Immunology and Allergies Flashcards
1
Q
kawasaki disease
A
- one of the most common vasculitides of childhood
- exact pathology not well understood
- probably abnormal immune response to some super-antigen
- epidemiology
- approximately 6 per 100,000 in U.S. children under 5 years
- peak age between 2 and 3 years
- rare over 7 years of age
- peaks between February and May
- highest incidence in Japan
- most common cause of acquired heart disease in children
2
Q
kawasaki disease criteria and disease phases
A
- diagnostic criteria
- fever for 5 or more days
- presence of 4 of the following:
- bilateral nonpurulent conjunctivitis with perilimbic sparing
- changes in the oropharyngeal mucous membranes
- extremity changes
- most often swelling and redness of the hands and feet
- rash (>80% of children)
- cervical adenopathy (>1.5 cm node, 70% of children)
- illness unexplained by other disease
- acute phase
- affected children are generally irritable
- abdominal pain is common
- hydrops of the gall bladder, CSF pleocytosis, arthritis and carditis can manifest in acute phase
- subacute phase
- thrombocytosis
- desquamation of groin, hands and feet
-
coronary aneurysms (up to 20% of untreated children)
- higher risk in boys, children with prolonged fever or inflammatory markers, age under 1 year
3
Q
laboratory changes in kawasaki disease
A
- ↑ WBC
- ↑ ESR, CRP
- anemia
- mild ↑ transaminases
- ↓ albumin
- sterile pyuria
- CSF pleocytosis
- ↑ platelets by day 10-14
4
Q
kawasaki disease diagnosis and differential diagnosis
A
- diagnosis
- based on clinical criteria
- echocardiography to search for cardiovascular complications
- myocarditis
- pericarditis
- evidence of coronary vasculitis
- Differential Diagnosis
-
viral exanthems
- measles, rubella, roseola, adenovirus, EBV
-
staphylococcal or streptococcal toxin-mediated syndrome
- staphylococcal scalded skin syndrome
- scarlet fever
- streptococcal toxic shock
- other
- meningococcemia
- drug reactions
- erythema multiforme
- Stevens-Johnson syndrome
- Reactive arthritis
- toxoplasmosis
- leptospirosis
- Rocky Mountain spotted fever
- systemic-onset juvenile rheumatoid arthritis
- polyarteritis nodosa
-
viral exanthems
5
Q
KD difficulties with diagnosis
A
- clinical diagnosis
- no single test is diagnostic
- Kawasaki disease remains a diagnosis of exclusion
-
atypical or incomplete Kawasaki disease also exists
- when illness does not fulfill all criteria
- more common in < 1 year and > 8 years
6
Q
kawasaki disease treatment
A
- admit to monitor cardiac function
- rule out other causes of similar diseases
- complete cardiac evaluation
- EKG and echocardiogram
-
IVIG (2 g/kg)
- reduces coronary aneurysm rate to <5%
- dose repeated once if symptoms persist or recur
-
aspirin
- high-dose for anti-inflammatory effect in first 24-96 hours
- low-dose for anti-thrombotic activity pending follow-up echocardiography for late-onset coronary aneurysms
- follow-up echocardiography in 6-8 weeks after IVIG
7
Q
when to suspect immunodeficiency
A
- Infections are VERY common in early childhood.
- 6 viral infections per year on average!
- But sometimes children DO have immune system disorders:
- So when should you be concerned?
8
Q
types of immunodeficiency overview
A
- Cell Mediated Immunity/T-cell and NK defects
- Antibody Mediated Immunity/B-cell defects
- Combined B and T cell
- Phagocytic Deficiency
- Complement Deficiency
9
Q
T cell defects
A
- Cellular immune system affected
-
Primarily viral, fungal and opportunistic infections
- Growth retardation, malabsorption, diarrhea, FTT
- Examples:
- HIV (acquired)
- DiGeorge, Wiskott Aldrich
- Screening tests of T cells:
- Absolute lymphocyte count and T cell count
- Intradermal skin test for candida albicans
- T cell and NK cell function testing
- Treatment: varies based on condition – thymic transplant, stem cell transplant
10
Q
B-cell defects
A
- Humoral Immune System affected –Antibodies
- Primarily bacterial infections – encapsulated organisms: Group A strep, strep pneumo, Haemophilus influenzae type B
- Otitis, Sinusitis, pneumonia (“sinopulmonary”
- Examples:
- Agammaglobulinemia, IgG, IgA deficiency, Common Variable Immunodeficiency (CVID can present later-in teens).
- Screening tests of B cell function:
- Absolute lymphocyte count and B cell count
- Quantitative tests of antibody production
- Titers to immunizations and isohemagglutinins– has the patient responded to vaccines, other blood types?
- Treatment
- Antibiotics, IVIG infusions
11
Q
Combined T and B cell defects
A
- Innate AND adaptive immune system affected
- Lots of infections of all kinds
- Examples:
- Severe Combined Immunodeficiency (SCID), Hyper IgM syndrome
- Screening tests:
- Both T cell and B cell screening abnormal
- Treatment: Bone Marrow Transplant
12
Q
phagocytic cell defects
A
- Phagocytic cells (NK cells, macrophages) do not work properly
- Bacterial infections: S. aureus, Gram negative
- Skin and soft tissue infections
- Examples:
- Leukocyte adhesion deficiency (LAD)
- Chronic Granulomatous Disease (CGD)
- Screening tests:
- Absolute Neutrophil Count
- Respiratory Burst Assay- (Nitroblue tetrazolium or DHR)
- Flow cytometry to check for LAD
- Treatment: Bone marrow transplant, future role of gene therapy?
13
Q
leukocyte adhesion deficiency
A
- Associated with delayed umbilical cord separation? (Maybe not says some research)
14
Q
complement defects
A
- Defects in the complement system
- Bacterial infections: meningococccal, pneumococcal
- Examples:
- C5,C6,C7,C8 deficiency
- Screening tests:
- CH50
Treatment: Supportive management - Immunizations
15
Q
low neutrophil count <1500
A
- Causes
- Acute infection – temporary marrow suppression
- Medications (penicillins, seizure meds, others)
- Autoimmune diseases
- Splenic sequestration
- Malignancy – Cancer cells replacing the functioning bone marrow.
- Chemotherapy
- B12, Folate deficiency
- Genetic and idopathic causes
