The immunocompromised hose Flashcards
What is an immunocompromised host?
a person who’s immune system is unable to respond apropiatly and effectively to infectious microorganisms- usually as a result of one or more components of the immune system
What is the difference between primary and secondary immunodeficiency
Primary is congenital secondary is aquired
Give an example of the disease which causes defect in a physical barrier leading to immunodeficiency
cystic fibrosis- mucous cannot be moved
What features of infections in an individual suggest that they may have an immunodeficiency?
- Severe (life threatening infections)
- persistant (wont go away on normal treatment)
- unusual (infections most ppl wouldnt normaly get- aspergillius)
- Recurrant (keeps coming back)
What are the main limitations of the 10 warning signs of someone with an immunodeficiency?
- lack of population based evidence (studies that created it are generally limited to specific conditions)
- different defects/ presenations
- non infectious manifestations
What non- infectious manifestations are common in ppl with immunodeficiencies?
- autoimmunity
- malignancies
- inflammatory responses
What are the 4 main classes of immuno deficiencies?
- antibody deficiencies (CVID, IgA deficiency)
- T and B cell deficiencies (SCID)
- phagocytic defects (chronic granulomatous disease)
- other odd ones
What does onset of symptoms before 6 months suggest about a pts immunodeficiency?
Its a T cell or phagocyte defect
What does onset of symptoms between 6 months and 5 yrs suggest about a pts immmunodeficiency?
b cell/ antibody or phagocyte defect
What does onset of symptoms after 5yrs suggest about a pts immunodeficiency?
B cell, antibody, complement or a secondary immunodeficiency
What diseases in general does t cell defects lead to?
- very serious infections
- all viruses
- trush, aspergillus, cryptococcus (fungi)
- many bacteria inc salmonella typhi, listeria as well as strep and staph, h. influenza
- deep skin abcesses
- failure to grow/ thrive
What diseases in general does phagocytes defect lead to?
- staph areus
- thrush
- aspergillus
- generally skin/ mucous infections
What infections do complement deficiencies lead to?
- neisseria
- strep
- H. influenzae
ENCAPSULATED bacteria - no viruses, fungi ect
What infections to antibody deficiencies lead to?
- strep and staph
- h. influenzae
- enteroviruses
- resp tract infections
- GI infections
- lots of malignancies and autoimmunities
What cell is defective in SCID?
- T cells
- these needed to activate b cell so functional b cell deficiency also
What is deficient in burtons disease/ XLA?
antibodies
What is defect in chronic granulomatous disease?
phagocytes
What is defect in common viral immunodeficiency (CVID)?
antibodies
How can SCID be treated?
- haematopeotic stem cell transplant in first 3 and a hald months of life
How can immunodeficiencies in general be managed?
- prophylaxis
- nutritional support (vit A and D)
- vaccines
- regular immunoglobulin therapy
- look out for and treat malignancies and autoimmunity swiftly
- avoid unnecessary radiation exposure
What can cause secondary immunodeficiencies due to decreased production of immune components?
production MILLS:
- Malnutrition
- Infections (HIV)
- Liver diseases
- Lymphoproliferative diseases (chemo also decrease neutrophils)
- Splenectomy (due to infarct, trauma, autoimmune haemolytic diseases, tumour, coeliac, congenital)
Why is the spleen so important in dealing with bacteria?
- it is the main centre for fighting blood bourne diseases
- by filtering blood and phagocytosing opsonised microbes
- as welll as producing antibodies for opsonisation of encapulsated bacteria
What can cause secondary immune deficiencies due to loss or catabolism of immune components?
- protein losing conditions (nephropathy, enteropathy,)
- burns
Aspergillus is a common infection in people who’re immunocompromised how does it present?
- often initially as inflammation of mouth with superficial ulcers
- with fever
- develops into cough and high resp rate
- large pulmonary nodules can be seen on CXR
What type of organism is aspergillus? Where does it normally reside?
- a fungi
- normally in the lungs and doesnt cause problems unless immunocompromised
What organism causes chicken pox?
varicella- zoster
What type of virus is varicella zoster? describe its structure
a herpes virus
enveloped, DS DNA
How is herpes zoster spread?
person to person by casual contact via respiratory droplets
the vesicular fluid of the chicken pox rash is also contagious if it becomes airborne
Describe the full course of a herpes zoster infection
- goes into respiratory mucosa
- spreads to lymphnodes and replicates
- then spreads to liver and spleen
- then to endothilial cells and finally epithilal cells resulting in chicken pox
- remains latent for life in nerve bodies and becomes reactivated when immunodeficient, it then travels down nerves to epidermis where is causes shingles in dermatomal distributions
How long is the incubation period of herpes zoster and when are these pts infectious?
incubation= 10-14 days infectious = 1 to 2 days before symptoms
How do you diagnose shingles?
clinical findings
sometimes cultures of vesicle fluid and insitu hybridisation of specific probes
How is herpes zoster treated?
acyclovir
