Paediatric Immunology Flashcards
1
Q
When should vaccines be postponed?
A
Vaccination should be postponed if acute illness; Minor infection without fever or systemic features is not contraindication
2
Q
Which vaccines should not be given to immunocompromised patients?
A
Live Vaccines should not be given to immunocompromised patients – BCG, MMR, Varicella, Nasal Flu, Rotavirus
3
Q
6in1 Vaccine
A
Diphtheria, Tetanus, Pertussis, HiB, Polio = DTaP/IPV/HiB/HepB) at 2, 3 and 4/12
4
Q
Polio Vaccine
A
Live polio (Sabin) no longer used due to risk of polio in the vaccinated patient and unvaccinated family members/immunocompromised Can cause Asceptic Meningitis and Paralytic Poliomyelitis
5
Q
Diphtheria
A
Local disease with membrane formation affecting Nose, Pharynx, Larynx or Systemic disease with Myocarditis and Neurological manifestations
6
Q
Pertussis Vaccine
A
Whopping cough; Pregnant women now recommended to get dTaP/IPV from 20wks gestation
7
Q
What other vaccines are given at 2,4 and `12 months
A
Pneumococcal Conjugate Vaccine (PCV13) and Meningococcal B
8
Q
Which vaccines is given at 2 and 3 months
A
Rotavirus Oral Vaccine
9
Q
What vaccines are given at 1year
A
Booster HiB and Meningococcus C
10
Q
Which vaccine is given at 1 year and 3yr4months
A
MMR at 1yr and 3yr4mths
o MMR vaccine can cause mild form of disease 7-10/7 later
11
Q
When is HPV vaccine given
A
HPV at girls aged between 12-13yrs,
12
Q
Which vaccine is given from 14 years
A
Meningococcal ACWY at 14yrs
13
Q
When is BCG given?
A
BCG given to newborns at high risk of TB infection
o Main value is prevention of Disseminated disease (E.g. Meningitis)
14
Q
When HepB vaccine given?
A
Hep B at birth for babies born to HBsAg positive mothers; If born to highly-infectious HBeAg mothers, receive HB Ig at birth
15
Q
When is varicella vaccine given?
A
May be given to siblings of at-risk children (E.g. Undergoing Chemotherapy)
16
Q
Signs of Immunodeficiency
A
o Recurrent (proven) bacterial infections, Severe infections (Meningitis, Osteomyelitis, Pneumonia), Atypical/Unusually Severe/Chronic/Resistant disease, Unexpected pathogen, Severe long-lasting warts or generalised Molluscum contagiosum, Extensive Candidiasis, Complications following live vaccination, Abscesses, Diarrhoea
17
Q
Primary Immunodeficiency
A
(Uncommon); Genetically determined defect of the Immune System
o Many are X-linked or Autosomal Recessive; FMHx might include consanguinity, unexplained death, especially of boys
o Considered in children with Severe, Prolonged, Unusual or Recurrent infections
18
Q
Secondary Immunodeficiency
A
(More common); Disease or treatment related, such as Malignancy, Chemotherapy, Malnutrition, HIV infection, Immunosuppression, Splenectomy or Nephrotic Syndrome (Loss of immunoglobulins in the urine)
19
Q
T Cell Defect Presentation
A
Severe, Unusual Viral and Fungal Infections E.g. Bronchiolitis, Diarrhoea, Oral Thrush, PCP, CMV Infection
20
Q
T Cell Defects: Diseases
A
- Severe Combined Immunodeficiency
- HIV Infection
- Wiskott-Aldrich; X-linked; Plus, Thrombocytopaenia and Eczema
- DiGeorge Syndrome (Athymus)
- Duncan Disease (X-linked Lymphoproliferative Disease)
- Ataxia Telangiectasia
21
Q
B Cell Defect Presentation
A
After Infancy, when maternal Ig wears off; Severe Bacterial infections (Ear, Sinus, Pulmonary, Skin), Recurrent diarrhoea, Pneumonia to Bronchiectasis
22
Q
B Cell Defects Diseases
A
- X-linked Agammaglobulinaemia (Bruton); Abnormal TK essential for B cell maturation
- Common Variable Immunodeficiency – B-cell deficiency; risk of Autoimmune disorders and malignancy; Later onset than Bruton
- Hyper IgM Syndrome – Class switching failure
- Selective IgA Deficiency – Most common primary immune defect; Usually asymptomatic, but can cause recurrent ear, sinus and pulmonary infections
23
Q
Neutrophil Defects: Presentation
A
Recurrent Bacterial Infections, Abscesses, Poor wound healing, Perianal and Periodontal infections; Invasive Fungal
24
Q
Neutrophil Diseases
A
Chronic Granulomatous Disease – X-linked mostly but can also be AR; Failure to produce superoxide after phagocytosis
