infectious diseases Flashcards
how do infectious diseases present in children
majority due to viruses (in developed world)
majority are self limiting
median duration is 8 - 14 days, 3 - 5 months/year
what is sepsis
systemic inflammatory response syndrome with suspected/proven infection
severe sepsis: sepsis + organ dysfunction
septic shock: sepsis + CVS dysfunction
how does systemic inflammatory response syndrome present?
- fever or hypothermia
- white cells
- tachycardia
- tachypnoea
what is the epidemiology of sepsis
peak incidence in early childhood
< 1 year: 1 in 200
1 - 4 years: 1 in 2000
5 - 15 years: 1 in 5000
what is used to identify fever in under 5s
colour (skin, lips, tongue)
activity
respiratory
circulation & hydration
what is the septic 6 score
temperature: <36°, >38° peripheral fusion: capillary refill time mental state: sleepiness, irritability, lethargy, floppiness tachycardia: refer to pews 8 tachypnoea: refer to pews 8 hypotension: refer to pews 8
why do we worry about infants <3 months
increased risk of
- bacterial infection
- sepsis
- meningitis
minimal signs and symptoms
- non specific presentation
may not mount a febrile response
what are risk factors for infections in infants <3 months
prematurity (<37/40)
prolonged rupture of membranes (PROM)
maternal
- pyrexia/chorioamnionitis
- GBS
- STI (chlamydia, gonorrhoea, syphilis, HSV)
what is the management of sepsis
airway
breathing
circulation - 20ml/kg fluid bolus
defg (don’t ever forget glucose - 2ml/kg 10% dextrose)
antibiotics
- cephalosporin (cefotaxime/ceftriaxone)
- IV Amoxicillin if <1m old
what are the investigations for sepsis
bloods
- FBC (leukocytosis, thrombocytopaenia)
- CRP
- coagulation screen (DIC)
- blood gas (metabolic acidosis, raised lactate)
- glucose
cultures - blood - urine - CSF (including send to virology) \+/- stool (micro + virology)
imaging
- CXR
what are responsible organisms for sepsis
neonates (<1 month)
- group B streptococci
- e.coli
- listeria monocytogenes
older infants & children
- group A streptococcus
- streptococcus pneumoniae
- staphylococcus aureus
- neisseria meningitidis
what is the pathophysiology of sepsis?
overwhelming response to infection
- LPS/bacterial components act on endothelium, neutrophils and monocytes
- secretion of pro and anti-inflammatory cytokines
- activation of complement
- activation and mobilisation of leukocytes
- activation of coagulation and inhibition of fibrinolysis
- increased apoptosis
what is meningitis
disease caused by inflammation of the meninges
what is meningism
clinical signs and symptoms suggestive of meningeal irritation
what are the signs and symptoms of meningitis
- fever
- headache
- photophobia
- neck stiffness
- nausea & vomiting
- reduced gcs
- seizures
- focal neurological deficits
what are the clinical signs of meningitis
nuchal rigidity: palpable resistance to neck flexion
bruduzinski’s sign: hips and knees flex on passive flexion of the neck
kernig’s sign: pain on passive extension of the knee
what are the causes of meningitis
- viral
- bacterial
- fungal
- unknown/aseptic
what are the responsible organisms for bacterial meningitis
neonates (<1 month)
- group B streptococcus
- e.coli
- listeria monocytogenes
older infants & children
- streptococcus pneumoniae
- neisseria meningitidis
- haemophilus influenzae
what is haemophilus influenza type B?
- gram-negative coccobacillus
- nasopharyngeal carriage
- encapsulated h influenza: bacteraemia, meningitis, epiglottis, pneumonia
- capsulated h influenza: otitis media & sinusitis
what is neisseria meningitidis
- gram negative diplococcus
- nasopharyngeal carriage
- transmission: respiratory secretions
- often after viral URTI
- polysaccharide capsule
- endotoxin LPS
what are the risk factors for invasive meningococcal disease
- age: <1 years, 15 - 24 years
- unimmunised
- crowded living conditions
- household or kissing contact
- cigarette smoking (active/passive)
- recent viral or mycoplasma infection
- complement deficiency
summarise presentation for invasive meningococcal disease
what is streptococcus pneumoniae
- gram-positive diplococcus
- colonises nasopharynx
- polysaccharide capsule
what are the risk factors for invasive pneumococcal disease
- age: <2 years
- smoking: active or passive
- recent viral URTI
- attendance at childcare
- cochlear implant
- sickle cell disease, asplenia, HIV infection
- nephrotic syndrome
- immunodeficiency/Immunosuppression
what is the common neurological sequelae in meningitidis
- hydrocephalus
- neurodisability
- seizures
- hearing loss
- blindness
what is the management of meningitidis
- airway
- breathing
- circulation (20ml/kg fluid bolus)
- defg (don’t ever forget glucose - 2ml/kg 10% dextrose)
- antibiotics (cefotaxime/ceftriaxone)
+ IV amoxicillin if <1 month
what are the investigations for meningitidis
bloods
- FBC (leukocytosis, thrombocytopaenia)
- U&Es, LFTs
- CRP
- coagulation screen (DIC)
- blood gas (metabolic acidosis, raised lactate)
- glucose
cultures (PCR)
- bloods
- CSF
- meningococcal/pneumococcal PCR
other
- focal neurological signs
- seizure
- cardiovascularly unstable
- coagulopathy
- thrombocytopenia
- extensive or extending purpura
what are signs of raised intracranial pressure
- GCS <9
- abnormal tone or posture
- HTN & Bradycardia
- pupillary defects
- papilloedema
what does lumbar puncture measure
- microscopy
- gram stain
- culture
- protein: increased
- glucose: decreased
- viral PCR
what is the microbiology of staphylococcus aureus
what is the microbiology of streptococcus pyogenes (GAS)
what are skin and soft tissue infection
- cellulitis
- boils/furuncles
- impetigo
- infected eczema
- lymphadenitis
what is staphylococcal scalded skin syndrome
age: <5y
presentation:
- toxin mediated (exfoliatoxin)
- bullous lesions widespread desquamation
- nikolsky sign
- mild fever, purulent conjunctivitis
management:
- IV flucloxacillin + IV Fluids
what is scarlet fever
presentation:
- fever
- malaise
- sore throat
- strawberrry tongue
- sandpaper rash
- skin peeling (desquamation)
management: phenoxymethylpenicillin (Penicillin V) 10 days
complications: abscess formation, acute rheumatic fever, post-streptococcal glomerulonephritis
what is toxic shock syndrome
- gram +ve bacteria S. aureus & GAS
- superantigen causes intense T cell stimulation
presentation:
- fever
- diffuse, maculopapular, ‘sunburn’ rash
- mucosal changes: non-purulent conjunctivitis, swollen lips, strawberry tongue
- profuse diarrhoea (S. aureus)
rapid progression to shock & multi-organ failure
- tachycardia
- prolonged CRT
- hypotension
- renal impairment
- transaminitis
- reduced GCS
what is the management of toxic shock syndrome?
- ABC
- fluid resuscitation +/- inotropes
- cultures: blood, throat swabs, wounds
- IV Antibiotics: flucloxacillin + clindamycin
- IVIG
- avoid NSAIDs
- surgical debridement
