Recommendations
Urgent
Be immediately alert to the possibility of meningococcal meningitis or meningococcal sepsis, or both, if the patient has any of: acute onset of fever, vomiting, rash, headache, or neck stiffness. Some patients present with non-specific symptoms and signs.[9][48]
Early recognition and treatment are crucial because patients can deteriorate very rapidly. Bacterial meningitis and meningococcal sepsis are associated with high morbidity and mortality.[48]
Perform a lumbar puncture if you suspect bacterial meningitis unless the procedure is contraindicated.[9][48][49]
Children and young people aged <16 years
Be alert to the possibility of bacterial meningitis or meningococcal sepsis when assessing anyone aged under 16 years with acute febrile illness.[9] If the patient is under 16 years old and you suspect meningococcal disease, escalate early - call a consultant/senior doctor in emergency medicine, paediatrics, anaesthesia, or intensive care immediately.[50]
Do not allow lumbar puncture to delay starting parenteral empirical antibiotics.[9][51] Give intravenous antibiotics (for specific recommendations, see Management recommendations) immediately to a child or young person with a petechial rash if any of the following occur at any point during their assessment:
Petechiae start to spread
Rash becomes purpuric
Signs of bacterial meningitis
Signs of meningococcal sepsis
You (or another healthcare professional) think the patient appears ill.
These children are at high risk of having meningococcal disease and need urgent treatment.
Adults
If the patient is an adult and you suspect meningococcal disease, within 1 hour of their arrival at hospital:
Perform a lumbar puncture if you suspect bacterial meningitis (unless contraindicated)
Take bloods for culture.
Give intravenous antibiotics immediately after blood cultures have been taken and definitely within the first hour of arrival at hospital.[48][49] Some guidelines recommend giving antibiotics after LP (where LP is indicated and as long as LP is not delayed) to allow the best chance of definitive diagnosis.[48] Bear in mind, however, that prompt molecular tests will still identify the causative organism even after antibiotics have been started. For specific recommendations, see Management recommendations.
Assess the need for urgent senior review early using a validated scoring system, such as the National Early Warning Score 2 (NEWS2).[48] Consult local guidelines for the recommended scoring system at your institution.
Key Recommendations
Take concerns expressed by the referring doctor or a carer/relative seriously because clinical features are often not clear cut.[9][48]
Examine the patient’s skin very carefully for rash. In the initial phases there may be only 1 or 2 petechiae. Document the presence or absence of rash.[48]
Rash in meningococcal sepsis is typically purpuric or petechial (non-blanching) but may take other forms, including a maculopapular rash.[48]
Be aware that a rash may be less visible in patients with darker skin tones - check soles of feet, palms of hands, and conjunctivae.[9]
If the patient is under 16 years old, take bloods for:[9] [50]
Blood gas (including lactate)
Blood glucose
Full blood count
C-reactive protein (CRP), procalcitonin (if available)
Coagulation screen
Blood culture
Whole-blood polymerase chain reaction (PCR) testing (EDTA sample) for Neisseria meningitidis
Urea, creatinine, electrolytes
Serum Calcium (Ca2+), ionised magnesium, and ionised phosphate (PO4-)
Liver function tests
Cross match in all children that are seriously unwell.
