Neurological investigationsNeurological investigations

Ann JohnstonAnn JohnstonSpR NeurologySpR Neurology

CardiffCardiff

NeurologyNeurology

ApproachApproach

• Same as CVS/Resp/GIT

• History is most important tool

• Diagnosis from history

• Investigations are supportive

• Investigations almost never diagnostic

Sleuth workSleuth work• Story-tellers

• Historians

• Evidence

• Help pts understand their story

EvidenceEvidence• Story

• primary source• secondary source• eye-witnessed account

• Numbers

• Pictures

• Too difficult box ???

Neurological investigationsNeurological investigationsNumbersNumbers• Blood• Cerebrospinal fluid CSF

PicturesPictures• CT • MRI• Angiogram• PET

CSFCSF• Produced by choroid plexus (95%)

• 500ml/day

• Energy dependent process ATPase pump

• Absorbed by arachnoid villi

1. Good practice to perform CT brain prior to LP

2. To assess for signs of raised intracranial pressure …. papilloedema

Complications of LPComplications of LP• Headache – commonest

• Related to persistent dural leak• Positional• Most resolve within 7-14 days• Commoner in young women• Risk factors – bad technique, needle size• Treatment – fluids, bedrest, analgesia, caffeine, blood-patch

• Brain herniation

• Bleeding

CSFCSF• Opening pressure• Cell counts – wcc, rcc• Microscopy, culture, staining• Biochemistry – protein, glucose• Xanthochromia• Oligoclonal bands• Cytology• Others – HSV, ACE, lyme, Protein 14-3-3

CSFCSF

• Appearance• Clear and colourless• Cloudy if >200 WCCs• Cloudy if >400 RBCs

• Xanthochromia• Yellow colour • Appears RBC > 500

CSF cytologyCSF cytology• Cytology should be done promptly after LP• Lymphocyte are predominant leukocyte

• No RBCs should be found in CSF• Unless traumatic tap• Should be in same ratio as WCC:RBC in blood• Subtract 1 WCC for every 700 RBCs

CSF proteinCSF protein• Non specific indicator of disease

protein – breakdown of blood-brain barrier

protein levels occur in dural leaks and intracranial hypotension

• Major immunoglobulin in CSF IgG

• Oligoclonal bands occur in some CNS diseases

CSF Glucose• Derived from the serum

• Reflects previous 4 hrs systemic glucose levels

• CSF:blood 0.6

• Check simultaneous serum glucose

glucose – bacterial, fungal or TB meningitis, inflammatory processes, carcinomatous meningitis and SAH

CSF valuesCSF values

• Opening pressure 10 – 20 cm CSF

• Protein < 0.4g/l

• Glucose ~ 2/3 plasma glucose

NeurophysiologyNeurophysiology

ElectricsElectrics• Electroencephalogram EEG

• Nerve Conduction Studies NCS

• Electromyography EMG

• Visual and sensory evoked potentials VEPs SSEPs

EEGEEG

CasesCases

CasesCases

Helpful hintsHelpful hints• Story is the most important• Clues from history• Examination findings• Prior to looking at the investigations• Piece it together

Case 1Case 1 A 19-year-old university student complains of

headache of 8 hours duration, she does not like the bright lights and has vomited twice.

On examination she is sweaty and there is no obvious rash.

The casualty doctor is worried about her and requests a CT scan of brain, which is normal and then proceeds to lumbar puncture

Appearance: cloudy, with no organisms on gram stainWCC: 228/mm3 (neutrophils)RBC: 4/mm3

Glucose: 2.1mmol/l ~ plasma glucose: 5.9mmol/lProtein: 1.6g/l

Describe the CSF…..

What is the diagnosis?

Treatment?

Case 2Case 2 A 16-year-old schoolgirl has been feeling

lethargic and unwell for the past 2-3 days.

She has a headache, low-grade fever and does not like bright lights. Examination is normal.

CSF opening pressure at time of lumbar puncture is 17cm CSF. The following results are obtained.

