Neurological conditions Flashcards
What is the function of the blood brain barrier?
Helps maintain a stable environment required for normal brain function (brain tissue is very sensitive)
Regulates the passage of most ions and fluid between the blood and the brain tissue
Regulates entry and exit of nutrients and waste
What is the structure of the blood brain barrier?
Endothelium (tight junction)
Basement membrane with pericytes (Pericytes monitor and control influx of substances but pulling apart the membrane)
Macrophages
Polarised astrocytic feet (Completely surround the vessels and tightly control electrolytes)
What can and can’t cross the blood brain barrier?
Most low molecular weight non polarised molecules can pass through the BBB easily. Polarised ions will be repelled.
Water, O2, CO2 and glucose can cross easily however ions such and calcium that would normally follow water cannot because they are polarised.
Many drugs can easily cross the BBB (cociane, nicotine, opiates etc.), many medications cannot (such as dopamine)
A limited number of pathogens can cross but immunosupressed patients may be more succeptible. Many viruses can cross but bacteria crossing is less common
How is CSF tested?
With a lumbar puncture (“spinal tap”)
The pt is led on their side with their knees to their chest to spread out their vertebrae and a 22G needle is inserted between L3/L4 OR L4/L5.
Most commonly used in meningitis diagnosis but medication can also be delivered this way (e.g. anaesthetics for child birth, antibiotics, cancer medication)
What causes menigococcal septicaemia?
Neisseria meningitidis
12 seroproups identified, 6 known to cause epidemics
What is the effect of meningitis on the CSF?
Increased pressure
Increased white blood cells
Increased protein
Decreased glucose
What is the circle of Willis?
The circle of Willis is a junction of several important arteries at the bottom part of the brain.
What is the cerebral ischaemic cascade and what main pathology does it lead to?
-Na+ and K+ pump dysfunction
-Na+ and Ca+ pump dysfunction
-Cytotoxic oedema
-Mitochondrial dysfunction
Excitiotoxicity
Degradative enzymes
BBB breakdown
Free radicals
How does the cerebral ischaemic cascade lead to cytotoxic oedema?
With a reduced blood supply the brain tissue turns to anaerobic respiration and acidosis (mitochondrial dysfunction). This is very inefficient and eventually the hypoxia will lead to a failure of first sodium then potassium pumps. The cell will fill with sodium and calcium, attracting the surrounding water from the extra-cellular fluid into the cell causing it to swell.
What happens to glutamate in the cerebral ischaemic cascade?
Glutamate binds to ionotropic receptors (iGluRs), promoting a major influx of calcium. This calcium overload triggers phospholipases and proteases that degrade essential membranes and proteins
What are iGluRs?
Ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that are activated by the neurotransmitter glutamate
What percentage of strokes are ischaemic?
87%
What percentage of strokes are haemorrhagic?
13%
What percentage of strokes are subarachnoid haemorrhage?
3%
What percentage of strokes are intracranial haemorrhages?
10%
What risk factors are more associated with haemorrhagic strokes?
Taking blood thinners
Arteriovenous malformations (AVMs)
What risk factors are more associated with ischaemic strokes?
Any increased risk of clot formation e.g.
Coronary heart disease
Atrial fibrillation
Heart valve disease
Carotid artery disease
Sickle cell disease
DVT
Contraceptive pill
Long hospital stay/bed-bound periods
etc.
What risk factors are shared between ischaemic and haemorrhagic strokes?
High blood pressure
Diabetes
High blood cholesterol
Poor lifestyle (Obesity, smoking, drinking, drugs etc.)
Age
Family history
Sex
Other medical conditions (sleep apnea, kidney disease, migraine headaches)
What is asphasia?
Changes in speech commonly caused by strokes
What is the timeframe for it to be classed as a TIA and not a full stroke?
24 hours
What can you use to assess risk if you suspect a patient has had a TIA?
ABCD2 scale
What can you use to differentiate between strokes and stroke mimics?
Rosier scale
What percentage of cases where stroke symptoms are present are not due to a stroke?
20%
What are the most common stroke mimics?
Seizures
Migraines
Fainting
Infections
Functional Neurological Disorder (FND)
What is functional neurological disorder?
