Infection, Immunology and Allergy Flashcards
1
Q
What is the overall mortality of bacterial meningitis?
A
5-10%
2
Q
What percentage of survivors from bacterial meningitis are left with long term neurological impairment?
A
10%
3
Q
What are the most common organisms which cause bacterial meningitis in under 3month olds?
A
GBS
E.coli
Listeria
4
Q
What are the most common organisms which cause bacterial meningitis in over 3month olds?
A
Neisseria meningitides
Strep. pneumoniae
5
Q
What is the Brudzinsk sign?
A
Flexion of the neck with the child supine causes flexion of knees and hips
6
Q
What is the Kernig sign?
A
If child lying supine, with hips and knees flexed, there is pain on extension of the knee
7
Q
What are the contraindications to LP?
A
Cardiorespiratory instability
Focal neurological signs
Signs of raised ICP
Coagulopathy
Thrombocytopenia
Local infection at site of LP
If it will cause delay in abx
8
Q
In a CSF sample for meningitis, what colour would the fluid be in a bacterial infection?
A
Turbid
9
Q
In a CSF sample for meningitis, what colour would the fluid be in a TB infection?
A
Turpid/clear/viscous
9
Q
In a CSF sample for meningitis, what would be expected to be found on the cell count for a bacterial infection?
A
Very increased WCC, mainly polymorphs
10
Q
In a CSF sample for meningitis, what colour would the fluid be in a viral infection?
A
Clear
10
Q
In a CSF sample for meningitis, what colour would the fluid be in a viral encephalitis infection?
A
Clear
11
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a viral infection?
A
Normal or protein +
11
Q
In a CSF sample for meningitis, what would be expected to be found on the cell count for a viral encephalitis infection?
A
Normal/increased lymphocytes
11
Q
In a CSF sample for meningitis, what would be expected to be found on the cell count for a viral infection?
A
Increased WCC, lymphocytes
11
Q
In a CSF sample for meningitis, what would be expected to be found on the cell count for a TB infection?
A
Increased WCC, lymphocytes
12
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a TB infection?
A
Protein +++
12
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a bacterial infection?
A
Protein ++
13
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a viral encephalitis infection?
A
Normal or protein +
14
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a bacterial infection?
A
Glucose –
15
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a viral infection?
A
Normal or glucose -
16
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a TB infection?
A
Glucose —
17
Q
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a viral encephalitis infection?
A
Normal or glucose -
18
Q
What are the potential complications from meningeal infection?
A
Hearing impairment
Local vasculitis
Local cerebral infacrtion
Subdural effusion
Hydrocephalus
Cerebral abscess
19
What prophylaxis is given to close contacts of a person with proven meningitis?
Ciprofloxacin to close contacts
In cases of A,C,W or Y infections, close contacts should be offered vaccination
20
What are the common pathogens causing viral meningitis?
Enterovirus
Parechovirus
EBV
Adenovirus
Mumps
21
What are the most common infectious causes of encephalitis in the UK>
Enteroviruses
Respiratory viruses
HSV
HHVs
21
What is the treatment for HSV encephalitis?
3 weeks of IV aciclovir
22
What is the prognosis for HSV encephalitis?
Untreated, mortality is >70%
Those who survive tend to have long term neurological sequelae
23
In HSV encephalitis, on doing a CT/MRI brain what may be seen other than typical signs encephalitis?
Focal changes in the temporal lobe(s)
23
Which organisms typically cause necrotising fasciitis?
Staph aureus or GAS
Can be synergistic anaerobes
23
Which organisms are responsible for causing toxic shock syndrome?
Staph aureus
GAS
24
What is the typical presentation in TSS?
Fever >39degrees
Hypotension
Diffuse, erythematous, macular rash
25
What is the evidence of organ dysfunction in TSS?
GI dysfunction
Renal or liver impairment
Deranged clotting and thrombocytopenia
Altered consciousness
25
In TSS what happens to the skin around 1-2weeks following acute infection?
Desquamation of palms, soles, fingers and toes
26
What is the significance of a PVL toxin in TSS and how does this differ the usual course of the disease?
Can cause necrotising fasciitis and necrotising haemorrhagic pneumonia both of which increase mortality rate
Leads to a procoagulant state to venous thromboses more likely to occur
26
How is TSS treated?
