Microbiology, infection, immunity, and allergy Flashcards
What is the main cause of UTIs in children?
E coli
What is the first line treatment for E coli UTI?
IV cefuroxime for 7 days
What is the oral switch with an E coli UTI?
Trimethoprim but may need full course IV
What is the worry with E coli UTIs?
Extended spectrum beta-lactamase producers - resistant to all penicillin and cephalosporins as will break them down
What are the alternative treatments for ESBL UTIs?
Meropenem - if suspect resistant and unsure of sensitivities (v broad spectrum)
Ideally - gentamicin
What should you be careful with with gentamicin?
Kidney function - often not an issue in children
How do you treat osteomyelitis/septic arthritis in over 3 months?
IV cefuroxime - liaise with microbiologists
Treat for min 6 weeks
IV -> PO switch once responding but patient led
Long term therapy - ?out patient antibiotic therapy
What might gram positive cocci in clusters that are golden on blood agar be?
S aureus
How do you treat MRSA?
IV teicoplanin/vancomycin
PO clindamycin/doxycycline (not under 12)
Depends on sensitivities
What is the first line treatment for bacterial meningitis/meningococcal sepsis?
IV cefotaxime/ceftriaxone
What investigations do you do for bacterial meningitis/menigococcal speticaemia?
Blood cultures
EDTA blood for PCR
CSF
What might gram negative diplococci be?
Neisseria meningitides
What prophylaxis do you give to meningitis contacts?
Ciprofloxacin stat dose
Rifampicin
What must you report to PHE?
All meningitis
All invasive meningococcal disease
All encephalitis
24/7
What might gram +ve diplococci, with alpha haemolysis that is optochin sensitive be?
Strep pneuominae
What is strep pneumoniae sensitive to?
IV benzylpenicillin or PO amox
What is the first line treatment for CAP?
Mild - oral amox
Severe - IV benzylpenicillin
Length depends on response
How common is infection?
Commonest single cause of admission of children to hospital
Younger > older children
Respiratory tract commonest site
May need antibiotic/antiviral treatment or just supportive care eg O2, fluids
Few rapid tests so treatment based on clinical picture
Symptoms of mild viral illness may be similar to serious bacterial infection
Viral illness can also be severe
What can cause pharyngitis/tonsilitis?
Group A strep, adenovirus, EBV
What can cause epiglotitis?
HiB
What causes whooping cough?
Pertussis
What can cause otitis media?
Pneumococcus, haemophilus, GpA strep, moraxella
What can cause croup?
Parainfluenza virus
What can cause tracheitis?
S aureus, Strep A, haemophilus
What can cause pneumonia?
Strep A, pneumo, staph, haemophilus, TB
What can cause atypical pneumonia?
Mycoplasma, chlamydia
What can cause bronchiolitis?
RSV, rhinovirus, flu, adenovirus, parainfluenza, metapneumo
What causes problems with varicella zoster virus?
Self-limiting but mortality if secondary infection staph or strep
What are the symptoms of HSV infection?
Stomatitis
Simple cold sore
Occasional encephalitis
Severe is eczema
What are the symptoms of Kawasaki disease?
Fever, rash, stomatitis
Periphery change
Adenopathy
Raised platelets
Coronary artery aneurysm
Unknown cause
What is important to remember with antibiotics?
Use the most appropriate antibiotic - not easy when you don’t know the cause
Narrow vs broad spectrum where possible
Minimum time period necessary
Follow local guidelines
Infection control
Start smart then focus PHE
Tolerability, formulation, toxicity and pharmacokinetics different in children
Paediatric access to new drugs may be 10 years behind adult availability
Need to come in a form that children can swallow
More vulnerable to antibiotic resistance
What investigations should you do for a child under 3 months with a fever without focus?
FBC
Blood culture
CRP
Urine culture
Other investigations as indicated
What investigations should you do for a child under 1 month with a fever without focus?
Same as child under 3 months
LP
When should you do a LP in a child 1-3 months of age?
Unwell or WBC < 5 or > 15
When should you give IV antibiotics?
All infants under 1 month and 1-3 months if unwell or WBC < 5 or > 15
What investigations should you do for a child under 1 month with a fever without focus?
Red features
- FBC, blood culture, CRP, urine culture
- LP if clinical features or unwell
- CXR consider if clinical features
Amber features
- As for red unless experienced paediatrician reviews
- CXR if WBC > 20 and temp > 39
Green
- Urine test
- No bloods
What are the green features?
Normal colour
Responds normally to social cues
Content/smiles
Stays awake/awakens quickly
Strong normal cry/not crying
Normal skin and eyes
Moist mucous membranes
What are the amber features?