FND is sometimes referred to as a ‘functional stroke’ or a ‘functional stroke mimic’. Caused by a disorder that effects the nervous system rather than the brain resulting in the signals between brain and body being interupted.
What are the symptoms of FND?
Loss of motor control
Sensory symptoms
Speech problems
Seizures
Visual symptoms
Cognitive problems
Bladder and bowel problems.
How much of the brain is involved in a focal seizure?
One localised area of the brain is initially involved – can spread to involve other areas
What are the most common causes of seizures outside of epilepsy?
Provoked (acute symptomatic seizures)
Psychogenic non-epileptic seizures (PNES)
Vasovagal syncope
Cardiogenic events
Eclampsia
Febrile seizures
What is a BTCS?
Bilateral Tonic-Clonic Seizure
What occurs in tonic phases of seizures?
Loss of consciousness
Stiffening of muscles
Can be have a “crying out” effect as air pushes past vocal cords
May bite their tongue
What occurs in the clonic phases of seizure?
Rhythmic jerking of limbs
Loss of control of bladder and/ or bowels
Breathing affected – cyanosis may occur
When do you treat a focal motor seizure as a BTCS?
Where there is impaired consciousness and last longer than 10 minutes
What are focal aware seizures?
The patient is fully aware of surroundings during the seizure but may not be able to move or respond
What are focal impaired awareness seizures?
When awareness is affected at some point during the seizure
What motor or non-motor features may present with focal seizures?
Motor - muscle activity localised jerking, loss of tone or repeated movement
Non Motor – no muscle activity but may affect emotions, thinking and sensations
What are signs of typical absent seizures and who usually has them?
Typical absences – usually last around 10 secs but can be in clusters
Appear as a “switching off” or “day-dreaming”. A sudden and unexpected stop for a few seconds. Can have some slight jerking movements or eye lid flutter especially with longer absences
They do not generally fall but will not know what is happening and can not be brought out of it
Some go unnoticed
Can have hundreds per day or just occasional ones
Most start in childhood or just into adulthood - usually patients with other existing neurological disorders
What are signs of atypical absent seizuresand who usually has them?
Atypical absences – usually last up to about 30 secs
Similar to typical but last longer and have a slower start and finish
May be able to move around but appear clumsy as muscles become limp
Can occur in any age group but usually associated with people who have learning difficulties or brain conditions
What are the features of myoclonic seizures/jerks?
Can be focal or generalised
Mild (twitch) or can be more forceful – enough to throw something they are holding or make them fall over
Does not usually affect level of consciousness
Usually last for less than a second but can be in clusters
What are the features of tonic seizures?
Can be focal or generalised
Muscles tense /stiff
If standing may fall to the floor
Neck extension and eyes open wide and roll upwards
Arms might move upwards
Legs may stretch or contract
May cry out and stop breathing briefly
Usually last three seconds to two minutes
What are the features of atonic seizures?
Muscles become limp
Will fall to floor if standing or may see a drop of the head forward and may “go weak at the knees”
Usually lasts less than a couple of seconds
What are Provoked Acute Symptomatic Seizures?
Seizures not caused by epilepsy but by damage to the brain or metabolic issues
What can cause Provoked Acute Symptomatic Seizures?
May be caused by structural damage to the brain:
TBI
Brain tumour
Stroke
Tuberculous meningitis (TBM)
Neurocysticercosis
May be due to metabolic issues:
Alcohol withdrawal and chronic alcohol over use
Renal failure
Heptatic failure
Blood Glucose – hypoglycaemia
What is the most common cause of TLOC?
Vasovagal syncope
What causes vasovagal syncope?
A temporary disruption of the supply of oxygen and glucose to the brain due to a fall in cerebral blood pressure. Has many causes including:
Standing for long periods.
Excess heat.
Intense emotion, such as fear.
Intense pain.
The sight of blood or a needle.
Prolonged exercise.
Dehydration.
Skipping meals.
and others
What seizure activity can vasovagal syncope exibit?
May have very short muscle jerking (usually less than 20 secs)
Patient may be able to hear but not respond verbally
Once supine recovery is usually quite rapid
What are vasovagal cardiogenic seizures?
