Infection, Immunology and Allergy Flashcards
What is the overall mortality of bacterial meningitis?
5-10%
What percentage of survivors from bacterial meningitis are left with long term neurological impairment?
10%
What are the most common organisms which cause bacterial meningitis in under 3month olds?
GBS
E.coli
Listeria
What are the most common organisms which cause bacterial meningitis in over 3month olds?
Neisseria meningitides
Strep. pneumoniae
What is the Brudzinsk sign?
Flexion of the neck with the child supine causes flexion of knees and hips
What is the Kernig sign?
If child lying supine, with hips and knees flexed, there is pain on extension of the knee
What are the contraindications to LP?
Cardiorespiratory instability
Focal neurological signs
Signs of raised ICP
Coagulopathy
Thrombocytopenia
Local infection at site of LP
If it will cause delay in abx
In a CSF sample for meningitis, what colour would the fluid be in a bacterial infection?
Turbid
In a CSF sample for meningitis, what colour would the fluid be in a TB infection?
Turpid/clear/viscous
In a CSF sample for meningitis, what would be expected to be found on the cell count for a bacterial infection?
Very increased WCC, mainly polymorphs
In a CSF sample for meningitis, what colour would the fluid be in a viral infection?
Clear
In a CSF sample for meningitis, what colour would the fluid be in a viral encephalitis infection?
Clear
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a viral infection?
Normal or protein +
In a CSF sample for meningitis, what would be expected to be found on the cell count for a viral encephalitis infection?
Normal/increased lymphocytes
In a CSF sample for meningitis, what would be expected to be found on the cell count for a viral infection?
Increased WCC, lymphocytes
In a CSF sample for meningitis, what would be expected to be found on the cell count for a TB infection?
Increased WCC, lymphocytes
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a TB infection?
Protein +++
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a bacterial infection?
Protein ++
In a CSF sample for meningitis, what would be expected to be found on the CSF protein level for a viral encephalitis infection?
Normal or protein +
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a bacterial infection?
Glucose –
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a viral infection?
Normal or glucose -
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a TB infection?
Glucose —
In a CSF sample for meningitis, what would be expected to be found on the CSF glucose level for a viral encephalitis infection?
Normal or glucose -
What are the potential complications from meningeal infection?
Hearing impairment
Local vasculitis
Local cerebral infacrtion
Subdural effusion
Hydrocephalus
Cerebral abscess
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
What are the common pathogens causing viral meningitis?
Enterovirus
Parechovirus
EBV
Adenovirus
Mumps
What are the most common infectious causes of encephalitis in the UK>
Enteroviruses
Respiratory viruses
HSV
HHVs
What is the treatment for HSV encephalitis?
3 weeks of IV aciclovir
What is the prognosis for HSV encephalitis?
Untreated, mortality is >70%
Those who survive tend to have long term neurological sequelae
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)
Which organisms typically cause necrotising fasciitis?
Staph aureus or GAS
Can be synergistic anaerobes
Which organisms are responsible for causing toxic shock syndrome?
Staph aureus
GAS
What is the typical presentation in TSS?
Fever >39degrees
Hypotension
Diffuse, erythematous, macular rash
What is the evidence of organ dysfunction in TSS?
GI dysfunction
Renal or liver impairment
Deranged clotting and thrombocytopenia
Altered consciousness
In TSS what happens to the skin around 1-2weeks following acute infection?
Desquamation of palms, soles, fingers and toes
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
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
How does necrotising fasciitis typically present?
Rapidly advancing, highly painful areas of tissue necrosis and systemic illness
How is necrotising fasciitis managed?
IV antibiotics
Surgical debridement
IVIG may be used
How does the rash in meningococcal infection usually appear?
Non-blanching
Irregular
May have necrotic centre
Typically lesions are larger than 5mm
What types of infection does strep pneumoniae often cause in children?