Pallor reported by parent/carer
Not responding normally to social cues
No smile
Wakes only with prolonged stimulation
Decreased activity
Nasal flaring
Tachypnoea
- RR > 50 age 6-12 months
- > 40 aged > 12 months
O2 sat < 95% OA
Crackles in chest
Tachycardia
- > 160 age < 12 months
- > 150 age 12-24 months
- > 140 2-5 years
CRT > 3 s
Dry mucous membranes
Poor feeding
Reduced urine output
Age 3-6 months temp > 39
Fever for > 5 days
Rigors
Swelling of limb or joint
Non-weight bearing limb/not using extremity
What are the red signs?
Pale/mottled/ashen/blue
No response to social cues
Appears ill to a healthcare professional
Doesn’t wake up or if roused does not stay awake
Weak, high-pitched or continuous cry
Grunting
Tachypnoea RR > 60
Moderate or severe chest indrawing
Reduced skin turgor
Age < 3 months temp > 38
Non-blanching rash
Bulging fontanelle
Neck stiffness
Status epilepticus
Focal neurological signs
Focal seizures
What CSF findings do you get for bacterial meningitis?
Raised white cell count (neutrophils)
Raised protein
Low glucose
Bacteria identified in blood or CSF culture or PCR
What CSF findings do you get for viral meningitis?
Raised white cell count (lymphocytes)
Normal protein
Normal glucose
Virus identified in CSF, stool, throat, or blood
HSV encephalitis
What are the main causes of bacterial meningitis in under 3 months olds?
Gp B strep
E coli
Listeria
Pneumococcus
Meningococcus
How do you treat bacterial meningitis in under 3 month olds?
Cefotaxime and amoxicillin
What are the main causes of viral meningitis in children?
HSV - acyclovir
Enterovirus
What are the main causes of bacterial meningitis in over 3 month olds?
Meningococcus
Pneumococcus
H influenza
How do you treat bacterial meningitis in over 3 month olds?
Cefotaxime/cetriaxone
What are the main symptoms of meningitis?
Neck stiffness
Photophobia (not reliable in young children)
Drowsy/irritable
Vomiting
Headache
Full fontanelle
What are the symptoms of septicaemia in children?
Red/purple non-blanching rash
Cold hands and feet
Tachypnoea
Flu like symptoms
What are the main causes of bronchiolitis?
RSV
Parainfluenza virus
Influenza A/B
Rhinovirus
Adenovirus
Bronchial secretions PCP (pneumocysitis pneumonia/jiroveci)
What is the immune function in children like?
Immune levels at 60% of total adult levels in baby
Newborns make IgM and some IgA but most of IgG is maternal
How common is immune deficiency?
1 in 2000 births underlying immune deficiency
1 in 50-60,000 severe immune defect
Severe disease presenting in neonates/infants, immunological emergency
What are the symptoms of immune deficiency?
Failure to thrive, skin problems, chronic chest problems, organomegaly/adenopathy
When should you investigate for immune deficiency?
Frequent/unusually severe infections, infection with unusual organisms, and family history
What tests should you do for immune deficiency?
FBC - low total WBC, neutrophil or lymphocytes
Total Ig GAM +/- E
Responses to routine immunisation
Lymphocyte subsets: numbers of T and B cells
Lymphocyte function
What is the treatment for immune deficiency?
Antibiotic/antiviral prophylaxis
Prompt treatment of infections
Replacement of immunoglobulin
Bone marrow transplant
What are the warning signs for primary immunodeficiency?
Most important family history
2 or more of
- 4 or more new ear infections within a year
- 2 or more serious sinus infections within a year
- 2 or more months on antibiotics with little effect
- 2 or more pneumonias within a year
- Failure of an infant to gain weight or grow normally
- Recurrent, deep skin or organ abscesses
- Persistent thrush in mouth or fungal infection on skin
- Need for IV antibiotics to clear infections
- 2 or more deep-seated infections including septicaemia
- A family history of primary immunodeficiency
How do vaccines work?
Induce immunity: T and B cells (antibody) specific for organisms/toxins
Induce immunological memory
Protein antigens stronger stimulation
Antibodies (B cell memory) easily measured
Specific T cell memory
Herd immunity
Name a live attenuated vaccine
MMR
BCG
Nasal flu
Rotavirus
Name an inactivated vaccine
Whole cell pertussis
Name an inactivated toxin
Diphtheria
Tetanus
Name a recombinant component vaccine
Acellular pertussis
Name a conjugate vaccine
Bacterial polysaccharide + protein carrier
Name a cell wall/envelope component vaccine
Flu
MenB
What vaccine preventable diseases are there in the UK that aren’t travel related?
Tetanus
Diphtheria
Whopping cough
Polio
Measles
Mumps
Rubella
Hib
MenC
Prevnar 13 (pneumococcal)
Pneumococcus
Meningococcus ACWY
Varicella
TB
Hepatitis
Influenza
Rotavirus
HPV
MenB
What vaccines do children get a 2 months?
