Infection & Immunity Flashcards
You do a lumbar puncture and find raised proteins and low glucose. Is this likely to be due to a bacterial or a viral infection?
Bacterial
Give 5 signs of SLE.
- Malar rash.
- Discoid rash.
- Photosensitivity.
- Oral ulcers.
- Arthritis.
- Pleuritis.
- Pericarditis.
- Renal failure.
- Seizures.
- Thrombocytopenia.
What is the most common causative organism of UTI in children?
E.coli.
Give 3 signs of UTI in children.
- infants: poor feeding, vomiting, irritability
- younger children: abdominal pain, fever, dysuria
- older children: dysuria, frequency, haematuria
- features which may suggest an upper UTI include: temperature > 38ºC, loin pain/tenderness
How is urine collection done in children?
clean catch is preferable
if not possible then urine collection pads should be used
cotton wool balls, gauze and sanitary towels are not suitable
invasive methods such as suprapubic aspiration should only be used if non-invasive methods are not possible
What is the mx of UTI in children?
- infants less than 3 months old should be referred immediately to a paediatrician
- children aged more than 3 months old with an upper UTI should be considered for admission to hospital. If not admitted oral antibiotics such as cefalexin or co-amoxiclav should be given for 7-10 days
- children aged more than 3 months old with a lower UTI should be treated with oral antibiotics for 3 days according to local guidelines, usually trimethoprim, nitrofurantoin, cephalosporin or amoxicillin. Parents should be asked to bring the children back if they remain unwell after 24-48 hours
- antibiotic prophylaxis is not given after the first UTI but should be considered with recurrent UTIs
How would you treat a UTI that has been caused by Extended Spectrum Beta-Lactamases (ESBL) e.coli?
You would give meropenem.
ESBL bacteria are resistant to all penicillins and cephalosporins.
Name an organism that commonly causes osteomyelitis in children.
Staphylococcus aureus.
Give 3 signs of osteomyelitis in children.
- Joint Pain
- Lethargy
- Fever
What investigations might you do on a child who you suspect has an infected joint?
- XR.
- MRI.
- Blood cultures.
- Joint aspirate
How would you treat a child with osteomyelitis?
- flucloxacillin for 6 weeks
- clindamycin if penicillin-allergic
What bacteria commonly causes meningitis in children?
Neonates:
GBS
E.coli
Listeria monocytogenes
1m -> 6 years:
Neisseria meningitidis (meningococcus)
Streptococcus pneumoniae (pneumococcus)
Haemophilus influenzae
>6 years: Neisseria meningitidis (meningococcus) Streptococcus pneumoniae (pneumococcus)
What investigations might you do on a child who you suspect has meningitis?
FBC CRP U & E LFT blood glucose & blood gas coagulation screen culture of blood, throat swab, urine, stool rapid antigen test for meningitis organisms PCR of blood & CSF lumbar puncture
Describe the mx for a child with meningitis.
- Antibiotics
< 3 months: IV amoxicillin + IV cefotaxime
> 3 months: IV cefotaxime - Steroids
if > 1 month and Haemophilus influenzae then give dexamethasone - Fluids
treat any shock, e.g. with colloid - Cerebral monitoring
mechanical ventilation if respiratory impairment - Public health notification and antibiotic prophylaxis of contacts
ciprofloxacin is now preferred over rifampicin
- All patients should be transferred to hospital urgently. If patients are in a pre-hospital setting (for example a GP surgery) and meningococcal disease is suspected then intramuscular benzylpenicillin may be given, as long as this doesn’t delay transit to hospital.
- Intravenous dexamethasone should also be given to reduce the risk of neurological sequelae.
What is a septic screen?
A septic screen is used to check for infection, in particular meningitis:
- Blood culture
- FBC
- CRP
- Urine sample
Consider if indicated:
- CXR
- LP
- Rapid antigen screen on blood/CSF/urine
- Meningococcal and pneumococcal PCR on blood/CSF
- PCR for viruses in CSF (especially HSV and enterovirus)
Why does a child with meningococcal septicaemia develop a rash?
The purpuric rash is due to bacterial endotoxins damaging blood vessels -> vasculitis -> bleeding into SC tissue -> thrombosis and DIC.