If the patient is an adult, take bloods for:[48][49]
Blood gas (including lactate)
Blood glucose
Full blood count, urea, creatinine, electrolytes, liver function tests
C-reactive protein (CRP), procalcitonin (if available)
Culture
Take as soon as possible and within 1 hour of arrival at hospital
Take before antibiotics wherever possible
Meningococcal and pneumococcal PCR (EDTA sample)
Coagulation screen
Escalate early. Call a consultant/senior doctor in emergency medicine, paediatrics, anaesthesia, or intensive care immediately if you suspect meningococcal disease in a child or young person.[50]
Be alert to the possibility of bacterial meningitis or meningococcal sepsis when assessing anyone aged under 16 years with acute febrile illness.[9]
Children and young people with bacterial meningitis commonly present with non-specific symptoms and signs.[9]
Classical signs of meningitis (neck stiffness, bulging fontanelle, high-pitched cry) are often absent in infants with bacterial meningitis.[9]
Do not be reassured by lack of fever in an unwell baby; around 50% of young infants diagnosed with bacterial meningitis are afebrile on presentation.[52]
Symptoms and signs of bacterial meningitis/meningococcal sepsis in children and young people:[9]
Non-spcecific symptoms and signs | More specific symptoms and signs |
|---|---|
Less commonly:
|
|
Practical tip
Children and young people with meningococcal disease may present with predominant sepsis (with shock), meningitis (with raised intracranial pressure), or both; some may have neither shock nor meningitis. Purpuric/petechial non-blanching rash is typical but rash may be atypical or absent in some cases.[50]
Do not allow a patient’s relatively alert state to mislead you into underestimating the potential degree of cardiovascular collapse. Previously healthy adolescents and young people with meningococcal sepsis often maintain brain perfusion and function until relatively late, despite severe shock.[48]
Shock in young people is not always accompanied by arterial hypotension but may be indicated by high blood lactate level (>4 mmol/L).[48]
Note that clinical features that may occur in infants <3 months of age (% of cases) are:[52]
Poor feeding (67%)
Lethargy (63%)
Respiratory distress including grunting (44%) and/or need for mechanical ventilation in a term baby
Poor perfusion (44%)
Temperature instability (20%)
Apnoea (23%)
Bulging fontanelle (20%)
Seizures (9% to 34%)[53]
Coma (5%)
Neck stiffness (3%)
Irritability in combination with fever (41%).
Also take into account:[9]
The level of concern being shown by the parent(s) or carer (particularly in the context of previous illness in the child or young person or in their family). Take any reported or perception of fever by the parent(s) or carer seriously.
How quickly the illness is progressing; patients with meningococcal disease can deteriorate rapidly
Your clinical judgement of the overall severity of the illness.
Take concerns expressed by the referring doctor or a carer/relative seriously because clinical features are often not clear cut.[48]
Consider meningococcal meningitis or meningococcal sepsis if the patient is an adult presenting with any of the following:[48]
Headache
Fever
Altered consciousness
Neck stiffness
Rash
Seizures
Shock.
Some of these signs may be absent and combinations of symptoms and signs may be more useful than individual clinical signs to identify serious disease.
Practical tip
Meningitis is the commonest presentation of meningococcal disease in adults, occurring in about 60% of patients. Around 10% to 20% of patients may have evidence of shock or fulminant sepsis with or without meningitis, and up to 30% of patients may have mild disease with fever and a rash but no evidence of either meningitis or shock.[48]
Be aware that clinical presentation can differ in specific populations.[48]
Older patients with bacterial meningitis are more likely to have altered consciousness and less likely to have neck stiffness or fever than younger patients.[48]
The most significant risk factor for bacterial meningitis is age <2 years.[56][57] Infants and neonates <3 months of age are particularly susceptible because they have impaired immunity.[56][57]
In addition, ask the patient or their parent/carer about risk factors associated with increased risk of meningococcal infection, including:[48]
Immunocompromise
People with asplenia or hyposplenia are at increased risk from all encapsulated bacteria, including Neisseria meningitidis
Complement deficiency increases risk of meningococcal disease
Patients on immunosuppressants have depressed cell-mediated immunity and are at increased risk for bacterial meningitis
HIV infection, in particular patients with a low CD4 count or high viral load[26][29][30][31]
Pregnancy
Recent travel abroad
Cranial structural defects[57]
Medical devices (e.g., cochlear implants, cerebrospinal fluid shunts) or recent neurosurgery/ear, nose, or throat surgery[57]
Exposure to pathogens (e.g., contact with another person with meningitis or sepsis)[57]
Contiguous infections (e.g., sinusitis, pneumonia, mastoiditis, otitis media)[57]
Crowding (e.g., in a household or dormitory)[57]
Younger age
Meningococcal disease has a bimodal distribution in children and young adults with peaks in:
Children aged under 5 years
Adolescents and early adulthood (16-25 years).
