Lecture 16 - Immunocompromised Host Flashcards

1
Q

What is Bronchiectasis?

A

The irreversible widening of airways (makes more susceptible to infection)

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2
Q

What can lead to Bronchiectasis?

A

Unrecognised/undiagnosed Primary Immunodeficiencies

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3
Q

What is the definition of an immunocompromised host?

A

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

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4
Q

What are the 2 types of immunity that could be affected in an immunocompromised host?

A

Cell mediated immunity (Cytotoxic response)

Humoral immunity

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5
Q

Why can a T cell defect (Cell mediated immunity)) lead to a B cell defect (Humoral immunity)?

A

Helper T cells are needed to activate B cells

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6
Q

What are the 2 ways a host can by immunocompromised?

A

Primary immunodeficiency
Secondary immunodeficiency

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7
Q

What is primary immunodeficiency?

A

Congenital/gene defect leads to immunodeficiency in hosts

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8
Q

What are the general ways a patient can have primary immunodeficiency?

A

Missing protein (cytokines or receptors)
Missing cells
Non-functional components

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9
Q

What are the general ways a patient can have secondary immunodeficiency?

A

Its acquired (not born with)

Disease (e.g HIV)

Treatment:
(Chemotherapy-can end up getting febrile neutropenia)
Asplenic patients (encapsulated bacterial infection)
Organ transplant

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10
Q

WHat are some examples of granulocytes?

A

Neutrophils
Eosinophils
Basophils

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11
Q

What type of immunity is compromised in immunodeficent patients who have T cell or B cell deficiency?

A

Adaptive immunity

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12
Q

What pneumonic do you use to determine if an infection suggests a possible immunodeficiency?

A

SPUR

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13
Q

What does SPUR stand for when describing an infection that may suggest immunodeficiency?

A

Severe
Persistent
Unusual
Recurrent

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14
Q

What is meant by an infection being described as Severe?
SPUR (Possibly immunocompromised)

A

Life threatening
So if not treated patient will die

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15
Q

What is meant by an infection being described as Persistent?
SPUR (Possibly immunocompromised)

A

Despite recommended treatment the infection persists

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16
Q

What is meant by an infection being described as Unusual?
SPUR (Possibly immunocompromised)

A

The site of infection is unusual (e.g deep tissues)
The type of microorganism is unusual (opportunistic infections e.g Candida albicans , shingles)

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17
Q

What is meant by an infection being described as Recurrent?
SPUR (Possibly immunocompromised)

A

Multiple episodes/multiple infections

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18
Q

What is a key identifier/presentation of a T cell deficiency?

A

Failure to thrive (growth, cant put on weight)

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19
Q

What non infectious manifestations are patients with Primary Immunodeficiency more likely to get?

A

Autoimmune diseases
Malignancy

Inflammatory responses

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20
Q

What types of defects cause Primary immune deficiency (PID)?

A

Antibody defects
T cell defects
Phagocytotic defects

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21
Q

What is an example of a defect in B cell development that leads to an antibody defect?

A

Bruton’s disease

B for Brutons disease
B for B cell development defect leading to antibody defect

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22
Q

What type of inheritance is Bruton’s disease?

Who are more likely to get Bruton’s disease?

A

X-linked inheritance

Males more likely to get it

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23
Q

What are 2 examples of defects in antibody production (PID)?

A

CVID (Common Variable Immunodeficiency)
Hyper-IgM syndrome

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24
Q

What is CVID (Common Variable Immmunodeficiency)?

A

NEEDS TREATMENT (MOST COMMON PRIMARY ANTIBODY DEFICIENCY)

B cells present but dont function properly

25
Q

What are patients with CVID (Common variable immunodeficency) highly susceptible to?

A

Malignancy
Autoimmune diseases

26
Q

What 3 questions do you need to ask when suspecting a Primary Immunodeficency?

A

Is there complement?
Is the complement in the correct amount?
Is the complement functional?

27
Q

What is an example of a T cell defect where a gene affecting T cell maturation and function is affected?

A

Severe Combined Immunodeficiency (SCID)

28
Q

What is Severe combined immunodeficiency (SCID)?

A

When a gene affecting T cell maturation/function (defect) leads to a B cell defect
Since the T cell defect also affects the B cells it’s COMBINED

29
Q

What type of defect is Di George syndrome?

A

T cell defect

30
Q

How does Digeorge syndrome lead to a T cell defect?

