Approach to Hypersensitivity/Autoimmune Topics

Question 1

Type I Hypersensitivity Steps

Answer 1

Ag exposure

IgE cross link on mast cells

Histamine, leukotrienes, prostaglandins, tryptase released

symptoms of urticaria, rhinitis, wheezing, diarrhea, vomit, hypotension & anaphylaxis (w/ in min of exposure)

Question 2

When does the reaction occur in type 1 hypersenstivity?

Answer 2

immediate, w/ in min of expsoure

symptoms can return 4-8 hrs after exposure

Question 3

What are some examples of type 1 hypersensitivities?

Answer 3

pollen allergies, dust mite allergy, bee sting

Question 4

What helps to treat type 1 rxns?

Answer 4

anti-histamines

Question 5

What is type 2 cytotoxic hypersensitivity?

Answer 5

IgM or IgG antibody destroys cells by:

opsonization
complement-mediated lysis
AB depend cell cytotoxicity

Question 6

What are examples of type 2 hypersensitivity?

Answer 6

ABO mismatch, Grave’s disease, myasthenia gravis

Question 7

What is the pathology of myesthenia gravis?

Answer 7

antibodies to ACH receptor which prevents Ach from binding (type 2)

IgM or IgG causing destruction

Question 8

Steps for Type 3 Hypersensitivity

Answer 8

Ag-Ab complex formation

Complexes activate complement & neutrophil infiltration of tissue

Tissue inflammation

Question 9

What are symptoms of tissue inflammation in type 3?

Answer 9

fever, urticaria, lymph node swelling, arthritis, glomerulonephritis, vasculitis

Question 10

What are the steps of Type 4 hypersensitivity?

Answer 10

Ag exposure activates T cells

T cell activation leads to tissue inflammation

Question 11

When do symptoms start in Type 4?

Answer 11

48-96 hours after exposure to antigen

Question 12

What are examples of type 4?

Answer 12

poison ivy rash, PPD testing for TB

delayed reaction

Question 13

What is an autoimmune condition?

Answer 13

characterized by an immune response against something that is normally found in the body

Question 14

What is rheumatoid arthritis?

Answer 14

systemic inflammatory disease affecting synovial membranes

granulation tissues develops in joint spaces & erodes into articular cartilage/bone

females>males

Question 15

How does RA present?

Answer 15

joint swelling, warmth, erythema, decreased ROM

morning stiffness > 1 hr

PIP, MCP, wrist, knees & ankles affected

Question 16

How do you differentiate RA from OA?

Answer 16

symptoms of RA: affects metacarp joints, no Herbeden’s nodes, joints are soft & warm, stiffness worse after resting

symptoms of OA: distal joints affected, present w/ Herbeden’s nodes, joints are hard & bony, stiffness worse w/ effort

Question 17

What is common in RA?

Answer 17

MCP joint swelling w/ boutonniere deformities bilaterally

erosions of joints on X rays

Question 18

What are complications assoc w/ RA?

Answer 18

increased risk of infection from immunosuppression

2x increase in incidence/mortality from leukemia or lymphoma

increased risk of CVD

Question 19

What is juvenile idiopathic arthritis?

Answer 19

collagen vascular disorder w/ persistent inflammation in 1 or more joints for 6 or more week sin pts<16 yo

Question 20

How does pauciarticular JIA present?

Answer 20

affects large joints, asymmetric

inflammation involves ciliary body

uveitis (eye inflammation)

Question 21

How does polyarticular JIA present?

Answer 21

large & small joints, symmetric

Question 22

How does systemic JIA present?

Answer 22

recurrent high fevers

myalgias, pericarditis, lymphadenopathy

anemia, leukocytosis

Question 23

What is a complication of systemic JIA?

Answer 23

50% pts develop destructive arthritis (complete resolution is rare)

Question 24

What is SLE?

Answer 24

inflammatory disorder that females>males

recurrent exacerbations & remissions secondary to auto-AB formation & immune complex deposition (type 3)

Question 25

What is the genetic component of SLE?

Answer 25

HLA DR2 & DR3

Question 26

How does SLE present & what is needed for diagnosis?