Usually with ceftriaxone and clindamycin
Debridement of areas of infection
IVIG may be needed to neutralise toxin
Usually needs managing in an PICU setting
27
How does necrotising fasciitis typically present?
Rapidly advancing, highly painful areas of tissue necrosis and systemic illness
28
How is necrotising fasciitis managed?
IV antibiotics
Surgical debridement
IVIG may be used
29
How does the rash in meningococcal infection usually appear?
Non-blanching
Irregular
May have necrotic centre
Typically lesions are larger than 5mm
30
What types of infection does strep pneumoniae often cause in children?
Pharyngitis
OM
Conjunctivitis
Sinusitis
Invasive infection
31
What antibiotic should be given prophylactically to immunocompromised or at risk children to prevent strep pneumoniae infection?
Penicillin
32
Which organism causes scarlet fever?
GAS
33
How does the rash in scarlet fever typically present?
Diffuse, erythematous, maculo-papular rash with a sandpaper texture
Usually appears on face, trunk and limbs
34
What are the typical oral findings in scarlet fever?
Circumoral pallor
Tongue initially white but desquamates to become a strawberry tongue
34
What is the treatment for scarlet fever?
10 days or PenV or erythromycin
34
How is periorbital cellulitis managed?
IV abx e.g. ceftriaxone to prevent spread to orbital tissues
35
How does the typical rash in impetigo present?
Lesions on face, neck and hands which are initially erythematous macules which then blister and then rupture to leave honey-crusted lesions
35
What oraganisms cause impetigo?
Usually staph aureus but may be strep
36
What is the treatment for impetigo?
Topical or oral abx (flucloxacillin) depending on severity
36
What is a boil?
Infection of hair follicle or sweat gland
37
What organism usually causes boils?
Staph aureus
37
What is the treatment for boils?
Swab lesion
Systemic abx
Occasionally I&D
38
How does periorbital cellulitis usually present?
Fever with erythema, tenderness and oedema of eyelid or other skin adjacent to eye
All anterior to orbital septum
38
How does orbital cellulitis present?
Proptosis
Painful or limited ocular movements
Potential decline in visual acuity
39
How does staphylococcal scalded skin syndrome present?
Fever and malaise
Purulent crusting and localised infection followed by widespread erythema and tenderness of the skin
40
What is the treatment of SSSS?
ABX IV
Analgesia
Careful fluid balance and rehydration
41
At what level does the skin separate in SSSS?
Epidermis
42
Do SSSS lesions cause scarring?
No
43
What is Nikolsky sign?
Areas of epidermis separate on gentle pressure
44
What conditions is HHV 8 associated with?
Kaposi sarcoma
45
What kind of lesion is HSV1 typically associated with?
lip and skin lesions
46
What kind of lesion is HSV2 typically associated with?
genital lesions
47
What is the treatment for HSV infections?
Aciclovir
47
How do gingivostomatitis HSV lesions typically present?
Usually from 10months to 3years
Vesicular lesions on lips, gums, anterior surface of tongue and hard palate which often progress to extensive and painful ulceration
48
Which pathogen causes cold sores?
HSV
48
How does eczema herpeticum present?
Widespread, 'punched-out' vesicular lesions on eczematous skin
49
What is a herpetic Whitlow?
Painful, erythematous, oedematous white pustules at the site of broken skin, esp fingers
49
How is eczema herpeticum managed?
IV aciclovir
50
How does HSV eye disease present?
Blepharitis or conjunctivitis usual
Can extend to cornea causing dendritic ulcers
Needs urgent ophthalmological assessment
50
What are the clinical features of chickenpox?
Fever
Rash
Itching and scratching may cause scarring and secondary bacterial infection
51
What does the typical rash look like in chickenpox?
50-500 lesions start on head and trunk and progress to limbs
Appear as crops of papules and vesicles with surrounding erythema
Then become pustules
Then crust over and heal
52
What are the complications of VZV infection?
Secondary bacterial infection - usually staph or strep
CNS infection
Purpura fulminans
52
What treatment is given to immunocompromised individuals for uncomplicated chickenpox?
IV aciclovir, switched to oral valaciclovir when safe
53
What treatment is given to immunocompetent individuals for uncomplicated chickenpox?
Calamine lotion for itching
Antivirals not recommended
53
How does EBV infection typically present?