Consider any risk factors during the perinatal period. Neonates are at increased risk of bacterial meningitis if:[58]
There is premature or prolonged (>18 hours) rupture of membranes
There is maternal colonisation with group B streptococcus
There is maternal chorioamnionitis
They are premature
They have low birth weight
Prioritise assessing:[48][49][50][52]
Airway
Breathing
Circulation
Disability
Assess conscious level and pupils, and check for signs of raised intracranial pressure
Exposure
Look for a non-blanching rash
Practical tip
Think 'Could this be sepsis?'
In adults, look for acute deterioration of a patient in whom there is clinical evidence or strong suspicion of infection.[59][60][61]
In children, have a low threshold for suspecting sepsis. Clinical presentation of sepsis in children is often subtle and non-specific. Take parental concern seriously.
Refer to local guidelines for the recommended approach at your institution for assessment and management of the patient with suspected sepsis.
See Sepsis in children and Sepsis in adults.
Children and young people aged <16 years
Gain vascular access (insert two large intravenous cannulae or establish intraosseous access).[50]
Assess initially for signs of:
Raised intracranial pressure[50][52]
Reduced or fluctuating level of consciousness (Glasgow Coma Scale <9 or drop of ≥3) [ Glasgow Coma Scale Opens in new window ]
In children unable to give a verbal response (in practice, those under 2 years), use the Glasgow Coma Scale with modification for children, or assess using focal neurological signs.[9] Glasgow Coma Scale: modification for children Opens in new window
Relative bradycardia and hypertension
Focal neurological signs
Abnormal posture or posturing
Seizures
Unequal, dilated, or poorly responsive pupils
Papilloedema (late sign)
An enlarged blind spot may be identified when you examine the visual fields
Abnormal ‘doll’s eye’ movements
Capillary refill time >2 seconds
Abnormal skin colour
Tachycardia and/or hypotension
Respiratory symptoms or breathing difficulty
Cold hands/feet
Toxic/moribund state
Altered mental state/decreased consciousness
Decreased urine output (<1 mL/kg/h)
Hypoxia on arterial blood gas
Base deficit (worse than -5 mmol/L)
Increased lactate (>2 mmol/L)
Examine the patient’s skin very carefully for a rash.[9] Always document its presence or absence.
In practice, a petechial or purpuric rash is typically associated with meningococcal disease, but it may be present with any type of bacterial meningitis.
In the initial phases there may be only 1 or 2 petechiae.
Be aware that a rash may be less visible in patients with darker skin tones - check soles of feet, palms of hands, and conjunctivae.[9]
Children with petechiae confined to the skin above the nipple line (the distribution of the superior vena cava) may be less likely to have meningococcal disease than those with petechiae below the nipple line.[62]
Check for:[9]
Kernig’s sign
With the patient lying flat, flex their thigh so that it is at a right angle to the trunk and extend the leg at the knee joint. If the leg cannot be completely extended due to pain, this is considered positive.
It is uncommon, but indicates meningeal inflammation and is suggestive of meningitis. However, it should not be relied on for diagnosis as sensitivity can be low.[48]
Kernig’s sign is more common in older children with bacterial meningitis.[63]
Brudzinksi’s sign
When the patient’s neck is abruptly flexed passively, meningeal irritation causes involuntary flexion of the hips and knees.
The sign results from inflammation of lumbosacral nerve roots.
It is uncommon, but indicates meningeal inflammation and is suggestive of meningitis. However, it should not be relied on for diagnosis as sensitivity can be low.[48]
Brudzinski’s sign is more common in older children with bacterial meningitis.[63]
Measure and record the following at least every hour:[9]
Heart rate
Respiratory rate
Oxygen saturations
Blood pressure
Temperature
Perfusion (capillary refill)
Neurological assessment (such as the Alert, Voice, Pain, Unresponsive [AVPU] scale).
