Pathology Flashcards
What is the best imaging for trauma of the head?
CT scan
What is the best vascular imaging?
CT angiogram
What is diffusion weighted imaging used for?
show cellular swelling in the brain when the brain tissue dies in stroke
What are the colours of the matter on a CT scan?
- white matter = lower density = lighter
- grey matter = higher density = darker
What are the colours on the two types of MRI of the brain?
- T1 MRI: fat is bright and water, air and cortical bone is dark
- T2 MRI: water and fat is bright, air and cortical bone is dark (tWo- water)
What is a Chiari malformation?
cerebellar tonsils descend into the cervical canal
What are the most common cancers to metastasise to the brain?
breast lung thyroid colon kidney melanoma
What is the main division in location for child vs adult brain tumours?
- children = infratentorial
- adults = supratentorial
What type of headache does a tumour cause?
- worse lying down
- worse first thing in the morning
- associated with blurred vision and vomiting
- causes patient to wake up due to pain
- worse on coughing or leaning forward
What is aseptic meningitis?
no bacteria identified (can be viral from HSV 1 and 2 but not necessarily)
What is the difference between viral encephalitis and viral meningitis?
- patient is confused, changes behaviour, speech difficulty
- because cerebral cortex is diffusely involved
What is red neuron?
- lethal injury to the neuron
- caused by hypoxia or ischemia
- shrinking of nuclei
- loss of nucleolus
- very red cytoplasm
What is simple neuronal atrophy?
chronic degeneration causes shrunken neurons and cell bodies of functionally related neurons
What are inclusions and when are they added?
added with ageing eg Alzheimer’s disease has neurofibrillary tangles
What happens when oligodendrocytes are damaged?
demyelination and apoptosis so there is reduced conduction
What is gliosis?
scar forming process in the CNS done by astrocytes and is an indication of injury
What happens when microglia are damaged?
proliferate and form aggregates at the site of injury
What are the main causes of nervous system injury?
- hypoxia
- trauma
- toxic insult
- metabolic abnormalities
- nutritional deficiency
- infections
- genetic abnormalities
- ageing
What happens in terms of ATP in hypoxia?
ATP is consumed in a few minutes and no more can be made
What is cerebrovascular disease?
any abnormality of the brain caused by a pathological process of blood vessels
What are the main types of cerebrovascular disease?
- brain ischaemia/infarction
- haemorrhages
- vascular malformation
- aneurysms
What is the classification of cerebral ischaemia?
- global (generalised due to cardiac arrest or hypotension)
- focal (vascular obstruction)
What can hypertension lead to the formation of?
- micro-aneurysms (Charcot-Bouchard) which can rupture and lead to haemorrhage
- lacunar infarcts which harm basal ganglia and can lead to dementia
What can severe hypertension lead to?
hypertensive encephalopathy which causes global cerebral oedema and herniation due to raised intracranial pressure
Where does intracerebral haemorrhage usually occur?
- basal ganglia is most common
- cerebellum
- thalamus
- white matter
What are the signs of an UMN lesion?
increased tone and hyperreflexia
What are the signs of a LMN lesion?
decreased tone, muscle wasting, fasciculation and diminished reflexes
What is Brown-Sequard syndrome?
cord hemisection where there is ipsilateral motor and dorsal column sensory but contralateral spinothalamic sensory
What is central cord syndrome?
- common
- caused by a hyperflexion or extension injury to neck
- affects the upper limbs more than the lower limbs
What is the difference in presentation between chronic and acute spinal cord compression?
same but in chronic the motor signs will predominate
What are the causes of acute spinal cord compression?
trauma, tumours, infection or spontaneous haemorrhage
What are the causes of chronic spinal cord compression?
degenerative spondylosis, tumours or RA
What are the features of trauma, tumours and spinal canal stenosis relating to spinal cord compression?
- Trauma: high energy injury, cervical
- Tumours: metastasis usually extradural, meningioma, schwannoma, astrocytoma and ependymoma, this can be chronic or acute with sudden collapse or haemorrhage
- Spinal canal stenosis: osteophytes, bulging of discs, subluxation or facet joint hypertrophy
What are the features of infection and haemorrhage relating to spinal cord compression?
- Infection: epidural abscess, surgery and trauma
- Haemorrhage: due to trauma, bleeding diathesis, anticoagulant or AV malformations
What is the treatment for spinal cord compression for trauma, tumours and infections?
- Trauma: CT, decompress and stabilise
- Tumours: mets- surgery if life expectancy >6m, dexamethasone, chemo or radio…primary- surgery
- Infection: antimicrobial therapy, surgical drainage, stabilisation if needed
What is the treatment for spinal cord compression for haemorrhage and degenerative disease?