Fever
Malaise
Tonsillitis/Pharyngitis
Lymphadenopathy
54
What treatment is given to immunocompromised individuals for close contact with VZV infection?
IVIG
55
How does shingles present?
Vesicular eruption in a dermatomal pattern - usually on torso
55
How is EBV diagnosed?
Atypical lymphocytes on blood film
Positive monospot test
56
How does CMV present in an immunocompetent individual?
Usually asymptomatic or a mild EBV-like syndrome
56
How may CMV present in an immunocompromised individual?
Retinitis
Pneumonitis
Bone marrow failure
Encephalitis
Hepatitis
Oesophagitis
Enterocolitis
56
How is CMV treated?
IV ganciclovir or oral valganciclovir/foscarnetor/cidofovir
56
What are the less common symptoms of EBV infection?
Petechiae on soft palate
Hepatomegaly - 10%
Splenomegaly - 50%
Maculopapular rash - 5%
Jaundice
56
What disease does HHV 6 and 7 usually cause?
Roseola Infantum
56
How does Roseola Infantum usually present?
High fever and malaise for a few days
Followed by generalised macular rash as fever subsides
57
What condition does parvovirus B19 typically cause?
Erythema Infectiosum aka Fifth disease aka Slapped cheek syndrome
57
How does slapped cheek syndrome typically present?
Fever, malaise, headache and myalgia
Followed by a rash on the face which spreads to the trunk and limbs (maculopapular 'lace-like')
57
What is the most serious complication of parvovirus B19 infection?
Aplastic crisis
Occurs more often in those with haemolytic disease or immunocompromised
57
How does hand foot and mouth disease typically present?
Painful vesicular lesions on hands, feet, mouth and often buttocks
58
Which organism causes hand foot and mouth disease typically?
Enteroviruses
58
What virus is the most common cause of viral meningitis in the UK?
Enterovirus
59
What is pleurodynia also known as?
Bornholm disease
59
Which organism is responsible for Bornholm disease?
Enterovirus
59
How does pleurodynia usually present?
Acute illness with fever, pleuritic chest pain and muscle tenderness
60
What can enterovirus D68 rarely cause?
Acute flaccid myelitis
60
What organism causes eczema coxsackium?
Enterovirus
60
How does eczema coxsackium present?
vesicles, bullae and erosions
60
How is influenza treated for children who are hospitalised?
Osteltamivir or zanamivir
60
What are koplik spots?
White spots on buccal mucosa
60
How does measles typically present?
Fever
Conjunctivitis and coryza
Cough
Rash
Koplik spots
61
What is the mortality for measles encephalitis?
15%
61
How does mumps typically present?
Fever, malaise and parotitis
61
How does the rash in measles typically present?
Discrete maculopapular rash which later becomes blotchy and confluent
Typically starts behind ear and spreads downwards to rest of body
62
What is the prevalence of CNS involvement in mumps?
Lymphocytes in CSF in 50%
Meningitis in 10%
Encephalitis in 1 in 5000
62
In how many cases of measles does measles encephalitis occur?
1 in 5000
62
How does measles encephalitis typically present?
Headache, lethargy and irritability leading to seizures and coma
62
What are the long term sequelae of measles encephalitis?
40% survivors will have some or all of:
Seizures
Deafness
Hemiplegia
Severe LD
63
What viral condition can sometimes cause orchitis?
Mumps
63
What is the treatment of measles?
Mainly supportive
Isolate form others
Ribavirin if immunocompromised
Vitamin A in low-income countries
63
What is the risk of developing SSPE following measles infection
1 in 100000 cases
63
Which condition does subacute sclerosing panencephalitis (SSPE) occur after?
Measles
63
How long after measles infection does SSPE occur?
7 years
64
How does SSPE present?
Loss of neurological function which leads to dementia and death over several years
64
What age group does Kawasaki disease most commonly affect?
6months - 4years
64
How does rubella typically present?
Mild prodrome with low-grade fever
Maculopapular rash starting on face then spreads to cover whole body
Lymphadenopathy is prominent
64
Which ethnic group is more prone to Kawasaki disease?
Japanese
Black-Caribbeans
65
Kawasaki disease can be diagnosed clinically by the presence of fever for 5 days and presence of 4 of 5 other features. what are these other features?