• Chediak-Higashi Syndrome – Failure of phagocytosis
25
Leukocyte Function Defects: Presentation
Delayed umbilical cord separation, Wound healing, Chronic skin ulcers
26
Leukocyte Function Defects: Diseases
Leukocyte Adhesion Defects – Inability for Neutrophils to migrate to sites of infection
27
Complement Defects: Presentation
Recurrent bacterial infections, SLE-like illness, Recurrent Encapsulated (Meningo, Pneumo, HiB)
28
Complement Defects: Disease
* Early and Terminal Complement Component Deficiencies
| * MBL Deficiency
29
Investigations into T Cell Defects
FBC, T cell subsets (CD3+ Total, CD4+ Helper, CD8+ Cytotoxic); T-cell proliferation in response to Mitogen
30
Investigations into B cell Defects
Ig levels (IgG, IgM, IgA, IgE), IgG subclasses (in children >2yrs), Specific antibody responses, Lymphocyte subsets
31
Investigation into SCID
Specific genetic/molecular tests
32
Investigation into Neutrophil Defects
FBC, Nitroblue-Tetrazolium Test, or newer assays for superoxide production (Abnormal in CGH), CD11b/CD18 expression in LAD, Chemotaxis tests
33
Investigation into Complement Defects
Tests for Classical and Alternative Complement Pathways, Assays for Complement proteins, MBL levels
34
Management of Primary Immunodeficiency: Antimicrobial Prophylaxis
Co-Trimoxazole to prevent PCP, Itraconazole/Fluconazole for other fungal infections for T and Neutrophil Defects; Antibiotics for B cell defects
Prompt treatment of infections; Longer courses, lower threshold for IV Abx
35
Management of Primary Immunodeficiency: Screening
Screening for End-organ disease e.g. HRCT for Bronchiectasis
36
Management of Primary Immunodeficiency: Ig Replacement
For Ig Deficiencies; via CVC or Subcut
37
Management of Primary Immunodeficiency: BMT and Gene Therapy
For SCID, CGD; Sibling donor, Matched unrelated or Parental transplant (Haploidentical)
Currently in development
38
What is an allergy
Hypersensitivity Reaction initiated by Specific Immunological Mechanisms; IgE mediated (e.g. Peanut allergy) or non-IgE (e.g. Coeliac)
39
What is hypersensitivity
Objectively reproducible response following exposure to defined stimuli at dose tolerated by most people
40
What is atopy
Tendency to produce IgE in ordinary exposure to potential allergens
o Associated with Asthma, Allergic Rhinitis, Conjunctivitis, Eczema, Food Allergy
41
Aetiology of allergy
Multigenetic; Polymorphisms or mutation can lead to susceptibility; Developing Immune system needs to be sensitized before response develops, which can be occult
42
Common Allergens
o Common allergens include Aeroallergens (HDM, Pollen, Dander, Moulds), Ingestants (Cow’s Milk Protein, Nuts, Soya, Egg, Wheat etc), Insect stings, Drugs, Latex
43
IgE Mediated Response
Early phase (release of Histamine and other Mast Cell Mediators) of Urticaria, Angioedema, Sneezing, Vomiting, Bronchospasm, Shock; followed by Late phase after 4-6hrs of Nasal congestion, Cough, Bronchospasm
44
Hygiene Hypothesis
Lower risk of allergy in rural environments; Altered microbial ex posure in modern life possibly leading to increase in allergic disease
45
The Allergic March
Eczema and Food Allergy usually in Infancy; Allergic Rhinitis, Conjunctivitis and Asthma in Preschool and Primary years; Asthma might follow
46
Signs of Allergy
Mouth Breathing/Snoring/Sleep Apnoea, Pale swollen Turbinates, Hyperinflation, Atopic Eczema (Limb flexures), Allergic Conjunctivitis, Blue-green discolouration of lower eyelids
47
Anaphylaxis
Severe, Life-threatening, Generalised or Systemic Hypersensitivity Reaction; Sudden onset, Progressive Life-threatening Airway, Breathing and Circulatory Arrest
o Skin, Mucosal signs of Urticaria, Angioedema
o 85% in children due to Food Allergy; IgE mediated reactions with cardiorespiratory compromise; Other causes are Insect stings, Drugs, Latex, Exercise, Aeroallergens
• Most occur in children under 5yrs age where food allergy is most prevalent
• Most deaths occur in adolescents with nut allergy
48
Anaphylaxis: Long Term Management