Name 2 drugs that can be given as meningitis prophylaxis.
- Rifampicin.
2. Ciprofloxacin.
2-years-old, 2m history of malaise, pallor and reduced appetite. Occasional febrile episodes associated with a pink rash and soreness in her left thigh. Now reluctant to weight bear despite walking at 13 months. All immunisations are up to date and developmental history shows no concerns. O/E: low grade fever and cervical lymphadenopathy. ESR is significantly raised. Give 3 differentials.
- JIA.
- ALL.
- Transient synovitis.
- Septic arthritis.
3-year-old, 7-day history of high fevers. Now developed red eyes, a rash, sore mouth and throat. Miserable and unwell with a diffuse maculopapular rash on his torso. He has bilateral injected conjunctiva, red cracked lips and a strawberry tongue. 3x2cm cervical swelling and swollen reddened palms. Give 3 differentials.
- Kawasaki disease.
- Scarlet fever.
- Shingles/chickenpox.
- Measles - ask about immunisation history.
What is the diagnostic criteria for Kawasaki disease?
>5 days fever. And 4/5 of the following: - Non-purulent conjunctivitis. - Red mucous membranes - Cervical lymphadenopathy. - Rash. - Red and oedematous palms and soles/ Peeling of fingers and toes
What is Kawasaki disease?
A systemic vasculitis that affects children.
Describe the treatment for Kawasaki disease.
IV immunoglobulin and high dose PO aspirin.
What might you see on the blood results in a patient with Kawasaki disease?
High CRP/WCC/ESR.
High platelet count.
Why do you give high dose aspirin to children with Kawasaki disease?
To prevent thrombosis. These children have thrombocytosis and so are at risk of thrombosis.
Give a potential complication that may develop in children with Kawasaki disease.
Coronary artery aneurysm.
Why is it important to avoid rapid rehydration?
Rapid rehydration can lead to cerebral oedema.
Describe the mx of DKA in children.
- Fluid resuscitation: 0.9% NaCl. Dehydration should be corrected gradually over 48 hours.
- Insulin infusion: 0.1units/kg/h. Blood glucose should be monitored hourly.
- Potassium replacement and cardiac monitoring.
What are indications to check urine sample?
- if there are any symptoms or signs suggestive or a UTI 2. with unexplained fever of 38°C or higher (test urine after 24 hours at the latest)
- with an alternative site of infection but who remain unwell (consider urine test after 24 hours at the latest)
What are the signs and symptoms in meningitis?
Symptoms: headache fever nausea/vomiting photophobia drowsiness seizures
Signs:
neck stiffness
purpuric rash (particularly with invasive meningococcal disease)
Give 3 features of hand, foot, mouth disease.
- mild systemic upset: sore throat, fever
- oral ulcers
- followed later by vesicles on the palms and soles of the feet
What is the mx of HFM disease?
- symptomatic treatment only: general advice about hydration and analgesia
- reassurance no link to disease in cattle
- children do not need to be excluded from school
What is the name of the microorganism which causes threadworm infestation?
Enterobius vermicularis
What are the features of threadworm infestation?
perianal itching, particularly at night
girls may have vulval symptoms
What is the mx of threadworm infestation?
hygiene measures + single dose of mebendazole for all the family
Overview of measles
RNA paramyxovirus
spread by droplets
infective from prodrome until 4 days after rash starts
incubation period = 10-14 days
Give 3 features of measles.
- prodrome: irritable, conjunctivitis, cough, , coryza
- Koplik spots (before rash): white spots (‘grain of salt’) on buccal mucosa
- rash: starts behind ears then to whole body, discrete maculopapular rash becoming blotchy & confluent
What is the ix done in measles?
IgM antibodies can be detected within a few days of rash onset
What is the mx of measles?
- mainly supportive
- admission may be considered in immunosuppressed or pregnant patients
- notifiable disease → inform public health
List 9 complications of measles.
- otitis media: the most common complication
- pneumonia: the most common cause of death
- encephalitis: typically occurs 1-2 weeks following the onset of the illness
- subacute sclerosing panencephalitis: very rare, may present 5-10 years following the illness
- febrile convulsions
- keratoconjunctivitis, corneal ulceration
- diarrhoea
- increased incidence of appendicitis
- myocarditis
Five 4 features of chickenpox.
