Neuroscience Flashcards
Define encephalitis.
Inflammation of the brain parenchyma.
Explain the aetiology / risk factors of encephalitis.
Causes:
- VIRAL - e.g. HSV, herpes zoster, mumps, adenovirus, coxsackie, echovirus, enteroviruses, measles, EBV, HIV, rabies (Asia), Nipah (Malasia), arboviruses transmitted by mosquitos (Jap B encephalitis - Asia, St Louis and West Nile encephalitis - USA)
- NON-VIRAL - e.g. syphillis, Staphylococcus aureus
- IMMUNOCOMPROMISED - e.g. CMV, toxoplasmosis, Listeria
- AUTOIMMUNE OR PARANEOPLASTIC - associated with antibodies - e.g. anti-NMDA or anti-VGKC
Summarise the epidemiology of encephalitis.
7.4 in 100,000 in UK
Recognise the presenting symptoms of encephalitis.
- Can be mild and self-limiting
- Subacute onset (hours to days)
- Headache
- Fever
- Vomiting
- Neck stiffness
- Photophobia - i.e. symptoms of meningism (meningoencephalitis)
- Behavioural changes
- Drowsiness
- Confusion
- History of seizures
- Focal neurological symptoms - e.g. dysphagia, hemiplegia
- DETAILED TRAVEL HISTORY
Recognise the signs of encephalitis on physical examination.
- Reduced level of consciousness with deteriorating GCS
- Seizures
- Pyrexia
- Neck stiffness
- Photophobia
- Kernig’s test positive
- Hypertension
- Bradycardia
- Papilloedema
- Focal neurological signs - e.g. dysphagia, hemiplegia
- Minimental examination may reveal cognitive or psychiatric disturbances
NB: Raised intracranial signs and meningism signs.
Identify appropriate investigations for encephalitis and interpret the results.
- Bloods
- MRI / CT
- Lumbar Puncture
- EEG
- Brain Biopsy
Bloods
- FBC - high lymphocytes
- U&E - SIADH may occur
- Glucose - compare with CSF glucose
- Viral serology
- ABG
MRI / CT
- Excludes mass lesion
- HSV produces characteristic oedema of the temporal lobe on MRI
Lumbar Puncture
- High lymphocytes
- High monocytes
- High protein
- Glucose usually normal
- CSF culture difficult
- Viral PCR now first line
EEG
- Epileptiform activity
- E.g. spiking activity in temporal lobes
Brain Biopsy
- Rarely performed
Define epilepsy.
> 2 seizures.
Seizure = paroxysmal synchronised cortical electrical discharges.
Focal Seizures
- Localised to specific cortical regions
- Temporal lobe, frontal lobe, occipital, complex partial
- Simple partial - does not affect consciousness
- Simple complex - does affect consciousness
Generalised Seizures
- Affect consciousness
- Tonic clonic, absence attacks, myoclonic, atonic (drop attacks), tonic seizures
Explain the aetiology / risk factors of epilepsy.
Result from an imbalansce in the inhibitory and excitatory currents (Na+ or K+) or neurotransmittors (glutamate or GABA) in the brain. Can be precipitated or are cryptogenic.
Precipitants:
- Flashing lights
- Drugs
- Sleep deprivation
- Metabolic
Idiopathic.
Primary Syndromes
- Idiopathic generalized epilepsy
- Temporal lobe epilepsy
- Juvenile myoclonic epilepsy
Secondary Seizures (Symptomatic)
- Tumour
- Infection - meningitis, encephalitis, abscess
- Inflammation - vasculitis, multiple sclerosis
- Toxic / metabolic - sodium imbalance, hyperglycaemia, hypoglycaemia, hypocalcaemia, hypoxia, porphyria, liver failure
- Drugs - alcohol withdrawal, benzodiazepine withdrawal
- Vascular - haemorrhage, infarction
- Congenital anomalies - cortical dysplasia
- Neurodegenerative disease - Alzheimer’s disease
- Malignant hypertension or eclampsia
- Trauma
Common Seizure Mimics
- Syncope
- Migrane
- Non-epileptiform seizure disorder (e.g. dissociative disorder)
Summarise the epidemiology of epilepsy.
Common.
1% of general population.
Peak age of onset is in early childhood or in elderly.
Recognise the presenting symptoms of epilepsy.
Obtain history from a witness as well as a patient.
Key features from history to determine seizure semiology:
- Rapidity of onset?
- Duration of episode?
- Any alteration of consciousness?
- Any tongue-biting or incontinence?
- Any rhythmic synchronous limb jerking?
- Any post-ictal period?
- Drug history - alcohol, recreational drugs
FOCAL SEIZURES
- Frontal lobe focal motor seizures - motor convulsions, Jacksonian march (spasm spreads from mouth or digit), post-ictal flaccid weakness (Todd’s paralysis)
- Temporal lobe seizures - aura (visceral and psychic symptoms, fear or deja-vu sensation), hallucinations (olfactory, gustatory)
- Frontal lobe complex partial seizures - loss of consciousness, automatisms, rapid recovery
GENERALISED SEIZURES
- Tonic-clonic (grand mal) - vague symptoms before attack (irritability), tonic phase (generalised muscle spasm), clonic phase (repetitive synchronous jerks), faecal or urinary incontinence, tongue biting, impaired consciousness, lethargy, confusion, headache, back pain, stiffness afterwards
- Non-convulsive status epilepticus - acute confusional state, fluctuating, difficult to distinguish from dementia
Recognise the signs of epilepsy on physical examination.