- Haemorrhage: reverse anticoagulation, decompression
- Degenerative disease: surgical decompression and stabilisation
What are the clinical signs of raised ICP?
- papilloedema
- headache
- reduced consciousness
- nausea + vomiting
- neck stiffness
What are the two types of injury in terms of head trauma?
- Primary injury: injury to neurons at the time which is irreversible
- Secondary injury: haemorrhage, oedema etc which is potentially treatable
What is a coup and contra-coup injury?
- coup = at the site of the impact
- contra-coup = at the site opposite from the impact, can be worse than coup
What is diffuse axonal injury?
- occurs at the moment of injury
- affects central areas and causes reduced consciousness and coma
What is the pathogenesis behind head trauma?
disrupt the BBB –> oedema and swelling –> hypoxia and ischemia –> glutamate release/oygen free radical formation/lipid membrane disruption –> Ca2+ influx –> apoptosis and necrosis
What is the most common traumatic haematoma?
intradural
What is the difference in recovery between a seizure and syncope?
seizures have a longer recovery than syncope
What is the one investigation that you always do for collapse?
ECG so you never miss long QT
What are EEGs good for?
determining if a patient is in non-convulsive status or encephalopathy
What are the side-effects of sodium valproate?
- weight gain
- teratogenicity
- hair loss
- fatigue
What drug interactions does carbamazepine have?
- contraceptive pill so never use progesterone only or an implant
- higher dose of morning after pill needed
- alters the work of chemotherapy
What are the main pitfalls of epilepsy drugs?
- increase pregnancy complications
- teratogenic
What is involved in functional localisation history taking?
- where the lesion is (date of onset, nature of main symptoms eg weakness, associated symptoms and exacerbating/relieving factors)
- what the condition is (evolution and recurrence)
What are the main CNS issue symptoms?
- Hemiplegia / paraplegia
- Heaviness
- Spasms associated
- Sensory symptoms are possible
- Cognitive and sphincter involvement
What are the main PNS issue symptoms?
- Peripheral or localised area
- Positional or ascending weakness
- Associated twitching
- Sensory issues possible
- Loss of grip, tripping
What is seen on examination of a PNS issue?
- Wasting or fasciculation OE
- Decreased tone
- Distal weakness which can be specific to a plexus or named nerve
- Decreased reflexes
- Glove and stocking decreased sensation
What are the main NMJ issue symptoms?
- Ocular and bulbar tracts
- Fatigable weakness worse at the end of the day
- Swallowing, speaking, eye issues, SOB
- No sensory issues
What is seen on examination of a NMJ issue?
- Ptosis OE
- No change in tone
- Fatiguability
What are the main muscle issue symptoms?
- Proximal and symmetrical
- Aching or insidious
- Myalgia associated
- No sensory issues
- Getting up from low chairs is difficult
What is seen on examination of a muscle issue?
- Proximal wasting and weakness OE
- No change in tone
- Myotonia is failure of relaxation
How is fatiguability of muscles demonstrated?
- counting out loud (bulbar)
- fixed horizontal gaze (ocular)
- fixed upgaze (ptosis)
- repetitive movements (limb)
What are the progressions of severity in inflammatory, vascular and SOL issues?
- Inflammation: relapsing and remitting pattern
- Vascular: huge incline and then gradual improvement
- SOL: problem will only get worse
What is the most common NMJ pathology?
Myaesthenia Gravis which will also present with ocular issues too and will have positive antibody testing
What is acute peripheral polyneuropathy suggestive of?
Guillain-Barre syndrome and most patients are positive for anti-ganglioside antibodies
What is a psychogenic non-epileptic attack?
functional attack that patients have no control of which can be related to traumatic events, sexual or physical abuse or stress
How do you diagnose a psychogenic non-epileptic attack?
seizure description and EEG monitoring during attack
What can functional attacks present with?
- prominent motor activity
- collapse with no movement
- abreactive attacks (hyperventilation etc)
- attacks last 10-20 minutes which is longer than seizures
What are psychogenic non-epileptic attacks treated with?
counselling and do not give anticonvulsant or anti-epileptic drugs
What is the classification of movement disorders?
- hypokinetic: too little movement eg Parkinson’s
- hyperkinetic: too much movement
What types of movements do hyperkinetic disorders include?
- tics
- tremor
- chorea
- myoclonus
- dystonia
- athetosis
What are the features of tremor?
- occur at rest, postural or kinetic
- rhythmic oscillations of a body part
What are the features of dystonia?
sustained or intermittent muscle contractions causing twisting movements and abnormal postures
What are the features of chorea?
irregular purposeless movements that flit between body parts eg restlessness and fidgeting
What are the features of myoclonus?
brief electric shock like jerks caused by activation of a group of muscles
What are the features of tics?
repetitive stereotyped movements which can be suppressed but this causes the patient anxiety
What is an essential tremor?