Fever initially
Itchy rash starting on head/trunk before spreading. Initially macular then papular then vesicular
Systemic upset is usually mild
Give 4 features of mumps.
Fever
Malaise
Muscular pain
Parotitis (‘earache’, ‘pain on eating’): unilateral initially then becomes bilateral in 70%
Give 2 features of rubella.
Rash: pink maculopapular, initially on face before spreading to whole body, usually fades by the 3-5 day
Lymphadenopathy: suboccipital and postauricular
Give 4 features of slapped-cheek syndrome.
Also known as fifth disease or ‘slapped-cheek syndrome’
Caused by parvovirus B19
Lethargy
Fever
Headache
‘Slapped-cheek’ rash spreading to proximal arms and extensor surfaces
Give 5 features of scarlet fever.
Reaction to erythrogenic toxins produced by Group A haemolytic streptococci
Fever Malaise Tonsillitis 'Strawberry' tongue Rash - fine punctate erythema sparing the area around the mouth (circumoral pallor)
Why is ibuprofen avoided in chicken pox?
There is an associated risk between use of NSAIDs and the development of necrotising fasciitis.
Describe the infectivity of chicken pox.
Chickenpox is highly infectious: spread via the respiratory route can be caught from someone with shingles infectivity = 4 days before rash, until 5 days after the rash first appeared* incubation period = 10-21 days
Give 4 mx of chicken pox.
- keep cool
- trim nails
- calamine lotion
- immunocompromised patients and newborns with peripartum exposure should receive varicella zoster immunoglobulin (VZIG). If chickenpox develops then IV aciclovir should be considered
Describe the school exclusion criteria for chicken pox.
Advise that the most infectious period is 1–2 days before the rash appears, but infectivity continues until all the lesions are dry and have crusted over (usually about 5 days after the onset of the rash).
Give 4 complications of chicken pox.
- pneumonia
- encephalitis (cerebellar involvement may be seen)
- disseminated haemorrhagic chickenpox
- arthritis, nephritis and pancreatitis may very rarely be seen
Describe the epidemiology of roseola infantum.
Caused by the human herpes virus 6 (HHV6).
It has an incubation period of 5-15 days
Affects children aged 6 months to 2 years.
Give 5 features of roseola infantum.
- high fever: lasting a few days, followed later by a
- maculopapular rash
- Nagayama spots: papular enanthem on the uvula and soft palate
- febrile convulsions
- diarrhoea and cough
School exclusion is not needed.
Give 2 complications of HHV6 infection.
aseptic meningitis
hepatitis
Give 5 contraindications to MMR.
- severe immunosuppression
- allergy to neomycin
- children who have received another live vaccine by injection within 4 weeks
- pregnancy should be avoided for at least 1 month following vaccination
- immunoglobulin therapy within the past 3 months
List 4 complications of mumps.
- Orchitis - uncommon in pre-pubertal males but occurs in around 25-35% of post-pubertal males. Typically occurs four or five days after the start of parotitis
- Hearing loss - usually unilateral and transient
- Meningoencephalitis
- Pancreatitis- raised serum amylase
List 4 criteria to arrange an USS on a child with UTI.
- During the acute infection in all children with atypical infection, indicated by:
Poor urine flow.
Abdominal or bladder mass.
Raised creatinine.
Sepsis.
Failure to respond to treatment with suitable antibiotics within 48 hours.
Infection with non-E. coli organisms.
Note: infants and children with abnormal imaging results should be assessed by a paediatric specialist. - During the acute infection in children aged under 6 months with recurrent UTI.
- Within 6 weeks for children aged 6 months and over with recurrent UTI.
- Within 6 weeks, for all children younger than 6 months of age with first-time UTI that responds to treatment.
List 2 criteria to carry out a DMSA scan.
DMSA scan to detect renal parenchymal defects is carried out within 4–6 months following the acute infection in:
All children aged under 3 years with atypical or recurrent UTI.
All children aged 3 years or over with recurrent UTI.
