The Immunocompromised Host Flashcards
Define what an immunocompromised host is
A state in which the immune system is unable to respond appropriately and effectively to infectious microorganisms due to a defect in one or more components of the immune system
What are the two types of immunodeficiency and describe the types
Primary - congenital defect, intrinsic gene defect causes a protein or cell to be missing, or there to be non-functional components
Secondary - acquired defect, underlying disease/treatment causes decreased production/function of immune components or increased loss/catabolism of components
Which mnemonic is used when identifying immunodeficiency
SPUR
Severe
Persistant
Unusual
Recurrent
What are the 10 warning signs used for and how are they used, and what are some limitations of its use
Used to recognise and diagnose PID, need at least two of them
Limitations:
Patients do not always present with normal symptoms of PID
PID patients can have non-infectioud manifestations, i.e. malignancy
What are the main malignancies seen in patints with PID
Adenocarcinoma
Hodgkin disease
Leukaemia
Lymphoma
What are the four catagories of PID
Predominantly antibody deficiencies
Combined B and T cell
Phagocytic defects
Other cellular immunodeficiencies
Name a type of antibody deficiency
Common variable immunodeficiency (CVID)
Name a type of combined B and T cell deficiency and describe it
Severe combined immunodeficiency (SCID) - T cell defect which causes a B cell defect as they are not activated by T cells, also causes antibody deficiency as B cells not activated
Name a type of phagocytic defect and describe it
Chronic granulomatous disease - patients lack enzyme for oxygen dependent killing in phagocytes
Name a PID classified under other cellular immunodeficiencies and describe it
DiGeorge syndrome - baby is born without developed thyroid or parathyroid galnds
How can PID be determined by age of symptom onset (classify the defects on age of onset)
Onset < 6 months - T cell or phagocyte defect
5 years > onset > 6 months - B cell/antibody defect or phagocytic defect
Onset > 5 years - B cell/antibody/complement defect or secondary immunodeficiency
Name the types of microbes that present with T cell defects
Bacteria; strep and staph. Intracellular bacteria non-tuberculous mycobacteria, salmonella typhi
Viruses; all viruses.
Fungi; candida, cryptococcus neoformans, aspergillus spp.
Protozoa; toxoplasma gondii.
Failure to thrive, deep skin and tissue abscesses, opportunistic infections
How are PIDs managed
Supportive - infection prevention (prophylactics), treat infections promtly, nutritional support, avoid live attenuated vaccines in severe PID patients
Specific - regular immunoglobulin therapy
What comorbidities can develop in patients with PID
Autoimmunity
Malignancies
Organ damage
Name some causes of secondary ID that decrease production of immune components
Malnutrition
Infection
Liver disease
Lymphoproliferative diseases
Splenectomy