Appearance: Clear, with no organisms on gram stainWCC: 101/mm3 (>95% lymphocytes)RBC: 9/mm3

Glucose: 3.9mmol/l ~ plasma glucose 5.8mmol/lProtein: 0.9g/l

What is the most likely diagnosis?

Lymphocyte predominate CSFLymphocyte predominate CSF

• Viral meningitis• Partially treated bacterial meningitis• TB• Neurosarcoid• SLE• Bechets• Cryptococcus

Case 3Case 3 A 18 year old girl presented after 3-4 weeks of headache

and vomiting. She had been admitted to hospital on several occasions over the course of her illness but discharged home following a normal CT brain.

She was not making much progress, so attended her GP who diagnosed sinusitis and prescribed a course of amoxicillin.

With no further improvement she was readmitted due to the persistence of her mother.

On examination her temperature was 372, she

had a VIth nerve palsy, and fundoscopy was as shown

CRP < 2mg/l WCC 4

How do you manage this patient?

Opening pressure 40 cm CSFWCC 230 – 100% lymphocytesNo organisms on staining or cultureProtein 2.4g/lGlucose 3.1 mmol/l with plasma 5.9mmol/l

What is the most likely diagnosis?

Case 4Case 4 A 48 year old suddenly collapses while

watching a football match. He loses consciousness and on regaining it complains of a severe occipital headache and vomits profusely.

What is your provisional diagnosis?How do you investigate him?

Case 5Case 5 A 35 year old female, complains of left orbital

pain, like a knife! She also notices some zig-zag lines in the outer aspect of her vision. Within 10 minutes she has tingling in her left arm and within a further 5 minutes also in her left leg.

She has had several similar episodes in the past and on occasions has been dyshasic.

What is the diagnosis?

Case 6Case 6

A 79 year old man presents with a gradual deterioration in mental state, he also has had difficulty in walking and has had frequent falls.

How would you investigate him?

What other piece of clinical information may be helpful in aiding the diagnosis?

Case 7Case 7 A 72 year old lady presents with double

vision on left lateral gaze. She also has had increasing headaches over the last 3-4 weeks. CT brain was normal.

CSF – WCC 600 – 90% lymphocytes Protein – 3.1g/l Glucose 0.7 ~ plasma 5.4mmol/l

What is the most likely diagnosis?

Case 8Case 8

A 18 year old female is celebrating her A-level results with her family in a restaurant. Just after eating her main course while seated, she collapses onto the table. Some jerks are noticed in her limbs. These settle spontaneously. She regains consciousness quickly and makes a complete recovery.

Due to parental concern, she attends A&E, where she tells staff that prior to the episode her hearing became muffled and she felt as those the ‘world was closing in on her…’

What is the diagnosis?Would you perform any investigations?

Case 9Case 9

A 15 year old schoolboy, has had 2 similar episodes, which were witnessed by his brother. Both occurred from sleep. He was seen to be thrashing about the bed and groaning for about 2-3 mins. On one occasion he bite the side of his tongue and was incontinent of urine.

The following day he complained of painful muscles. One of these events occurred after he had been out late at a school formal. He is otherwise well, but is occasionally clumsy in the mornings.

Any other questions?What is the diagnosis?Would you do any investigations

Case 10Case 10 19 year old art student has a one month history of

daily constant headache and flashing lights in her vision if she turns her head quickly, no vomiting and a pulsing sensation in her ears. She has gained weight in the last few months and has a BMI of 31. Examination demonstrates bilateral optic disc blurring and a left VIth nerve palsy.

What investigations do you do?What is the likely diagnosis?

Case 11

55 year old lorry driver presented with headaches worst in the mornings over the last 9 months. He smokes 20 per day. He describes difficulty in concentrating during work and excessive daytime tiredness. He is overweight, with slightly raised BP, 165/95 mm Hg.

Any other questions?Any investigations?What is the diagnosis?

Case 12 30 year old gym instructor, describes one episode of

severe occipital headache while exercising vigorously in the gym. He also reports another similar episode of severe headache during sexual intercourse after which he vomited. No signs on examination.

What are your thoughts?Would you investigate him?Any treatment?

Thank-you, any

questions ?