Dysrhythmias causing syncope
Don’t usually cause convulsions but may have impairment of consciousness and have decerebrate posturing
What is meningitis?
Infection of the protective membranes surrounding the brain and spinal cord, specifically the leptomeninges
What are the three forms of meningitis and which is most dangerous?
Bacterial is rarer but usually more serious then viral. If caught early can make a full recovery. Around 1 in 10 cases are fatal
Viral is rarely life threatening and usually resolves itself in 7 – 10 days
Fungal is very rare in the UK and is usually only found in immunosupressed patients
All can cause septicaemia
How is meningitis usually contracted?
Usually caught from someone carrying the virus or bacteria in their nose or throat but not ill themselves (although is occasionally caught from someone with meningitis)
Transmitted usually through:
Coughing
Sneezing
Kissing
Who is most likely to catch meningitis?
Anyone can contract meningitis but most common in:
<25 yrs old
People living in community settings (Refugees, military, students)
Pregnant people
Animal workers
The immunosupressed/deficient
What is encephalitis?
Inflammation of the encephalon (brain)
Who is most at risk of encephalitis?
Anyone can have encephalitis but most common in the very old and very young
What are the first symptoms of encephalitis?
The first symptoms of encephalitis can be similar to flu, such as:
High temperature
Headache
Nausea and Vomiting
Aching muscles and joints
Some people may also have a spotty or blistery rash on their skin
These early symptoms do not always appear and the first signs of encephalitis may be more serious symptoms.
What are more serious symptoms of encephalitis?
Confusion or disorientation
Drowsiness
Seizures
Changes in personality and behaviour (agitation)
Difficulty speaking
Weakness or loss of movement in some parts of the body
Hallucinations (visual and auditory)
Loss of feeling in certain parts of the body
Uncontrollable eye movements / eyesightproblems
Loss of consciousness
There may also be symptoms of meningitis:
Severe headache
Photophobia
Stiff neck
Non- blanching rash
What is the difference between dizziness and vertigo?
Dizziness is a general, non-specific term to indicate a sense of disorientation. Vertigo is a subtype of dizziness and refers to a false perception of self or object motion or an unpleasant distortion of orientation/sense of gravity whilst stationary
It is a result of a mismatch between vestibular, visual, and somatosensory systems.
Vertigo is a symptom not a condition.
What are the two types of vertigo?
Peripheral - caused by balance mechanisms in the inner ear
Central - caused by issues within the brain
What are the main causes of peripheral vertigo?
Benign Paroxysmal Positional Vertigo - BPPV
Head injury - BPPV(t)
Labyrinthitis
Vestibular Neuronitis
Ménière’s disease
Taking certain types of medication
What is Nystagmus?
Nystagmus is a rhythmical, repetitive and involuntary movement of the eyes. It is usually from side to side, but sometimes up and down or in a circular motion. Both eyes can move together or independently of each other. A person with nystagmus has no control over this movement of the eyes.
How can we test nystagmus?
H test
What causes BPPV?
BPPV occurs when small crystals of calcium carbonate, shift in the inner ear and/or fall into another area within the balance canals. The crystals may move for many reasons, such as, an inner ear infection, recent surgery, long periods of rest, fever, head injury or whiplash injury.
What is Labyrinthitis?
An inner ear infection. It causes a delicate structure deep inside your ear called the labyrinth to become inflamed, affecting your hearing and balance.
What is vestibular neuritis?
Vestibular neuritis, also known by the name vestibular neuronitis, is thought to be caused by inflammation of the vestibular portion of the eighth cranial nerve. Does not usually affect hearing
What is ménière’s disease and its symptoms?
Ménière’s disease are caused by the buildup of fluid in the labyrinth. Unknown cause and episodes can last from hours to days. Symptoms include: dizziness (vertigo), ringing in the ears (tinnitus), hearing loss, and a feeling of fullness or congestion in the ear
What are the main causes of central vertigo?
Medications
Drugs and alcohol
MS
TIAs
Tumors
Migraines
What is Guillain Barre syndrome?
A rare condition where the immune system attaks the peripheral nervous system. Can affect all ages but most common in adult males, most recover fully.
Symptoms develop usually over hours or days, usually reaching most severe within 4 weeks.
What are the early symptoms of Guillain Barre syndrome?