Practical tip
In children aged ≤5 years, do not routinely use measurements of oral and rectal temperature to determine body temperature.[64]
Instead:
In infants aged <4 weeks, use an electronic thermometer in the axilla[64]
In children aged 4 weeks to 5 years, use of one of the following:[64]
Electronic thermometer in the axilla.
Chemical dot thermometer in the axilla. However, use an alternative type of thermometer if multiple temperature measurements are required.
Infra-red tympanic thermometer.
Do not use forehead chemical thermometers because they are unreliable.[64]
Adults
Assess the need for urgent senior review early using a validated scoring system. Consult local guidelines for the recommended scoring system at your institution. If you are using the National Early Warning Score 2 (NEWS2):[48]
Arrange urgent assessment by a team with critical care competencies if the patient has an aggregate score ≥7
Arrange urgent review by a clinician competent to assess the acutely ill patient with an aggregate score of 5/6 (or score of 3 in any single physiological parameter)
Do not be falsely reassured if the patient’s NEWS2 score is lower than an aggregate score of 5/6 (or score of 3 in any single physiological parameter) because patients with meningitis, particularly those with meningococcal sepsis, can deteriorate rapidly.
Check for:[9]
Kernig’s sign
With the patient lying flat, flex their thigh so that it is at a right angle to the trunk and extend the leg at the knee joint. If the leg cannot be completely extended due to pain, this is considered positive.
It is uncommon, but indicates meningeal inflammation and is suggestive of meningitis. However, it should not be relied on for diagnosis as sensitivity can be low.[48]
Brudzinksi’s sign
When the patient’s neck is abruptly flexed passively, meningeal irritation causes involuntary flexion of the hips and knees.
The sign results from inflammation of lumbosacral nerve roots.
It is uncommon, but indicates meningeal inflammation and is suggestive of meningitis. However, it should not be relied on for diagnosis as sensitivity can be low.[48]
Rash
Examine the patient’s skin very carefully for rash and document its presence or absence.[48]
In the initial phases there may be only 1 or 2 petechiae.
Rash in meningococcal sepsis is typically purpuric or petechial (non-blanching) but may take other forms, including a maculopapular rash.[48][50]
Rash may be atypical or absent in some cases.[50]
Be aware that a rash may be less visible in patients with darker skin tones - check soles of feet, palms of hands, and conjunctivae[9]
Practical tip
Children with petechiae confined to the skin above the nipple line (the distribution of the superior vena cava) may be less likely to have meningococcal disease than those with petechiae below the nipple line.[62]
In general, do not delay giving antibiotics and other treatments while waiting for investigations if you suspect bacterial meningitis clinically.[9] However, in practice, always use your clinical judgement - lumbar puncture (the most important investigation for suspected bacterial meningitis) can be performed before giving antibiotics if the child is clinically stable, as long as there are no contraindications and lumbar puncture can be done promptly. See Lumbar puncture below.
Blood tests
In a child or young person with symptoms of meningococcal disease, with or without unexplained petechial rash and fever (or history of fever), carry out these key investigations:[9][50][52]
Blood gases (including lactate bicarbonate, base deficit, ionised calcium [Ca2+])
Blood glucose
Full blood count
C-reactive protein (CRP), procalcitonin (if available)
Coagulation screen
Blood cultures
Whole-blood (EDTA) polymerase chain reaction (PCR) for Neisseria meningitidis
Urea, electrolytes, and creatinine
Serum calcium (Ca), ionised magnesium (Mg2+), ionised phosphate (PO4-)
Liver function tests
Cross-match in all children who are seriously unwell
Practical tip
If blood volume is limited, prioritise: blood gas, lactate, glucose, electrolytes, full blood count, coagulation.[50]
PCR test for Neisseria meningitidis
Perform whole blood real-time polymerase chain reaction (PCR) testing (EDTA sample) for N meningitidis to confirm a diagnosis of meningococcal disease.[9]
Take the blood sample for PCR testing as soon as possible because early samples are more likely to be positive.