Detailed strategies and training; Allergen avoidance, Treatment of Allergic Reactions, Adrenaline Auto-injectors; Preventative Allergen Immunotherapy
49
Anaphylaxis ABCDE Assessment
* ABCDE Stabilisation
* Diagnosis – Acute onset Airway (Swelling, Hoarseness, Stridor), Breathing (Tachypnoea, Wheeze, Cyanosis, Desaturating), Circulation (Pale, Clammy, Hypotensive, Drowsy, Comatose)
50
Emergency Management of Anaphylaxis
• Call for help; Sit up if difficulty breathing, Supine and Elevated legs if Hypotensive; Recovery position if unconscious; BLS/ALS resuscitation if needed
• IM Adrenaline 1:1000 IM
• Definitive Airway, High Flow O2, IV Fluids (20ml/kg Crystalloid), Chlorphenamine IM/slow IV, Hydrocortisone IM/slow IV, Salbutamol if wheeze
o Monitor SpO2, ECG, BP
51
Food Allergy
Food allergy occurs due to pathological immune response against specific food protein; Mostly IgE-mediated
52
Food Intolerance
Non-immunological hypersensitivity
| Non-IgE food allergy occurs hours after ingestion and involves GI disturbances
53
Food Allergy Presentations in Paediatrics
Food allergy most commonly primary, reacting to first exposure; Presentation variable
o Infants – Milk, Eggs and Peanut; Older Children – Peanut, Tree Nut, Fish, Shellfish
• Can also be secondary due to cross-reactivity between Proteins and Pollens (e.g. Apple and Birch Tree Pollens); also called Pollen Food Allergy Syndrome; Itchy mouth but not systemic
54
Food Aversion
Refusal for Psychological or Behavioural Reasons
55
IgE Mediated Food Allergy: Symptoms
Urticaria, Facial Swelling up to Anaphylaxis; Occurs 10-15 mins, up to 2hrs after ingestion
56
Non IgE Mediated Food Intolerance: Symptoms
Diarrhoea, Vomiting, Abdominal Pain, Colic or Eczema might be present; Sometimes bloody stools due to Proctitis
57
Food Protein Induced Enterocolitis Syndrome
Repetitive Vomiting leading to Shock
58
Management of Food Allergy: Investigations
Clinical History, Skin Prick Testing and Specific IgE blood tests; Negative SP makes IgE mediated allergy unlikely;
For non-IgE; Endoscopy/Biopsy can identify Eosinophilic infiltrates
• Gold standard – Food exclusion followed by double-blind controlled incremental challenge
59
Management of Food Allergy: Treatment
Avoidance of relevant foods, Paediatric dietitian advice, Education, Drug Management (Non-sedating Antihistamines, Adrenaline Auto-injector)
60
Atopic Eczema
Dermatitis: With IgE antibodies to common allergens
FMHx; at least 50% develop other allergic diseases
o Filaggrin gene mutation identified as key genetic RF; Impairment of skin barrier function leading to Cutaneous sensitisation to allergens
o Up to 40% with Severe Eczema also have IgE-mediated Food Allergy
61
Atopic Eczema: Stats
20% of children have Atopic Eczema; Usually presents in first year of life; Uncommon in first 2 months (C/f Infantile Seborrheic Dermatitis, which is not itchy)
• Mainly disease of childhood; 50% resolve by 12yrs, 75% by 16yrs
62
Atopic Eczema: Diagnosis
Clinical diagnosis; If Severe, Atypical or associated with Unusual infections or Faltering growth, consider Immunodeficiency
o Pruritus is the main symptom; Atopic skin is usually dry; Lichenification occurs following prolonged scratching and rubbing
63
Atopic Eczema: Ddx
Chickenpox, Allergy, Contact Dermatitis, Insect Bites, Scabies, Fungal Infections, Pityriasis Rosea
64
Atopic Eczema: Exacerbations
Exacerbations can be caused by Infection, Allergen exposure, Environment (heat, humidity), Medication changes, Psychological stress or Idiopathic
65
Atopic Eczema: Infections
Eczematous skin readily infected; Staph or Strep commonly; More Severe infections
o HSV Infection – Uncommon but spreads rapidly = Eczema Herpeticum
o Regional LNA is common; Resolves when the skin improves
66
Management of Atopic Eczema: Irritant Avoidance
• Irritant Avoidance – Detergent, Clothing, Mittens and Nail clipping to reduce scratching, Allergens, where proven, should be avoided
67
Management of Atopic Eczema: Treatments