Early symptoms tend to be in feet and hands:
Numbness
Pins and needles
Muscle weakness
Pain
Balance and coordination problems
Usually affect both sides of the body at the same time
What are the later symptoms of Guillain Barre syndrome?
Difficulty walking
Paralysis
DIB
Difficulty speaking
Difficulty swallowing or chewing
Difficulty with bladder and bowel motions
Persistent pain
What is Bell’s Palsey?
Temporary weakness or lack of movement usually affecting one side of the face (other symptoms include, drooling, drooping eyelid, loss of taste, dry mouth and dry or watering eye). Treated with steroids, eye drops to stop drying out, tape to close eye during sleep. Recovery period is usually around 6 months.
What is progressive supranuclear palsy?
A rare neurological condition that can cause problems with balance, movement, vision, speech and swallowing. It is caused by a build up of protein (tau) damaging brain cells, with increasing damage over time.
Other symptoms include falls, changes in behaviour muscle stiffness, inability to control eye movement, memory problems
Usually develop in people over the age of 60
How are brain tumors classified?
Position - Supratentorial/Infratentorial
Cells involed - E.g. astrocytoma
Severity - i.e. stage and grade
What processes cause brain tumors, how?
DNA mutations causing uncontrolled cell division, mutations to:
Proto-oncogenes - Promotion of cell division (Accelerator)
Tumor suppressor genes - Loss of inhibition of cell division (Brakes)
Promotion of the accelerator and a loss of the breaks causes uncontrolled cell division
What are malignant and benign tumors?
Benign - Not harmful, self contained
Malignant - Cancerous, cross basement membranes
Do supratentorial or infratentorial tumors make up the majority of adult tumors?
Supratentorial
What are pseudopalisades and how are they formed?
In glioblastoma, they are dense cellular arrangements that surround necrotic foci, formed when aggresive malignant cell division leads to not enough blood being able to reach the centre of the tumor, the peripheral cells continue to divide.
Where do menigomas form, what structure do they form?
In parasagittal regions and on the surface of the brain under the dura mater. They form multinuclear synctiums of fused cells, usually arachnoid cap cells
What is the most common brain tumor in adults?
Glioblastomas, a common type of strocytoma - fast growing supratentorial tumors.
What are pituitary adenomas?
Common usually benign tumors formed from the enocrine tissue of the pituiatry, classified by hormones released in tumor form.
What are oligodenrogliomas, what microscopic forms can they take?
Relatively rare supratentorial tumors formed from oligodendrocytes.
More common in frontal and temporal lobes where cells are heavily myelinated
Relatively slow growing - can become malignant
“Fried egg” or “Chicken-wired”
What are haemangioblastomas?
Haemangioblastomas are rare non cancerous (benign) brain tumours. They start in the cells that line the blood vessels in the brain, spinal cord and brain stem. They usually grow slowly over some years.
Most haemangioblastomas start in the back of the brain (cerebellum).
What are common brain tumor symptoms?
-Headaches
-Seizures (fits)
-Persistently feeling sick (nausea), being sick (vomiting) and drowsiness
-Mental or behavioural changes, such as memory problems or changes in personality
-Progressive weakness or paralysis on one side of the body
-Vision or speech problems
How are brain tumors diagnosed?
Medical imaging
Tissue BIOs
How are brain tumors treated?
-Steroids
-Medicines to help with symptoms
-Surgery
-Radiotherapy
-Chemotherapy
What are coup and contrecoup brain injuries?
Coup - injury on side of impact
Contrecoup - injury on opposite side to impact
Bothh can be present - Coup-contrecoup
What normally causes secondary brain injuries?
Hypoxia/iscaemia
Oedema
Haematoma
Release of toxic chemicals (Free radicals)
What is a concusion?
A transient and reversible post-traumatic alteraation to mental status with no visible structural damage on imaging, however repeated concussions can lead to traumatic encephelopathy.
Neuronal damage caused by excessive release of excitaory neurotransmitters.
What classifications are there of spinal cord injuries?
Unstable - fragments of bone may move around and cause further damage
or
Stable - structured resistant to further damage
Complete - No function
or
Incomplete - Some function retained
What is spina bifida?
