Clinical Medicine Flashcards
What are the 10 warning signs of primary immunodeficiency
- 4 or more new ear infections within 1 yr
- 2 or more serious sinus infections w/in 1 yr
- 2 or more mnths on abx with no effect
- 2 or more pneumonias w/in 1 yr
- Failure of an infant to gain weight
- Recurrent, deep skin/organ abscesses
- Persistent thrush in mouth or fungal infection on skin
- Need for IV ABX to clear infections
- 2 or more deep-seated infecting including septicemia
- A family hx of PI
Think Zebra campaign
The immune deficiency foundation started a campaign to promote awareness of PI. Meaning that although PI is less common, it is often not suspect. “when you hear hoofbeats, think of horses not zebras
According to the zebra campaign what are the signs that may point to primary immunodeficiency
- Persistent
- Unusual
- Recurrent
- Runs in family
What does SCID stand for
Severe Combined immunodeficiency. Not a single disease but is a group of diseases caused by different defects in genes
What are the cell deficiencies in SCID
- Absent or extremely low production of naive T cells from thymus
- Defects of T and B cells, # and function
- Sometimes absent NK cells
All 3 of these leads to infants who are severely compromised in fighting infection (which leads to many deaths)
How is SCID treated if recognized early
With hematopoietic cell transplantation (HCT) aka bone marrow transplant. This supplies B and T cells to system
When do infants typically show signs of SCID
At about 4-7mnths. The first few months they are protected by passive transfer of maternal antibodies
What are clinical presentations that suggest a presumptive diagnosis of HIV
- Pneumocystis pneumonia
- Esophageal candidiasis
- Kaposi sarcoma
- CNS lymphoma
- TB
- Toxoplasmosis
At what level of CD4 cells is it considered AIDS
Below 200 cells/mcL.
What is the epidemiology of HIV
- Modes of transmission include sex, parenteral and vertical transmission (needle sticks)
- Receptive anal has highest risk (1:30-100)
- If open wounds with sex higher risk
- Needle sticks (1:300)
- -increased risk in uncircumised
What is the risk of mom to baby transfer of HIV
13-40% risk of infection when mother has not received treatment or baby has not received perinatal HIV prophylaxis. Higher risk with vaginal delivery
What is the most common mode of transmission of AIDS for men and women world wide
Heterosexual spread. Highest in central/east africa
What co receptors are necessary for HIV entry into a cell
CCR5 - chemokine co receptors. These are located on the CD4 cells that the virus binds to
During HIV, B cells and macrophages are also infected, what effect does this have on the immune system
Because B cells need CD4 cells to induce proliferation, a lack of CD4 means a decrease in B cell antibody production. This can lead to hypergammaglobulinemia. This is a big reason why HIV patients are so susceptible to infection. Macrophages can disseminate to other organ system and carry the virus with it (i.e. CNS)
Orthotropic grafts
Tissue/organ that is placed in their normal anatomic location
Heterotopic grafts
Grafts that are placed into a site other than their normal one
Autografts
Grafts that are transferred from one part of an individual to another location on that same individual
Syngeneic grafts
Grafts transferred between 2 people who are almost identical (i.e. twins)
Allogeneic or allografts
Grafts transferred between 2 genetically disparate individuals of the same species (brother sister, parent child)
Xenogeneic grafts
Grafts that are exchanged between members of different species (i.e. primate heart into a human)
What is the major cause of host donor graft rejections
The MHC molecules differ between a host and a recipient which causes an immune attack against the foreign molecule. Can be the host cells that attack or the recipient cells that attack
How does graft rejection work (pathophysiology)
The genes of the graft tissue may encode “non self” molecules that will be detected by the recipient immune system. These become “antigens” to recipient and the CD8 cells (mostly) will bind to the MHC complex and kill new foreign graft cells
What are the 3 stages of rejection
- hyperacute
- acute
- chronic
2/3 establish blood flow. 1 does not
How do antibodies play a role in blood transfusion
natural antibodies (aka antibodies that are found in the body due to natural exposures) provide an attack on transferred blood. This is why the blood type has to match, other wise you get a reaction
How do antibodies play a role in graft transplant
Antibodies are made by B cells that attack against histocompatibility antigens on graft tissue. This is usually only seen in the hyper acute rejections
What is the main treatment for transplantation
Immunosuppression - involves blocking the general immune response (not specific)
What are 2 immunosuppressive techniques
- Irradiation
2. Toxic drugs that eliminate immune response
What are some risk factors associated with immunosuppression (long term)
- May be open to opportunistic infections
- Liver damage - extended use
- Secondary malignancy
- Increased risk of CV disease due to chronic inflammatory state
How does stem cell transplant work (hematopoietic)
Transplanting bone marrow from an immunocompetent person into an immunodeficient person
How does graft versus host disease occur (GVHD)
- Immunocompetent cells of donor recognize MHC antigens in the recipient as foreign and attack.
- Attack also stems from mature T cells. May be able to remove this before transplant in order to prevent
Host attacks recipient