- common
- postural tremor
- holding the hands outstretched
- can run in families autosomal dominant
What are the two presynaptic neuromuscular junction issues?
- botulinum
- lambert eaton myasthenic syndrome
How is muscle strength graded?
MRC muscle power grading from 0 no movement to 5 normal strength
What are the muscle investigations?
blood tests, muscle biopsy and MRI of muscle tissue
What is the main drug that can cause myopathy?
statins which can be myalgia or necrotising myopathy
What is rhabdomyolysis?
dissolution of muscle and a cascade of events causing myalgia, muscle weakness and myoglobinuria
What is the main difference between large and small fibre neuropathies?
large fibre causes a loss of reflexes but small fibre doesn’t
What are the two main demyelinating neuropathies?
Guillan Barre
CIDP
What is the common type of neuropathy if the patient is young?
hereditary neuropathy
What are two signs of hereditary neuropathy?
- champagne bottle deformity
- very high arched foot
What are the parts of the GCS score?
- Eye opening- spontaneously, to speech, to pain, none (4)
- Motor- oriented, confused, inappropriate, incomprehensible, none (5)
- Verbal- obeying, localising, flexing, abnormal flexing, extending, none (6)
What are the main types of brain herniation?
subfalcine, transtentorial and cerebellar tonsillar
What is the medical management of raised ICP?
- sedation
- head of bed tilt (30 degrees)
- ensure neck collars aren’t too tight so venous drainage is working
- CO2 control
- osmotic diuretic eg mannitol or hypertonic saline
- CSF release
What is the essence of a brainstem death declaration?
cranial nerve exam
What is seen on CNS issue examination?
- Limb posture OE
- Increased tone velocity dependent so spasticity or clonus
- Pyramidal pattern of weakness so in arms ex more than flex, legs flex more than ex
- Increased reflexes
- Abnormal extensor plantar response
- Hemisensory disturbance for a brain injury or a sensory level disturbance for a spinal cord issue
What is syringomyelia?
fluid filled cyst or cavity in the spinal cord
What is a sudden onset 10/10 headache with vomiting, neck stiffness and photophobia?
subarachnoid haemorrhage until proven otherwise
What are the features of chronic regional pain syndrome?
- one limb
- allodynia (things that shouldn’t hurt do)
- hyperalgesia
- welling
- colour change
- hair and nail changes
- osteopenia
What is nociceptive pain?
pain from injury relayed through a normal nervous system
What is neuropathic pain?
pain generated within the nervous system eg post herpetic neuralgia, surgery, trauma, diabetic neuropathy, amputation
What is the main treatment options for neuropathic pain?
tricyclic antidepressants and anticonvulsant
What are the main primary demyelination disorders?
- MS
- acute disseminated encephalomyelitis
- acute hemorrhagic leukoencephalitis
What are the main secondary demyelination disorders?
- viral eg progressive multifocal leukoencephalopathy
- metabolic eg central pontine myelinolysis
- toxic eg CO, solvents or cyanide
What is transient global amnesia?
once off issue with amnesia which can be triggered by emotion or temperature but the pathophysiology is unknown
What is transient epileptic amnesia?
forgetfulness and repetitive questioning which is short-lived due to seizures
What is functional cognitive impairment?
everyday forgetfulness which impacts on functioning which fluctuate but is just patient’s having a higher expectation of what things they should be able to remember
What is Prion disease?
eg CJD is a very aggressive dementia which causes death due to strange folding of proteins
What is limbic encephalitis?
inflammatory condition causing short term memory deficits sometimes associated with a tumour
What is the main cause of all dementias?
neurodegenerative proteinopathies
What does narcolepsy involve?
- daytime sleepiness
- cataplexy which is loss of muscle tone related to an onset of emotion
- sleep paralysis
- hallucinations at sleep onset
- patients go into REM very quickly
What are watershed infarcts?
- hypotension
- outside areas of the brain die
- areas of small vessel overlap not large vessel supply
Where does metastasis tend to occur in the brain?
small bits lining where the grey and white matter meets
What does darkness in the white matter mean?
white matter = myelin so the darkness means demyelination ie MS
What are the red flags for headache?
- New onset headache >55
- Known or previous malignancy
- Early morning headache
- Immuno-suppressed
- Exacerbation by valsalva
What is the equation for cerebral perfusion pressure?
MAP - ICP = CPP
usually around 80mmHG in a normal person
What is cerebral auto regulation?
the body keeps cerebral blood flow constant despite BP changing with pressure and metabolic autoregulation
What are the causes for raised ICP?
- mass effect
- brain swelling
- increase in central venous pressure
- problems with CSF flow
What is the point of decompensation in ICP?
pressure will increase but ICP will remain stable until this point when it will begin to rise exponentially
