Flashcards in The Immunocompromised Host Deck (109):
What is meant by immunocompromisation?
State in which the immune system is unable to respond appropriately and effectively in infectious microorganisms
What is immnocompromisation due to?
A defect in one or more components of the immune system
What can infections suggest?
An underlying immune deficiency
When can infections suggest an underlying immune deficiency?
If they meet the criteria of SPUR
What is in the SPUR criteria?
What is considered to be a severe infection?
What is considered to be a persistent infection?
Minimal response to standard treatment
What factors may be considered unusual in an infection?
Type of microbe
What site might be considered unusual in an infection?
What type of microbe may be considered unusual in an infection?
What is meant by a recurrent infection?
Returns regularly after treatment
What are the types of immunodeficiency?
What kind of conditions are primary immunodeficiencies?
What are primary immune deficiencies due to?
Intrinsic cell defect
How many intrinsic cell defects are there causing primary immunodeficiencies?
What can intrinsic cell defects lead to in primary immune deficiencies?
What kind of conditions are secondary immunodeficiencies?
What are secondary immune deficiencies due to?
Underlying disease/treatment leading to ;
Decreased production/function of immune components
Increased loss or catabolism of immune components
Do primary immune deficiencies affect the innate or adaptive immune system?
Can be either
What conditions have a decreased production of immune components as a result of a secondary immune deficiency?
What are the functions of the spleen?
Sensing blood borne pathogens
Removal of opsonized microbes and immune complexes
What blood borne pathogens does the spleen especially sense?
What antibodies does the spleen produce?
When does the spleen produce IgM?
When does the spleen produce IgG?
Long term response
How does the spleen remove opsonised microbes and immune complexes?
By splenic macrophages
How does someone with a splenectomy present?
Increased susceptibility to encapsulated bacteria
Overwhelming post-splenectomy infection
What bacteria are asplenic people susceptible to?
What is the risk of death from post-splenectomy infection?
1-2% risk of death from overwhelming sepsis/meningitis over 15 years
How is a person with a splenectomy managed?
Lifelong penicillin prophylaxis
Immunisation against encapsulated bacteria
Medic alert bracelet
What can an increased susceptibility to infections in haematological malignancies be due to?
Chemotherapy induced neutropenia
Chemotherapy induced damage to mucosal surfaces
Vascular catheters penetrating innate immune barriers
How should a suspected neutropenia sepsis be treated?
As an acute medical emergency, with empiric antibiotics
Assess a patients risk of septic complications
What can an increased loss or catabolism of immune components be due to?
Protein losing conditions
Give two protein losing conditions
What gives the large spectrum of primary immune deficiencies (PIDs)?
Different clinical phenotypes
How many PIDs are there?
What is needed regarding PIDs?
Better diagnostic criteria
Why is a better diagnostic criteria needed for PIDs?
General failure to recognise and diagnose PIDs
When are most PIDs diagnosed?
~8-12 years from onset of symptoms
What % of patients will be 18 years old + when diagnosis is made?
What % of patients will have permanent tissue/organ damage by the time a diagnosis is made?
What can help recognise PIDs?
The 10 warning signs
What are the 10 warning signs of PID for children?
4 or more new ear infections within 1 year
2 or more serious sinus infections within 1 year
2 or more months on antibiotics with little effect
2 or more pneumonias within 1 year
Failure of an infant to gain weight or grow normally
Recurrent, deep skin or organ abscesses
Persistent thrush in mouth, or fungal infections on skin
Need for intravenous antibiotics to clear infections
Two or more deep-seated infections including septicaemia
A family history of PID
What are the 10 warning signs of PID for adults?
2 or more new ear infections in 1 year
2 or more new sinus infections within 1 year in the absence of allergy
One pneumonia per year for more than 1 year
Chronic diarrhoea with weight loss
Recurrent viral infections (colds, herpes, warts, and condyloma)
Recurrent need for intravenous antibiotics to clear infections
Recurrent, deep abscesses of the skin or internal organs
Persistent thrush or fungal infections on skin or elsewhere
Infection with normally harmless tuberculosis-like bacteria
A family history of PID
What are the limitations of the 10 warning signs?
Lack of population-based evidence that can aid diagnosis
PID patients have different defects/presentations
PID patients with non-infectious manifestations
What population based evidence is there regarding the warning signs for PID?
Study on children concluded that 96% of PIDs could be diagnosed with the '3 warning signs'
What are the 3 warning signs that a study says 96% of children with PID can be diagnosed based on?
Failure to thrive
Diagnosis of sepsis treated with IV antibiotics
What is the problem with the 3 warning signs when diagnosing PID?
