Neurology

Matthew J Harris

Outline

Station 5.1: Meningitis

You are the junior doctor working in the emergency department when a 22-year-old student, Simon Peters (01/07/92), is brought in by ambulance with a headache, vomiting and neck stiffness. He looks unwell and is shielding his eyes from the light. The ambulance crew report that he seems confused and his temperature is elevated at 38.5°C. Please assess him and instigate appropriate management.

Patient Details

Name:	Simon Peters
DOB:	01/07/92
Hospital Number:	F2083912
Weight:	75 kg
Height:	1.8 m
Consultant:	Dr Epp
Hospital/Ward:	SGH Neurology
Current Medications:	Nil
Allergies:	Nil
Admission date:	12/10/14

Differential diagnosis of headache with a fever

Meningitis/encephalitis

Intracranial abscess

Intracranial bleed

Sinusitis

Complications

Immediate: septic shock, DIC, coma, seizures, raised intracranial pressure, adrenal haemorrhage, SiADH, multiorgan failure

Long term, e.g. learning disability, memory impairment, hearing/visual loss, focal paralysis, hydrocephalus, subdural effusion, ataxia

Management summary

Resuscitate using an ABCDE approach

CT brain

Blood cultures and lumbar puncture (if no contraindications)

Broad-spectrum antibiotics (consider corticosteroids and antiviral agents)

IV fluids

Initial Assessment

Airway

Assess patency of the airway. Is there any stridor or noisy breathing? Is there any vomit that could be obstructing the airway? Is the patient conscious enough to maintain a safe airway?

‘The airway is patent, with no obstruction. The patient is maintaining a safe airway.’

No additional airway support is required.

Breathing

Assess respiratory rate, oxygen saturations and accessory muscle use. Auscultate for air entry, and additional sounds of wheeze or crepitations

‘The respiratory rate is 22/min, oxygen saturations are 99%. There are no signs of respiratory distress. The lung fields are clear.’

The oxygen saturations are normal and therefore supplementary oxygen is not required. Oxygen therapy should be considered in all patients with sepsis. The respiratory rate is mildly raised, this is likely to be due to the systemic inflammatory response. Respiratory rate is a sensitive marker of when a patient is unwell and is often one of the first vital signs to become abnormal.

In a case of suspected meningitis you must alert your senior immediately, assess the patient promptly and do not delay antibiotic treatment. Following an initial ABCDE assessment, obtain IV access and take blood cultures. Ideally, patients should have brain imaging prior to lumbar puncture (if CT scanning is readily available and LP is not contraindicated), but antibiotic therapy should not be delayed beyond 3 hours after presentation.

Systemic inflammatory response syndrome (SIRS) [1]

Signs of SIRS [1]

Temperature<36°C or>38°C

Heart rate>90 bpm

Respiratory rate>20/min

White cell count<4 or>12×10⁹/L

Circulation

Assess circulatory status by measuring pulse, blood pressure and capillary refill time. Is the pulse bounding (seen early in sepsis) or weak (associated with hypotension)? Are the peripheries warm (vasodilatation secondary to sepsis) or cold (is the patient peripherally shut down?)

The patient has been vomiting and it is therefore particularly important to assess fluid status. As well as BP and pulse, also examine skin turgor, mucous membranes and look for sunken eyes. None of these signs are particularly specific on their own, so an overall assessment should be made

Perform a cardiovascular examination. Assess the JVP and central pulse. Auscultate for heart sounds and any additional murmurs. Examine for evidence of peripheral oedema

‘The HR is 110 bpm, BP 125/60 mmHg, CRT is 1 second peripherally. The pulse is bounding and the peripheries are warm. Mucous membranes are dry but skin turgor is normal. On cardiovascular examination the JVP is not visible. Heart sounds are normal with no added murmurs. There is no evidence of peripheral oedema.’

The patient is maintaining an adequate blood pressure but is tachycardic and vasodilated. There are also some signs of dehydration which are likely to be secondary to vomiting

Obtain IV access, take bloods and start intravenous maintenance fluids at 125 mL/h (see initial management)

Consider the need to insert a urinary catheter to measure urine output hourly and start a fluid balance chart. Urinary catheterization should be performed in all patients with severe sepsis.