Use PCR testing of blood samples from other hospital laboratories if available, to avoid repeating the test.
Be aware that a negative blood PCR test result for N meningitidis does not rule out meningococcal disease.
Submit cerebrospinal fluid (CSF) obtained during lumbar puncture (see below) to the laboratory to hold for PCR testing for N meningitidis and Streptococcus pneumoniae. Request PCR testing only if the CSF culture is negative.[9]
CSF samples taken up to 96 hours after admission to hospital may give useful results.
Lumbar puncture
Perform a lumbar puncture unless any of the following relative contraindications are present:[9]
Signs suggesting raised intracranial pressure
Shock
Extensive or spreading purpura
After convulsions, until stabilised
Coagulation abnormalities
Coagulation results (if obtained) outside the normal range
Platelet count <100 x 109/L
Receiving anticoagulant therapy
Local superficial infection at the lumbar puncture site
Respiratory insufficiency
Lumbar puncture is thought to have a high risk of precipitating respiratory failure.
Do not allow the lumbar puncture or waiting for lumbar puncture results to delay administration of parenteral antibiotics.[9]
In practice, timing of lumbar puncture is a clinical decision. Lumbar puncture can be performed before giving antibiotics if the child is clinically stable, as long as there are no contraindications and lumbar puncture can be done promptly. Seek senior advice if you are unsure.
Practical tip
Use your clinical assessment to decide whether it is safe to perform a lumbar puncture. Do not use cranial computed tomography (CT) for this purpose.[9][51] CT is unreliable for identifying raised intracranial pressure.[9] However, if a CT scan has been performed and shows radiological evidence of raised intracranial pressure, do not proceed with a lumbar puncture.[9]
CSF assessment should include:[9]
White blood cell count and examination
Total protein concentration
Glucose concentration
Gram stain
Microbiological culture, checking for the causative organism N meningitidis.
Request CSF results promptly.
CSF white blood cell counts, total protein, and glucose concentrations should be available within 4 hours to inform decision making on adjunctive corticosteroid therapy.[9]
The National Institute for Health and Care Excellence (NICE) in the UK recommends starting antibiotic treatment for bacterial meningitis in children without petechial rash if the CSF white blood cell count is abnormal:[9]
≥20 cells/microlitre in neonates (but continue to consider bacterial meningitis if <20 cells/microlitre and other symptoms and signs are present)
>5 cells/microlitre or >1 neutrophil/microlitre in older children and young people, regardless of other CSF variables
If the cell count is lower, still consider bacterial meningitis if other symptoms and signs suggest the diagnosis, especially in neonates.
If the CRP and/or white blood cell count is raised and there is a non-specifically abnormal CSF on lumbar puncture (e.g., consistent with viral meningitis), treat as bacterial meningitis.[9]
If no CSF is available for examination or the CSF findings are uninterpretable, manage as if a diagnosis of meningitis is confirmed.[9]
Consider alternative diagnoses if the patient is significantly ill and has CSF variables within accepted normal ranges.[9] See Differentials.
Perform a repeat lumbar puncture in neonates with any of the following:[9]
Persistent or re-emergent fever
Deterioration in clinical condition
New clinical findings (particularly neurological)
Persistently abnormal inflammatory markers.
Do not perform a repeat lumbar puncture in neonates:[9]
Receiving antibiotic treatment tailored to the causative organism and making a good clinical recovery
Before stopping antibiotic therapy if clinically well.
Cranial computed tomography
Order a CT scan to look for alternative intracranial pathology in children and young people with suspected bacterial meningitis and reduced or fluctuating level of consciousness (Glasgow Coma Scale [GCS] <9 or drop of ≥3), or focal neurological signs; in children unable to give a verbal response (in practice, those under 2 years), use the Glasgow Coma Scale with modification for children.[9] [ Glasgow Coma Scale Opens in new window ] Glasgow Coma Scale: modification for children Opens in new window
Do not delay treatment to wait for a CT scan.
