Infection - meningococcaemia/septicaemia Flashcards by Csaba Sali

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

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Invasive meningococcal disease leads to only meningitis in …

30-50% of cases

7-10% only havr septicaemia.
40% have both

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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

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Which Neisseria meningitied serotypes cause meningococaemia?

A, B, C are the most significant

B and C predominate in Europe

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How is neisseria meningitidis transmitted

humans are the only reservoir

aerosol or nasopharyngeal secretion

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Pathophysiology of meningitis

Infection is preceded by nasopharyngeal colonisation

Meningococci enter bloodstream and spread to specific sites (meninges, joints, disseminate - 5% carriers)

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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)

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At what ages is the Meningitis C vaccine given?

3 months
4 months
1 year

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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

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How does meningococcaemia present

The younger, the less likely to have classic symptoms of fever, headache, meningism

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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

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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

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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

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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

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Classical clinical presentation of meningococcaemia

Headache
Fever
Vomiting
Photophobia
Lethargy
Neck stiffness
Rash - 50%
Seizures - 20%

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Definition of purpura

> 2mm in diameter

no exact definition

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Differentials for meningococcaemia

Sepsis
Febrile seizures
Measles
Mumps
HSP
ITP
Reye's syndrome

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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.

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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

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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

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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