Bilateral non-purulent conjunctivitis
Erythema and cracking of lips, strawberry tongue +/- erythema of oral mucosa
Cervical lymphadenopathy
Maculopapular rash
Erythema and oedema of hands and feet in acute phase or peeling of skin in subacute phase
65
What blood findings would be expected in Kawasaki disease?
Raised WCC, CRP, ESR and platelets
65
What proportion of children with Kawasaki disease have coronary artery involvement?
1/3
66
What are the coronary artery issues in Kawasaki disease?
Coronary artery aneurysms
Narrowing of vessels which can lead to ischaemia and sudden death
66
What treatment is given in Kawasaki disease?
IVIG
Aspirin
66
What is the mortality rate in Kawasaki disease primarily due to coronary artery disease?
0.5%
66
What are the presenting features or PIMS?
Persistent fever
Evidence of inflammation
Single or multi-organ failure
GI symptoms, rash and conjunctivitis common
67
What is the cardiac involvement in PIMS?
Myocarditis
Coronary artery abnormalities
Valve involvement
Pericardial effusion
67
How is PIMS treated?
IVIG
Low dose aspirin
Corticosteroids
67
What increases the risk of TB transmission?
Close proximity
Large infectious load in index case
Underlying immunodeficiency
68
What are the symptoms of primary TB infection?
Local and regional lymphadenopathy
Systemic symptoms:
Fever
Anorexia and weight loss
Cough
CXR changes - hilar lymphadenopathy
68
What percentage of children are asymptomatic with primary TB infection?
50% neonates
90% older children
68
What percentage of children with TB have pulmonary TB?
75%
68
How is TB diagnosed?
Gastric washings or induced sputum from 3 separate mornings examined for acid-fast bacilli and culture
Mantoux test also done (>5mm is a +ve result)
IGRA also useful
69
What is the treatment for TB?
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
All of the above for 2 months, then reduced to just rifampicin and isoniazid
Total treatment for uncomplicated disease is for 6 months
69
What are the typical symptoms of malaria?
Fever
D&V
Flu-like Sx
Jaundice
Anaemia
Thrombocytopenia
69
How is malaria diagnosed?
Thick blood film diagnoses condition and thin blood film confirms species
70
How does typhoid infection present?
Worsening fever
Headaches
Cough
Abdominal pains
Anorexia
Malaise
Myalgia
Occasionally splenomegaly, bradycardia and rose coloured spots
70
How is plasmodium falciparum infection treated?
Quinine or artemisinin based formulation
70
What are the serious complications of typhoid?
GI perforation
Myocarditis
Hepatitis
Nephritis
71
What is the treatment for typhoid?
Co-trimoxazole and chloramphenicol/ampicillin
If drug resistance then 3rd gen. cephalosporin or azithromycin may be needed
71
How does Dengue fever typically present?
Erythematous rash, myalgia, arthralgia and high fever
71
Where does Dengue fever commonly occur?
Tropics
72
Where is Chikungunya commonly found?
Endemic in parts of Africa, Asia and India
73
How does Chikungunya typically present?
Fever
Arthritis
Arthralgia
73
Where is the Zika virus commonly found?
Transmitted by aedes mosquitoes in Central and South America and the Caribbean
73
How does zika virus commonly present?
Fever
Rash
Conjunctivitis
Arthralgia
74
How does the zika virus affect pregnant women?
Causes fetal microcephaly and other brain abnormalities
74
What causes lyme disease?
Borrelia Burgdorferi transmitted via ticks
74
Describe the lesion associated with lyme disease infection?
Erythematous macule at the site of lesion enlarged to cause typical "target" lesion aka erythema migrans
75
How does early lyme disease present?
Fever
Headache
Malaise
Myalgia
Arthralgia
Lymphadenopathy
75
How does late lyme disease present?
Neurological:
- fluctuating fatigue
- meningoencephalitis
- peripheral, central or autonomic neuropathies
Cardiac:
- myocarditis
- heart block
MSK:
- brief migratory arthritis
- acute asymmetrical mono or oligoarthritis or large joints
75
How is lyme disease diagnosed?
Clinically and lyme serology
76
What is the treatment of lyme disease in those <8y/o
Amoxicillin
77
What is the treatment of lyme disease in those >8y/o
Doxycycline
77
What are examples of live attenuated vaccines?
