● Treatment lasts 28 days ● Prevents transmission in 80% of cases ● Nausea is a common side effect
HIV TREATMENT IS
MONEY
Dental Patient Management
HIV/AIDS patients should be able to tolerate most routine dental procedures
● Perform comprehensive intraoral soft tissue, periodontal, and hard tissue
examination
● If there is a presence of HIV in the oral cavity, first priority is to relieve pain and
treat infections
● Procedures should minimize bleeding
● Consult physician if needed
more procedures
Invasive procedures (extractions and endodontics) should be cautioned
○ An effort to reduce bleeding during procedures should be made
○ Especially important if patient has low platelet count
○ HIV/AIDS patients are immunocompromised. Antibiotic prophylaxis should be considered to reduce
chances of infection
● Routine procedures like dental restorations (implants, fillings) have not shown to
pose greater risks to HIV/AIDS patients.
Dental Setting Precautions
Gloves (should never be reused) ● Protective eyewear ● Mask ● Safe handling/disposal of sharp objects (needles) ● Disposal of all PPE ● Sterilization ● Administer post-exposure prophylaxis within 72 hours if exposure occurs
dental sterilization
HIV can be transmitted by dental tools ● Autoclaves are used to sterilize dental equipment and eliminate viruses like HIV ● All dental tools must be disinfected, as well as heat sterilized
Antigen Antibody Test:
Looks for antigens and antibodies of HIV in the patient
● Most common (18-45 days after exposure)
Antibody Test: Only looks for antibodies in the patient
● Most rapid tests for HIV fall under this category (23-90 days after exposure)
CD4 Count test:
normal patients have between 500-1200 cells/mm3, less than 200 indicates onset of AIDS
Viral Load:
Test for copies of RNA ● Less than 20 is ideal ● Less than 10,000 is low ● Over 100,000 is high ● Patients can have counts of over 1 million
CD4 T cell levels
CD4 T cell levels should be tested for prior to invasive procedures
○ If less than 50 cell/mm3, consider antibiotic prophylaxis in order to prevent opportunistic disease.
○ Emphasize good oral health care post-procedure to prevent opportunistic disease.
■ Patient should inform dentist immediately if any unusual pain or discomfort
occur post-procedure.
○ Neutrophil count less than 500 cell/mm3 may also warrant antibiotic prophylaxis
■ Measured using absolute neutrophil count (ANC)