Pharyngitis
OM
Conjunctivitis
Sinusitis
Invasive infection
What antibiotic should be given prophylactically to immunocompromised or at risk children to prevent strep pneumoniae infection?
Penicillin
Which organism causes scarlet fever?
GAS
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
What are the typical oral findings in scarlet fever?
Circumoral pallor
Tongue initially white but desquamates to become a strawberry tongue
What is the treatment for scarlet fever?
10 days or PenV or erythromycin
How is periorbital cellulitis managed?
IV abx e.g. ceftriaxone to prevent spread to orbital tissues
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
What oraganisms cause impetigo?
Usually staph aureus but may be strep
What is the treatment for impetigo?
Topical or oral abx (flucloxacillin) depending on severity
What is a boil?
Infection of hair follicle or sweat gland
What organism usually causes boils?
Staph aureus
What is the treatment for boils?
Swab lesion
Systemic abx
Occasionally I&D
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
How does orbital cellulitis present?
Proptosis
Painful or limited ocular movements
Potential decline in visual acuity
How does staphylococcal scalded skin syndrome present?
Fever and malaise
Purulent crusting and localised infection followed by widespread erythema and tenderness of the skin
What is the treatment of SSSS?
ABX IV
Analgesia
Careful fluid balance and rehydration
At what level does the skin separate in SSSS?
Epidermis
Do SSSS lesions cause scarring?
No
What is Nikolsky sign?
Areas of epidermis separate on gentle pressure
What conditions is HHV 8 associated with?
Kaposi sarcoma
What kind of lesion is HSV1 typically associated with?
lip and skin lesions
What kind of lesion is HSV2 typically associated with?
genital lesions
What is the treatment for HSV infections?
Aciclovir
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
Which pathogen causes cold sores?
HSV
How does eczema herpeticum present?
Widespread, ‘punched-out’ vesicular lesions on eczematous skin
What is a herpetic Whitlow?
Painful, erythematous, oedematous white pustules at the site of broken skin, esp fingers
How is eczema herpeticum managed?
IV aciclovir
How does HSV eye disease present?
Blepharitis or conjunctivitis usual
Can extend to cornea causing dendritic ulcers
Needs urgent ophthalmological assessment
What are the clinical features of chickenpox?
Fever
Rash
Itching and scratching may cause scarring and secondary bacterial infection
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
What are the complications of VZV infection?
Secondary bacterial infection - usually staph or strep
CNS infection
Purpura fulminans
What treatment is given to immunocompromised individuals for uncomplicated chickenpox?
IV aciclovir, switched to oral valaciclovir when safe
What treatment is given to immunocompetent individuals for uncomplicated chickenpox?
Calamine lotion for itching
Antivirals not recommended
How does EBV infection typically present?
Fever
Malaise
Tonsillitis/Pharyngitis
Lymphadenopathy
What treatment is given to immunocompromised individuals for close contact with VZV infection?
IVIG
How does shingles present?
Vesicular eruption in a dermatomal pattern - usually on torso
How is EBV diagnosed?
Atypical lymphocytes on blood film
Positive monospot test
How does CMV present in an immunocompetent individual?
Usually asymptomatic or a mild EBV-like syndrome
How may CMV present in an immunocompromised individual?
Retinitis
Pneumonitis
Bone marrow failure
Encephalitis
Hepatitis
Oesophagitis
Enterocolitis
How is CMV treated?
IV ganciclovir or oral valganciclovir/foscarnetor/cidofovir
What are the less common symptoms of EBV infection?
Petechiae on soft palate
Hepatomegaly - 10%
Splenomegaly - 50%
Maculopapular rash - 5%
Jaundice
What disease does HHV 6 and 7 usually cause?
Roseola Infantum
How does Roseola Infantum usually present?
High fever and malaise for a few days
Followed by generalised macular rash as fever subsides
What condition does parvovirus B19 typically cause?
Erythema Infectiosum aka Fifth disease aka Slapped cheek syndrome
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’)
What is the most serious complication of parvovirus B19 infection?