MMR
Rotavirus
BCG
77
What are examples of inactivated vaccines?
Polio
Influenza
78
What are examples of subunit vaccines?
Diphtheria
Pneumococcal
HPV
HBV
79
What vaccines are routinely given in the UK at 2 months?
6 in 1
Rotavirus
Meningococcal B
79
What is included in the 6 in 1 vaccine?
Diphtheria
Tetanus
Pertussis
Polio
H. influenzae B
Hepatitis B
79
What vaccines are routinely given in the UK at 3 months?
6 in 1
Rotavirus
Pneumococcal conjugate vaccine (PCV)
80
What vaccines are routinely given in the UK at 4 months?
6 in 1
MenB
80
What vaccines are routinely given in the UK at 12 months?
PCV
MenB
HiB/MenC
MMR
80
What vaccines are routinely given in the UK at 2-7 years?
Influenza seasonal vaccine
80
What vaccines are routinely given in the UK at 3 years and 4 months?
MMR
4 in 1 (Diphtheria, tetanus, pertussis, polio)
81
What vaccines are routinely given in the UK at 12-13 years?
HPV
81
What vaccines are routinely given in the UK at 14 years?
Men ACWY
3 in 1 (diphtheria, pertussis, polio)
81
What are the contraindications of immunisation?
Postponed if acute infection
Live vaccines should not be given to immunocompromised patients
Anaphylaxis to previous dose
82
In immunodeficiency how do T-cell defects typically present?
Severe and/or unusual viral and fungal infections
Faltering growth in the first months of life
PCP or disseminated/severe CMV
82
Is SCID a T-cell or B-cell immunodeficiency?
Can affect both
82
What is SCID?
A heterogenous group of inherited disorders of profoundly defective cellular and humoral immunity
82
What triad of features is typical of Wiskott-Aldrich syndrome?
Immunodeficiency
Thrombocytopenia
Eczema
83
What is Duncan disease and how does it present?
X-linked proliferative disease
Inability to generate a normal response to EBV
Patients either succumb to initial infection or develop secondary lymphoma
83
What is ataxia telangiectasia and how does it present?
Defect in DNA repair
Increased risk of lymphoma
Cerebellar ataxia and developmental delay
83
In immunodeficiency how do B-cell defects present?
Severe bacterial infections especially ear, sinus, pulmonary and skin
Recurrent diarrhoea
Faltering growth
83
What are some types of B-cell defects?
X-linked agammaglobulinaemia
Common variable immune deficiency (CVID)
Hyper IgM syndrome
Selective IgA deficiency
84
In immunodeficiency how do neutrophil defects present?
Recurrent bacterial defects - abscesses, poor wound healing, perianal disease, periodontal infections and invasive fungal infections
Diarrhoea and faltering growth
Granulomas from chronic inflammation
85
What is an example of neutrophil defect disease?
Chronic granulomatous disease
86
How is chronic granulomatous disease inherited?
Mostly x-linked recessive but some AR
87
In immunodeficiency how do leukocyte function defects present?
Delayed separation of umbilical cord
Delayed wound healing
Chronic skin ulcers
Deep-seated infections
88
What is the basic pathophysiology of leukocyte adhesion deficiency?
Deficiency of neutrophil surface adhesion molecules CD15a
Leads to inability of neutrophils to migrate to sites of infection/inflammation
89
What is the basic pathophysiology of chronic granulomatous disease?
Neutrophils fail to produce superoxide after phagocytosis of microorganisms
89
What is an example of a leukocyte function defect?
Leukocyte adhesion deficiency
90
In immunodeficiency how do complement defects present?
Recurrent bacterial infections
SLE-like illness
Recurrent meningococcal, pneumococcal and H.influenzae infections
90
What are some examples of complement defect disorders?
Early complement component deficiency
Terminal complement component deficiency
Mannase-binding lectin (NBL) deficiency
91
What investigations should be done for T-cell defects?
FBC
Lymphocyte subsets
92
What investigations should be done for neutrophil defects?
FBC
NBT (nitroblue tetrazolium test) - abnormal in chronic granulomatous disease
Tests for leukocyte adhesion deficiency
Tests for chemotaxis
92
What investigations should be done for B-cell defects?