6-in-1: DTP, HiB, whooping cough, Hep B, pneumococcus, rotavirus
What vaccines do children get a 3 months?
Tetanus, diphtheria, pertussis, polio, HiB, MenC
What vaccines do children get at 4 months?
Tetanus, diphtheria, pertussis, HiB, perv 13, MenB
What vaccines do children get at 1 year?
HiB/MenC, MMR, pneumococcal, MenB
What vaccines do children get a 3-4 years?
MMR, DTP, whooping cough
What vaccines do children get a 13 years?
MenACWY, HPV, flu (some), tetanus
What are conjugate vaccines?
Polysaccharide coat of bacteria
Poorly immunogenic
Improved by conjugation to protein carrier
Generates immunological memory and reduced carriage of organism
What is latent TB?
Asymptomatic, uninfectious, treat to prevent disease in future
What is active TB?
Symptomatic/clinical evidence eg x-ray, lymphnodes - mortality high if untreated
How do you diagnose TB in children?
Children often not infectious but older children may be
Symptoms - fever, sweats, weight loss, cough
Contact tracing
Tests - sputum, XR, mantoux, IFN gamma bloods
BCG some protection against neonatal TB meningitis
How do you treat active TB?
2 months - 4 drugs
4 months - 2 drugs
How do you treat latent TB?
3 months 2 drugs
What can reduce risk of congenital infection?
HIV maternal Rx
Hepatitis B immunisations at birth
CMV - treatment of infant modifies disease
Rubella
HSV
VZV
TB - maternal treatment
Syphilis - maternal treatment
Gp B step - maternal peridelivery treatment
How common is HIV in children of UK?
> 1300 children
What is the prognosis of HIV in children?
With treatment should live relatively normal life to late adulthood
What is the risk of HIV transmission from mother to child?
Mother to child transmission significantly reduced in UK now < 1%
Transmission 25% with no intervention
How is risk of HIV transmission from mother to child reduced?
Pregnant mother given medication with controlled infection
Sometimes C section necessary
Infant medication 4 weeks
What is a cavernous haemangioma?
Birthmark AKA strawberry birthmark
Gets bigger over time
Don’t want them on nose or anywhere else that could get blocked or somewhere where it could easily bleed
Treated if one of these with beta blockers
Go away by 18 months to 2 years
Scar
What is a capillary haemangioma?
Birthmark AKA port wine stain
Doesn’t go away
In what condition are naevus more common?
Turner’s syndrome
In what population would you find mongolian blue spot birthmarks?
Non-Caucasian
Where would you find Mongolian blue spots?
Buttocks and back of children
What condition is associated with lots of cafe au lait marks?
Neurofibromatosis
How many cafe au lait spots can you have before we worry about neurofibromatosis?
More than 5
What are milia?
AKA milk spots
Sebaceous plugs
What is erythema toxicum neonatorum?
If baby well then normal
If baby unwell possibly staphylococcal infection
Infantile urticaria - histamine reaction
What causes chicken pox and shingles?
Varicella zoster virus
When should you be worried in a child with chicken pox?
Immunocompromised
Eczema
When might children get shingles?
Immunocompromised
Can pass on to other children - sheds virus
What does measles look like?
Rash all over body
What is the prodrome to measles like?
CCCK
- Cough
- Conjunctivitis
- Croyza
- Koplik spots
When should we worry about rubella and why?
Congenital form
Teratogenic
Multi-organ inflammation
What causes slapped cheek syndrome?
Parvovirus AKA erythema infectiosum
When is slapped cheek syndrome worrying?
Adults
Pregnancy
Haemoglobinopathies
How does roseola infantum present?
Non-specific rash
Follows misery, high fever
Often investigated for UTI or meningitis
Gets better when rash appears
What causes roseola infantum?
HHV6
Retrospective diagnosis
What is hand foot and mouth disease caused by?
Coxsackie
What does hand foot and mouth disease look like?
Tender lumps on hands, feet, and mouth
What is mumps?
Infectious parotitis
When do we worry about mumps?
Older boys
What is herpes stomatitis?
Primary herpes simplex
Can also get whitlow from sucking thumb
When do we worry in a child with coldsores?
If they stop drinking/eating
What is eczema herpeticum?
Infection of eczema with herpes simplex virus
Treat with IV acyclovir
What is impetigo caused by?
Staph aureus
What is impetigo?
Highly contagious infection
Golden crusting
Caused by staph aureus
Need to stay at home if have this
How is impetigo treated?
Depends on spread
Either oral or topical antibiotics
Flucloxacillin ideal but doesn’t taste nice so some children won’t take it, alternative co-amox
What is scaled skin syndrome?