Aplastic crisis
Occurs more often in those with haemolytic disease or immunocompromised
How does hand foot and mouth disease typically present?
Painful vesicular lesions on hands, feet, mouth and often buttocks
Which organism causes hand foot and mouth disease typically?
Enteroviruses
What virus is the most common cause of viral meningitis in the UK?
Enterovirus
What is pleurodynia also known as?
Bornholm disease
Which organism is responsible for Bornholm disease?
Enterovirus
How does pleurodynia usually present?
Acute illness with fever, pleuritic chest pain and muscle tenderness
What can enterovirus D68 rarely cause?
Acute flaccid myelitis
What organism causes eczema coxsackium?
Enterovirus
How does eczema coxsackium present?
vesicles, bullae and erosions
How is influenza treated for children who are hospitalised?
Osteltamivir or zanamivir
What are koplik spots?
White spots on buccal mucosa
How does measles typically present?
Fever
Conjunctivitis and coryza
Cough
Rash
Koplik spots
What is the mortality for measles encephalitis?
15%
How does mumps typically present?
Fever, malaise and parotitis
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
What is the prevalence of CNS involvement in mumps?
Lymphocytes in CSF in 50%
Meningitis in 10%
Encephalitis in 1 in 5000
In how many cases of measles does measles encephalitis occur?
1 in 5000
How does measles encephalitis typically present?
Headache, lethargy and irritability leading to seizures and coma
What are the long term sequelae of measles encephalitis?
40% survivors will have some or all of:
Seizures
Deafness
Hemiplegia
Severe LD
What viral condition can sometimes cause orchitis?
Mumps
What is the treatment of measles?
Mainly supportive
Isolate form others
Ribavirin if immunocompromised
Vitamin A in low-income countries
What is the risk of developing SSPE following measles infection
1 in 100000 cases
Which condition does subacute sclerosing panencephalitis (SSPE) occur after?
Measles
How long after measles infection does SSPE occur?
7 years
How does SSPE present?
Loss of neurological function which leads to dementia and death over several years
What age group does Kawasaki disease most commonly affect?
6months - 4years
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
Which ethnic group is more prone to Kawasaki disease?
Japanese
Black-Caribbeans
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
What blood findings would be expected in Kawasaki disease?
Raised WCC, CRP, ESR and platelets
What proportion of children with Kawasaki disease have coronary artery involvement?
1/3
What are the coronary artery issues in Kawasaki disease?
Coronary artery aneurysms
Narrowing of vessels which can lead to ischaemia and sudden death
What treatment is given in Kawasaki disease?
IVIG
Aspirin
What is the mortality rate in Kawasaki disease primarily due to coronary artery disease?
0.5%
What are the presenting features or PIMS?
Persistent fever
Evidence of inflammation
Single or multi-organ failure
GI symptoms, rash and conjunctivitis common
What is the cardiac involvement in PIMS?
Myocarditis
Coronary artery abnormalities
Valve involvement
Pericardial effusion
How is PIMS treated?
IVIG
Low dose aspirin
Corticosteroids
What increases the risk of TB transmission?
Close proximity
Large infectious load in index case
Underlying immunodeficiency
What are the symptoms of primary TB infection?
Local and regional lymphadenopathy
Systemic symptoms:
Fever
Anorexia and weight loss
Cough
CXR changes - hilar lymphadenopathy
What percentage of children are asymptomatic with primary TB infection?
50% neonates
90% older children
What percentage of children with TB have pulmonary TB?
75%
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
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
What are the typical symptoms of malaria?
Fever
D&V
Flu-like Sx
Jaundice
Anaemia
Thrombocytopenia
How is malaria diagnosed?
Thick blood film diagnoses condition and thin blood film confirms species
How does typhoid infection present?
Worsening fever
Headaches
Cough
Abdominal pains
Anorexia
Malaise
Myalgia
Occasionally splenomegaly, bradycardia and rose coloured spots
How is plasmodium falciparum infection treated?
