Paediatric Infectious Disease Flashcards
At what age are children most at risk of sepsis?
The younger they are the more at risk of sepsis
- 1 in 200 children under 1yr get sepsis
Fatality rate is around 10% for children who get sepsis
What is sepsis?
it’s a systemic inflammatory response syndrome + suspected or proven infection
Sepsis = SIRS + infection
What are the requirements for a child to be classified as having a systemic inflammatory response syndrome (SIRS)?
Need to have 2 or more of:
- Temperature: >38 or <36
- WCC: >15x10^9/L or <5x10^9/L
- Tachycardia > 2SD above normal for age
- Tachpnoea > 2SD above normal for age
What is severe sepsis? What is septic shock?
Severe sepsis = sepsis + organ dysfunction
Septic shock = sepsis + CVS dysfunction
(Sepsis = SIRS + infection)
What are some particularly worrying signs that point towards sepsis in children?
- Change in skin colour (pale / blue)
- Low activity, not responding to social cues, crying
- Grunting, tachypnoea, laboured breathing
- Tachycardia, reduced cap refill, reduced skin turgor
- High temperature, neurological signs, neck stiffness
What is the paediatric SEPSIS 6?
- Temperature: >38 or <36
- Inappropriate tachycardia
- Poor peripheral perfusion
- Altered mental state
- Inappropriate tachypnoea
- Hypotension
What are some factors that predispose infants < 3 months to infection (sepsis)?
Prematurity Prolonged rupture of membranes Maternal pyrexia / chorioamnionitis Maternal group B strep Previous pregnancy / child with group B strep Maternal STI
How do you treat a child with sepsis?
- Give high flow oxygen
- Take bloods
- Give IV antibiotics
- Consider fluid resuscitation
- Consider inotropic (heart contraction) support
What fluids do you give to a child experiencing sepsis?
20mL/kg of 0.9% NaCl
2mL/kg of 10% dextrose (don’t ever forget glucose)
What antibiotics are used to treat a child with sepsis?
3rd generation cephalosporin (cefotaxime)
Add IV amoxycillin if <1 month old
Which bloods do you want to take for a child with sepsis?
FBC CRP Coagulation screen (DIC) Blood gas (metabolic acidosis, raised lactate) Glucose Blood culture
What cultures would you do for an infant suffering from sepsis?
Blood
Urine
CSF
+/- stool depending on history of diarrhoea?
What are the main organisms causing sepsis in neonates less than one month old?
Group B streptococcus
E. Coli
Listeria Monocytogenes
What are the main organisms causing sepsis in infants older than 1 month and older children?
Streptococcus pneumoniae
Nisseria Meningitidis
Group A streptococcus
Staphylococcus Aureus
What are some of the characteristics of staphylococcus aureus?
Gram positive cocci
Coagulase positive (turns fibrinogen - fibrin)
Colonizes skin and mucosa
What are some of the characteristics of sreptococcus pyogenes?
Gram positive cocci
Beta haemolytic
Colonizes the oropharynx
what are the majority of skin and soft tissue infections caused by?
Staphylococci and Streptococci
Mostly staph aureus and step pyogenes
What is staphylococcal scalded skin syndrome? Characteristics?
Condition characterized by initial bullous lesions followed by widespread desquamation (loss of skin)
- Severe widespread erythema
- Nikolsky sign: press on what seems to be intact skin and it desquamatizes on minimal pressure
- Mild fever
- Purulent conjunctivitis
How do you treat staphyloccocal scalded skin syndrome?
IV antibiotics - Flucloxacillin
IV Fluids
What organism causes scarlet fever? How does scarlet fever tend to present?
Group A Strep (strep pyogenes) (toxin mediated)
At first - fever, malaise, sore throat Then: - Very red "strawberry" tongue - Sandpaper erythematous rash - Rash isn't on: palms, soles of feet, around mouth
How is scarlet fever managed?
Notifiable disease - inform public health
10 day course of antibiotics: phenoxymethylpenicillin (penicillin V)
What are some of the complications of scarlet fever? (incidence reduced by antibiotic use)
- Retropharyngeal or peritonsillar abscesses (quincy)
- Acute rheumatic fever (most common cause of acquired heart disease in children)
- Post-streptococcal glomerulonephritis
How does acute rheumatic fever present?
- Occurs 2/3 weeks after pharyngitis
- Arthritis
- Carditis
- Chorea (involuntary, unpredictable movements)
- Erythema marginatum
- Subcutaneous nodules
What is the causative organism for toxic shock syndrome? How severe is this condition? What is the mechanism of the condition?
Caused by gram positive bacteria (S aureus and group A strep)(fatality much higher with GAS)
Very severe - can rapidly progress to shock and multiorgan failure
Superantigen causes intense T cell stimulation: excessive immune activation and pro-inflammatory cytokine release
What is group A strep?
Streptococcus pyogenes
What is the initial presentation of toxic shock syndrome?
- Non-purulent conjunctivitis
- Swollen lips
- Strawberry tongue
- Diffuse, maculopapular “sunburn” rash
- If S. Aureus: severe diarrhoea
What are some signs that toxic shock syndrome is progressing?
- Tachycardia
- Prolonged Capillary refill
- Hypotension (more rapid onset than usual)
- Reduced GCS
- Renal impairment
- Transaminitis (high liver enzymes)
Investigations for toxic shock syndrome?
Cultures:
- Bloods
- Throat swabs
- Wounds
Management of toxic shock syndrome (TSS)?
