Meningitis & N. meningitidis

Question 1

Explain N. meningitidis.

Answer 1

Neiserria meningitidis is meningococcus found in upper respiratory tract as a commensal.

It adheres to non-ciliated epithelial cells in the nasopharynx and tonsils.

Question 2

Explain N. meningitidis transmission.

Answer 2

Person to person via droplets or upper resp tract secretions.

Most strains are harmless but induce immunity.

The pathogenic, virulent strains are mostly encapsulated and have the potential to cause septicaemia and meningitis.

Serogroups A, B, C, W and Y account for nearly all invasive forms.

Question 3

Epidemiology of N. meningitidis.

Answer 3

< 2 years of age and around 18 years.

Incubation is 2-7d.

Risk factors such as complement system defects, hyposplenism and HIV.

Question 4

Presentation of N. meningitidis.

Answer 4

Meningitis

Meningococcaemia

Question 5

Explain presentation of meningitis due to N. meningitidis.

Answer 5

Main proliferation of the bacteria is in the CSF.

There is an insidious onset with malaise, nausea, headache and vomiting.

Later in the meninginism there is headache, vomiting, nuchal/back rigidity, photophobia and altered consciousness.

Question 6

Complications of meningitis due to N. meningitidis.

Answer 6

Sensorineural hearing loss

Impaired vestibular function

Epilepsy

Diffue brain injury

Question 7

Explain meningococcaemia due to N. meningitidis.

Answer 7

The symptoms depend on the amount of circulating bacteria in the blood.

Mild disease presents with fever, macular rash but no signs of shock.

Severe disease causes pyrexia and septic shock within 6 to 12h due to rapidly escalating endotoxin levels.

There is circulatory failure and coagulopathy with skin haemorrhage.

Thrombosis of extremities/adrenals, AKI, ARDS.

Question 8

Complications of meningococcaemia due to N. meningitidis.

Answer 8

Amputation

Skin necrosis

Pericarditis

Arthritis

Ocular infection

Pneumonia (Y and W)

Permanent adrenal insufficiency

Question 9

Investigations of N. meningitidis.

Answer 9

Intra and extracellular diplococcia on microscopy of CSF/blood/skin lesions.

PCR of CSF/blood/skin lesion.

Question 10

Treatment of N. meningitidis.

Answer 10

Do not wait for confirmation if meningitis or meningococcal sepsis are possible diagnoses.

Urgent antibiotics treatment of benzylpenicillin, ceftriaxone.

Cefotaxime, chloramphenicol and meropenem are also bactericidal.

Question 11

Prevention of N. meningitidis.

Answer 11

Routine infant vaccination against capsular group C in UK.

Capsular group B vaccine in UK infants since 2015

Quadrivalent ACWY vaccine at age 14 and if high-risk travel.

Additional B, C, ACWY doses if hyposplenism and complement deficiency.

Prophylaxis can also be given if in close contact with infected.

Question 12

If a non-blanching rash is present, what intervention should be done?

Answer 12

Give Benzylpenicilline 1.2g IM/IV before admitting.

Question 13

Organisms causing meningitis.

Answer 13

Meningococcus or pneumococcus.

Less commonly H. influenzae, Listeria monocytogenis, HSV, VZV, enteroviruses, CMV, Cryptococcus or TB

If immunocompromised, e.g. HIV +ve, organ transplant and malignancy.

Question 14

Differential of meningitis.

Answer 14

Malaria

Encephalitis

Septicaemia

Subarachnoid

Dengue

Tetanus

Question 15

Early features of meningitis.

Answer 15

Headache

Fever

Leg pains

Cold extremities

Abnormal skin colour

Question 16

Later features of meningitis.

Answer 16

Meninginism - neck stiffness, photophobia, Kernig’s sign, Brudsinzki’s sign.

Decreased GCS and coma

Seizures, +/- focal CNS signs +/- opisthotonus

Non-blanching petechial rash.

Shock with prolonged capillary refill time, DIC, decreased BP

Question 17

Signs of disease causing meningitis.