Quinine or artemisinin based formulation
What are the serious complications of typhoid?
GI perforation
Myocarditis
Hepatitis
Nephritis
What is the treatment for typhoid?
Co-trimoxazole and chloramphenicol/ampicillin
If drug resistance then 3rd gen. cephalosporin or azithromycin may be needed
How does Dengue fever typically present?
Erythematous rash, myalgia, arthralgia and high fever
Where does Dengue fever commonly occur?
Tropics
Where is Chikungunya commonly found?
Endemic in parts of Africa, Asia and India
How does Chikungunya typically present?
Fever
Arthritis
Arthralgia
Where is the Zika virus commonly found?
Transmitted by aedes mosquitoes in Central and South America and the Caribbean
How does zika virus commonly present?
Fever
Rash
Conjunctivitis
Arthralgia
How does the zika virus affect pregnant women?
Causes fetal microcephaly and other brain abnormalities
What causes lyme disease?
Borrelia Burgdorferi transmitted via ticks
Describe the lesion associated with lyme disease infection?
Erythematous macule at the site of lesion enlarged to cause typical “target” lesion aka erythema migrans
How does early lyme disease present?
Fever
Headache
Malaise
Myalgia
Arthralgia
Lymphadenopathy
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
How is lyme disease diagnosed?
Clinically and lyme serology
What is the treatment of lyme disease in those <8y/o
Amoxicillin
What is the treatment of lyme disease in those >8y/o
Doxycycline
What are examples of live attenuated vaccines?
MMR
Rotavirus
BCG
What are examples of inactivated vaccines?
Polio
Influenza
What are examples of subunit vaccines?
Diphtheria
Pneumococcal
HPV
HBV
What vaccines are routinely given in the UK at 2 months?
6 in 1
Rotavirus
Meningococcal B
What is included in the 6 in 1 vaccine?
Diphtheria
Tetanus
Pertussis
Polio
H. influenzae B
Hepatitis B
What vaccines are routinely given in the UK at 3 months?
6 in 1
Rotavirus
Pneumococcal conjugate vaccine (PCV)
What vaccines are routinely given in the UK at 4 months?
6 in 1
MenB
What vaccines are routinely given in the UK at 12 months?
PCV
MenB
HiB/MenC
MMR
What vaccines are routinely given in the UK at 2-7 years?
Influenza seasonal vaccine
What vaccines are routinely given in the UK at 3 years and 4 months?
MMR
4 in 1 (Diphtheria, tetanus, pertussis, polio)
What vaccines are routinely given in the UK at 12-13 years?
HPV
What vaccines are routinely given in the UK at 14 years?
Men ACWY
3 in 1 (diphtheria, pertussis, polio)
What are the contraindications of immunisation?
Postponed if acute infection
Live vaccines should not be given to immunocompromised patients
Anaphylaxis to previous dose
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
Is SCID a T-cell or B-cell immunodeficiency?
Can affect both
What is SCID?
A heterogenous group of inherited disorders of profoundly defective cellular and humoral immunity
What triad of features is typical of Wiskott-Aldrich syndrome?
Immunodeficiency
Thrombocytopenia
Eczema
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
What is ataxia telangiectasia and how does it present?
Defect in DNA repair
Increased risk of lymphoma
Cerebellar ataxia and developmental delay
In immunodeficiency how do B-cell defects present?
Severe bacterial infections especially ear, sinus, pulmonary and skin
Recurrent diarrhoea
Faltering growth
What are some types of B-cell defects?
X-linked agammaglobulinaemia
Common variable immune deficiency (CVID)
Hyper IgM syndrome
Selective IgA deficiency
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
What is an example of neutrophil defect disease?
Chronic granulomatous disease
How is chronic granulomatous disease inherited?
Mostly x-linked recessive but some AR
In immunodeficiency how do leukocyte function defects present?