Disability

Assess the patient’s conscious level using the Glasgow Coma Scale (GCS). Ask the nursing staff to start the patient on neurological observations. Check pupil sizes and reactions. Check bedside glucose levels

‘The patient is rousable to voice and confused with a GCS of 13 (E 3, V 4, M 6). The pupils are equal and reactive to light and the blood sugar is 4.5 mmol/L.’

A full neurological examination is required to assess for any focal neurological deficit; however, initial antibiotic treatment should not be delayed while a lengthy examination is performed

Examine the cranial nerves (including fundoscopy), upper and lower limbs. If there is any focal neurological deficit this could suggest raised intracranial pressure which would be a contraindication to lumbar puncture. If there is a pressure difference between the supratentorial and infratentorial compartments, lumbar puncture may increase this pressure difference and cause brain herniation. In such cases, lumbar puncture should not be performed and antibiotics given immediately. Other signs that could suggest raised intracranial pressure include a reduced or fluctuating GCS and papilloedema

In a case of meningitis with signs of raised intracranial pressure, the nearest neurosurgical centre should be contacted and the patient should be cared for on an intensive care unit

‘Full neurological examination is limited due to patient confusion; however, there do not appear to be any focal neurological signs. Specifically, there is no evidence of papilloedema on fundoscopy; power, reflexes and tone are normal in all four limbs and there is no facial asymmetry or obvious cranial nerve deficit.’

Signs suggestive of raised intracranial pressure

Reduced or fluctuating GCS

Focal neurological deficit

Unequal or abnormal pupils

Papilloedema

Exposure

Expose the patient and in particular look for any evidence of rash. The presence of a non-blanching petechial rash indicates septicaemia and the patient should be reviewed by critical care for intensive care admission

Measure the temperature. Examine for neck stiffness and assess Kernig’s sign (flex the patient’s hip and when the knee is extended, there is pain and resistance). Palpate for any lymphadenopathy and examine the abdomen to exclude any pathology

‘The temperature is elevated at 38.1°C, there is no obvious rash. There is neck stiffness and Kernig’s sign is positive.’

Initial Investigations

Bloods: FBC, U&Es, LFTs, glucose, CRP, clotting, meningococcal and viral PCR. Look for evidence of infection and check platelet count and clotting before performing lumbar puncture. In severe meningitis, disseminated intravascular coagulation can occur causing deranged clotting and low platelets, both of which would be a contraindication to lumbar puncture. Send a meningococcal PCR (this is important for public health)

Blood cultures: Ensure aseptic technique when taking blood and that at least 10 mL of blood is collected in each blood culture bottle to give the most chance of culturing an organism

Venous blood gas: This is useful to assess the patient’s acid–base status and their lactate. A raised lactate may suggest reduced tissue perfusion which is a poor prognostic sign and an indicator of severe sepsis. Note that partial pressure of oxygen is difficult to assess on a venous blood gas, and if there is a significant concern about this, an arterial blood gas should be performed

CT head: If CT scanning is readily available and will not lead to significant delays, a CT head should be performed prior to lumbar puncture in all cases. If CT scanning is not readily available, lumbar puncture can be performed if deemed safe by a neurologist (i.e. none of the contraindications described below). If a neurologist is not available then the EFNS guidelines [2] state antibiotics should be given while awaiting imaging. The CT protocol may vary in individual hospitals

Lumbar puncture: This is the key investigation in this case which will give the most diagnostic information. However, as already described there are a number of contraindications to performing a lumbar puncture–these are: reduced or fluctuating GCS, raised intracranial pressure, suspected intracranial mass, focal neurology, septicaemia, shock, respiratory failure, trauma and middle ear pathology. If there are no contraindications, proceed as described below:

Ensure that the platelets, clotting and CT scan are normal prior to lumbar puncture and consent the patient if they are able to

Measure the opening pressure using a manometer (normal<25 cmH₂O)

