Infections in the Immunocompromised Host Flashcards
What types of pathogens typical infect immunocompromised people?
Endogenous flora
Hospital acquired infections
Environmental organisms
Opportunistic pathogens e.g. CoNS, aspergillus
Primary immunodeficiency is more common than secondary immunodeficiency. T/F?
False - the opposite is true
Why are we seeing increased numbers of immunocompromised patients?
Advances in modern medicine leads to improved survival at extremes of life, improved cancer management, developments in transplant techqnieues, developments in intensive care, management of chronic inflammatory conditions and the use of steroids.
Isolated immunodeficiencies are rare. T/F?
True - a malfunction in one part of the immune system often influences another
What are the possible causes of neutropenia?
Cytotoxic chemotherapy
Therapeutic irradiation
What immune deficiency is the most important risk factor for infection?
Neutropaenia
How is neutropenia defined?
<0.5x10^9/L
What treatments can result in neutrophil function disruption?
Cytotoxic drugs
Irradiation
Steroids
Give examples of pathogens which take advantage of poor neutrophil function?
S.aureus Coagulase negative staphylococci Strep.viridans Enterococci Bacteroides Clostridia E.coli Pseudomonas Klebsiella Enterobacter
What type of inheritance does chronic granulomatous disease follow?
X linked
What is the cause of chronic granulomatous disease?
A defect in the gene coding for NADPH oxidase resulting in deficient production of oxygen free radical and defective intracellular killing.
What is the result of chronic granulomatous disease?
Recurrent bacterial and fungal infections
Abscesses in the lung, lymph nodes and skin
Pulmonary infection is common in chronic granulomatous disease. What organisms typically cause pulmonary infection in this case?
Aspergillus
S.aureus
Nocardia
What conditions/treatments can suppress cellular immunity?
Di George syndrome Malignant lymphoma Cytotoxic chemotherapy Extensive irradiation Immunosuppressive drugs Allogenic stem cell transplantation Infections
What conditions/treatments can cause humeral immunity?
Bruton agammaglobulinaemia
Decreased antibody production in lymphoproliferative disorders
Intensive chemotherapy or radiotherapy
Humoral immunity is usually preserve in acute leukaemia. T/F?
True
Disrupted splenic function can lead to increased infection with which organisms?
Encapsulated organisms such as strep.pneumoniae, haemophilia influenzae type b and neiserria meningitidis
How is severe nutritional deficiency defined?
<75% ideal body weight or rapid weight loss combined with hypoalbuminaemia
What are the signs and symptoms of severe nutritional deficiency?
Anorexia, nausea, vomiting, mucositis, metabolic derangements, compromise in integrity of host defences
What affect does iron deficiency have on the immune system?
Reduce microbicidal capacity of neutrophils
Reduces T cell function
Obstruction by a tumour can lead to infection. Which organ is particularly susceptible to this?
Lung
How does stress affect immune function?
Reduces T cell function
How does diabetes mellitus affect immune function?
Reduces opsonisation and chemotaxis
What factors can reduce the risk of infection in solid organ transplant?
optimal tissue typing donor evaluation organ procurement good surgical technique tailored immunosuppressive regimens
Give examples of common latent donor-derived infections in solid organ transplant.
TB
Syphillis
Viruses such as HIV, hepatitis B and CMB
In solid organ transplant, active blood stream infection at procurement can be caused by. which organisms?
Staphylococci, pneumococci and salmonella
Reactivated infections in solid organ transplant can occur. What are the common causative organisms of this?
M.tuberculosis
HSV
CMV
VZV
When can neutropenic fever develop?
In solid tumours
Non, leukaemia haematological malignancies
Acute leukaemia
What are the most common pathogens to infect patients with neutropenic cancer?
Gram negative aerobic bacteria