Stabilise the patient clinically before CT scanning.
Consult a senior emergency physician, anaesthetist, paediatrician, or intensivist if there are indications for a CT scan.
Consider CT or magnetic resonance imaging (MRI) in patients with a history of trauma, recent neurosurgery, rhinorrhoea, or otorrhoea to identify any source of CSF leak and source of contiguous spread of infection to the meninges.[65][66]
Practical tip
Do not use CT to decide whether it is safe to perform a lumbar puncture; use your clinical assessment instead.[51] CT is unreliable for identifying raised intracranial pressure.[51] However, if a CT scan has been performed and shows radiological evidence of raised intracranial pressure, do not proceed with a lumbar puncture.
Magnetic resonance imaging (MRI)
Consider CT or MRI in patients with a history of trauma, recent neurosurgery, rhinorrhoea, or otorrhoea to identify any source of cerebrospinal fluid leak and source of contiguous spread of infection to the meninges.[65][65]
Throat swab
Take a throat swab for meningococcal culture (N meningitidis).[51]
Screen for predisposing factors
Test children and young people for complement deficiency if they have had any of the following:[9]
More than one episode of meningococcal disease
One episode of meningococcal disease caused by serogroups other than B (e.g., A, C, Y, W135, X, 29E)
Meningococcal disease caused by any serogroup and a history of other recurrent or serious bacterial infections.
Discuss appropriate testing for complement deficiency with local immunology laboratory staff.[9]
Do not test children and young people for complement deficiency if they have had a single episode of meningococcal disease caused by serogroup B meningococcus or have had unconfirmed meningococcal disease.
Test a child or young person who has had meningococcal disease and has a family history of meningococcal disease or complement deficiency.
Test parents and siblings for complement deficiency if a child or young person who has had meningococcal disease is found to have complement deficiency.
Do not test children and young people for immunoglobulin deficiency if they have had meningococcal disease unless they have a history of serious, persistent, unusual or recurrent infections that is suggestive of immunodeficiency.[9]
Ideally, lumbar puncture (the most important investigation for suspected bacterial meningitis) should be performed before giving antibiotics if the patient is clinically stable, as long as there are no contraindications, and lumbar puncture can be done promptly. However, in practice, always use your clinical judgement - do not delay antibiotics and other treatments while awaiting LP if there is respiratory or cardiac compromise, there are signs of severe sepsis or a rapidly evolving rash, or there are contraindications to LP such as infection at the LP site or a coagulopathy.[48] See Lumbar puncture below.
Blood tests
Cultures
Take as soon as possible and within 1 hour of arrival at hospital
Take before antibiotics wherever possible
Blood gases; patients with severe meningococcal infections often have metabolic abnormalities, including acidosis
Storage, to allow serological testing if a cause is not identified
Full blood count; urea, electrolytes and creatinine, serum calcium (Ca), ionised magnesium (Mg2+), ionised phosphate (PO4); liver function tests
Raised white blood cell count (especially neutrophil count) indicates an increased risk of having meningococcal disease but can be normal or low even in severe meningococcal disease
Blood urea may be elevated
Serum electrolytes are frequently deranged
Glucose
Lactate
Procalcitonin (or CRP if unavailable)
Can be helpful to differentiate between bacterial and viral infections Elevated in meningococcal disease
Coagulation profile
Unless a coagulation defect is suspected, proceed with lumbar puncture without waiting for results
May show evidence of disseminated intravascular coagulation (prolonged thrombin time, elevated fibrin degradation products or D-dimer, low fibrinogen or antithrombin levels.