It does not take into account PIDs in adults - the largest proportion of people with PID
Found not to be good at diagnosing antibody deficiencies
Give 4 examples of deficiencies leading to PIDs?
How can PID patients have different presentations?
Some infections have subtle presentations
What PID patients may have a noninfectious manifestation?
Does the distribution of malignancies among primary immunodeficiency disorder subgroups vary?
How can the types of PID be identified?
Age at symptom onset
Types of microbes
Sites of infection
What does a PID onset of <6 months highly suggest?
A T-cell or phagocyte defect
What does a PID onset of >6 months and <5 years often suggest?
A B-cell/antibody or phagocyte defect
What does a PID onset of > 5 years and later in life usually suggest?
A B-cell/antibody/complement or secondary immunodeficiency
What bacteria are associated with a complement deficiency PID?
Other encapsulated bacteria
What bacteria are associated with phagocytic defect PIDs?
What fungi are associated with phagocytic defect PIDs?
What bacteria are associated with antibody deficiency PIDs?
What viruses are associated with antibody deficiency PIDs?
What protozoa are associated with antibody deficiency PID?
What bacteria are associated with T cell defect PIDs?
Similar to antibody deficiencies, but also include;
What viruses are associated with T cell defect PIDs?
What fungi are associated with T cell defect PIDs?
What protozoa are associated with T cell defect PIDs?
What sites of infection are complement deficiencies associated with?
What complement deficiency is associated with pyogenic infections?
What complement deficiency is associated with meningitis/sepsis/arthritis?
What sites of infection are associated with phagocyte defects?
Deep seated infections
Invasive fungal infections
What invasive fungal infection is associated with phagocyte defects?
What sites of infection are associated with antibody deficiencies?
What will T cell defects lead to if not treated?
Failure to thrive and death
What sites of infection are associated with T cell defects?
Deep skin and tissue abscesses
What are the classes of primary immunodeficiencies?
Predominantly antibody deficiencies
Combined T and B cell
Other cellular immunodeficincies
What % of PIDs are predominantly antibody deficiencies?
Give 5 predominantly antibody deficiency PIDs
Autosomal recessive agammaglobulinaemia
Common variable immunodeficiency (CVID)
Selective IgA deficiency
IgG subclass deficiency
What % of PIDs are combined T and B cells?
Give 2 combined T and B cell deficiencies
What % of PIDs are phagocytic defects?
Give 3 phagocytic defects
Chronic granulomatous disease
Severe congenital neutropenia
What % of PIDs are other cellular immunodeficiency
Give 4 other cellular immunodeficiencies
Hyper IgE syndrome
Why is it important to consider the pattern of family history with PIDs?
To help identify any possible X-linked conditions
Give an example of an X-linked PID?
How will patients with CGD often present?
With pulmonary aspergilliosis and skin infections
How are PIDs managed?
Avoid non-essential exposure to radiation
Assess organ damages
What are the supportive treatments for PID?
Treat infection promptly and aggressively
Use UV-irradicated CMVneg blood products only
Avoid live attenuated vaccines in patients with severe PIDs
How are infections prevented in PID?
What nutritional support is given in PID?
Vitamins A and D
What are the specific treatments for PID?
Regular immunoglobulin therapy
Avoid non-essential exposure to radiation
Assess organ damages
What is the aim of regular immunoglobulin therapy in PIDs?
Get serum IgG > 8g/l
How can immunoglobulin be administered?
IV or SC
What is regular immunoglobulin therapy used for?
Does aspergillus cause disease?
Does not usually cause disease in immunocompetent, but major problem for immunocompromised
What is aspergillusosis?
An opportunistic fungal infection
Where can aspergillus be found?
In most buildings
What can aspergillus inhalation cause?
Can cause aspergillosis in the lungs
What happens to the varicella-zoster virus in immunocompetent individuals?
It is kept in the latent phase by T cell surveillance after chickenpox infection
When may the VSV virus be reactivated?
When there is an altered T-cell response or number in immunodeficient patients
What does the reactivation of the VSV virus cause?
When does shingles usually appear in healthy patients?
Usually in aging patients (thought to be linked to reduced T cell responses)
What are the potential sites of infection of S. aureus?
Skin and soft tissue
Diseases caused by toxins
What skin and soft tissue infections are caused by S. Aureus?
Wound infection (traumatic or surgical)
What respiratory infections can be caused by S. Aureus?
What musculoskeletal infections can be caused by S. Aureus?
What cardiovascular infections can be caused by S. Aureus?
What genitourinary infections can be caused by S. Aureus?
Lower urinary tract infections