Depends on aetiology, usually normal between seizures.
Look for focal abnormalities indicative of brain lesions.
Identify appropriate investigations for epilepsy and interpret the results.
Bloods
- FBC, U&E, LFTs
- Glucose, Ca2+, Mg2+
- ABG, toxicology screen
- Prolactin - transient increase shortly after a true seizure
EEG
- Helps confirm or refute the diagnosis
- Assists in clarifying the epileptic syndrome
- Usually performed inter-ictally and often normal and does not rule out epilepsy
- Ictal EEGs combined with video telemetry are more useful but requires adequate facilities
CT / MRI
- For structural, space-occupying and vascular lesions
Others
- Particularly for secondary seizures according to suspected aetiology
- E.g. lumbar puncture, HIV serology
Generate a management plan for epilepsy.
STATUS EPILEPTICUS: seizure lasting longer than 30 minutes, failure to regain consciousness
- Early treatment has higher success - give at 5-10 minutes
- Resuscitate and protect airway, breathing and circulation
- Check glucose and give if hypoglycaemic
- Consider thiamine
- IV lorazepam or IV/PR diazepam - repeat once after 15 minutes if needed
- Reoccur or fail to respond- give IV phenytoin (15mg/kg) under ECG monitoring
- Alternative IV agents - phenobarbitone, levetiracetam, sodium valproate
- If these measures fail, consider general anaesthesia - requires intubation and mechanical ventilation
- Treat cause - e.g. correct hypoglycaemia or hyponatraemia
- Check plasma levels of all anticonvulsants
PHARMACOLOGICAL TREATMENT
- Only start anti-convulsant therapy after >2 unprovoked seizures
- Lamotrigine or carbamazepine - 1st line focal seizures
- Sodium valproate - 1st line generalised seizures
- Others - phenytoin, levetiracetam, clobazam, topiramate, gabapentin, vigabatrin, ethosuximide (absence)
- Start treatment with single anti-epileptic drug (AED)
PATIENT EDUCATION
- Patient education
- Avoid triggers - e.g. alcohol
- Encourage seizure diaries
- Recommend supervision for swimming or climbing
- Driving only permitted if seizure free for 6 months
- Women of childbearing age should be counselled regarding possible teratogenic effects of AEDs and should consider taking supplemental folate to limit the risk
- Drug interactions can limit the effectiveness of oral contraception
SURGERY
- For refractory epilepsy
- Removal of definable epileptogenic focus - determined from detailed EEG, intra-cortical recordings, ictal SPECT, neuropsychometry
- Vagus nerve stimulator
Identify the possible complications of epilepsy (including status epilepticus) and its management.
- Fractures with tonic-clonic seizures
- Behavioural problems
- Sudden death in epilepsy (SUDEP)
- Complications of AEDs
SE of phenytoin = gingivial hypertrophy
SE of carbamazepine = neutropenia, osteoporosis
SE of lamotrigine = Stevens-Johnson syndrome
Summarise the prognosis for patients with epilepsy.
50% remission at 1 year
Mortality 2 in 100,000 per year
Directly related to seizure or secondary to injury
Define extradural haemorrhage.
Aka epidural haematoma.
Collection of blood that forms between the inner surface of the skull and outer layer of the dura, which is called the endosteal layer.
Associated with a history of head trauma and associated skull fracture.
Explain the aetiology / risk factors of extradural haemorrhage.
Causes:
- Traumatic skull fracture - to a temple just lateral to the eye - temporal or parietal bone
- Laceration of middle meningeal artery and vein
- Tear in dural venous sinus
Differentials - epilepsy, carotid dissection, carbon monoxide poisoning.
Summarise the epidemiology of extradural haemorrhage.
2% of all head injuries
15% of all fatal head traumas
Recognise the signs of extradural haemorrhage on physical examination.
- Deteriorating consciousness after head injury
- No initial loss of consciousness
- Initial drowsiness post injury seems to have resolved
- Lucid interval pattern - lasts a few hours to a few days before reducing GCS from raised ICP
- Severe headache
- Vomiting
- Confusion
- Seizures
- Hemiparesis with brisk reflexes and upgoing plantar
If bleeding continues:
- Ipsilateral pupil dilation
- Coma deepening
- Bilateral limb weakness
- Breathing becomes deep and irregular due to brainstem compression
- Death following period of coma due to respiratory arrest
- Bradycardia and high BP are late signs
Recognise the presenting symptoms of extradural haemorrhage.
- Deteriorating consciousness after head injury
- No initial loss of consciousness
- Initial drowsiness post injury seems to have resolved
- Lucid interval pattern - lasts a few hours to a few days before reducing GCS from raised ICP
- Severe headache
- Vomiting
- Confusion
- Seizures
- Hemiparesis with brisk reflexes and upgoing plantar
If bleeding continues:
- Ipsilateral pupil dilation
- Coma deepening
- Bilateral limb weakness
- Breathing becomes deep and irregular due to brainstem compression
- Death following period of coma due to respiratory arrest
- Bradycardia and high BP are late signs
Identify appropriate investigations for extradural haemorrhage and interpret the results.
