Infection - Immunocompromised Host

Question 1

What is an immunocompromised host?

Answer 1

A state in which the immune system is unable to respond appropriately and effectively to infectious microorganisms

Question 2

What is the difference between primary and secondary immunodeficiency?

Answer 2

Primary immunodeficiency is congenital, and due to an intrinsic gene defect. Secondary immunodeficiency is acquired, and due to an underlying disease/treatment

Question 3

What are the characteristic signs of an immunodeficiency?

Answer 3

Infections which are:

• severe
• persistent
• unusual
• recurrent

Question 4

What are the ‘10 warning signs’ used for?

Answer 4

They are used to diagnose an immunodeficiency

Question 5

Give some limitations of the ‘10 warning signs’ for diagnosing immunodeficiencies

Answer 5

• lack of population based evidence
• PID patients may have different defects/presentations
• PID patients may have non-infectious manifestations

Question 6

What may be defective if the onset of ID symptoms comes younger than age 6 months?

Answer 6

A T-cell or phagocyte defect

Question 7

What may be defective if the onset of ID symptoms comes between age 6 months and 5 years?

Answer 7

B-cell or antibody and phagocyte defect

Question 8

What may be defective if the onset of ID symptoms comes when the patient is 5 years old or older?

Answer 8

B-cell/antibody/complement problem OR a secondary immunodeficiency

Question 9

What is chronic granulomatous disease?

Answer 9

This is a hereditary disease where certain cells in the immune system are unable to form the reactive oxygen species (specifically the superoxide radical) which are used to kill ingested pathogens

Question 10

Give some examples of supportive treatments for PID diseases

Answer 10

• infection prevention
• treat infections promptly and aggressively
• nutritional support
• no live vaccines!

Question 11

Give some examples of specific treatments for primary immunodeficiency diseases

Answer 11

• immunoglobulin therapy

- in SCID, can do haematopoietic stem cell therapy

Question 12

Give some causes of secondary immune deficiencies

Answer 12

Decreased production of immune components due to:

• malnutrition
• infection
• liver diseases
• lymphoproliferative diseases
• splenectomy

Question 13

What are asplenic patients particularly at risk of?

Answer 13

Encapsulated bacteria infection and OPSI (overwhelming post-splenectomy infection)

Question 14

How are asplenic patients protected from infection?

Answer 14

• penicillin prophylaxis (life-long)
• immunisation against encapsulated bacteria
• medic alert bracelet

Question 15

What does it suggest if someone constantly has problems with viruses and fungi?

Answer 15

T cell deficiency

Question 16

What does it suggest if someone constantly has problems with bacteria and fungi?

Answer 16

B cell/granulocytes deficiency