Infection/immunology || Flashcards
What is meningococcal disease/meningococcaemia?
Infections caused by Neisseria meningitidis
What 2 conditions do meningococcaemia cause?
- Meningococcal meningitis
2. Meningococcal septicaemia
What are the 3 main causes of bacterial meningitis?
- Streptococcus pneumoniae
- Group B Streptococcus
- Neisseria meningitidis
What age group do Neisseria meningitidis usually affect?
The age of over 1 month
What serotypes of Neisseria meningitidis are there (5)?
Group A, B, C, W, Y
What meningococcal vaccinations are there and what age are they given (3)?
MenC = 1 year MenB = 2 months, 4 months, 1 year MenACWY = 14 years
What is the pathophysiology of Neisseria meningitides?
Gram-negative bacterium found in the nasopharynx.
Lipopolysaccharide (LPS) is a component of the outer membrane of N. meningitidis which acts as an endotoxin and is responsible for septic shock and hemorrhage due to the destruction of red blood cells.
They produce an IgA protease, an enzyme that cleaves IgA class antibodies and thus allows the bacteria to evade a subclass of the humoral immune system
What is the mortality of bacterial meningitis?
What % of survivors of bacterial meningitis have long-term neurological impairment?
5-10%
10%
How does meningococcal meningitis present i.e. what are the 3 classical symptoms?
- Headache
- Neck stiffness
- Photophobia
How does meningococcal meningitis present, other than the classical 3 symptoms (7)?
- Lethargy
- Poor feeding/vomiting
- Irritability
- Hypotonia
- Drowsiness
- LOC
- Seizures
What does purpura in a febrile child indicate?
How should they be treated (2)?
Meningococcal sepsis - meningitis may or may not be present
- Urgent admission
- Immediately with iv penicillin or iv 3rd gen cephalosporin
What is a purpuric rash?
Red or purple discolored spots on the skin that do not blanch on applying pressure. Irregular in size and outline and may have a necrotic centre
What is the definition of a fever in a child?
> 37.5
How do you measure temperature in a child less than 4 weeks of age, and between 4 weeks to 5 years?
<4 weeks = electronic thermometer in axilla
4 weeks-5 years = Electronic or chemical dot thermometer in the axilla or infrared tympanic thermometer
In the assessment of how ill a child is, what red flags would you look for (6)?
- Fever >38
- Pale, mottled, cyanosed
- Reduced consciousness, neck stiffness, bulging fontanelle, status epilepticus, focal neuro signs or seizures
- Significant respiratory distress
- Bile-stained vomiting
- Severe dehydration or shock
What is the management of a febrile child that is not seriously ill?
Managed at home with a regular review by parents who have been given clear instructions
What is the management of a febrile child that are significantly unwell and have no focus of infection (6)?
- Be in hospital
- Investigations: Bloods, culture, swabs, LP, PCR etc
- Septic screen
- Parenteral Abx given immediately e.g. cefotaxime
- Supportive care
- Antipyretic agents e.g. paracetemol/ibrupofen
What are the investigations done for the work up of meningococcal sepsis and meningitis (5)?
- Bloods: FBC, U+E, CRP, LFT
- LP
- Blood culture
- PCR
- Throat swabs for bacterial culture and viral PCRs
What is the management of meningococcal sepsis and meningitis (2)?
- Abx - Ceftriaxone
- Supportive therapy
Do not delay
Is meningococcaemia a notifiable disease?
Yes
Can a septic child without a purpuric rash have meningococcaemia?
Yes
What are the possible complications of meningococcaemia (6)?
- Hearing impairment
- Local vasculitis
- Local cerebral infarction
- Subdural effusion
- Hydrocephalus
- Cerebral abscess
What is sepsis?
When bacteria proliferate in the bloodstream, where the host response, which includes release of inflammatory cytokines and activation of endothelial cells
What are the common organisms that cause sepsis in neonates? Early onset (2) Late onset (1)
Early onset: Group B strep and E. coli
Late-onset: CoNS
What are the common organisms that cause sepsis in infants and young children (5)?
- Streptococcus pneumoniae
- Neisseria meningitidis
- S aureus and group A streptococci
- Haemophilus influenzae type b
- Bordetella pertussis
What are the red flag signs or symptoms of a febrile child on the NICE ‘traffic light assessment’ (8)?
- Pale or mottled, or ashen or blue.
- No response to social cues. Unable to rouse, or if roused does not stay awake.
- Weak, high-pitched, or continuous cry.
- Grunting. Tachypnoea (respiratory rate of 60 breaths per minute or more). Moderate or severe chest indrawing.
- Reduced skin turgor.
- Temperature of 38°C or higher in children 0–3 months of age.
- Non-blanching rash. Bulging fontanelle. Neck stiffness.
- Status epilepticus. Focal neurological signs. Focal seizures.
What are the amber flag signs or symptoms of a febrile child on the NICE ‘traffic light assessment’ (11)?
- None of the red symptoms or signs.
- Pallor reported by parent or carer.
- Does not respond normally to social cues. Does not smile. Wakes only with prolonged stimulation. Decreased activity.
- Nasal flaring. Tachypnoea (respiratory rate more than 50 breaths per minute in children aged 6–12 months, and more than 40 breaths per minute in children over 12 months of age). Oxygen saturation equal to or less than 95% in air. Crackles.
- Poor feeding in infants.
- Dry mucous membranes. Capillary refill time of 3 seconds or more. Reduced urine output (in infants ask about wet nappies).
- Tachycardia:
More than 160 beats/minute under 1 year of age.
More than 150 beats/minute 1–2 years of age.
More than 140 beats/minute 2–5 years of age. - Temperature of 39°C or higher in children 3–6 months of age.
- Rigors.
- Fever for 5 days or more.
- Swelling of a limb or joint. Not weight bearing or not using a limb
What is shock?
The circulation is inadequate to meet the metabolic demands of the tissues
What are the features of early shock (8)?
Normal bp maintained by:
- Tachycardia
- Tachypneoa
- Re-distribution of blood from venous reserve volume
- Diversion of blood flow from nonessential tissues such as skin+peripheries
- Delayed cap refill time
- Sunken eyes and fontanelle
- Decreased skin turgor
- Decreased urinary output
What are the features of late shock (6)?
- Falling bp as compensatory responses are failing
- Acidosis (Kussmaul breathing)
- Bradycardia
- Confusion/depressed cerebral state
- Blue peripheries
- Absent urine output