Infection - meningococcaemia/septicaemia Flashcards
Incidence and demographics of meningococcaemia
0.7-1.4 per 100,000
2 out of 3 CNS infections are viral
> 80%of bacterial meningitis is in <16 year olds
More commonly in males
Peak incidence:
6-24 months
Most cases under 4 years
Invasive meningococcal disease leads to only meningitis in …
30-50% of cases
7-10% only havr septicaemia.
40% have both
Why is it important to differentiate between meningococcaemia and septicaemia?
Patients preseting with shock are treated differently than the ones presenting primarily with increased ICP
Which Neisseria meningitied serotypes cause meningococaemia?
A, B, C are the most significant
B and C predominate in Europe
How is neisseria meningitidis transmitted
humans are the only reservoir
aerosol or nasopharyngeal secretion
Pathophysiology of meningitis
Infection is preceded by nasopharyngeal colonisation
Meningococci enter bloodstream and spread to specific sites (meninges, joints, disseminate - 5% carriers)
What are the 3 important virulence factors of Meningococci?
Polysaccharide capsule
Lipo-oligosaccharide endotoxin (the body responds to this)
Immunoglobulin A1 protease (cleaves membranes and helps the organism to survive)
Much of the damange cause by meningitis is due to host response (cerebral oedema and raised ICP from release of inflammatory mediators and activated leucocytes)
At what ages is the Meningitis C vaccine given?
3 months
4 months
1 year
Causative organisms of meningococcaemia (at different ages)
Neonates (<3 months): Group B strep, E.coli, Listeria
1 month - 6 years: N. meningitis
Strep pneumonia
H. influenza
> 6 years:
N. meningitis
Strep pneumonia
How does meningococcaemia present
The younger, the less likely to have classic symptoms of fever, headache, meningism
Meningitis presentation in neonates (<3 months)
Associated with maternal infection or pyrexia on delivery
Hyperthermia or hypothermia
Change in sleeping or eating habits
Irritability
Lethargy
Vomiting
High-pitched cry
SEIZURES
A child who is quiet at rest, but cries when moved.
Bulging fontanel
Presentation of meningococcaemia in >3 months old children?
Fever Vomiting Irritability Lethargy Change in behavior
After 2-3 years:
Headache
Stiff neck
photophobia
Clinical course may be fulminant or gradual onset with several days of URTI and severe symptoms
Describe the rash pattern in meningococcaemia
Petechial (N. meningitidis)
50-80% of patients
Axillae
Flanks
Wrists
Ankles
Usually located in the centre of light coloured macules (non-blanching) - a sign of vasculitis
Signs in meningoccocaemia
Opisthotonus - arching of back with increased ICP
Brudzinski - flexion of the neck with the child supine causing flexion of the knees and hips
Kernigs - with the child lying supine and the hips and knees flexed, there is back pain
Classical clinical presentation of meningococcaemia
Headache Fever Vomiting Photophobia Lethargy Neck stiffness Rash - 50% Seizures - 20%
Definition of purpura
> 2mm in diameter
no exact definition
Differentials for meningococcaemia
Sepsis Febrile seizures Measles Mumps HSP ITP Reye's syndrome
What is the pathophysiology of septicaemia
From activation and continued stimulation of the immune system by proinflammatory cytokines (caused by endotoxin)
4 elements: Capillary leak. Coagulopathy. Metabolic derangement. Myocardial failure.
Presentation of septicaemia
Fever Rash - erythematous and later petechia and purpura Vomiting Headache Myalgia Abdo pain Tachycardia/tachypnoea Hypotension Cool extremities Initially normal conscious level
Investigations for fulminant meningococal sepsis
FBC Blood glucose and gas for acidosis Coagulation screen CRP U and Es LFTs
Culture - blood, throat swab, urine, stool
Lumbar puncture, unless contraindicated
PCR for possible organisms (blood and CSF)
Consider CT/MRI head and EEG
Management of meningitis
NO delay in antibiotics and supportive therapy
3rd generation cephalosporin (cefotaxime or ceftriaxone) cover most
Length of course depends on causative organism and clinical response
If child is beyond neonatal period, give dexamethasone to reduce chance of longterm complications such as DEAFNESS
Management of meningococcal septicaemia
Rapid stabilisation and possibly ICU
Broad spectrum antibiotics initially
CVP and urinary catheterisation for fluid balance
Mechanical ventilation of resp failure from pulmonary oedema
Ionotropic support may be needed for myocardial contractility
FFP and platelets if DIC occurs
Finally….. household contacts should be immunised if type C.
Treatment with rifampicin eradicates nasopharyngeal carriage
Is meningitis a notifiable disease? (is this a trick question?? Double bluff???)