Spina bifida is when a baby’s spine and spinal cord does not develop properly in the womb, causing a gap in the spine. Spina bifida is a type of neural tube defect. The neural tube is the structure that eventually develops into the baby’s brain and spinal cord.
What complications arise from spina bifida?
Frequent urinary tract infections
Fluid buildup on the brain (hydrocephalus)
Displaced cerebellum
Loss of bowel or bladder control
Brain infection (meningitis)
Permanent weakness or paralysis of legs
This list may not be all-inclusive.
What treatments are used for spinal bifida?
Surgery within the first few days of birth is usually the priority
Children who also have hydrocephalus may need to have a ventriculoperitoneal shunt placed. This will help drain the extra fluid from the ventricles (in the brain) to the peritoneal cavity (in the abdomen).
Antibiotics may be used to treat or prevent infections such as meningitis or urinary tract infections.
Most children will need lifelong treatment for problems that result from damage to the spinal cord and spinal nerves.
What is cerebral palsy?
Umbrella term for conditions marked by impaired muscle coordination (spastic paralysis) and/or other disabilities, typically caused by damage to the brain before or at birth (bleed, hypoxia etc.).
What is the leading cause of childhood disibilty?
Cerebral palsy
How many types of cerebral palsy are there and what defines them?
What is hydrocephalus?
A neurological disorder caused by an abnormal buildup of cerebrospinal fluid in the ventricles (cavities) deep within the brain. This excess fluid causes the ventricles to widen, putting harmful pressure on the brain’s tissues.
What causes hydrocephalus?
A mismatch between CSF production and usage e.g.
-Obstruction
-Poor absorption
-Overproduction
What are the symptoms of hydrocephalus?
-Bulging of the cranium
-Eyes fixed downward (sunsetting)
-Lethargy
-Irritability
-Seizures
-Nausea and vomiting
-Poor eating
-Problems with muscle tone and strength
What is multiple sclerosis?
Immune mediated inflammatory disease that attacks myelinated axons of the CNS. Chronic and progressive with episodes of exacerbation and remission.
What is the pathophysiology of MS?
White blood cells attack myelin surrounding nerve cells leaving scars and plaques. Loss of myelin interferes with conduction leading to dysfunction as impulses are slowed or blocked.
What are the symptoms of MS?
The symptoms of MS vary widely from person to person and can affect any part of the body.
The main symptoms include:
-Fatigue
-Difficulty walking
-Vision problems, such as blurred vision
-Problems controlling the bladder
-Numbness or tingling in different parts of the body
-Muscle stiffness and spasms
-Problems with balance and co-ordination
-Problems with thinking, learning and planning
Is MS more common in women or men?
It’s about 2 to 3 times more common in women than men
When does MS onset?
It can onset at any age but usually in the 20s to 40s
What is Parkinson’s disease?
Dysfunction of the extrpyramidal motor system due to progressive degenerative changes in the basal nuclei.
Associated with two major pathological findings:
1) A loss of dopaminergic neurons (due to the above) and a decrease in dopamine levels - dopamine has an inhibatory affect on the motor system
2)The presence of Lewy bodies and neurites
What are lewy bodies?
clumps of abnormal protein particles that, for reasons that are not fully understood, accumulate in the brain and cause cell damage/dusfunction/death
What main and other clinical findings are present with Parkinson’s disease?
3 main:
Resting tremor
Rigidity
Bradykinesia
Others:
Stooped posture
Decreased facial expression
Balance impairment
Depression
Reduced dexterity
Soft voice
Slow thinking
Sleep issues
What treatment is given to Parkinson’s patients?
Supportive therapies
-such as physiotherapy
Medication
-Dopamine replacement (Levodopa)
-Dopamine agonists
-Monoamine oxidase-B inhibitors (Block the effects of an enzyme or brain substance that breaks down dopamine)
Surgery (for some people)
-Deep brain stimulation
What is myasthenia gravis (MG)?
A chronic autoimmune disorder in which antibodies destroy the communication between nerves and muscle, resulting in fluctuating fatigue and weakness of the skeletal muscles.
-The immune system releases antibodies that target and block acetylcholine receptors at the neuromuscular junction.