Delayed separation of umbilical cord
Delayed wound healing
Chronic skin ulcers
Deep-seated infections
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
What is the basic pathophysiology of chronic granulomatous disease?
Neutrophils fail to produce superoxide after phagocytosis of microorganisms
What is an example of a leukocyte function defect?
Leukocyte adhesion deficiency
In immunodeficiency how do complement defects present?
Recurrent bacterial infections
SLE-like illness
Recurrent meningococcal, pneumococcal and H.influenzae infections
What are some examples of complement defect disorders?
Early complement component deficiency
Terminal complement component deficiency
Mannase-binding lectin (NBL) deficiency
What investigations should be done for T-cell defects?
FBC
Lymphocyte subsets
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
What investigations should be done for B-cell defects?
Immunoglobulins
IgG subclasses
Lymphocyte subsets
Specific antibody responses
What investigations should be done for complement defects?
Tests of classical and alternative complement pathways
MBL levels
Assays for individual complement proteins
What is the antibiotic prophylaxis of T-cell and neutrophil defects?
Co-trimoxazole to prevent PCP
Itraconazole/fluconazole to prevent fungal infections
What is the antibiotic prophylaxis of B-cell defects?
Azithromycin to prevent recurrent bacterial infections
Other than prophylactic antibiotics what are the other treatments for immunodeficiency?
Screening for end organ disease
Immunoglobulin replacement therapy
Bone marrow Tx
Gene therapy
What are the symptoms of non-IgE mediated allergy?
D&V
Abdo pain
Faltering growth
What tests can be done in suspected allergy?
Skin prick tests
IgE blood tests
Spirometry and lung function tests
Allergy challenge
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
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
How does eosinophilic oesophagitis present?
Persistent vomiting and swallowing difficulty in young children
Difficulty swallowing and food impaction in older children
What gene mutations are a risk factor for development of atopic eczema?
Fillagrin gene mutations
At what stage is urticaria considered chronic?
6 weeks
How is chronic urticaria managed?
Non-sedating antihistamines
Refractory disease may need omalizumab
What does a child with Chediak-Higashi syndrome typically look like?
Pale with red hair
How is Chediak-Higashi syndrome inherited?
AR
What is the prognosis for Chediak-Higashi syndrome?
Often fatal in childhood
After erythema migrans, what is the next most common symptom in lyme disease?
Neurological disorders - facial nerve palsy is most common
What are the neurological symptoms in lyme disease?
Facial nerve palsies
Meningitis
Encephalitis
Peripheral mononeuritis
Lymphocytic meningoradiculitis
What are the cardiac symptoms in lyme disease?
Myopericarditis
Heart block (1st degree)
What are lymhocytomas and where do they typically present?
Bluish-red nodules infiltrated with lymphocytes
Typically on earlobe or nipple
How is SCID usually inherited?
AR
May be de novo
In SCID what would be seen on the lymphocyte count?
Lymphopenia <2.5-3
In SCID what would the CXR show?
Absent thymic shadow
In SCID what would be seen on checking immunoglobulin levels?
Low IgG, IgM and IgA
If an individual with SCID needs a blood transfusion what additional precautions should be taken?
Blood should be CMV -ve and irradiated
What may precipitate hereditary angioedema?
Trauma
Stress
Menstruation
ACEIs
OCPs
What are the GI symptoms of Omenn syndrome?
Chronic diarrhoea
Protein loss leading to generalised oedema
What are the skin symptoms of Omenn syndrome?
Generalised erythroderma with thickened and leathery skin and alopecia
What is Omenn syndrome?
Exaggerated inflammatory response by oligoclonal T-cells
What are the reticuloendothelial symptoms of Omenn syndrome?
Lymphadenopathy
Hepatosplenomegaly
What protein is behind the symptoms in hereditary angioedema?
C1 esterase inhibitor
Type 1 is a deficiency
Type 2 is a defective version
What proteins are deficient in Omenn syndrome?
