Immunodeficiencies Flashcards
How can you recognise patients who are immunocompromised?
S - severe ie life threatening
P - persistent
U - unusual - opportunist pathogens
R - recurrent
Define immunocompromised
State in which immune system is unable to respond appropriately and effectively to infectious microorganisms
Features of a primary immunodeficiency?
Caused by an intrinsic (immune defect)
Congenital or acquired
Relatively rare
Features of secondary immunodeficiencies?
Relatively common
Secondary to another condition
Acquired
What can a secondary immunodeficiency be caused by?
Infection (HIV) Malnutrition Liver disease Splenectomy Drug-induced neutropenia Lymphoproliferative diseases
What is neutropenia?
Abnormally low neutrophils in the blood, leading to increased susceptibility to infection
What can cause neutropenia?
Drugs Autoimmune neutropenia Bone marrow infiltration with malignancy B12/folate/iron deficiency Chemo-cytotoxic/immunosuppressant Chemical agents Radiotherapy
Management of suspected neutropenic sepsis?
Treat as acute medical emergency
Empiric antibiotics immediately
Assess risk of septic complications
What are asplenic patients more susceptible to? Give examples
Encapsulated bacteria
H influenzae
Streptococcus pneumoniae
N meningitidis
What are asplenic patients more at risk of?
Overwhelming post-splenectomy infection
-sepsis and meningitis
What do asplenic patients have to have?
Lifelong penicillin prophylaxis
Immunisation against encapsulated bacteria
Medical alert bracelet
What does the spleen do?
Immune function against blood-borne pathogens
Antibody production
- acute response: IgM
- long-term protection: IgG
Splenic macrophages
- remove opsonised microbes
- remove immune complexes
What can cause loss of catabolism of immune components and the fore secondary immunodeficiency?
Protein losing conditions eg nephropathy, enter ovary
Burns
What can primary immunodeficiencies be classified into?
B cell (50%)
Phagocytes (18%)
T cell (30%)
Complement (2%)
When are primary deficiencies normally seen?
First few months of life
What are the B cell deficiency types?
Common variable immunodeficiency (CVID)
IgA deficiency
Bruton’s disease (X-linked agammaglobulinaemia)