Send the 1st and 3rd bottles for microscopy, culture and sensitivity

Send the 2nd bottle for biochemistry (protein and glucose) and send a paired serum glucose

Send the 4th bottle for meningococcal PCR and viral PCR (if encephalitis suspected)

If subarachnoid haemorrhage is suspected, a CT head should be performed prior to lumbar puncture. If this is clear, a 5th bottle can be sent for xanthochromia (taken at least 12 hours following the time of the suspected subarachnoid haemorrhage)

Send the samples urgently to the lab and contact the microbiologist on call to alert them of the patient (urgent microscopy will be required) and for advice on antibiotic choice

EEG and MRI head: If there is concern of encephalitis then EEG and MRI can be useful, both usually illustrating changes in the fronto-temporal lobes

Throat swab: Send throat swabs for bacterial and viral culture

Septic screen: In view of the temperature, a chest X-ray and mid-stream urine analysis should be performed to exclude any evidence of pneumonia or urinary tract infection. In view of the vomiting, aspiration pneumonia should also be suspected; however, clinical examination in this case does not suggest any evidence of pneumonia

‘Blood testing reveals WCC 25×10⁹/L, neutrophils 21×10⁹/L, CRP 80 mg/L. Platelets and clotting are normal. Venous gas shows normal acid–base balance and a lactate of 1.5 mmol/L. CXR is clear, blood cultures and MSU are sent. A CT head is arranged prior to lumbar puncture.’

Table 5.1

Mr Peters’ blood test results

Parameter	Value	Normal range (Units)
WCC	25×10⁹/L	4–11 (×10⁹/L)
Neutrophil	21×10⁹/L	2–7.5 (×10⁹/L)
Lymphocyte	2×10⁹/L	1.4–4 (×10⁹/L)
Platelet	230×10⁹/L	150–400 (×10⁹/L)
Haemoglobin	150 g/L	Men: 135–177 (g/L)Women: 115–155 (g/L)
PT	11.8 seconds	11.5–13.5 seconds
APTT	30 seconds	26–37 seconds
CRP	80 mg/L	0–5 (mg/L)
Urea	6 mmol/L	2.5–6.7 (mmol/L)
Creatinine	100 μmol/L	79–118 (μmol/L)
Sodium	140 mmol/L	135–146 (mmol/L)
Potassium	4 mmol/L	3.5–5.0 (mmol/L)
eGFR	>60 mL/min	>60 (mL/min)
Bilirubin	10 μmol/L	<17 (μmol/L)
ALT	20 IU/L	<40 (IU/L)
ALP	40 IU/L	39–117 (IU/L)
Lactate	1.5 mmol/L	0.6–2.4 (mmol/L)
Bicarbonate	24 mmol/L	22–26 (mmol/L)
pH	7.4	7.3–7.45
PaCO₂	5 kPa	4.8–6.1 (kPa)

Common organisms causing bacterial meningitis

Neisseria meningitidis

Streptococcus pneumoniae

Haemophilus influenzae

Initial Management [2]

Airway support: In this case, no intervention required. Consider intubation in any patient with a GCS<8

Supplementary oxygen: Give supplementary oxygen in any patient with saturations<94% or severe sepsis

Intravenous fluids: Intravenous fluids should be given to all patients with sepsis. In this case, the patient is given 0.9% saline at 125 mL/h. Reassess fluid status frequently and titrate fluid therapy as necessary. Once the urea and electrolytes are available, further fluids can be prescribed with supplementary potassium added as necessary

In a case of suspected meningitis, it is important to maintain neutral fluid balance–patients with sepsis should be given intravenous fluid therapy to maintain good tissue perfusion; however, overhydration can worsen raised intracranial pressure which occurs in meningitis

Antibiotics: The choice of antibiotics depends on the local antibiotic policy and early microbiological advice should be sought. Usually, a third generation cephalosporin is given as first line, e.g. cefotaxime 2 g IV 6-hourly. Atypical organisms should be considered in certain cases and advice from the microbiologist will be important in determining the most effective choice of antibiotics. In the elderly, consider Listeria infection which is covered by the addition of amoxicillin. If the patient has recently been abroad, they may have infection with penicillin-resistant pneumococci and you should add high-dose vancomycin

