The immunocompromised hose

Question 1

What is an immunocompromised host?

Answer 1

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

Question 2

What is the difference between primary and secondary immunodeficiency

Answer 2

Primary is congenital secondary is aquired

Question 3

Give an example of the disease which causes defect in a physical barrier leading to immunodeficiency

Answer 3

cystic fibrosis- mucous cannot be moved

Question 4

What features of infections in an individual suggest that they may have an immunodeficiency?

Answer 4

• Severe (life threatening infections)
• persistant (wont go away on normal treatment)
• unusual (infections most ppl wouldnt normaly get- aspergillius)
• Recurrant (keeps coming back)

Question 5

What are the main limitations of the 10 warning signs of someone with an immunodeficiency?

Answer 5

• lack of population based evidence (studies that created it are generally limited to specific conditions)
• different defects/ presenations
• non infectious manifestations

Question 6

What non- infectious manifestations are common in ppl with immunodeficiencies?

Answer 6

• autoimmunity
• malignancies
• inflammatory responses

Question 7

What are the 4 main classes of immuno deficiencies?

Answer 7

• antibody deficiencies (CVID, IgA deficiency)
• T and B cell deficiencies (SCID)
• phagocytic defects (chronic granulomatous disease)
• other odd ones

Question 8

What does onset of symptoms before 6 months suggest about a pts immunodeficiency?

Answer 8

Its a T cell or phagocyte defect

Question 9

What does onset of symptoms between 6 months and 5 yrs suggest about a pts immmunodeficiency?

Answer 9

b cell/ antibody or phagocyte defect

Question 10

What does onset of symptoms after 5yrs suggest about a pts immunodeficiency?

Answer 10

B cell, antibody, complement or a secondary immunodeficiency

Question 11

What diseases in general does t cell defects lead to?

Answer 11

• 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

Question 12

What diseases in general does phagocytes defect lead to?

Answer 12

• staph areus
• thrush
• aspergillus
• generally skin/ mucous infections

Question 13

What infections do complement deficiencies lead to?

Answer 13

• neisseria
• strep
• H. influenzae
  ENCAPSULATED bacteria
• no viruses, fungi ect

Question 14

What infections to antibody deficiencies lead to?

Answer 14

• strep and staph
• h. influenzae
• enteroviruses
• resp tract infections
• GI infections
• lots of malignancies and autoimmunities

Question 15

What cell is defective in SCID?

Answer 15

• T cells

- these needed to activate b cell so functional b cell deficiency also

Question 16

What is deficient in burtons disease/ XLA?

Answer 16

antibodies

Question 17

What is defect in chronic granulomatous disease?

Answer 17

phagocytes

Question 18

What is defect in common viral immunodeficiency (CVID)?

Answer 18

antibodies

Question 19

How can SCID be treated?

Answer 19

• haematopeotic stem cell transplant in first 3 and a hald months of life

Question 20

How can immunodeficiencies in general be managed?

Answer 20

• prophylaxis
• nutritional support (vit A and D)
• vaccines
• regular immunoglobulin therapy
• look out for and treat malignancies and autoimmunity swiftly
• avoid unnecessary radiation exposure

Question 21

What can cause secondary immunodeficiencies due to decreased production of immune components?

Answer 21

production MILLS:

• Malnutrition
• Infections (HIV)
• Liver diseases
• Lymphoproliferative diseases (chemo also decrease neutrophils)
• Splenectomy (due to infarct, trauma, autoimmune haemolytic diseases, tumour, coeliac, congenital)

Question 22

Why is the spleen so important in dealing with bacteria?

Answer 22

• 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

Question 23

What can cause secondary immune deficiencies due to loss or catabolism of immune components?

Answer 23

• protein losing conditions (nephropathy, enteropathy,)

- burns

Question 24

Aspergillus is a common infection in people who’re immunocompromised how does it present?

Answer 24

• 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

Question 25

What type of organism is aspergillus? Where does it normally reside?

Answer 25

• a fungi

- normally in the lungs and doesnt cause problems unless immunocompromised

Question 26

What organism causes chicken pox?

Answer 26

varicella- zoster

Question 27

What type of virus is varicella zoster? describe its structure

Answer 27

a herpes virus

enveloped, DS DNA

Question 28

How is herpes zoster spread?

Answer 28

person to person by casual contact via respiratory droplets

the vesicular fluid of the chicken pox rash is also contagious if it becomes airborne

Question 29

Describe the full course of a herpes zoster infection

Answer 29

• 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

Question 30

How long is the incubation period of herpes zoster and when are these pts infectious?

Answer 30

incubation= 10-14 days 
infectious = 1 to 2 days before symptoms

Question 31

How do you diagnose shingles?

Answer 31

clinical findings

sometimes cultures of vesicle fluid and insitu hybridisation of specific probes

Question 32

How is herpes zoster treated?

Answer 32

acyclovir