Infectious Diseases Flashcards
How do infectious diseases differ between children and adults?
- Most characterised by fever and rash
- Range of disease severity
- Developing immune system so different clinical presentation
- Can be presenting symptom of primary immunodeficiency
Define paediatric sepsis
Systemic inflammatory response syndrome with suspected/ proven infection
How doe sepsis present?
- Fever or hypothermia
- Tachycardia
- Tachypnoea
- Leucocytosis or leucocytopaenia
What is bacteraemia?
Bacteria multiplying in the blood
What are the normal vital signs for <1 year?
RR
30-40
HR
110-160
SBP
70-90
What are the normal vital signs for 1-2 years?
RR
25-35
HR
100-150
SBP
80-95
What are the normal vital signs for 2-5 years?
RR
25-30
HR
95-140
SBP
80-100
What are the normal vital signs for 5-12 years?
RR
20-25
HR
80-120
SBP
90-110
What are the normal vital signs for >12 years?
RR
15-20
HR
60-100
SBP
100-120
What is severe sepsis?
SIRS + multi organ failure
How is severe sepsis defined?
SIRS +2 or more
- Respiratory failure
- Renal failure
- Neurologic failure
- Haematological Failure
- Liver failure
What is ARDS?
Acute respiratory response syndrome
-Inflammatory response of the lungs
What is the incidence of sepsis?
- Children 1:2,000
- M>F
- Incidence decreases with age
What pathogens are implicated in sepsis in neonates (<1 month)?
- Group B streptococci
- E.coli
- Listeria monocytogenes
What pathogens are implicated in sepsis in children?
- Strep. pneumoniae
- Meningococci
- group A streptococci
- Staph aureus
What is the pathophysiology of sepsis?
- LPS and bacterial components act on endothelium, neutrophils and monocytes
- Release of oxygen radicals, cytokines and lipid mediators
- Activation of complement leading to chemotaxis and lysosomal enzymes
- Increased TF and PAI1 have a procoagulant effect
- Microvascular occlusion, vascular instability
- Sepsis and multi-organ failure
What are the symptoms of sepsis in children?
- Fever or hypothermia
- Cold hands/feet, mottled
- Prolonged capillary refill time
- Chills/rigors
- Limb pain
- Vomiting and/or diarrhoea
- Muscles weakness
- Muscle/joint aches
- Skin rash
- Diminished urine output
What pathogens are implicated in meningitis in neonates (<1 month)?
- Group B streptococci
- E coli
- Listeria monocytogenes
What pathogens are implicated in meningitis in children?
- Strep pneumoniae
- Meningococci
- Haemophilus inflaeunzae
What are the symptoms of meningitis in children?
- Nuchal rigidity
- Headaches, Photophobia
- Diminished consciousness
- Focal neurological abnormalities
- Seizures
What are the symptoms of meningitis in neonates?
- Lethargy, Irritability
- Bulging fontanelle
- Nappy pain’
How is meningitis +/- sepsis treated?
- ABCD approach
- Antibiotics with good penetration in CSF and broad-spectrum (3rd generation cephalosporin’s and amoxicillin if neonate
- Chemoprophylaxis for close household contacts (particularly meningococcus B and strep A)
What will be seen on bloods of meningitis?
- FBC (leucocytosis, thrombocytopenia)
- Elevated CRP
- Low coagulation factors (DIC)
- Hypoglycaemia
How is meningitis investigated?
- Bloods
- Blood and CSF cultures (PCR)
- CSF (pleocytosis, increased protein level, low glucose)
- Urine culture, skin biopsy
- Imaging including T cerebrum
How is strep pneumoniae transmitted?
By droplets
Where does strep pneumoniae colonise?
Colonizes upper airways
- 5-10% adults
- 20-40% children
What is strep pneumoniae?
- Gram-positive Duplo-cocci (Diplococcus pneumoniae)
- 90 serotypes identified
What is a predisposing factor for invasive disease by strep pneumoniae?
Viral infection
What can pneumococcal disease cause in the alveoli?
Pneumonia
What are the possible complications of pneumococcal meningitis?
- Brain damage
- Hearing loss
- Hydrocephalus
What is haemophilus influenza type B?
- Gram-negative bacterium
- Encapsulated H. influenza (resists phagocytosis and complement mediated lysis)
- 6 serotypes
What conditions is haemophilus influenza type B associated with?
- Bacteraemia
- Meningitis
- Pneumonia
- Epiglottitis
How can meningococcal disease lead to meningitis?
- Meningococcus in nasopharynx
- Passage through epithelia
- Meningococcus in the bloodstream
- < 12 hours signs of septic shock
- < 18-36 hours signs of meningitis
What morbidity is associated with meningococcal disease?
- Amputation (14%)
- Skin scarring (48%)
- Cognitive impairment/ epilepsy/ hearing loss
What is the case fatality associated with meningococcal disease?
- Case-fatality rate 5-15%
- 50% of deaths in first 12 hrs, 80% within 48 hrs
What is meningococcal disease virulence dependent on?
Endotoxin levels
-Lipooligosaccharide
What can pneumococcal disease cause in the pleura and pericardium?
Empyema
What can pneumococcal disease cause in the peritoneum?
Peritonitis
What can pneumococcal disease cause in the joints?
- Arthritis
- Osteomyelitis
What can pneumococcal disease cause in the blood?
Septicaemia
What can pneumococcal disease cause in the meninges?
Meningitis
What can pneumococcal disease cause in the nasopharynx?
- Otitits media
- Sinusitis