CT
- Shows haematoma lens-shaped / biconvex
- Rounded blood shape
NB: Sickle-shaped subdural haematoma as touch dural attachments to skull keep it more localized
Skull X-RAY
- Normal
- Fracture lines crossing course of middle meningeal vessels
LUMBAR PUNCTURE IS CONTRAINDICATED.
Define meningitis.
Inflammation of the leptomeningeal (pia mater and arachnoid) coverings of the brain, most commonly caused by infection.
Aseptic meningitis - characterised by clinical and laboratory evidence for meningeal inflammation and negative routine bacterial culture
Mollaret’s meningitis - recurrent benign lymphocytic meningitis
Explain the aetiology / risk factors of meningitis.
Bacterial
- Neonates - Group B streptococci, Escherichia coli, Listeria monocytogenes
- Children - Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae
- Adults - Neisseria meningitidis (meningococcus), Streptococcus pneumonia, tuberculosis
- Elderly - Streptococcus pneumoniae, Listeria monocytogenes
Viral
- Enteroviruses
- Mumps
- HSV
- VZV
- HIV
Fungal
- Cryptococcus - associated with HIV infection
Aseptic Meningitis
- Enterovirus, mycobacteria, fungi, spirochetes
- Autoimmune - e.g. Sarcoidosis, Behcet’s disease, Systemic lupus erythematosus
- Malignancy - lymphoma, leukaemia, metastatic carcinomas
- Medication - NSAIDs, trimethoprim, azathioprine
Mollaret’s Meningitis
- 50% exhibit transient neurological manifestations
- HSV-2
- Large granular plasma cells on Papnicolaou’s stain, PCR for HSV DNA
- Treat with acyclovir
Risk Factors:
- Close communities - e.g. dormitories
- Basal skull fractures
- Mastoiditis
- Sinusitis
- Inner ear infections
- Alcoholism
- Immunodeficiency
- Splenectomy
- Sickle cell anaemia
- CSF shunts
- Intracranial surgery
Summarise the epidemiology of meningitis.
Variation according to geography, age, social conditions.
UK Public Health Laboratory Service receives approx 2500 notifications / year.
Recent visitors to Haj (meningococcal serogroup W135).
Epidemics occur in the meningitis belt of Africa (meningococcal serogroup A).
Recognise the presenting symptoms of meningitis.
- Severe headache
- Photophobia
- Neck or backache
- Irritability
- Drowsiness
- Vomiting
- High-pitched crying or fits (common in children)
- Clouding of consciousness
- Fever
Check travel and exposure history:
- Rodents - lymphocytic choriomeningitis virus
- Ticks - Lyme borrelia, Rocky Mountain spotted fever
- Mosquitoes - West Nile virus, St. Louis encephalitis virus
- Sexual activity - HSV-2, HIV, syphilis
- Travel - C.immitis, A.cantonensis
- Contact with other individuals with vrial exanthems - enteroviruses
Recognise the signs of meningitis on physical examination.
Signs of Meningism:
- Photophobia
- Neck stiffness
- Kernig’s sign - with hips flexed, pain / resistance on passive knee extension
- Brudzinski’s sign - flexion of hips on neck flexion
Signs of Infection
- Fever
- Tachycardia
- Hypotension
- Skin rash - petechiae with meningococcal septicaemia
- Altered mental state
Identify appropriate investigations for meningitis. and interpret the results.
- Bloods
- Imaging
- Lumbar Punctre
- viral
- TB
Bloods
- 2 sets of blood cultures - do not delay antibiotics
Imaging
- CT scan to exclude a mass lesion or raised intracranial pressure before LP
- LP may lead to cerebral herniation due to subsequent CSF removal
- CT head before LP in patents with immunodeficiency, history of CNS disease, reduced consciousness, fit, focal nerologic deficit, papilloedema
LP
- Note opening CSF pressure
- Send for microscopy with culture, sensitivity, Gram staining, biochemistry, cytology
- Streptococcus pneumoniae - Gram-positive diplococcic
- Neisseria Meningitidis - gram-negative diplococcic
Bacterial
- Cloudy CSF
- Increased neutrophils
- Increased protein
- Reduced glucose
- CSF serum glucose ratio of <0.5
Virus
- Increased lymphocytes
- Increased protein
- Normal glucose
TB
- Fibrinous CSF
- Increased lymphocytes
- Increased protein
- Reduced glucose
Staining of petechiae scrapings may detect meningococcus in 70%.
Additional studies - e.g. viral PCR, staining / culture for mycobacteria and fungi, HIV test depending on the clinical presentation / CSF findings.
Generate a management plan for meningitis.
