NEURO: Primary Brain tumours, Meningitis, Encephalitis and Zoster Hepres Flashcards
What are primary tumours
Tumour growing at the anatomical site where tumour progression began + proceeded to form a cancerous mass
What is the telencephalon
Cerebral hemispheres
What is the mesencephalon
Midbrain
Role of glial cells
Maintain homeostasis
Support and protection for neurones
Form myelin
Name 4 glial cells
- Oligodendrocytes
- Astrocytes
- Ependymal cells
- Microglial
Role of astrocytes
Form BBB
Role of microglia
Resident macrophages of CNS
What are glial cell carcinomas called
Gliomas - malignant by the time they are diagnosed
Role of the pineal gland
Produces Melatonin which modulates sleep patterns
Name 4 primary tumours of the brain
Anaplasia
Atypic
Neoplasia
Necrosis
What is anaplasia
Loss of DIFFERENTIATED cells
Total loss of control over normal function
How do cells become anaplastic
Neoplastic tumour cells dedifferentiate to become anapaestic
Cancer stem cells over multiply (uncontrolled growth due to failure of differentiation)
What is Atypia
Cancer cells with structural abnormalities
What is neoplasia
Uncontrolled division of cells
How do neoplasms effect the brain
Grow in confined spaces increasing ICP and invading into the brain as they grow in small spaces - compression of brain structure
Consequences of neoplastic growth
ICP
Destruction of brain parenchyma
In what patients are primary brain tumours common
- Paediatric cancer
What are the main types of gliomas
- Astrocytoma (MOST COMMON PRIMARY BRAIN TUMOUR)
2. Oligodendroglioma
Risk factors for primary brain tumours
- Ionising radiation
- Vinyl Chloride
- Immunosuppreison
- Family History - Genetics
Name Grade I astrocytoma
- Pilocytic astrocytoma
2. Subependymoma
`characteristics of grade I astrocytomas
- Slow growing tumours where total remission is achieved by removal (stereotactic surgery)
Characteristic of grade II astrocytomas
Slow growing benign to malignant tumours
Invasive gliomas that penetrate into surrounding brain (CAN’T be surgically removed)
Name a grade II astrocytoma
- Fibrillary astrocytoma
Clinical presentation of grade II astrocytoma
- SEIZURES
Name a grade III astrocytoma
Anapaestic astrocytoma
Characteristics of grade III astrocytomas
Astrocytes lack vascular proliferation and necrose (These are undifferentiated gliomas)
MALIGNANT
How are grade III astrocytomas
- Radiotherapy
Name a grade IV astrocytomas
Glioblastoma multiform
Characteristics of grade IV astrocytomas
MALIGNANT tumours
Grow quickly and spread to other parts of the brain
So infiltrative no surgical removal of tumour impossible + RADIOTHERAPY doesn’t work
Necrosis
Symptoms of grade IV astrocytomas
BEGIN abruptly with seizures
What do all gliomas progress to at end-stage cancer
Glioblastoma Multiforme (EXCEPT pilocytic astrocytoma)
Clinical presentation of brain gliomas
- Headaches
- Vomiting
- Seizures
- Cranial nerve disorders
- PAPILLOEDEMA
——-INCREASED ICP symptoms——
Clinical presentation of spinal cord gliomas
- Pain
- Weakness
- Numbness
How do gliomas metastasise
Spread via the CSF
What causes malignant gliomas
(50-60)
- Initial genetic error in glucose glycolysis
- Mutation of ISOTRATE DEHYDROGENASE
- Excess build up of 2-hydroxyglutarate
This triggers instability in glial cells and oevrmitosis
OR (older)
CATASTROPHIC GENETIC MUTATION which is sporadic
Clinical presentation of oligodendromas
- Seizures of the frontal lobe
- Increased ICP symptoms
- Visual loss, motor weakness and cognitive decline
What grade cancer are oligodendromas
II
What causes oligodendromas
IDH-1 mutation
In what dura layer are meningiomas made
Arachnoid mater: push into brain but are usually benign
What are neurofibromas
Solid benign tumours form Shwann cells
Where are neurofibromas found
Cerebellopontine angle
What are craniopharyngiomas
Brian tumour from pituitary gland embryonic tissues
Where are craniopharyngiomas common
Children
Are crnaiopharyngiomas benign or malignant
Benign
If Primary brian tumours are benign how can they cause damage
Act as SPACE OCCUPYING LESIONS which increase ICP
Why is there no symptoms when tumour is small
Initially brain removes CSF from ventricles and spinal cord to offset increase in ICP
How does ICP affect brian structures
Midline structure shift and herniation through foramen magnum = brain damage
Symptoms of ICP associated headaches
- WORSE on waking in the morning (we don’t pee at night so accumulation of fluid = ICP)
- Pain can be so bad it can wake patient up
- Pain increased by coughing, straining and bending forwards (increased venous pressure in brain)
- Relieved by vomiting (reduces fluid levels)
Is papilloedema bilateral or unilateral
BILATERAL
What causes papilloedema
Increased ICP
Resp failure!