Immunoglobulins
IgG subclasses
Lymphocyte subsets
Specific antibody responses
93
What investigations should be done for complement defects?
Tests of classical and alternative complement pathways
MBL levels
Assays for individual complement proteins
93
What is the antibiotic prophylaxis of T-cell and neutrophil defects?
Co-trimoxazole to prevent PCP
Itraconazole/fluconazole to prevent fungal infections
93
What is the antibiotic prophylaxis of B-cell defects?
Azithromycin to prevent recurrent bacterial infections
93
Other than prophylactic antibiotics what are the other treatments for immunodeficiency?
Screening for end organ disease
Immunoglobulin replacement therapy
Bone marrow Tx
Gene therapy
94
What are the symptoms of non-IgE mediated allergy?
D&V
Abdo pain
Faltering growth
94
What tests can be done in suspected allergy?
Skin prick tests
IgE blood tests
Spirometry and lung function tests
Allergy challenge
94
What happens in the late phases of an IgE mediated allergic reaction?
Nasal congestion in the upper airway, cough and bronchospasm in the lower airway
95
What happens in the early phases of an IgE mediated allergic reaction?
Urticaria, angioedema, sneezing, vomiting, bronchospasm and/or cardiovascular shock
Caused by release of histamine and other mediators from mast cells
95
How does eosinophilic oesophagitis present?
Persistent vomiting and swallowing difficulty in young children
Difficulty swallowing and food impaction in older children
96
What gene mutations are a risk factor for development of atopic eczema?
Fillagrin gene mutations
97
At what stage is urticaria considered chronic?
6 weeks
98
How is chronic urticaria managed?
Non-sedating antihistamines
Refractory disease may need omalizumab
99
What does a child with Chediak-Higashi syndrome typically look like?
Pale with red hair
100
How is Chediak-Higashi syndrome inherited?
AR
101
What is the prognosis for Chediak-Higashi syndrome?
Often fatal in childhood
102
After erythema migrans, what is the next most common symptom in lyme disease?
Neurological disorders - facial nerve palsy is most common
103
What are the neurological symptoms in lyme disease?
Facial nerve palsies
Meningitis
Encephalitis
Peripheral mononeuritis
Lymphocytic meningoradiculitis
104
What are the cardiac symptoms in lyme disease?
Myopericarditis
Heart block (1st degree)
105
What are lymhocytomas and where do they typically present?
Bluish-red nodules infiltrated with lymphocytes
Typically on earlobe or nipple
106
How is SCID usually inherited?
AR
May be de novo
107
In SCID what would be seen on the lymphocyte count?
Lymphopenia <2.5-3
107
In SCID what would the CXR show?
Absent thymic shadow
108
In SCID what would be seen on checking immunoglobulin levels?
Low IgG, IgM and IgA
109
If an individual with SCID needs a blood transfusion what additional precautions should be taken?
Blood should be CMV -ve and irradiated
110
What may precipitate hereditary angioedema?
Trauma
Stress
Menstruation
ACEIs
OCPs
111
What are the GI symptoms of Omenn syndrome?
Chronic diarrhoea
Protein loss leading to generalised oedema
111
What are the skin symptoms of Omenn syndrome?
Generalised erythroderma with thickened and leathery skin and alopecia
112
What is Omenn syndrome?
Exaggerated inflammatory response by oligoclonal T-cells
112
What are the reticuloendothelial symptoms of Omenn syndrome?
Lymphadenopathy
Hepatosplenomegaly
112
What protein is behind the symptoms in hereditary angioedema?
C1 esterase inhibitor
Type 1 is a deficiency
Type 2 is a defective version
113
What proteins are deficient in Omenn syndrome?
RAG1 and RAG2
113
How is hereditary angioedema inherited?
AR
113
What would screening tests show in hereditary angioedema type 1?
C1INH functional level decreased
C1INH antigenic level reduced
C4 low
114
How does hereditary angioedema present?
Episodic attacks of angioedema
Abdo pain common due to GI mucosal oedema
114
Which type of hereditary angioedema is most common?
Type 1 - 85% of cases
115
How are hereditary angioedema attacks prevented?
Antifibrinolytics
- epsilon amino caproic acid
- TXA
Purified C1INH from human plasma
Landelumab
115
What would screening tests show in hereditary angioedema type 2?