- IMMEDIATE ANTIBIOTICS IV or IM
- If meningitis suspected before lumbar puncture or CT
- 3rd generation cephalosporin - cefotaxime 2g QDS or ceftriaxone 2g BD
- Benzylpenicillin - initial blind therapy, sensitive meningococci and pneumococci
- Listeria = amoxicillin + gentamicin
- Penicillin & Cephalosporin resistant pneumococci = + vancomycin + rifampicin
- History of anaphylaxis to penicillin or cephalosporins = chloramphenicol
- Patients treated with benzylpenicillin or chloramphenicol = 2 days rifampicin (eliminate nasopharyngeal carriage)
- DEXAMETHASONE IV
- 10mg QDS for 4 days
- Given shortly before or with first dose of antibiotics
- Continue in pneumococcal or H. influenzae meningitis - reduce complications of death (pneumococcal) and hearing loss (H.influenzae)
- Avoid dexamethasone if HIV suspected
- RESUSCITATION
- ITU - PREVENTION
- Notify public health services
- Consult a consultant in communicable disease control for advice regarding chemoprophylaxis - e.g. rifampicin for 2 days
- Vaccination for close contacts
- Vaccination against meningococcal serogroups A and C (none for B)
Identify the possible complications of meningitis and its management.
- Septicaemia
- Shock
- DIC
- Renal failure
- Fits
- Peripheral gangrene
- Cerebral oedema
- Cranial nerve lesions
- Cerebral venous thrombosis
- Hydrocephalus
- Water house - Friderichsen Syndrome - bilateral adrenal haemorrhage
Summarise the prognosis for patients with meningitis.
Bacterial meningitis mortality at 10-40% with meningococcal sepsis.
In developing countries - higher mortality rate
Viral meningitis - self-limiting
Define subarachnoid haemorrhage.
Arterial haemorrhage into the subarachnoid space.
Explain the aetiology / risk factors of subarachnoid haemorrhage.
- Rupture of a saccular aneurysms at the base of the brain - usually at Circle of Willis (85%).
- Permesencephalic haemorrhage - e.g. parenchymal haemorrhages tracking onto surface of brain (10%)
- Arteriovenous malformations
- Bleeding diatheses
- Vertebral or carotid artery dissection with intracranial extension
- Mycotic aneurysms
- Drug abuse - e.g. cocaine, amphetamines
Associated with:
- Hypertension
- Smoking
- Excess alcohol intake
- Polycystic kidney disease
- Marfan’s Syndrome
- Peseudoxanthoma elasticum
- Ehlers-Danlos Syndrome
Summarise the epidemiology of subarachnoid haemorrhage.
Incidence 10 in 100,000
Peak incidence = 50-60 years
Recognise the presenting symptoms of subarachnoid haemorrhage.
- Sudden onset severe headache - hit at the back of the head
- Nausea
- Vomiting
- Neck stiffness
- Photophobia
- Reduced level of consciousness
Recognise the signs of subarachnoid haemorrhage on physical examination.
Meningism
- Neck stiffness
- Kernig’s sign - resistence or pain on knee extension when hip is flexes
- Irritation of meninges by blood
- Pyrexia
GCS
- Assess and regularly monitor for deterioration
Increased intracranial pressure
- Papilloedema
- IV or III cranial nerve palsy
- Hypertension
- Bradycardia
Fundoscopy
- Subhyaloid haemorrhage - between retina and vitreous membrane
Focal Neurological Signs
- 2nd day
- Ischaemia from vasospasm and reduced brain perfusion
- Aneurysms - pressure on cranial nerves causing opthalmoplegia (III or VI nerve palsy)
Identify appropriate investigations for subarachnoid haemorrhage and interpret the results.
- Bloods - FBC, U&E, ESR, CRP, Clotting (?bleeding diathesis)
- CT
- Angiography (CT or intra-arterial)
- LP
CT
- Hyperdense area in basal regions of the skull - due to blood in subarachnoid space
- Identifies any intraparenchymal or intraventricular haemorrhages
Angiography
- To detect the source of bleeding if the patient is a candidate for surgery or endovascular treatment
LP
- Increased opening pressure
- Increased red cells
- Few white cells
- Xanthochromia - straw-coloured CSF due to Hb breakdown
- Confirmed by spectrophotometry of CSF supernatant after centrifugation
Define subdural haemorrhage.
A collection of blood that develops between the surface of the brain and the dura mater.
Acute - within 72h
Subacute - 3-20 days
Chronic - 3 weeks
Explain the aetiology / risk factors of subdural haemorrhage.
Trauma causing rapid acceleration and deceleration of the brain results in shearing forces which tear veins (bridging veins) that travel from the dura to the cortex.
Bleeding occurs between the dura and arachnoid membranes.
In children, non-accidental injury should always be considered.
Summarise the epidemiology of subdural haemorrhage.
Acute
- Younger patients
- Associated with major trauma (5-25% of cases in severe head injury)
More common than extradural haemorrhage.
Chronic
- Elderly
- 1-5 per 100,000
Recognise the presenting symptoms of subdural haemorrhage.
Acute
- History of trauma with head injury
- Patient has reduced conscious level
Subacute
- Worsening headaches 7-14 days after injury
- Altered mental status
Chronic
- Headache
- Confusion
- Cognitive impairment
- Psychiatric symptoms
- Gait deterioration
- Focal weakness
- Seizures
May not be a history of fall or trauma, hence low index of suspicion especially in elderly and alcoholics.
Recognise the signs of subdural haemorrhage on physical examination.