Corticosteroids: In cases of community-acquired meningitis (particularly pneumococcal meningitis), there is evidence that high-dose corticosteroids may reduce neurological complications if given before or at the same time as the first dose of antibiotics [3]. Following senior advice, consider starting dexamethasone 10 mg IV QDS. High-dose corticosteroids should not be given in those with meningococcal septicaemia, septic shock, in the immunosuppressed and those who have undergone recent neurosurgery. If corticosteroids are to be given, a proton pump inhibitor (such as omeprazole 40 mg IV OD) should be given in addition to prevent gastric ulceration

Antiviral treatment: In cases where encephalitis is suspected (headache, fever, seizures, altered personality, focal neurology), also give aciclovir 10 mg/kg IV TDS. It is reasonable to give it in the above case because of the patient’s confusion. Outcome in encephalitis significantly worsens the longer treatment is delayed; therefore, if you ever suspect encephalitis you should start treatment immediately–this can easily be stopped later when the viral PCR results are available

Analgesia: Start regular paracetamol for the patient’s headache. Use opioids with considerable caution in a patient with a reduced GCS

DVT prophylaxis treatment: pharmacological prophylaxis with LMWH should initially be avoided. Intracerebral and adrenal haemorrhage can both occur in meningitis as well as clotting abnormalities and consumption of platelets due to sepsis and disseminated intravascular coagulation. In all cases, LMWH treatment should be delayed until at least 6 hours after lumbar puncture. Following initial investigations and treatment, the appropriateness of LMWH prescription for DVT prophylaxis can be determined

Notify public health authority: Meningitis is a notifiable disease and close contacts should be treated with antibiotic prophylaxis–the choice of antibiotic depends on the causative organism and microbiology advice should be taken

As the GCS is 13, all medications are given intravenously.

Figure 5.1

Figure 5.2

Figure 5.3

Reassessment after Investigation Results

After initial assessment, a CT head is undertaken in view of the reduced GCS–this shows no evidence of intracranial mass or raised intracranial pressure. Lumbar puncture is therefore performed, the results of which are below:

WBC: 5000 cells/mm³ (95% polymorphs)	(normal range 0–5 cells/mm³)
Protein 1 g/L	(normal range 0.15–0.5 g/L)
Glucose 1.5 mmol/L (plasma was 4.5 mmol/L)	(normal range 0.6×plasma level)

Interpreting lumbar puncture results

Table 5.2

Lumbar puncture results

The lumbar puncture results are consistent with bacterial meningitis. Following discussion with the microbiology consultant, cefotaxime and dexamethasone are continued while awaiting CSF culture and sensitivities. Aciclovir is continued pending viral PCR results.

Handing over the Patient (in this case would likely be to intensive care)

‘Simon is a 22-year-old student with community acquired bacterial meningitis, on cefotaxime, aciclovir and dexamethasone.

He presented with headache, vomiting and neck stiffness. On examination, he is maintaining his own airway and is not in any respiratory distress. BP is 125/60 mmHg and pulse rate is 110 bpm. There are some signs of dehydration and he has been started on intravenous fluids. The GCS is 13/15: he is eye opening to voice and is confused but there are no focal neurological signs. The temperature is elevated at 38.1°C, there is no evidence of rash but he is Kernig’s positive. He has initially been treated with cefotaxime 2 g, dexamethasone 10 mg and aciclovir 750 mg.

Cerebrospinal fluid examination reveals a significantly raised white cell count predominantly of polymorphs. The protein is elevated and glucose level reduced.

The lumbar puncture results are typical of bacterial meningitis and, following microbiology advice, the plan is to continue current medications.

The patient is to be transferred to the intensive care unit for closer observation. The local public health authority has been informed and close contacts are being traced. Bloods are to be repeated in the morning and CSF/blood cultures need to be chased, as well as meningococcal and viral PCR.’