PCR test for Neisseria meningitidis and Streptococcus pneumoniae
Test for meningococcal and pneumococcal PCR (EDTA sample).[48]
Lumbar puncture
Perform a lumbar puncture (LP)within 1 hour of arrival at hospital unless any of the following relative contraindications are present:[48][49]
Signs of sepsis or rapidly evolving rash
Severe respiratory/cardiac compromise
Significant bleeding risk/coagulopathy
Infection at the site of the lumbar puncture
Signs suggesting shift of brain compartments (perform CT scan before lumbar puncture, as long as patient is stable):
Focal neurological signs
Presence of papilloedema
Continuous or uncontrolled seizures
Glasgow Coma Scale score ≤12. [ Glasgow Coma Scale Opens in new window ]
How to perform a diagnostic lumbar puncture in adults. Includes a discussion of patient positioning, choice of needle, and measurement of opening and closing pressure.
Do not delay starting antibiotics for LP.
The need for a rapid LP has to be weighed against the desire to start antimicrobial treatment urgently.[48]
Carry out LP even if the patient has started antibiotics, preferably within 4 hours of starting treatment.[48]
Some guidelines recommend giving antibiotics after LP (where LP is indicated and as long as LP is not delayed) to allow the best chance of definitive diagnosis.[48] The culture rate can drop off rapidly after 4 hours, making it difficult to identify the causative organism (but prompt molecular tests will still identify the causative organism even after antibiotics have been started).
If an LP is not possible immediately, review the decision to delay LP at 12 hours and regularly thereafter.[48]
Wait 4 hours after the lumbar puncture before starting prophylactic subcutaneous low molecular weight heparin should the patient require anticoagulation. Be aware that specific recommendations exist for lumbar puncture in patients already on anticoagulants.[48] UK Joint Specialist Societies guideline: when should a lumbar puncture be performed in patients who are on anticoagulants? Opens in new window
Document the CSF opening pressure (unless the lumbar puncture is performed in the sitting position).[48]
The opening pressure is usually elevated above 20 cm CSF in bacterial meningitis and is often higher.
If a lumbar puncture is performed, assess the CSF for:[48][49]
White blood cell (WBC) count and examination
CSF WBC count can be fewer than 0.1 x 109/L or normal in the early phase of bacterial meningitis.[48]
Gram stain
Gram-negative diplococci may be present in patients with meningococcal disease
Glucose (with concurrent blood glucose)
CSF glucose is lowered in bacterial meningitis; the concentration also varies with the plasma glucose, so the CSF:plasma glucose ratio should be assessed - a cut off of 0.36 has a high sensitivity and specificity for diagnosing bacterial meningitis
Protein
May be elevated
Microscopy; looking for N meningitidis
Culture and sensitivities; looking for N meningitidis
Lactate
CSF lactate has a high sensitivity and specificity for distinguishing between bacterial and viral meningitis if antibiotics have not been given
Lactate is raised
Meningococcal and pneumococcal PCR
Enteroviral, herpes simplex, and varicella-zoster PCR; consider investigations for tuberculous meningitis.
In practice the first dose of antibiotics should not be delayed by lumbar puncture or CSF results if there is clinical concern.
Cranial computed tomography
Arrange a CT scan only if a patient with suspected meningitis has signs suggestive of shift of brain compartments secondary to raised intracranial pressure, once stabilised:[49]
Focal neurological signs
Presence of papilloedema
Continuous or uncontrolled seizures
Glasgow Coma Scale score ≤12; before brain scan, arrange assessment by a critical care physician.
Throat swab
Take a throat swab for meningococcal culture.[48][49]
Meningococci can be isolated from the nasopharynx in up to 50% of patients with meningococcal disease.
Screen for predisposing factors
Test all patients with meningitis for HIV.[48]
HIV can cause meningitis directly or indirectly via opportunistic infections. See HIV-related opportunistic infections.
Arrange review by a clinical immunologist for patients with two or more episodes of meningococcal or pneumococcal meningitis or family history of more than one episode of meningococcal disease, to carry out appropriate immunological investigations.[48]
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