C1INH functional level decreased
C4 low
116
How are acute attacks of hereditary angioedema managed?
C1INH IV
Ecallantide
Icantibant
117
How is Wiskott-Aldrich syndrome inherited?
X-linked recessive
117
What type of bacteria causes gonorrhoea?
Gram negative coccus
117
What mutation causes Wiskott-Aldrich syndrome?
WAS gene on x-chromosome p11.22-11.23
117
What mediates a type I hypersensitivity reaction?
Immediate reaction mediated by IgE antibodies
117
What mediates a type II hypersensitivity reaction?
IgG or IgM mediated cytotoxic reaction occurring over hours to days
117
Give examples of type I hypersensitivity reactions.
Allergy
Anaphylaxis
Atopic disease
118
Give examples of type II hypersensitivity reactions.
Haemolytic disease of the newborn
AI haemolytic anaemia
Goodpastures
119
What mediates a type III hypersensitivity reaction?
Antibody-antigen complex mediated occurring over several hours, to days to weeks
120
Give examples of a type III hypersensitivity reaction.
RA
SLE
Post-streptococcal GN
121
What mediates a type IV hypersensitivity reaction?
T-cell mediated occuring 24-72hours after exposure
122
Give examples of a type IV hypersensitivity reaction.
Dermatitis
Mantoux testing
123
What infection is a major cause of SNHL in young children?
CMV
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How does symptomatic congenital CMV present?
Blueberry muffin rash
Symmetrical IUGR
Congenital cataracts
Jaundice
Petechiae
Hepatosplenomegaly
Microcephaly
Unexplained ventriculomegaly
Hearing loss
DD
125
How does acquired CMV present?
Pneumonia
Colitis
Retinitis
Encephalitis
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How is CMV treated?
Ganciclovir or valganciclovir in severe infections
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Which virus causes roseola infantum?
HHV6
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How is the Dengue virus transmitted?
Aedes mosquitoes
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Where are aedes mosquitoes typically found?
tropical regions e.g. Sri Lanka and Brazil
128
What are the characteristic symptoms of Dengue fever?
High fever
Eye pain
Lethargy
Rash
Most severe type causes haemorrhagic fever
128
What is the first line treatment for mucormycosis?
Ambisome
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What causes Taenia solium?
Tapeworm - ingesting undercooked pork containing larval cysts
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What causes Echinococcus granulosus?
Tapeworm that causes hydatid disease
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How is a Mantoux test read?
48-72 hours after injection the reaction should be read via the diameter of induration
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What causes trachoma infection?
Chlamydia
130
What is the treatment of choice for malaria falciparum in the paediatric population?
Proguanil and atovaquone
131
How is a severe attack of hereditary angioedema with stridor treated?
C1 inhibitor concentrate
131
What are the features of severe malaria?
Cerebral malaria
Severe anaemia
Respiratory abnormalities
Renal failure
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How does malaria typically present?
Headache
Cough
Fatigue
Arthralgia
Fevers
GI issues and jaundice
132
What is hyper-IgD syndrome?
Fever every 4-8 weeks with abdo pain, arthralgia, diarrhoea, vomiting, lymphadenopathy and skin rashes
133
What immunodeficiency is recurrent Neisseria meningitidis meningitis associated with?
Defects in the lytic complement pathway (C5-C9)
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What is the typical history of enteric fever (typhoid or paratyphoid fever)?
Travel to Indian subcontinent
Fever >1week
More unwell with time
Abdo pain
Vomiting
Rash on trunk
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How is typhoid fever treated?
Ceftriaxone
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Where is the antigen binding site located?
Within the variable region of the Ig structure, made up of both heavy ad light chains
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Why are those of West African origin resistant to plasmodium vivax infection?
Duffy blood-group antigen alleles FYA and FYB encoding Fya and Fyb which are the receptors for penetration of the red cell by plasmodium vivax.
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How does X-linked agammaglobulinaemia present?
Recurrent bacterial infections in the first 2 years of life (lung and sinus most common)
Usually protected for first 3-6months by placental IgG
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What is the most important factor to consider when assessing need for post-exposure prophylaxis against rabies?
Country in which the bite occurred
139
Which infection can cause neurocysticercosis?
T.solium
140
How are pinworms treated?