Answer 17

Zoster

Cold sore/genital vesicles (HSV)

HIV signs of lymphadenopathy, dermatitis, candidiasis and uveitis.

Bleeding +/- red eye in leptospirosis.

Parotid swelling in mumps

Sore throat +/- jaundice +/- nodes (glandular fever)

Splenectomy scar

Question 18

Management algorithm of suspected bacterial meningitis and meningococcal sepsis.

Answer 18

ABCs

IVI + Fluid resus

Check and correct blood glucose

Then assess whether the patient is meningitic or septicaemic.

Question 19

Management algorithm of meningococcal sepsis.

Answer 19

Such as shock, prolonged capillary refill, cold hands and feet as well as low BP.
Also evolving petechial rash.

Get ICU help;
Take blood cultures
IV antibiotics
Airway support/pre-emptive intubation
Fluid resus/ionotropes/vasopressors and aim for MAP > 70 mmHg and urine output > 30ml/h
Delay LP investigation until stable.

Question 20

Management algorithm of meningitic meningitis.

Answer 20

Such as neck stiffness and photophobia without the shock.

Take blood cultures

Assess whether there is signs of increased ICP or midline shift of brain. (Papilloedema, uncontrolled seizures, focal neurology, GCS 12 or less)

If Yes;
Get ICU help;
IV antibiotics
Dexamethasone 10mg IV
Airway support
Fluid resus
Delay LP until stable
Nurse at 30C

If No;
Get senior help;
Perform an LP within the hour
IV antibiotics pre-LP if the LP is delayed > 1h
Dexamethasone 10mg IV

Question 21

Subsequent therapy of meningitis.

Answer 21

Discuss antibiotic therapy with microbiology and adjust based on organism and local sensitivities.

Maintain normovolaemia with IVI if needed.

Isolate for 1st 24h

Inform public health

Question 22

Explain the regimen of initiating early antibiotics.

Answer 22

Take blood cultures first.

Perform LP prior to an antibiotic only in patients wihout any evidence of shock, petechial rash, or raised ICP.

Consult local policies and seek advice.

Empirical options of antibiotics include ceftriaxone 2g/12h IV add e.g. amoxicillin 2g/4h IV if > 60 years or immunocompromised.

Question 23

Other investigations in meningitis.

Answer 23

U&Es

FBCs

LFTs

Glucose

Coagulation

Throat swabs

CXR

Consider HIV and TB tests if relevant.

Question 24

Prophylaxis of meningitis.

Answer 24

In those of household contacts in droplet range, those who have kissed the patient’s mouth.

Give ciprofloxacin 500mg PO 1 dose

Question 25

Answer 25

Normal values are

5 or less lymphocytes/mm3

No neutrophils

Protein 0.15-0.45 g/L

CSF glucose 2.8-4.2 mmol/L

Question 26

Treatment of viral meningitis

Answer 26

Often milder and might not even require any specific treatment but only supportive.

If it does get bad -> Aciclovir for HSV meningitis

Question 27

Explain investigations and treatment of meningitis

Answer 27

Ideally a blood culture and a lumbar puncture for cerebrospinal fluid (CSF) should be performed prior to starting antibiotics however if the patient is acutely unwell antibiotics should not be delayed.

Send blood tests for meningococcal PCR if meningococcal disease is suspected. This tests directly for the meningococcal DNA. It can give a result quicker than blood culture depending on local services and will still be positive after the bacteria has been treated with antibiotics.

There should be a low threshold for treating suspected bacterial meningitis, particularly in babies and younger children. Always follow the local guidelines however typical antibiotics are:

< 3 months – cefotaxime plus amoxicillin (the amoxicillin is to cover listeria contracted during pregnancy from the mother)

> 3 months – ceftriaxone

Steroids are also used in bacterial meningitis to reduce the frequency and severity of hearing loss and neurological damage. Dexamethasone is given 4 times daily for 4 days to children over 3 months if the lumbar puncture is suggestive of bacterial meningitis.