Acute
- Low GCS
- Midline shift haematoma - ipsilateral fixed dilated pupil (compression of ipsilateral third nerve parasympathetic fibres)
- Pressure on brainstem results in reduced consciousness and bradycardia
Chronic
- Neurological examination may be normal
- Focal neurological signs - III or VI nerve dysfunction, papilloedema, hemiparesis, reflex asymmetry
Identify appropriate investigations for subdural haemorrhage and interpret the results.
CT Head
- Crescent or sickle-shaped mass
- Concave over brain surface - extradural is lentiform in shape
- CT appearance changes with time
- Acute - hyperdense, become isodense over 1-3 weeks (presence may be inferred from effacement of sulci, midline shift, ventricular compression, obliteration of basal cisterns)
- Chronic - hypodense - approach that of CSF
MRI Brain
- Higher sensitivity for isodense or small SDH
Generate a management plan for subdural haemorrhage.
Acute
- ALS protocol with priorities of cervical spine control and ABC
- GCS, pupillary reactivity
- If signs of raised ICP, head elevation and consider osmotic diuresis with mannitol or hyperventilation
- Stabilise - then CT head
Conservative
- Especially if small and minimal midline shift
- SDH <10 mm thickness
- Midline shift <5mm
Surgical
Chronic
- If symptomatic or mass effect on imaging - surgical treatment with Burr hole, craniotomy, drainage (24-72h)
- If asymptomatic or no significant mass effect - conservative management, serial imaging to monitor for spontaneous resorption
- May require craniotomy with membranectomy if haematoma does not fully liquify
Children
- Percutaneous aspiration via open fontanelle
- Placement of subdural to peritoneal shunt
Identify the possible complications of subdural haemorrhage and its management.
- Raised ICP
- Cerebral oedema
- Secondary ischaemic brain damage
- Mass effect - transtentorial or uncal herniation
Post-Op
- Seizures
- Recurrence (33% for SDH)
- Intracranial haemorrhage
- Subdural empyema
- Brain abscess
- Meningitis
- Tension pneumocephalus
Summarise the prognosis for patients with subdural haemorrhage.
Acute
- Underlying brain injury most important factor on outcome
Chronic
- Generally better outcome than acute
- Lower incidence of underlying brain injury
- Good outcomes in 3/4 of those treated by surgery
Define CNS tumours.
= Meningioma, Acoustic neuroma, Medulloblastoma, Astrocytic brain tumour, Craniopharyngioma, Primary CNS lymphoma, Non-functional pituitary adenoma, Acromegaly, Cushing’s, Prolactinoma
A brain tumour is an abnormal growth occuring in any tissue contained within the cranium, including the brain, cranial nerves, meninges, skull, pituitary gland and pineal gland.
May be benign or malignant and originate from within the cranium (primary) or from a metastatic tumour found elsewhere (secondary).
Present with signs of raised ICP and gait abnormality.
Meningioma:
- Primary tumour of cranial and spinal compartments
Acoustic Neuroma (Vesticular Schwannoma): - Benign, slow-growing cerebellopontine angle tumour that grows from the superior vestibular component of the vestibulocochlear nerve
Medulloblastoma:
- Malignant, invasive brain tumour arising from cerebellar vermis
Astrocytic Brain Tumours:
- Primary tumour of the brain arising from astrocytes, which are an important part of the blood-brain barrier
- A neuroepithelial type tumour categorised by histological type and grade with each subtype having different age-adjusted incidence rate, behaviour and clinical course
Craniopharyngioma:
- Benign extra-axial non-glial epithelial tumours of the CNS
Acromegaly:
- Due to pituitary somatotroph adenoma in 99% of cases
Cushing’s Disease :
- Hypercortisolism caused by an ACTH-secreting pituitary adenoma
Prolactinoma:
- Benign, prolactin-expressing and secreting pituitary adenoma
Explain the aetiology / risk factors of CNS tumours.
= Meningioma, Acoustic neuroma, Medulloblastoma, Astrocytic brain tumour, Craniopharyngioma, Primary CNS lymphoma, Non-functional pituitary adenoma, Acromegaly, Cushing’s, Prolactinoma
Acoustic Neuroma (Vesticular Schwannoma): - Neurofibromatosis Type 2 - autosomal dominant
Craniopharyngioma:
- Arise within the sellar / suprasellar space
Primary CNS lymphoma:
- Immunosuppression
- HIV infection
- EBV infection
Non-functional pituitary adenoma:
- Multiple endocrine neoplasia Type 1 (MEN-1)
Acromegaly:
- Pituitary somatotroph adenomas chronically secrete excessive GH
- Stimulates IGF-1 production
Summarise the epidemiology of CNS tumours.
= Meningioma, Acoustic neuroma, Medulloblastoma, Astrocytic brain tumour, Craniopharyngioma, Primary CNS lymphoma, Non-functional pituitary adenoma, Acromegaly, Cushing’s, Prolactinoma
Meningioma:
- Represent over 36% of primary brain tumours, 53.5% of all non-malignant tumours
- More common in women and usually benign
Medulloblastoma:
- Usually in first 2 decades of life
- Common brain tumours of childhood
Astrocytic Brain Tumours:
- Common in industrial countries
- White males
Craniopharyngioma:
- Both children and adults
- Presents at any age
- Bimodal age distribution - peak between 5-14 years and 50-70 years
Primary CNS lymphoma:
- <1% of all non-Hodgkin’s lymphoma
- Uncommon
Prolactinoma:
- Women during childbearing years
Recognise the presenting symptoms of CNS tumours.