RAG1 and RAG2
How is hereditary angioedema inherited?
AR
What would screening tests show in hereditary angioedema type 1?
C1INH functional level decreased
C1INH antigenic level reduced
C4 low
How does hereditary angioedema present?
Episodic attacks of angioedema
Abdo pain common due to GI mucosal oedema
Which type of hereditary angioedema is most common?
Type 1 - 85% of cases
How are hereditary angioedema attacks prevented?
Antifibrinolytics
- epsilon amino caproic acid
- TXA
Purified C1INH from human plasma
Landelumab
What would screening tests show in hereditary angioedema type 2?
C1INH functional level decreased
C4 low
How are acute attacks of hereditary angioedema managed?
C1INH IV
Ecallantide
Icantibant
How is Wiskott-Aldrich syndrome inherited?
X-linked recessive
What type of bacteria causes gonorrhoea?
Gram negative coccus
What mutation causes Wiskott-Aldrich syndrome?
WAS gene on x-chromosome p11.22-11.23
What mediates a type I hypersensitivity reaction?
Immediate reaction mediated by IgE antibodies
What mediates a type II hypersensitivity reaction?
IgG or IgM mediated cytotoxic reaction occurring over hours to days
Give examples of type I hypersensitivity reactions.
Allergy
Anaphylaxis
Atopic disease
Give examples of type II hypersensitivity reactions.
Haemolytic disease of the newborn
AI haemolytic anaemia
Goodpastures
What mediates a type III hypersensitivity reaction?
Antibody-antigen complex mediated occurring over several hours, to days to weeks
Give examples of a type III hypersensitivity reaction.
RA
SLE
Post-streptococcal GN
What mediates a type IV hypersensitivity reaction?
T-cell mediated occuring 24-72hours after exposure
Give examples of a type IV hypersensitivity reaction.
Dermatitis
Mantoux testing
What infection is a major cause of SNHL in young children?
CMV
How does symptomatic congenital CMV present?
Blueberry muffin rash
Symmetrical IUGR
Congenital cataracts
Jaundice
Petechiae
Hepatosplenomegaly
Microcephaly
Unexplained ventriculomegaly
Hearing loss
DD
How does acquired CMV present?
Pneumonia
Colitis
Retinitis
Encephalitis
How is CMV treated?
Ganciclovir or valganciclovir in severe infections
Which virus causes roseola infantum?
HHV6
How is the Dengue virus transmitted?
Aedes mosquitoes
Where are aedes mosquitoes typically found?
tropical regions e.g. Sri Lanka and Brazil
What are the characteristic symptoms of Dengue fever?
High fever
Eye pain
Lethargy
Rash
Most severe type causes haemorrhagic fever
What is the first line treatment for mucormycosis?
Ambisome
What causes Taenia solium?
Tapeworm - ingesting undercooked pork containing larval cysts
What causes Echinococcus granulosus?
Tapeworm that causes hydatid disease
How is a Mantoux test read?
48-72 hours after injection the reaction should be read via the diameter of induration
What causes trachoma infection?
Chlamydia
What is the treatment of choice for malaria falciparum in the paediatric population?
Proguanil and atovaquone
How is a severe attack of hereditary angioedema with stridor treated?
C1 inhibitor concentrate
What are the features of severe malaria?
Cerebral malaria
Severe anaemia
Respiratory abnormalities
Renal failure
How does malaria typically present?
Headache
Cough
Fatigue
Arthralgia
Fevers
GI issues and jaundice
What is hyper-IgD syndrome?
Fever every 4-8 weeks with abdo pain, arthralgia, diarrhoea, vomiting, lymphadenopathy and skin rashes
What immunodeficiency is recurrent Neisseria meningitidis meningitis associated with?
Defects in the lytic complement pathway (C5-C9)
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
How is typhoid fever treated?
Ceftriaxone
Where is the antigen binding site located?