IT IS A NOTIFIABLE DISEASE
Local public health department must know about this
What is the commonest cause of sepsis in children?
meningococcus
THUS, suspect even when there is no RASH
What are the potential sequelae of meningococcaemia (nervous system)
15-25% mortality in neonatal period
5% afterwards
Focal neurological sequelae:
Hearing lossLocal vasculitis causing cranial nerve palsies
Local cerebral infarction (focal or multifocal seizures - may lead to epilepsy)
Subdural effusion
Hydrocephalus (from impaired CSF resorption or blockage of ventricular outlets)
Cerebral abscess
-signs of space occupying lesion and deterioration
Complications of meningococaemia (non-nervous system)
DIC Thrombocytopenia Septic arthritis Pericarditis Bacterial endocarditis Gangrene
Which rare underlying deficit may lead to recurrent meningococcaemia
Complement deficiency
Define sepsis and septicaemia
Sepsis: a bacterial infection in the blood stream or body tissues. It is a very broad term covering the presence of many types of microscopic disease causing organisms
Septicaemia when bacteria cause a focal infection or proliferate in the blood stream the host response includes the release of inflammatory cytokines and activation of endothelial cells, which may lead to septic shock
List the relevant causative organisms of sepsis for neonates
Acquired from birth canal or ascended into amniotic fluid:
Group B strep
Gram -ves (E.coli, Hib, Listeria monocytogenes)
In late-onset sepsis, source is often in the environment:
S. epidermidis, E.coli, Klebsiella, Pseudomonas, enterobacter
List the relevant causative organisms of sepsis for infants
Hib
Strep pneumoniae
N. meningitides
Salmonella
List the relevant causative organisms of sepsis for children (older)
Hib
Strep pneumoniae
N. meningitides
Salmonella
Which is the commonest organism causing bacteraemia, but not usually septic shock
Pneumococcus
What are the main causative organisms of sepsis in “at-risk” groups (immunocompromised, respiratory illness)
Chronic respiratory illness - risk of Pseudomonas
Immunodeficiency - particularly pneumococcus
Normal BP, Pulse, RR in neonates, infants, young and old children
RR: tachypnoea is >60 (neonate) >50 (infants) >40 (young child) >30 (old child)
HR - normal range 110-160 (<1 year) 95-140 (2-5 yrs) 80-120 (5-12yrs) 60-100 (>12 years)
BP upper limit (SBP)
110mmHg (1-5yrs)
120mmHg (6-10 yrs)
Presentation of sepsis in children (early and late)
Fever
Minimal tachycardia
Widened pulse pressure
Minimal tachypnoea
Minimally delayed cap refill
Later: Hypotension Mental state changes Anuria Hypothermia Cool extremities Petecial/purpuric rash
What are red flag sings in sepsis? (NICE)
Pale/mottled/blue
No response to social cues
Unable to roused
Weak, high-pitched continuous cry
Grunting
Tachypnoea (>60)
Moderate or severe recessions
Reduced skin turgor
>38°C (0-3months) >39°C (3-6months) Non-blanching rash Bulging fontanelle Neck stiffness Status epilepticus Focal neurological signs/seizures Bile stained vomiting
Amber signs in sepsis (NICE)
Pallor
Decreased activity
No smile
Nasal flaring
Tachypnoea
Oxygen sats <95% on air
Crackles
Dry mucous membranes
Poor feeding in infants
Cap refill > 3 seconds
Reduced urine output
Swelling of limb or joint (osteomyelitis?)
New lump >2cm
What is shock?
Circulation is inadequate to meet the demands of the tissue - insufficient perfusion
(eg. sepsis or intestinal obstruction)
Early clinical features of shock
Manifestations of compensatory physiological mechanisms:
Tachypnoea Tachycardia Decreased skin turgor Sunken eyes and fontanelle Delayed cap refill (>2s) Mottled, pale, cold skin Core-peripheral temerature gap >4°C Decreased urinary output
Late decompensated signs of septic shock
Acidotic (Kussmaul) breathing Bradycardia Hypotension Confusion No urinary output Blue peripheries
Which antibiotics are most empiric in septicaemia for a Newborn/infant (first 6-8 weeks)
Ampicillin and Gentamicin
Ampicillin and Cefotaxime
Ampicillin and ceftriaxone
Which antibiotics are most empiric in septicaemia for an older child
Third generation cephalosporin alone:
ceftriaxone or cefotaxime
Priority in septic shock management
Fluid resuscitation:
0.9% saline OR blood (after trauma)(20ml/kg)
TWICE if NECESSARY
PICU if no improvement
Management of septicaemia and shock on PICU
Tracheal intubation and mechanical ventilation
Invasive monitoring of BP
Inotropic support
Correction of heamatological, biochemical and metabolic derangement
Support for renal or liver failure
In the notes, these symptoms in conjunction with fever point towards meningococcal disease
Non-blanching rash Ill-looking child Lesion larger than 2 mm (purpura) Cap refill >3sec Neck stiffness
In the notes, these symptoms in conjunction with fever point towards bacterial meningitis disease
Neck stiffness
Bulging fontanelle
Decreased level of consciousness
Convulsive status epilepticus
In the notes, these symptoms in conjunction with fever point towards Herpes simplex encephalitis
Focal neurological signs
Focal seizures
Decreased level of consciousness
In the notes, these symptoms in conjunction with fever point towards pneumonia
Tachypnoea Crackles in the chest Nasal flaring Chest indrawing Cyanosis Oxygen sats <95%
In the notes, these symptoms in conjunction with fever point towards UTI
Vomiting Poor feeding Lethargy Irritability Abdo pain or tender Urinary frequency Dysuria
In the notes, these symptoms in conjunction with fever point towards septic arthritis
Swelling of limb or joint
Not using an extremity
Non-weight bearing