Emollients – 2 or more times a day and after bath; Ointments of 50:50 White soft paraffin and Liquid paraffin; Preferable to cream if skin is very dry
• Topical Steroids – 1% Hydrocortisone applied 1-2 times daily if needed; Minimal use of moderately-potent steroids in Acute Exacerbations; Applied thinly and face avoided
o Excessive use can cause thinning of skin and systemic SE
• Immunomodulation (IL2 Inhibition) – Tacrolimus Ointment or Pimecrolimus cream if topical steroids not helpful; for children >2yrs
• Occlusive Bandages – Helpful if scratching and Lichenification is problem; can be medicated
• Antibiotics, Aciclovir, Antihistamines
68
Management of Atopic Eczema: Dietary Elimination
Food allergy suspected if moderate or severe Eczema, especially if associated with GI dysmotility or growth faltering
o Most commonly egg or cow’s milk protein
69
Infantile Haemangioma: What is it
• 1% of infants; Presents at or shortly after birth as single, red lumpy nodule that grows rapidly for first few months; May spontaneously resolve with good cosmesis, but take up to 7yrs
o Plastic surgery might be required to remove residual slack skin
70
When does a haemangioma require treatment
Urgent treatment if – Interference with Feeding or Vision, Ulceration and Frequent Bleeding, Associated with High-output Cardiac Failure due to shunting, or consumption of platelets and clotting factors, causing life-threatening Haemorrhage (Kasabach-Merritt syndrome)
71
Haemangioma Treatment
Treatment with Oral Propanolol (2mg/kg/day in 3 divided doses) rapidly shrinks lesions; High-dose Systemic Steroids, Vincristine or Embolisation for non-responding patients rarely
72
Portwine Stain
Not true haemangioma; Abnormal dilation of dermal capillaries
• Presents as birth as flat, red macular area; Commonly found on face; Does not improve spontaneously and may thicken over time
73
Sturge Weber Syndrome
Mark in distribution of Ophthalmic (CN V1), associated with underlying Meningeal Vascular Anomalies; can cause Epilepsy and Hemiplegia
o If involves skin near the eye, can lead to Glaucoma; Ophthalmic assessment required
74
Port Wine Stain Treatments
Treatment with Tunable/Pulsed Dye Laser; Facial lesions respond best
75
Nappy Rash: Causes
Common; Most commonly due to Irritant (Contact) Dermatitis
| o Due to urine; Urea-splitting organisms increase alkalinity and likelihood of rash
76
Nappy Rash: What does it look like
Irritant eruption covers convex surfaces; flexures are characteristically spared
77
Nappy Rash: Treatment
Treat with mild Emollients while severe cases require mild Topical Steroids
78
Nappy Rash: Ddx
Infantile Seborrhoeic Dermatitis, Candida Infection and Atopic Eczema
79
Infantile Seborrhoeic Dermatitis
Eruption of unknown cause in first 3/12; Non-itchy (C/f Eczema); Scaly eruption followed by thick, yellow adherent layer; Resolves with Emollients, or if required steroids and antimicrobials can be used
80
Candida
Erythematous, includes skin flexures, and may have satellite lesions; Topical antifungal agents
81
Mongolian Blue Spots
Deep, blue-grey bruise-like area typically Sacrum or Back; Mistaken for NAI; Due to deep, Dermal Melanocytes; Common in Oriental children; Disappears by 7yrs
82
Café Au Lait Spots
Pigment-producing Melanocytes; Multiple/large spots might be associated with NF1, McCune Albright Syndrome, Tuberous Sclerosis and Fanconi Syndrome
83
Milia (Milk Spots)
Small follicular epidermal cysts (White pimples); Commonly found on face of infants; Spontaneously resolve without intervention
84
Miliaria (Sweat Rash)
Small, Itchy Erythematous rash; Common in hot and humid conditions; Common in infants, due to underdeveloped Sweat glands
85
Toxic Erythema of Newborn
Common, Transient Maculo-papular Rash in Newborns; Occasionally Pustular; Child is not toxic or unwell; Spontaneously resolve within days
86
Acrodermatitis Enteropathica
Rare, Inherited Deficiency of Zn Absorption; Presents 4-6/52 after weaning; Erythematous sometimes Blistering rash; Might be associated with Photophobia, Diarrhoea or Alopecia; Rapidly responds to Zn supplementation