Within the variable region of the Ig structure, made up of both heavy ad light chains
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.
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
What is the most important factor to consider when assessing need for post-exposure prophylaxis against rabies?
Country in which the bite occurred
Which infection can cause neurocysticercosis?
T.solium
How are pinworms treated?
Single dose of mebendazole or albendazole
Where in the world is hepatitis E more common?
East and South Asia
How does Enterobius vermicularis present?
Anal itching, especially at night
Abdo pain
Vulvovaginitis
How does hepatitis E present?
Fever
Abdo pain
Jaundice
Hepatomegaly
How does hepatitis A typically present?
Diarrhoea
Abdo pain
Jaundice
How does hepatitis B present?
Diarrhoea
Abdo pain
Jaundice
Asymptomatic
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
Which types of hepatitis are transmitted via the faecal-oral route?
A&E
What type of infections are those with hypogammaglobulinaemia particularly prone to?
Encapsulated bacterial infections e.g. H.influenzae
What is the most common subtype of shigella infection in the developed world?
Shigella sonnei
What is the recommended treatment for schistomiasis?
Praziquantel
How long after the onset of a measles rash should a child be excluded from any nursery settings?
5 days
What is the treatment for chlamydia conjunctivitis in neonates?
Oral erythromycin QDS for 2 weeks
When do symptoms typically start in S.aureus food poisoning?
2-4hours after food ingestion
When should a mast cell tryptase level be taken in anaphylaxis?
Between 1-2hours following onset
What infections are those with chronic granulomatous disease prone to getting?
Skin and resp infections especially S.aureus and aspergillus
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
What infection does terminal complement component deficiency predispose to?
Meningococcal disease
What symptoms does Corynebacterium diphtheriae cause?
Fever
Sore throat
Difficulty swallowing
Pseudomembrane coating tonsils, pharynx and larynx
What are the signs of congenital varicella
Multiple congenital abnormalities
Microcephaly
Limb deformities
Chorioretinitis
Scarring
Hydrocephalus
What is the function of neuraminidase?
Hydrolyses sialic acid residues on host cells to release newly formed virions
What are C3 and C4 levels like in those with HAE between attacks?
C3 always normal
Persistently low C4
What is the most common cause of viral meningitis?
Enteroviruses
What treatment should children with HIV >6 weeks and <12 months recieve?
cART and PCP prophylaxis
What treatment should children with HIV 1-4 years old have?
cART
PCP if CD4 count <15% or <500x10^6/l
What treatment should children with HIV >5 have?
cART
PCP if CD4 count <15% or <200x10^6/l
What cellular process results in the degranulation of eosinophils?
Fusion of the lysosomal membrane with the plasma membrane
What are the most common causes of meningitis in babies <4weeks old?
E.coli
GBS
Listeria
What is the best antibiotic combination for meningitis in a child <4weeks old?
Ampicillin and cefotaxime
What is the most common vector for the leishmaniasis parasite?
Sandfly
What is the most sensitive test for diagnosing CGD?
DHR test (Dihydrorhodamine)
What cell deficiency is associated with DiGeorge syndrome?
T cell deficiency
What is the management of tetanus?
Wound debridement
Penicillin and tetanus toxoid
Prompt ICU with ventilation and sedation
Diazepam for spasms
Rest
What are the initial signs of cholera?
Vomiting
Watery, non-bloody diarrhoea (rice-water)
What is the management of cholera?
Oral rehydration therapy
Antibiotics
How does Brucellosis present?
Prolonged fever
Anorexia
Arthralgia
Hepatosplenomegaly
What type of bacteria is brucella melitensis?
Gram -ve cocco-bacillus
What are leukotrienes synthesised from?
Leukocytes and mast cells
What is the treatment of choice for meningitis prophylaxis?
Ciprofloxacin
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
Which pathogen is the most common cause of endocarditis with prosthetic valves?
Staph epidermidis