Toxin mediated reaction to a staph infection somewhere in body
Need a penicillin to treat staph infection and clindamycin to treat toxins
What can cause periorbital cellulitis?
HiB and staph
What does the rash in HSP look like and what can this be confused with?
Non-blanching purpuric rash
Meningococcal septicaemia
What does scarlet fever look like?
Strawberry tongue
Red spots on skin except nose and around mouth
What is tinea?
Ringworm
How do you treat nappy rash without crease spread?
Barrier cream
Nappy free time
How do you treat nappy rash with crease spread?
Candida infection
Can also find in mouth so mother may also need treatment if breast feeding
Antifungal topical
What are the symptoms of congenital toxoplasmosis and where else can it come from?
Microcephaly
Fits
Nerve deafness
Cat poo
What is larva migrans cause by and where does it come from?
Dog poo
Toxocara
What can larva migrans cause?
Acquired blindness
What is infantile eczema otherwise known as?
Cradle cap
How is eczema treated?
Moisturising cream
Steroid cream
What is contact dermatitis otherwise known as?
Uritcaria
What does acanthosis nigricans and obesity together suggest?
Insulin resistance
What is a septic screen?
Name of a group of investigations carried out to look for possible infection - determines site and cause of infection
What would you do in a septic screen?
Bloods
Urine MC&S
CXR
LP
Stool sample
Swabs - throat, skin
Sputum culture
What bloods would you do in a septic screen and which is most important?
Blood culture most important
FBC
CRP
Blood gas
Lactate
U&Es
Blood glucose
Procalcitonin
What are the key investigations in a septic screen?
Blood cultures
Urine MC&S
CXR
LP
What bacteria is gram negative diplococci?
Neisseria meningitides
What is the immediate management of a child who has lowered consciousness?
ABCDE assessment
What is the sepsis 6 in children?
High flow O2
Obtain IV/IO access and take Bloods
Give IV/IO Antibiotics
Fluid resuscitation - 100ml bolus over 5 mins, repeat if necessary - measure Urine output
Involve senior clinicians early
Consider ICU admission if physiological parameters not resolved at > 40ml/kg
What antibiotics would you give for meningitis in a > 3 month old?
Ceftriaxone
What antibiotics would you give for meningitis in a < 3 month old and why?
Cefotaxime + amoxicillin to cover for listeria
How might you give O2 in a child?
Non-rebreathe 15L
Ventilation eg CPAP
How do you manage airway?
Check airway is open
Check nothing blocking it
Airway manoeuvres
How do you manage breathing?
Ventilation
Non-rebreathe 15L
How would you manage circulation with low CRT?
Fluids
0.9% NaCl give 200ml bolus over 5 mins
If doesn’t work ICU admission + inotrophs
Why would you give ceftriaxone over cefotaxime?
Cefotaxime doesn’t clear nasal carriage
Cefotaxime is 4 times per day whereas ceftriaxone is once per day
What is the cause of purpura?
DIC and using up clotting factors so get bleeding in vessels that cannot be stopped
How is meningitis spread?
Sharing respiratory of throat secretions - coughing, kissing, lengthy contact
What is the close contact treatment for meningitis?
Ciprofloxacin - stat dose
Rifampicin - don’t give in pregnancy, on oral contraceptive, when wearing contacts as can turn red
What is a close contact?
People in same household
Roommates
Anyone in direct contact with patient’s oral secretions eg partner
Any healthcare professional who wasn’t wearing correct PPE during intubation if intubated
What are the fever differentials in children?
Infection
Malignancy
Endocrine issues
Inflammation
Name 3 thigh pain differentials
Osteomyelitis
Fracture
Cellulitis
Bone cancers
JIA
Muscle infection
What is the criteria for Kawasaki disease diagnosis?
Fever for 5 or more days with at least 4/5 principle clinical features
- Bilateral conjunctival injection
- Changes in lips and oral cavity
- Cervical lymphadenopathy
- Extremity changes
- Polymorphus rash
How is Kawasaki disease managed?
NSAIDs - aspirin
IVIG
Corticosteroids
What complications can you get from aspirin?
GI ulcers
Reye’s disease - brain and liver damage
What complications can you get from IVIG?
Headache
Allergic reactions/transfusion reactions
Risks associated with blood products
What complications can you get with steroids?
Adrenal suppression
Weight gain
Acne
Eye problems
Hypertension
What further investigations does a child with Kawasaki disease need and why?
Echo - monitoring for coronary aortic aneurysms
Long term follow-up
What is the long-term prognosis of Kawasaki disease?
Full recovery can take around 6 weeks but can be longer
With prompt treatment 0.1-2% mortality
With coronary artery aneurysm 25% mortality rate