Guillain-Barre syndrome due to increased protein levels
Tumours of frontal lobe
What is papilloedema
Optic disc swelling
Clinical presentation papilloedema
- Venous engorgement
- Haemorrhages over optic disc
- Blurring of optic margins
- Enlarged blind spot on examination
Pathophysiology of papilloedema
Optic nerve sheath is continuous with subarachnoid space of the brain so increased ICP is transmitted through this sheath
how long does it take for papiloedema to present
DAYS
Clinical presentation of tumours affecting different parts of the brain
Temporal - Dysphagia, amnesia Forntal: Hemiparesis, personality change, brook's dysphagia, lack of initiative, unable to plan tasks Parietal lobe: Hemisensory loss, reduction in 2-point discrimination, dysphagia, astereognosis (unable to recognise object from touch alone) Occipital: Contralateral visual defects Cerebellum: DASHING D - Dysdiadochokinesis A - Ataxia S - Slurred speech (dysarthria) Hypotonia Intention tremor Nystagmus Gait abnormality
What seizures are common with brian tumours
PARTIAL or FOCAL
Differential Diagnosis of primary brain tumours
- Aneurysm
- Abscess
- Cyst
- haemorrhage
- Idiopathic intracranial hypertension
Diagnostic of primary brain tumours
- EEG
- MRI and CT (looks at disruption of BBB)
- FBC
- BIOPSY
Why does tumour of the frontal lobe cause site loss and what kind of hemianopia is this
COMPRESSION of optic chiasm
Causes bilateral temporal visual field defect
How do carry out a biopsy for primary brian tumours
- BURR-HOLES
Why is lumbar puncture contraindicated in primary brain tumours
- Withdrawing CSF with presence of mass lesion causes CONING
What is coning
Herniation of the brain through the foramen magnum resulting in BRAINSTEM COMPRESSION as it passes through foramen magnum
Treatment for primary brain tumours
- ORAL DEXAMETHASONE
- ORAL CARBAMAZZEPINE (anticonvulsant)
- Chemotherapy
Why is oral dexamethasone given for primary brain tumours
- Rapidly improves brain performance and reduces inflammation caused
Why is dexamethasone not given after 2:00
Keep patient awake
Chemotherapy for gliomas
- TEMOZOLOMIDE
Where are the most common neoplasms to metastasise to CNS
- Non small cell lung
- Small cell lung
- Breast
- Melanoma
- Renal cell
- GI
How is secondary brain tumours treated
- Surgery
- Radiotherapy
- Chemotherapy
- Palliative therapy
What is meningitis
Acute inflammation of the meninges (dura, arachnoid and pia)
What causes meningitis
Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenza
Clinical presentation of meningitis
- SEVERE headache
- Neck stiffness due to increased muscle tone)
TRIAD:
High Fever
Altered mental health
RIGIDITY
- Photophobia
- Photophobia
(children just look irritable and don’t suffer from 3 and 4) - POSITIVE Kerning’s sign and Brudzinski’s sign
6. Signs of increased ICP: Papilloedema Headaches Fevers Malaise
- Patient is irritable
How is Kerning’s sign tested on a patient
- Patient lies supine and flexes hip and kneed to 90 degrees
POSITIVE - pain limits passive extension of the knee
How is Brudzinski’s sign tested on a patient
- Flexion of the neck causes flexion of knee and hip
How can Neisseria meningitidis be differentiated from other forms of meningitis
- Rapidly spreading petechial rash which precedes the symptoms that is NON-BLANCHING (redness does not disappear when pressed) + purpuric skin rash
What is a petechial rash
- Irregular purple or red spots on trunk, lower extremities, conjunctiva and palms or soles
Clinical presentation of viral meningitis
1, Genital Herpes
- Hand
- Foot and Mouth disease
How is neisseria meningitidis spread
- DROPLET SPREAD
What causes meningitis in pregnant women
LISTERIA MONOCYTOGENES found in cheese (why they are told to avoid) and transmitted to baby
Neonatal cause of meningitis
- E.coli (found in digestive system of pregnant women)
- Cryptococcus neoformans
- TB
- HIV
- Hepres simplex virus
- B-Haemolytic streptococcus which usually inhabit vagina
Risk factors of meningitis
- Spinal canal drug administration