= Meningioma, Acoustic neuroma, Medulloblastoma, Astrocytic brain tumour, Craniopharyngioma, Primary CNS lymphoma, Non-functional pituitary adenoma, Acromegaly, Cushing’s, Prolactinoma
Meningioma:
- Neurological deficit
- Progressive, focal or general headaches in large tumours
- Visible bony growth
Acoustic Neuroma (Vesticular Schwannoma):
- Unilateral sensorineural hearing loss
- Found on routine hearing examinations
- Progressive dizziness
- Unilateral facial numbness
Medulloblastoma:
- Due to mass effect from tumour or due to obstructive hydrocephalus
- Morning headaches
- Nausea
- Vomiting (relieving headaches)
- Diplopia - 6th nerve palsy
- Ataxia
Astrocytic Brain Tumours:
- Focal neurological defecits according to location
- Signs of raised ICP
Craniopharyngioma:
- Mass effect symptoms
- Visual loss
- Symptoms of ICP
- Pituitary dysfunction
- Children - growth failure
- Adults - diabetes insipidus and sexual dysfunction
Non-functional pituitary adenoma:
- Features of hormonal insufficiency
- Longstanding and progress slowly
Prolactinoma:
- Hyperprolactinaemia
- Hypogonadism
- Sexual dysfunction
- Galactorrhoea
- Hypopituitarism
- Osteoporosis
Recognise the signs of CNS tumours on physical examination.
= Meningioma, Acoustic neuroma, Medulloblastoma, Astrocytic brain tumour, Craniopharyngioma, Primary CNS lymphoma, Non-functional pituitary adenoma, Acromegaly, Cushing’s, Prolactinoma
PITUITARY MASS ASSESSMENT
- 2 type
- Clinically Non-functional Adenoma (CNFA) - no hypersecretion of hormone
- Functional Adenoma - hypersecretion of hormone
Functional:
- Acromegaly
- Cushing’s disease
- Prolactinoma
Compression of adjacent structures:
- Visual disturbances
- Ophthalmoplegia
- Headaches
ACUTE HEADACHE ASSESSMENT:
- Most with a benign diagnosis
- HIgh index of suspicion
- Brain tumours causing headaches seen on non-enhancing contrast CT
- 0.7-1.3% of all paeds emergency visits
- 62% of patients with childhood brain tumours have a headache, 98% have 1 neurological symptom on exam
ATAXIA ASSESSMENT:
- Hereditary or acquired
- Cerebellar, sensory or vestibular
- Extensive list of acquired causes - e.g. vascular, demyelinating, neoplastic, autoimmune, toxic, degenerative, compressive, infectious aetiologies
HYPERPROLACTINAEMIA
- Prolactinomas - micro or macroadenomas
- Acromegaly
- Interruption of the hypothalamic-pituitary axis
SHORT STATURE
- Craniopharyngioma
- Cushing’s syndrome during childhood
- Symptoms of Craniopharyngioma: Diplopia, vision loss, headache, short stature
Identify appropriate investigations for CNS tumours and interpret the results.
= Meningioma, Acoustic neuroma, Medulloblastoma, Astrocytic brain tumour, Craniopharyngioma, Primary CNS lymphoma, Non-functional pituitary adenoma, Acromegaly, Cushing’s, Prolactinoma
Meningioma:
- MRI with and without contrast enhancement
- Asymptomatic lesions followed up with serial observation
Acoustic Neuroma (Vesticular Schwannoma): - Gadolinium-enhanced MRI
Medulloblastoma:
- Cranial CT and MRI
Astrocytic Brain Tumours:
- Cranial imaging with surgical biopsy
Craniopharyngioma:
- Crania CT / MRI
- Full endocrine evaluation
Primary CNS lymphoma:
- Cranial CT
- Clinical history
- LP & CSF analysis
Non-functional pituitary adenoma:
- Endocrine evaluation
- Cranial imaging
Acromegaly:
- IGF-1 hypersecretion biochemical confirmation
Cushing’s Disease :
- Demonstration of unsuppressed ACTH
- Cranial MRI
Prolactinoma:
- Assessment of serum prolactin levels
- Cranial imaging
Define lumbosacral radiculopathy.
A disorder that causes pain in the lower back and hip, which radiates down the back of the thigh into the leg.
Describes a predictable constellation of symptoms occuring secondary to mechanical and/or inflammatory cycles compromising at least one of the lumbosacral nerve roots.
Explain the aetiology / risk factors of radiculopathy.
Damage caused by compression fo nerve roots exiting spine at levels L1-S4.
Most disc herniations occur posterolaterally, root that gets compressed is actually the root that exists the foramen below the herniated disc. Protrusion at L4/L5 will compress L5 root, protrusion at L5/S1 will compress S1 root.
Most common in lower back and neck = lumbar-sacral, cervical.
Majority of cases are benign and will resolve spontaneously.