Station 5.2: Seizures

A 37-year-old female, Lucy, is brought in to the emergency department by ambulance following a collapse. She is currently having a generalized seizure while lying on a bed. The ambulance crew has just managed to place a cannula and ask if you want to give any medication. They report that Lucy has been seizing for about 10 minutes. She is not on any regular medications, and has never had a seizure before. Please assess her and instigate appropriate management.

Patient Details

Name:	Lucy Wall
DOB:	02/02/77
Hospital Number:	C1261452
Weight:	50 kg
Height:	1.6 m
Consultant:	Dr Epp
Hospital/Ward:	SGH Neurology
Current Medications:	Nil
Allergies:	Nil
Admission date:	12/10/14

Seizure complications

Status epilepticus (associated with significant cerebral, cardiovascular, metabolic/systemic deterioration, including multiorgan failure)

Injury secondary to seizure

Cognitive and behavioural deterioration

Management of seizures

Resuscitate using an ABCDE approach

Oxygen

Recovery position

Consider reversible causes, e.g. hypoglycaemia

Benzodiazepines

Initial Assessment

Airway

Assess patency of the airway. In the case of a generalized seizure, it is critically important that the airway is protected and the patient is protected from injury. Open the airway and ensure it is patent. Is there any stridor or noisy breathing? Is there any vomit that could be obstructing the airway?

‘The patient is actively seizing and has therefore been placed in the recovery position. The airway is patent and unobstructed.’

First roll the patient onto their left side and into the recovery position if possible: if the patient vomits this will reduce the risk of aspiration. Ensure that the patient is not at risk of falling out of bed and call for a nurse to help assist you

If there is a history of trauma, use cervical spine precautions as necessary

Remove any loose fitting teeth but do not place anything in the mouth

If there are excess secretions or vomit use suction to clear the airway

Use head tilt, chin lift or jaw thrust manoeuvres as necessary to maintain the airway

Insert a nasopharyngeal airway with lubrication (unless there is a suspected basal skull fracture)

Intubation should be considered early if necessary and the on-call anaesthetist informed.

Breathing

Assess respiratory rate, oxygen saturations and accessory muscle use. Auscultate for air entry and additional sounds of wheeze or crepitations

‘The respiratory rate is 25/min, oxygen saturations are 100% on high-flow oxygen. There is accessory intercostal muscle use. The lung fields are clear to auscultation.’

Apply high-flow oxygen via a non-rebreather mask–make sure you inflate the reservoir bag with oxygen before placing it on the patient

High-flow oxygen therapy should be given to all patients who are having a generalized seizure unless there is a specific contraindication (e.g. known CO₂ retainer). The respiratory rate is usually raised in the setting of a seizure. If oxygen saturations are reduced, consider performing an arterial blood gas–hypoxia can be a cause of seizures.

Prescribe (see Figs 5.4–5.6)

HIGH-FLOW OXYGEN, e.g. 15 L/min via a NON-REBREATHER MASK

Figure 5.4

Figure 5.5

Figure 5.6

Circulation

Assess circulatory status by measuring pulse, blood pressure and capillary refill time

Perform a focused cardiovascular examination. Assess the central pulse and auscultate for heart sounds and any additional murmurs. Examine for evidence of peripheral oedema

‘The pulse is regular at 110 bpm, BP 155/90 mmHg, CRT is 1 second peripherally. Heart sounds are normal with no added murmurs. There is no evidence of peripheral oedema.’

The blood pressure and pulse are slightly elevated (possibly due to seizure activity). Obtain IV access and take bloods.

Disability

Attempt to assess the patient’s conscious level using either AVPU (is the patient Alert? If not, do they respond to Verbal or Painful stimuli? Or are they Unresponsive?) or the Glasgow Coma Scale. Check bedside glucose levels

‘The patient is actively seizing and it is therefore difficult to assess the GCS. The pupils are equal and reactive to light and the blood sugar is 5.1 mmol/L.’