Single dose of mebendazole or albendazole
140
Where in the world is hepatitis E more common?
East and South Asia
140
How does Enterobius vermicularis present?
Anal itching, especially at night
Abdo pain
Vulvovaginitis
141
How does hepatitis E present?
Fever
Abdo pain
Jaundice
Hepatomegaly
141
How does hepatitis A typically present?
Diarrhoea
Abdo pain
Jaundice
141
How does hepatitis B present?
Diarrhoea
Abdo pain
Jaundice
Asymptomatic
141
Why is hepatitis E more likely to be diagnosed than hepatitis A than someone who has travelled to an endemic area from the UK?
Travel vaccination readily available for Hep A
142
Which types of hepatitis are transmitted via the faecal-oral route?
A&E
142
What type of infections are those with hypogammaglobulinaemia particularly prone to?
Encapsulated bacterial infections e.g. H.influenzae
142
What is the most common subtype of shigella infection in the developed world?
Shigella sonnei
142
What is the recommended treatment for schistomiasis?
Praziquantel
143
How long after the onset of a measles rash should a child be excluded from any nursery settings?
5 days
144
What is the treatment for chlamydia conjunctivitis in neonates?
Oral erythromycin QDS for 2 weeks
144
When do symptoms typically start in S.aureus food poisoning?
2-4hours after food ingestion
144
When should a mast cell tryptase level be taken in anaphylaxis?
Between 1-2hours following onset
145
What infections are those with chronic granulomatous disease prone to getting?
Skin and resp infections especially S.aureus and aspergillus
146
What is the most common manifestation of cutaneous TB?
Lupus vulgaris - gradually progressive red plaque with crusting and induration at periphery and scarring at centre
147
What infection does terminal complement component deficiency predispose to?
Meningococcal disease
147
What symptoms does Corynebacterium diphtheriae cause?
Fever
Sore throat
Difficulty swallowing
Pseudomembrane coating tonsils, pharynx and larynx
147
What are the signs of congenital varicella
Multiple congenital abnormalities
Microcephaly
Limb deformities
Chorioretinitis
Scarring
Hydrocephalus
147
What is the function of neuraminidase?
Hydrolyses sialic acid residues on host cells to release newly formed virions
148
What are C3 and C4 levels like in those with HAE between attacks?
C3 always normal
Persistently low C4
148
What is the most common cause of viral meningitis?
Enteroviruses
148
What treatment should children with HIV >6 weeks and <12 months recieve?
cART and PCP prophylaxis
149
What treatment should children with HIV 1-4 years old have?
cART
PCP if CD4 count <15% or <500x10^6/l
149
What treatment should children with HIV >5 have?
cART
PCP if CD4 count <15% or <200x10^6/l
149
What cellular process results in the degranulation of eosinophils?
Fusion of the lysosomal membrane with the plasma membrane
149
What are the most common causes of meningitis in babies <4weeks old?
E.coli
GBS
Listeria
149
What is the best antibiotic combination for meningitis in a child <4weeks old?
Ampicillin and cefotaxime
149
What is the most common vector for the leishmaniasis parasite?
Sandfly
149
What is the most sensitive test for diagnosing CGD?
DHR test (Dihydrorhodamine)
149
What cell deficiency is associated with DiGeorge syndrome?
T cell deficiency
150
What is the management of tetanus?
Wound debridement
Penicillin and tetanus toxoid
Prompt ICU with ventilation and sedation
Diazepam for spasms
Rest
150
What are the initial signs of cholera?
Vomiting
Watery, non-bloody diarrhoea (rice-water)
150
What is the management of cholera?
Oral rehydration therapy
Antibiotics
150
How does Brucellosis present?
Prolonged fever
Anorexia
Arthralgia
Hepatosplenomegaly
150
What type of bacteria is brucella melitensis?
Gram -ve cocco-bacillus
150
What are leukotrienes synthesised from?
Leukocytes and mast cells
151
What is the treatment of choice for meningitis prophylaxis?
Ciprofloxacin
151
What are the features of congenital VZV?
Skin scarring in dermatomal distribution
Eye defects
Hypoplasia of limbs
Microcephaly
Cortical atrophy
DD
Dysfunction of bladder and bowel sphincters
151
Which pathogen is the most common cause of endocarditis with prosthetic valves?
Staph epidermidis
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