Risk factors:
- Activities placing an excessive or repetitive load on spine
- Heavy labour
- Contact sports
- Age 45-64 yrs
- Smoking
- Mental stress
- Frequent lifting
- Driving - vibration of whole body
Causes:
- Lesions of intervertebral discs and degenerative disease of spine
- Herniated disc with nerve root compression
- Tumours
- Congenital abnormalities
- Scoliosis
- Osteomyelitis
Summarise the epidemiology of radiculopathy.
3-5% prevalence rate.
Recognise the presenting symptoms of radiculopathy.
- Tingling
- Radiating pain
- Numbness
- Paraesthesia
- Shooting pain
- Gait abnormalities
- Predictable patterns affecting corresponding dermatome or myotome.
Sciatica:
- Unilateral leg pain greater than lower back pain
- Leg pain follows dermatomal pattern
- Pain traveling below knee to foot or toes
- Numbness and paraesthesia
- Straight leg raise positive - induces more pain
Recognise the signs of radiculopathy on physical examination.
- Tingling
- Radiating pain
- Numbness
- Paraesthesia
- Shooting pain
- Gait abnormalities
- Predictable patterns affecting corresponding dermatome or myotome.
Sciatica:
- Unilateral leg pain greater than lower back pain
- Leg pain follows dermatomal pattern
- Pain traveling below knee to foot or toes
- Numbness and paraesthesia
- Straight leg raise positive - induces more pain
Identify appropriate investigations for radiculopathy and interpret the results.
DDX:
- Radicular syndrome/ sciatica
- Pseuoradicular syndrome
- Thoracic disc injuries
- Low back pain
- Cauda equina
- Inflammatory / metabolic causes - e.g. diabetes, ankylosing spondylitis, Paget’s disease, Arachnoiditis, Sarcoidosis
- Trochanteric bursitis
- Intraspinal synovial cysts
CXR - presence of trauma or osteoarthritis, signs of tumour or infection
EMG - detect radiculopathies, limited utility in diagnosis
MRI - see if disc herniation and nerve root compression are present
Define Bell’s Palsy.
An acute unilateral peripheral facial nerve palsy in patients for whom physical examination and history are otherwise unremarkable, consisting of deficits affecting all facial zones equally that fully evolve within 72 hours.
DIAGNOSIS OF EXCLUSION.
Facial palsy of an otherwise known aetiology (e.g., Lyme disease-associated facial palsy), or facial palsy that is progressive, waxing and waning, or affects facial zones in an uneven fashion, is not Bell’s palsy..
Explain the aetiology / risk factors of Bell’s palsy.
Acute unilateral facial palsy of probable viral aetiology.
Risk factors:
- Intranasal influenza vaccination
- Pregnancy
- URTI
- Black or Hispanic ancestry
- Arid / cold climate
- HTN
- Family history
- Diabetes
Summarise the epidemiology of Bell’s palsy.
Most population studies generally show an annual incidence of 15–30 cases per 100,000 population. Bell palsy is thought to account for approximately 60–75% of cases of acute unilateral facial paralysis, with the right side affected 63% of the time. It can also be recurrent, with a reported recurrence range of 4–14%
Recognise the presenting symptoms of Bell’s palsy.
- Single episode
- Unilateral
- Absence of constitutional symptoms
- Involvement of all facial nerve branches
- Keratoconjunctivitis sicca (dry eye)
- Pain
- Synkinesis (late Bell’s palsy) - involuntary and abnormal synchronous movement
- Any age
- Hyperacusis - unusual sensitivity to sound ipsilateral to facial palsy due to insult to branchial efferents of stapedius muscle
- Dysgeusia - taste disturbance of ipsilateral anterior 2/3rds of tongue
Recognise the signs of Bell’s palsy on physical examinstion.
- Single episode
- Unilateral
- Absence of constitutional symptoms
- Involvement of all facial nerve branches
- Keratoconjunctivitis sicca (dry eye)
- Pain
- Synkinesis (late Bell’s palsy) - involuntary and abnormal synchronous movement
- Any age
- Hyperacusis - unusual sensitivity to sound ipsilateral to facial palsy due to insult to branchial efferents of stapedius muscle
- Dysgeusia - taste disturbance of ipsilateral anterior 2/3rds of tongue
Identify appropriate investigations for Bell’s palsy and interpret the results.
1st Line:
- Clinical diagnosis - acute unilateral facial palsy with a normal physical examination
- ENoG (evoked eEMG) - >90% decrease in amplitude of compound muscle action potential (CMAP)
- Needle EMG - absence of voluntary motor unit potentials
- Serology for Borrelia burgdorferi - negative
Consider:
- Pure-tone audiometry - normal
- Tympanometry and stapedius reflex - absent or impaired reflex of the ipsilateral efferent limb
- MRI gadolinium-enhanced fine cut of facial nerve course - post-contrast enhancement of distal meatal, labyrinthine, geniculate, and sometimes tympanic and mastoid segments of facial nerve, without enlargement
- CT fine-cut, non-enhanced - normal
Generate a management plan for Bell’s palsy.
CORTICOSTEROID - Prednisolone OD within 72h of symptoms onset
EYE PROTECTION as keratoconjunctivitis may lead to exposure keratopathy - glasses worn, artificial tears used as needed, ophthalmic lubricant and eyelid taped closed, eye patching avoided.