Myasthenia gravis affects the voluntary muscles of the body, especially those that control the eyes, mouth, throat and limbs.
What are the symptoms of myasthenia gravis?
-Trouble holding up your head
-Drooping eyelids
-Eye muscles weakness
-Change in your facial expression
-Double vision
-Shortness of breath
-Trouble swallowing
-Problems walking and lifting things
-Speech problems
In severe MG conditions the respiratory muscles become so weak that one can’t control them. This is a medical emergency that requires the use of a ventilator to assist patients in breathing. Around 15% to 20% of people with myasthenia gravis will have at least one myasthenic crisis. It can be caused by an infection, stress, surgery, or a medical reaction.
What is Huntingdons disease?
An incurable adult onset inherited disorder, associated with cell loss in the brain due to a genetic fault causing a loss of a protein called Huntingtin. It is not fully understood why but the protein is important for neuronal function. This disease specifically affects the neurons of the basal ganglia
What are the early and late symptoms of Huntington’s disease?
The first symptoms of Huntington’s disease often include:
Difficulty concentrating
Memory lapses
Depression
Stumbling and clumsiness
Mood swings, irritability or aggressive behaviour
Over time, someone with Huntington’s disease may develop:
Involuntary jerking
Difficulty speaking clearly
Swallowing problems
Increasingly slow or rigid movements
Personality changes
Breathing problems
Difficulty moving around – they may eventually lose the ability to walk or sit up by themselves
In the later stages, people with Huntington’s disease find daily activities increasingly difficult and will need full-time nursing care.
What is motor neurone disease?
Motor neuron disease (MND) refers to a group of chronic sporadic and hereditary neurological disorders characterized by progressive degeneration of motor neurons. Motor neurones degenerate and stop sending signals to the muscles which weaken and atrophy
What is Amyotrophic lateral sclerosis (ALS)?
Amyotrophic lateral sclerosis (ALS) is the most common form of MND.
What causes MND?
Exact cause not known but thought to be caused by toxins released by astrocyte cells
How does motor neurone disease progress?
Progressively over several years.
A person with MND will usually die between two to three years after diagnosis
What are the most common types of MND?
ALS: This is the most common type of MND. It affects both the upper and lower motor neurons — the neurons in the brain and spinal cord
Primary lateral sclerosis: This affects the neurons in the brain. It is a rare form of MND that advances more slowly than ALS. It is not fatal, but it can affect the quality of life.
Progressive bulbar palsy (PBP): This involves the brain stem, and people with ALS often have PBP, too. It causes frequent choking spells and difficulty speaking, eating, and swallowing.
Progressive muscular atrophy: This type of MND is rare. It affects the lower motor neurons in the spinal cord and causes slow but progressive muscle wasting, especially in the arms, legs, and mouth.
Spinal muscular atrophy (SMA): This inherited MND develops in children. It tends to affect the trunk, legs, and arms. The long-term outlook depends on the type.
Which type of meningitis is more likely to present as a “bad cold”?
Bacterial (Meningococcus)
How does bacterial meningitis move from the blood stream into the brain and CNS?
The anatomical site of bacterial invasion from the bloodstream remains unidentified. Experimental evidence suggests that the choroid plexus may be a site of invasion.
Meningococci are found in the choroid plexus as well as in the meninges and pneumococci infiltrate the leptomeningeal blood vessels in meningitis.
What is the pathophysiology of meningitis infection?
The pathogens take advantage of the specific features of the immune system in the CNS, replicate and induce inflammation. A hallmark of bacterial meningitis is the recruitment of highly activated leukocytes into the CSF. Beside bacteria, viruses, fungi and non-infectious causes as in systemic and neoplastic disease as well as certain drugs can induce meningeal inflammation. Usually the inflammatory process is not limited to the meninges surrounding the brain but also affects the brain parenchyma (meningoencephalitis), the ventricles (ventriculitis) and spreads along the spinal cord. In recent years the damage of neurons, particularly in hippocampal structures, has been identified as a potential cause of persistent neuropsychological deficits in survivors.
Which specific diagnostic test is used to diagnose meningitis?
A lumbar puncture (spinal tap)
What is a cavernoma?
Where will headaches due to raised ICP first present?
The occiput (usually)