A

There is aplasia or hypoplasia of the thymus which is where T cells mature

31
Q

What can go wrong in phagocytic defects?

A

Defects in respiratory burst

Defect in fusion of lysosome/phagosome

Defect in neutrophil production and chemotaxis

32
Q

What is an example of a disease where theres a defect in respiratory burst?

A

Chronic Granulomatous Disease (CGD)

33
Q

What is defective in Chronic Granulomatous Disease (CGD)?

A

NADPH Oxidase
Therefore can do respiratory burst to destroy pathogens

34
Q

What is an example of a disease where theres a defect in the fusion of lysosomes or phagosomes?

A

Chediak-Higashi syndrome

35
Q

What type of defect is suggested when a patient has presentation of Primary Immunodeficiency diseases BEFORE age of 6MONTHS?

A

T cell defect
Or
Phagocyte defect

36
Q

What type of defect is suggested when a patient has presentation of Primary Immunodeficiency diseases between the ages of 6 months and 5 years old?

A

B-cell antibody defect
Phagocyte defect

Think that after 6 months mothers antibodies would have depleted so likely a B-cell antibody defect

37
Q

What type of defect is suggested when a patient has presentation of Primary Immunodeficiency diseases at 5 years or OLDER?

A

B-cell/antibody/complement
Secondary immunodeficiency

38
Q

What type of bacterial infections are people with a Complement deficiency as there immune defect vulnerable to and why?

A

Encapsulated bacteria (NHS):
Neisseria species
Haemophilus influenzae
Streptococci (pneumoniae)

Since complement is needed to opsonise encapsulated bacteria so phagocytosis can occur

39
Q

What are the 2 most common Neisseria species that a complement deficient individual may get?

A

Neisseria meningitidis
Neisseria gonorrhoeae

40
Q

What infections are individuals with phagocytotic defects likely to get?

A

Staph a
Candida spp

(Skin/mucous infections
Deep seated infections)

41
Q

What type of infections are common in individuals with an antibody defect?

A

Sino-respiratory infections
GI infections
Malignancies
Autoimmunity

42
Q

Why are GI infections and Sino-respiratory infections common in people with antibody deficiency?

A

The antibody IgA is produced at mucosal surfaces and provides protection there

If no IgA made you are vulnerable to infection at these surfaces

43
Q

What type of infections are common with defects in T cells?

What are the key ways that T cell defects infections are described?

A

Deep skin and tissue abscesses
Opportunistic infections

Failure to thrive
Death if not treated

44
Q

Check the Clinical cases for practice questions in the lecture from Slide 18.

A

..

45
Q

How does a HRCT (High Resolution CT) appear in a patient with Chronic Granulomatous Disease (CGD)?

A

Halo signs

46
Q

What supportive treatment can be given to manage Primary Immunodeficiency?

A

Infection prevention (prophylactic anti microbials)
Nutritional support (Vit A/D)

47
Q

How do you treat somebody if they have a Primary antibody deficiency or PID?

A

Immunoglobulin replacement therapy = Serum IgG as a lifelong treatmet

48
Q

What are some examples of conditions that you’d treat with Immunoglobulin replacement therapy?

A

All of the antibody defects

CVID
Brutons disease
Hyper-IgM syndrome

49
Q

What are some common causes of secondary immune deficiencies which cause decreased production of immune components?

A

Malnutrition (often in the elderly)
Infection (HIV)
Haematological malignancies
Splenectomy

50
Q

What can be tested for if you suspect protein is being lost?

A

Albumin

51
Q

What is an example of a way secondary immune deficiency can occur?

A

Loss of immune components (excess)
E.g nephropathy, enteropathy

52
Q

Why are patients with haematological malignancies more likely to get infections?

A

Chemotherapy-induced neutropenia
Chemotherapy-induced damage to mucosal barriers
Vascular catheters

53
Q

How does chemotherapy damage to mucosal barriers make infection more likely?

A

Mucositis leads to normal flora being able to invade the mucosal barrier

54
Q

What bacteria are likely to invade the body via a vascular catheter?

A

Staphylococcus epidermidis
Staphylococcus Saprophyticus

55
Q

What is febrile neutropenia?

A

When episodes of fever coincide with time of low levels of neutrophils

56
Q

How dangerous is febrile neutropenia?

A

Very serious
Acute medical emergency

57
Q

What common form of primary antibody deficiency doe not require treatment?

A

IgA

58
Q

What causes hyper IgM syndrome?

A

T cell defect of CD40L