- Give oxygen and take bloods
- Fluid resuscitation (.9% NaCl & 10% dextrose)
- IV antibiotics: flucloxacillin and clindamycin
- IV immunoglobulins (IVIG)
Avoid NSAIDS (can cause necrotizing fasciitis)
What is one very important step in the management of toxic shock syndrome?
Surgical debridement: if there are any areas of pus remaining there is still ongoing toxin production and inflammatory response
What is meningitis? What is meningism?
Meningitis - A disease caused by the inflammation of the meninges
Meningism - the clinical signs and symptoms suggestive of meningeal irritation
How do older children with meningitis tend to present?
- Fever
- Headache
- Photophobia
- Neck stiffness
Nausea and vomiting
Reduced GCS
Seizures
Focal neurological deficits
How do young infants tend to present with meningitis?
- Fever or hypothermia
- Poor feeding & vomiting
- Lethargy, irritability
- Respiratory distress
- Apnoea
- Bulging fontanelles
What is apnoea?
Temporary cessations in breathing
What are some clinical signs of meningitis?
- Neck stiffness: palpable resistance to neck flexion
- Brudzinski’s sign: hips and knees flex on passive flexion of the neck
- Kernig’s sign: pain on passive extension of the knee
What is the most common cause of childhood meningitis?
Viral - mainly enterovirus
What causes childhood meningitis?
Bacterial 4 - 18%
Viral 54 - 88%
Unknown / aseptic 40 - 76%
Fungal neonates / immunocompromised
What organisms are responsible for causing bacterial meningitis in young infants?
Group B Strep (strep agalactiae)
E. Coli
Listeria monocytogenes
What organisms are responsible for causing bacterial meningitis in older children?
Strep pneumoniae
Nisseria meningitidis
Haemophilus influenzae type B (Hib)
What condition does non-encapsulated haemophilus influenzae cause commonly?
Otitis media
& sinusitis
What are some characteristics of nisseria meningitidis?
Gram negative diplococcus
Nasopharyngeal carriage
Invasive infection often follows viral URTI
What are some risk factors for invasive meningococcal disease?
Age (< 1 year or 15-24 years) Unimmunised Crowded living conditions Household or kissing contact Cigarette smoking (active or passive) Recent viral / mycoplasma infection Complement deficiency
What is the cardinal sign of meningococcal meningitis?
Petechial and more so purpuric rash
- Petechiae: small red / purple non-blanching spots on skin
- purpura: bigger red / purple rashes
How severe of a disease is invasive meningococcal disease?
Severe:
- Rapidly progressive
- Case fatality of 5-15%
- 50% of deaths in first 12h, 80% in 48h
- Significant long term complications: amputation (14%), scarring (48%), hearing loss, cognitive impairment / epilepsy
What organism causes meningococcal meningitis / meningococcal disease?
Nisseria meningitidis
What are the characteristics of streptococcus pneumoniae?
Gram positive
> 90 serotypes, all can cause invasive disease
colonizes the nasopharynx
Invasive infection commonly preceded by URTI
Why is it hard to vaccinate against strep pneumoniae?
Because there are so many serotypes and as you vaccinate one a higher proportion of cases becomes composed of other serotypes
What are some risk factors for pneumococcal disease?
Age (< 2 years) Cigarette smoking (active / passive) Recent viral URTI Attendance at childcare Cochlear implant Sickle cell disease Asplenia (bad spleen function) HIV infection Nephrotic syndrome Immunodeficiency / immunosuppression
Main big risk factors for bacterial meningitis?
preceding URTI
Age < 1 or 2
Exposure to lots of people
Cigarette smoking
What are some common complications of pneumococcal meningitis?
Neurological consequences are common:
- Hydrocephalus
- Neurodisability
- Seizures
- Hearing loss
- Blindness
How do you treat meningitis?
Same as sepsis:
- Give oxygen and take bloods
- Fluid resuscitation (.9% Nacl & 10% dextrose)
- Antibiotics: 3rd gen cephalosporins (cefoxatime) as well as IV amoxycillin if <1 month old)
What are the two main investigations for meningitis in children?
Bloods
Lumbar puncture*** (diagnostic)
What bloods are done for children with suspected meningitis?
FBC U&E's / LFTs CRP Coagulation screen Blood gas Glucose Blood culture **** (ideally before antibiotics but don't delay) Meningococcal / pneumoccocal PCR
What are the main contraindications to lumbar puncture?
Signs of raised ICP:
- GCS<9, abnormal tone / posture, high BP & bradycardia, pupillary defects, papilloedema)
- Focal neurological signs
- Recent seizure
- Cardiovascular instability
- Coagulopathy
- Thrombocytopenia
- Extensive or extending purpura
What do you send the CSF for once you’ve done your lumbar puncture?
Microscopy Gram stain Culture Protein Glucose Viral PCR ******* (most common cause of meningitis)
What findings are expected from the CSF after a lumbar puncture if bacterial meningitis?
Turbid or purulent CSF appearance
High opening pressure when doing LP
High CSF WCC (neutrophils)
High Protein in CSF
Low glucose in CSF
What findings are expected from the CSF after a lumbar puncture if viral meningitis?
Clear appearance
Protein mildly raised or normal
WCC very high (lymphocytes)
Glucose unchanged
What accounts for the differences between viral and bacterial CSF findings?
- Bacteria swimming in the CSF will release proteins and use up the glucose.
- Viruses don’t use glucose but may release a small
amount of protein. - The immune system releases neutrophils in response to bacteria and lymphocytes in response to viruses
Most common causes of viral meningitis?
herpes simplex virus (HSV),
enterovirus
varicella zoster virus (VZV)