- Immunocompromised (FUNGAL)
- Elderly
- Pregnant
- Bacterial endocarditis
- Crowding
- Diabetes
- Malignancy
- IV drug abuse (FUNGAL)
Pathophysiology of staph, pseudomonas and gram-negative bacterial meningitis
- Skull trauma allows nasal cavity bacteria to enter meningeal space (meningococcal septicaemia)
Clinical presentation of meningococcal septicaemia
- Petechial rash (purpuric skin rash) + signs of sepsis
Pia-arachnoid is congested with polymorphs forming a layer of pus which organise to form adhesions causing cranial nerve palsy and hydrocephalus
How does TB cause meningitis
Crosses BBB and forms small subpial focus
Becomes a rich focus (large sized granuloma) and ruptures = meningitis
Viscous green-grey exudate covering brain
How is TB meningitis diagnosed
LUMBAR PUNCTURE
NAAT
Viral causes of meningitis
- Herpes simplex virus
- Enteroviruses
- Mumps
Fungal cause of meningitis
Cryptococcus neoformans
Clinical presentation of viral caused meningitis
- NO pus formation with lymphocytic infiltration
NO cerebral oedema unless encephalitis develops
Complications of meningitis
- DIC
- Gangrene
- Sepsis features
- Waterhouse-Friderichsen syndrome due to bleeding of adrenal glands
- Herniation through skull base
- Focal seizures
- Loss of consciousness
- Hearing loss
- ENCEPHALITIS
What is Waterhouse-Friderichsen syndrome
Haemorrhage of adrenal glands = failure due to meningococemia
Organ failure
Low BP
Shock
DIC with widespread purport seen
How long does viral meningitis last
4-10 days
What causes chronic meningitis
Mycobacterium tuberculosis
Differential diagnosis of meningitis
- Aseptic meningitis (tumour)
- Sub-arachnoid haemorrhage (headache more sudden)
- Encephalitis
Diagnosis of meningitis
- BLOOD TEST/CULTURE FIRST
- Lumbar puncture (CSF PCR for viruses!!! - Culture for bacteria!!!)
- Throat swabs
- Pneumococcal serum PCR
CSF findings in different causes of meningitis
Bacterial (acute): Low Glucose, High protein
Acute viral: Normal glucose, Normal protein
TB (chronic): Low Glucose, High Protein
Fungal: Low Glucose, High Protein
Malignant: Low Glucose, High Protein
What should FBC show for meningitis
- Hyponatreamia common due to ADH over-porudction and too much IV fluid administration
How do we test CSF for bacterial and listeria causes of meningitis
CULTURE it do not gram stain as it isn’t specific
Treatment of bacterial meningitis
- Treatment using Empiric antibiotics (Cefalosporins like cefotaxime)
Ampicillin - Listeria monocytogenes - Corticosticostreoids (DEXAMETHASONE) to reduce cerebral oedema
- IV vancomycin in return travellers
How long should TB meningitis be treated for
A year (compared to 6 months lung TB)
Prophylaxis of meningitis
- ORAL CIPROFLOXACIN stat
Complications of meningitis treatment
Hearing loss
Seizures
Developmental problems
How is meningococcal septicaemia treated
IV BENZYLPENICLLIN immediately or IV CEFOTAXIME in hospitals
When is lumbar puncture contraindicated
- Mass or abscess present
- ICP raised
- MENINGOCOCCAL SEPSIS as it causes coning of cerebellar tonsils
What is encephalitis
- Inflammation of the brain
Viral causes of encephalitis
HERPES SIMPLEX VIRUS
RABIES
POLIOVIRUS
MEASLES
How does Herpes Simplex Virus cause encephalitis
1, Transmission of virus from peripheral site on face following HSV-1 reactivation along nerve axon, to the brain
2. Virus lies dormant in GANGLION of trigeminal cranial nerve
Bacterial causes of encephalitis
- Bacterial meningitis
- Syphilis
- TB
- Malaria
Risk factors of encephalitis
1, HIV
2. Immunocompromised
What lobes of the brain are affected in encephalitis
Frontal and temporal lobes mainly but affects the whole brain
Clinical presentation of encephalitis
- Consciousness decrease
TRIAD: Fevre, headache and altered mental status - Viral infection signs
- Seizures
- Raised ICP (papilloedema)
- Focal neurological deficit (hemiparesis and dysphagia)
- Coma
SIGNS OF MENINGITIS if caused in meaning-encephalitis
Differential diagnosis of Encephalitis
- Meningitis
- Stroke
- Brain Tumour