If severe palsy / complete paralysis on presentation:
- Concurrent antiviral therapy - e.g. valaciclovir, aciclovir
- Surgical decompression
Identify the possible complications of Bell’s palsy and its management.
- Irreversible damage
- Abnormal regrowth and healing
- Involuntary contraction - synkinesis
Summarise the prognosis for patients with Bell’s palsy.
Complete recovery to normal facial function occurs in approximately 70% of untreated cases, with permanently impaired facial function occurring to a minor degree in 13% and to a major degree in 16% of cases.
Onset of clinical recovery is nearly always demonstrated within 4 to 6 months of symptom onset; absence of any return of hemi-facial tone or movement by this time is highly suggestive of an alternative diagnosis.
Define cluster headache.
An attack of severe pain localised to the unilateral orbit, supra-orbital and/or temporal areas that lasts from 15 mins to 3 hours.
Occurs once every other day to 8 times a day.
Attacks occur at the same time period for several weeks = cluster period.
Accompanied by ipsilateral autonomic signs (secondary to parasympathetic HYPERactivity and sympathetic HYPOactivity) and restlessness.
(Migraine = motion sensitivity presentation)
Both cluster bouts and attacks during a cluster period can show cyclical periodicity occurring at the same time of year or the same time of day.
Explain the aetiology / risk factors of cluster headache.
- Hypothalamic activation with secondary trigeminal and autonomic activation
- Precipitated by alcohol, volatile smells, warm temperatures and sleep
Risk factors:
- Male sex
- Family history
- Head injury
- Cigarette smoking
- Heavy drinking
Summarise the epidemiology of cluster headache.
Cluster headache is a primary headache disorder affecting up to 0.1% of the population.
Approximately 90% of patients have episodic cluster headache, which consists of at least two cluster periods of attacks lasting from 7 days to 1 year when untreated (cluster periods usually last from 2 weeks to 3 months), separated by remission periods lasting at least 3 months.
The chronic form of cluster headache is seen in approximately 10% of patients and consists of attacks that occur for 1 year or longer without remission, or with remission periods lasting less than 3 months.[1][2] The condition may be chronic from onset or may evolve over time from the episodic form.
Recognise the presenting symptoms of cluster headache.
Occurs once every other day to 8 times a day. Lasts from 15mins-3 hours.
Attacks occur at the same time period for several weeks = cluster period.
Accompanied by ipsilateral autonomic signs (secondary to parasympathetic HYPERactivity and sympathetic HYPOactivity) and restlessness.
(Migraine = motion sensitivity presentation)
Both cluster bouts and attacks during a cluster period can show cyclical periodicity occurring at the same time of year or the same time of day.
Autonomic features:
- Ptosis
- Conjunctival injection
- Lacrimation
- Rhinorrhoea
- Nasal stuffiness
- Eyelid and facial swelling
- Aural fullness
- Facial sweating
- Redness
Also associated with N&V, photophobia, phonophobia and migrainous aura.
Recognise the signs of cluster headache on physical examination.
Occurs once every other day to 8 times a day. Lasts from 15mins-3 hours.
Attacks occur at the same time period for several weeks = cluster period.
Accompanied by ipsilateral autonomic signs (secondary to parasympathetic HYPERactivity and sympathetic HYPOactivity) and restlessness.
(Migraine = motion sensitivity presentation)
Both cluster bouts and attacks during a cluster period can show cyclical periodicity occurring at the same time of year or the same time of day.
Autonomic features:
- Ptosis
- Conjunctival injection
- Lacrimation
- Rhinorrhoea
- Nasal stuffiness
- Eyelid and facial swelling
- Aural fullness
- Facial sweating
- Redness
Also associated with N&V, photophobia, phonophobia and migrainous aura.
Identify appropriate investigations for cluster headache and interpret the results.
1st Line:
- Brain CT or MRI - normal in primary, abnormal in secondary (tumour, cavernous sinus pathology)
- ESR - normal in primary
- Pituitary function tests - normal in primary, abnormal in secondary (pituitary adenoma)
Consider:
- Polysomnogram - abnormal with sleep apnoea
- ECG - normal, conduction abnormalities or evidence of ischaemiac changes (check drug prescription)
Define Guillainn-Barré Syndrome.
An acute inflammatory polyneuropathy.
Classified according to symptoms.
= AXONAL AND DEMYELINATING FORMS.
Explain the aetiology / risk factors of Guillain-Barré Syndrome.
Associated with outbreaks of ZIKA.
2/3rds of patients have a history of gastroenteritis or influenza-like illness weeks before onset of neurological symptoms.
Risk factors:
- Preceding viral illness
- Preceding bacterial infection
- Preceding mosquito-borne viral infection
- Hepatitis E infection
- Immunisation
- Cancer and lymphoma
- Older age
- HIV infection
- Male
Summarise the epidemiology of Guillainn-Barré Syndrome.
Up to 30% will develop respiratory muscle weakness requiring ventilation.
Neurophysiology is confirmatory and is abnormal in 85% of patients, even early in the disease.
Most common variant = acute inflammatory demyelinating polyradiculoneuropathy.
GBS occurs throughout the world with a median annual incidence of 1.3 cases per population of 100 000, with men being more frequently affected than women. GBS is considered to be an autoimmune disease triggered by a preceding bacterial or viral infection.
