Immunocompromised Host Flashcards
What is an immunocompromised host?
State in which the immune system is unable to respond appropriately and effectively to infectious MO
In general what is the cause of immunodef?
Defect in one or more components of the immune system: innate or adaptive
A def in which cell would cause a more severe immune system def?
B cell
What is primary vs sec immunodef?
P = congenital: intrinsic gene defect S = acquired: underlying disease/treatment
When should you suspect immunodef?
S = severe P = persistent U = unusual R = recurrent
What is an opportunistic infection?
- infectionthat takes advantage of an opportunity not normally available, such as a host with a weakened immune system, an altered microbiota (such as a disrupted gut flora), or breached integumentary barriers.
- Example = herpes virus
What is SCID?
- Severe combined immunodef
- T cell and B cell def
What does immunodef increase the risk of?
Infection, Cancer/malignancies
What is CVID?
- Common viable immunodef
- High risk of cancer
What is selective IgA def?
Quite prevalent but most asymptomatic
In regards to immunodef, outline phagocytic defects?
- Chronic granulomatous disease CGD = count fine, function defective (skin infect, pulmonary aspergillosis)
- Severe congenital neutropenia
How does the age on onset link to the type of primary immunodef?
- <6 months = T cell or phagocyte defect
- > 6 months – 5 years = B cell/Ab or phagocyte defect
- > 5 years = B cell/Ab/complement or secondary immunodef
What infection are complement def associated with?
Bacterial
What infections are phagocytic defect associated with?
Bacterial and fungal
What infections are Ab def associated with?
Bacterial, viral, protozoa
What infections are T cell defect associated with?
Bacterial, viral, fungal, protozoa
How does different defs in complement link with infection type?
- C3 = pyogenic
- C5-C9 = meningitis/sepsis/arthritis
- C1 = angiooedema
Outline how immunodef can be managed
- Supportive = infect prevention,immunisation, vits, blood products, avoid live attenuated vacs
- Specific = Ig therapy, SCID – hematopoietic stem cell therapy
- Manage comorbidities = lung function assessment
What is Ig replacement therapy?
- Donor Ig
- Goal IgG >8g/l
- Life long treatment
What is the main cause of immunodef worldwide?
Malnutrition
What causes secondary immune def?
Decreased prod of immune components = Malnutrition, infection, liver disease, lymphoproliferative diseases, splenectomy, loss/catabolism of immune components
Why is the spleen so important?
- Encapsulated bacteria
- Ab prod
- Splenic macrophages
What types of treatment increase the susceptibility to infections?
- Chemo-induced neutropenia
- Chemo-induced damage to mucosal barriers
- Vascular catheters
In what situations and illnesses is a patient immunocompromised?
- Chemo
- HIV
- Broken barriers
What are the lab investigations for immunodef?
- General = FBC, differential
- Humoral = Igs, levels specific to vaccines, test immunisation
- Cell mediated = lymphocyte count/subsets, T cell function
- Phagocytic cells = neutrophil count
- Complement