Answer 26

``` Pleuritis Oral ulcers Arthritis Photosensitivity Hemolytic anemia Proteinuria/urinary cell casts Positive ANA Postivie anti-dsDNA Lupus cerebritis/seizures Malar rash Discoid rash ``` need at least 4 of manifestations

Question 27

How do you distinguish between RA & SLE?

Answer 27

in SLE, erosions in joints are rare & morning stiffness only lasts few min & deforming arthritis is uncommon in RA, ESR & CRP are SIGNIFICANTLY elevated

Question 28

What usually causes mortality in SLE pts?

Answer 28

end organ damage opportunistic infections secondary to immunosuppression

Question 29

What is psoriasis?

Answer 29

chronic, hyper-proliferative inflammatory disorder characterized by thick adherent scales

Question 30

How does psoriasis present?

Answer 30

``` mild pruritus salmon pink plaques w/ adherent silver-white scale extensor surface involvement nail pitting *genetic component ```

Question 31

How do you diagnose psoriasis?

Answer 31

history & PE (Auspitz sign w/ pinpoint bleeding after removal of scale)

Question 32

What are complications assoc w/ psoriasis?

Answer 32

``` CVD malignancy diabetes HTN metabolic syndrome IBD serious infections other autoimmune disorders ```

Question 33

What is MS?

Answer 33

demyelinating disorders of CNS, females>males & develops from 20-40yo

Question 34

How does MS present?

Answer 34

``` vision changes (1st sign) vertigo weakness numbness/tingling/pain urinary incontinence/retention Lhermitte's sign ```

Question 35

What is Lhermitte's sign?

Answer 35

electrical sensation running down spine & LE w/ neck flexion + for MS

Question 36

How is MS diagnosed?

Answer 36

MRI | CSF (spinal tap)

Question 37

What are examples of primary immunodeficiencies?

Answer 37

T cell specific B cell specific T/B cell combined Phagocytic disorders

Question 38

What are clinical signs that suggest primary immunodeficiency disease?

Answer 38

+ family history infections in many anatomical locations increasing frequency & severity of infections w/ age recurrent serious infections w/ common pathogens serious infections w/ unusual pathogens

Question 39

T cell primary immunodef

Answer 39

disseminated intracellular disease that presents in 3-4 months of life DiGeorge syndrome

Question 40

B cell primary immunodef

Answer 40

present @ 6 months of age when maternal antibodies disappear, show sinopulmonary & GI infections CVID

Question 41

T/B cell combined primary immunodef

Answer 41

combo of T cell & B cell features SCID

Question 42

DiGeorge Syndrome presentation

Answer 42

22q11 deletion thymic aplasia (absent thymic shadow on Xray) hypoparathyroidism & hypocalcemia (tetany & seizures)

Question 43

CVID presentation

Answer 43

defect in B cell maturation present w/ lymphadenopathy & splenomegaly

Question 44

SCID presentation

Answer 44

onset @ 3 months of age w/ diarrhea, pneumonia, otitis, sepsis failure to thrive

Question 45

Phagocytic primary immunodef

Answer 45

sinopulmonary & soft tissue infections Chediak Higashi syndrome

Question 46

Chediak Higashi syndrome

Answer 46

defect in microtubular function that leads to decreased phagocytosis partial oculocutaneous albinism, progressive neuropathy

Question 47

HIV/AIDS pathogenesis & presentation

Answer 47

spreads thru transmission of body fluids initially asymptomatic & then have flu-like symptoms: ``` myalgias fever anorexia headache/fatigue pharyngitis ```

Question 48

How is HIV/AIDS diagnosed?

Answer 48

ELISA screen Western blot confirmation HIV RNA viral load

Question 49

What is important to ask about in new patient appointment?

Answer 49

ask about past HIV screen b/c all pts btwn ages 13-64 need to be screened for HIV at least once

Question 50

How is AIDS diagnosed?

Answer 50

CD4 count<200 cells presence of an AIDS-defining illness

Question 51

What are AID defining illnesses?

Answer 51

cytomegalovirus mycobacterium avium-intracellulare candidal esophagitis