Diagnostics of Encephalitis
- MRI
- EEG
- Lumbar Puncture
- FBC
Role of MRI in Encephalitis
- Shows area of inflammation and swelling of temporal lobes in HSV encephalitis
- May be midline shifting due to raised ICP
Role of EEG in encephalitis
- Shows periodic sharp and slow wave complexes
Role of lumbar puncture in Encephalitis
- CSF shows elevated lymphocyte count
- CSF PCR for viral detection (herpes simplex virus)
- FBC and CSF serology
Treatment of encephalitis
- ANTI-VIRAL treatment - IV ACYCLOVIR before investigation
- Anti-seizure medication (PRIMIDONE)
- IM BENZYLPENICILIN if meningitis is suspected
BENXYLPENICILLIN is the emergency drug for meningitis
What is Herpes Zoster virus
- Reactivation of varicella zoster virus - chickenpox in the dorsal root ganglia
What is the significance of shingles developing
- Decline in cell-mediated immunity such as age
Risk factors of shingles
- Increasing age
- Immunocompromised
- HIV, Hodgkin’s lymphoma and bone marrow transplants
What happens when virus in dorsal root ganglia are activated
travels down affected nerve via sensory root in dermatomal distribution over 3-4 days
CAUSES perineurial and intramural inflammation
In HIV patients where is site of reactivation of Herpes Zoster found
Thoracic nerves and trigeminal nerve
When can a person with shingles cause chicken pox in another person
if they have a weeping shingles rash
Clinical presentation of Herpes Zoster
- Pain and paresthesiae in dermatomal distribution priced rash (if thoracic then chest and abdo)
- Malaise, myalgia, headache and fever
- Rash - papules and vesicles restricted to the same dermatome
- Neuritic pain
- Crust formation and drying over next week (takes 2-3 weeks to resolve)
- RASH does not extend out of dermatome
Differential diagnosis of herpes zoster
- Initial pain in chest or abdo could be cholangitis or renal stones
- Cluster headaches or migraines
- Atopic eczema, contact dermatitis or herpes simplex/impetigo
Diagnosis of herpes zoster
- Eruption of rash is diagnostic
Treatment of herpes zoster
IMMEDIATE ANTIVIRAL TEHRAPY
1. Oral ACICLOVIR X5 DAILY
Done to minimise risk of peripheral herpetic neuralgia
Topical antibiotic treatment for secondary bacterial infection
Analgesics
Complications of herpes Zoster
- ophthalmic branch of trigeminal - SIGHT
- Post herpetic neuralgia (pain lasting more than 4 months after shingles, burning pain and does Not respond to analgesics)
How is PNH treated
- Antidepressant (AMYTRYPTYLINE)
- GABAPENTIN - anti eplieptic)
- ORAL CARABMAZEPINE (anti-convulsant)
What is the main outcome of cerebellar dysfunction
ATAXIA
What ion channels are found in purkyne cells
Calcium ion channels
Clinical presentation of cerebellar ataxia
- Staccato speech
- Choking bouts
- Oscillopsia
- Clumsiness
- Action Tremors
- Loss of fine movement
- Unseatdiness when walking (worse in dark)
- Stumbles and falls
What is staccato speech
SLURRING
What is choking bouts
Swallowing difficulties
What is oscillopsia
Visual disturbances where objects tend to vibrate
How do we examine cerebellar ataxia
- Gait
- Limb ataxia (truncal, limb and gait ataxia)
- Eye movements (nystagmus)
- Speech (dysarthria)
- Sensory ataxia
What is mild ataxia
Only one walking aid needed for independent movement
What is moderate ataxia
Mobilised and needs a walking frame
What is severe ataxia
Wheelchair dependant
What ways can cerebellar disorders be inherited
- Recessive
- Dominant
- Mitochondrial
- X-linked
Example of autosomal recessive ataxia
Friedrich’s ataxia
Ataxia of gait and limb - absent reflexes
Example of autosomal dominant ataxia
- Spinocerbellar ataxia 6
Slowly progressive form 40
What toxicities can cause ataxia
- Alcohol
- Phenytoin
- Lithium
Examples of immune-mediated cerebellar disorder
- Gluten ataxia
Clinical presentation of neruodegerenative ataxia
- Ataxia
- Bulbar symptoms
- Resp hypoventialtion
- Characteristic MRI finding
Diagnosis of cerebellar ataxia
- MRI to exclude tumours, hydrocephalus, MS etc
What causes Friedrich’s ataxia
DIABETES
CARDIOMMYOPATHY