It is important not to miss hypoglycaemia as a cause of seizures as it is easily treatable. Beware in those with malnutrition or alcoholics that intravenous glucose can precipitate Wernicke’s encephalopathy in the presence of thiamine deficiency–therefore give intravenous thiamine at the same time if this is suspected

Once the patient has stopped fitting it will be important to perform a full neurological examination to look for any deficits. Be aware, however, that following a seizure patients can have a Todd’s paresis–transient focal arm or leg weakness that occurs after a seizure

Ask the nursing staff to start the patient on neurological observations. Check pupil sizes and reactions.

Exposure

Expose the patient and in particular look for any evidence of rash that may indicate the underlying cause, e.g. petechial rash in meningococcal septicaemia, shingles associated with viral encephalitis. Examine for any obvious signs of injury

Measure the temperature. Examine the abdomen if possible to exclude any pathology

‘The temperature is 37.6°C, examination is otherwise unremarkable.’

Initial Investigations

Bloods: FBC, U&Es, LFTs, glucose, CRP, calcium, magnesium, and clotting. Look for evidence of infection or electrolyte abnormality that could have precipitated the seizure. Note that the white blood cell count will often go up secondary to a seizure in and of itself. Consider sending toxicology screen and if the patient is taking antiepileptic medications measure drug levels. If the patient is a woman of child-bearing potential send βHCG levels or perform a urinary pregnancy test after the seizure has terminated. If pregnancy is strongly suspected, perform an emergency ultrasound, or auscultate for a fetal heart: eclampsia usually doesn’t occur until about 20 weeks pregnancy so evidence of a baby should be present!

Blood cultures: Infection can precipitate seizures in those with epilepsy or be the primary cause; therefore blood cultures should be taken. If the temperature is elevated this may not always be due to infection as seizures themselves can lead to a rise in body temperature

Arterial blood gas: Perform an arterial blood gas if possible, otherwise a venous blood gas can be taken at the same time as cannulation. In particular, check for hypoxia, hyponatraemia and confirm normal glucose levels. Most blood gas machines will also analyse carboxyhaemoglobin levels, although carbon monoxide poisoning is a very rare cause of seizures

Respiratory and cardiac monitoring: Arrange for continuous monitoring of the BP, oxygen saturations and ECG tracing (to exclude arrhythmia). It is important to monitor for hypoxia during a seizure as well as changes in the pulse and BP. Some of the medications given to terminate seizures (e.g. phenytoin) can lead to arrhythmias and therefore continuous cardiac monitoring is required if these are given

Table 5.3

Ms Wall’s blood and ABG test results

Parameter	Value	Normal range (Units)
WCC	15×10⁹/L	4–11 (×10⁹/L)
Neutrophil	8×10⁹/L	2–7.5 (×10⁹/L)
Lymphocyte	5×10⁹/L	1.4–4 (×10⁹/L)
Platelet	200×10⁹/L	150–400 (×10⁹/L)
Haemoglobin	140 g/L	Men: 135–177 (g/L)Women: 115–155 (g/L)
PT	12 seconds	11.5–13.5 seconds
APTT	30 seconds	26–37 seconds
CRP	3 mg/L	0–5 (mg/L)
Urea	6 mmol/L	2.5–6.7 (mmol/L)
Creatinine	100 μmol/L	79–118 (μmol/L)
Sodium	140 mmol/L	135–146 (mmol/L)
Potassium	4 mmol/L	3.5–5.0 (mmol/L)
eGFR	>60 mL/min	>60 (mL/min)
Bilirubin	10 μmol/L	<17 (μmol/L)
ALT	14 IU/L	<40 (IU/L)
ALP	110 IU/L	39–117 (IU/L)
Glucose	5 mmol/L	4.5–5.6 (mmol/L) (fasting)
Calcium	2.23 mmol/L	2.20–2.67 (mmol/L)
Magnesium	1 mmol/L	0.7–1.1 (mmol/L)
pH	7.40	7.35–7.45
PaO₂	12.0 kPa on air	10.6–13.3 (kPa) on air
PaCO₂	5.0 kPa	4.8–6.1 (kPa)
HCO₃	24 mmol/L	22–26 (mmol/L)