Neuro Other Flashcards
Radiographing features of brain atrophy?
CT and MRI are equally able to demonstrate cortical atrophy, but MRI is more sensitive in detecting focal atrophic changes in the nuclei.
Characteristic features include prominent cerebral sulci (i.e. cortical atrophy) and ventriculomegaly (i.e. central atrophy) without bulging of the third ventricular recesses.
What is neisseria meningitidis and what serious conditions can it cause?
Neisseria meningitidis is a gram negative diploccous bacteria. They are circular bacteria (“-cocci”) that occur in pairs (“diplo-”). It is commonly known as meningococcus.
Meningococcal septicaemia is when the meningococcus bacterial infection is in the bloodstream. Meningococcal refers to the bacteria and septicaemia refers to infection in the blood stream. Meningococcal septicaemia is the cause of the classic “non-blanching rash” that everybody worries about as it indicates the infection has caused disseminated intravascular coagulopathy (DIC) and subcutaneous haemorrhages.
Meningococcal meningitis is when the bacteria is infecting the meninges and the cerebrospinal fluid around the brain and spinal cord.
What is meningitis?
Meningitis is inflammation of the meninges. The meninges are the lining of the brain and spinal cord (dura mater, arachnoid mater, pia mater) This inflammation is usually due to a bacterial or a viral infection.
Causes of bacterial meningitis?
Neisseria meningitidis (meningococcus) and Streptococcus pneumoniae (pneumococcus)
Listeria monocytogens
Group B sterptococcus in neonates (GBS - contracted at birth - vertical transmission)
What rash is charecteristic of meningococcal septicemia?
Non-blanching
Typical meningitis symtpoms?
Fever
Neck stiffness
Vommiting
Headache
Photophobia
Altered conciousness
Seizures
When do children warrent a lumbar puncture?
Under 1 months presenting with fever
1 – 3 months with fever and are unwell
Under 1 years with unexplained fever and other features of serious illness
Non-specific presentation of meningitis in neonates and babies?
Hypotonia
Poor feeding
Lethargy
Hypothermia
Bulging frontanelle
What special tests can be performed to look for meningeal irritation?
Kernigs Test
Brudzinski’s Test
What is Kernig’s test?
Kernig’s test involves lying the patient on their back, flexing one hip and knee to 90 degrees and then slowly straightening the knee whilst keeping the hip flexed at 90 degrees. This creates a slight stretch in the meninges and where there is meningitis will produce spinal pain or resistance to this movement.
What is Brudzinski’s test?
Brudzinski’s test involves lying the patient flat on their back and gently using your hands to lift their head and neck off the bed and flex their chin to their chest. A positive test is when this causes the patient to involuntarily flex their hips and knees.
Management of suspected bacterial meningitis in the community?
Children seen in the primary care setting with suspected meningitis AND a non blanching rash should receive an urgent stat injection (IM or IV) of benzylpenicillin prior to transfer to hospital as time is so important:
< 1 year – 300mg
1-9 years – 600mg
> 10 years and adults – 1200mg
This shouldn’t delay transfer. Where there is a true penicillin allergy transfer should be the priority rather than other antibiotics.
Management of bacterial meningitis in the hospital?
Ideally a blood culture and a lumbar puncture for cerebrospinal fluid (CSF) should be performed prior to starting antibiotics however if the patient is acutely unwell antibiotics should not be delayed.
Send blood tests for meningococcal PCR if meningococcal disease is suspected. This tests directly for the meningococcal DNA. It can give a result quicker than blood culture depending on local services and will still be positive after the bacteria has been treated with antibiotics.
There should be a low threshold for treating suspected bacterial meningitis, particularly in babies and younger children. Always follow the local guidelines however typical antibiotics are:
< 3 months – cefotaxime plus amoxicillin (the amoxicillin is to cover listeria contracted during pregnancy from the mother)
> 3 months – ceftriaxone
Vancomycin should be added to these if there is a risk of penicillin resistant pneumococcal infection such as from recent foreign travel or prolonged antibiotic exposure.
Steroids are also used in bacterial meningitis to reduce the frequency and severity of hearing loss and neurological damage. Dexamethasone is given 4 times daily for 4 days to children over 3 months if the lumbar puncture is suggestive of bacterial meningitis.
Bacteria meningitis and meningococcal infection are notifiable diseases so public health need to be informed of all cases.
Most common causes of viral menigitis?
HSV - herpes simplex virus
Enterovirus
Varicella zoster virus
How is viral menigitis diagnosed?
Viral PCR of CSF
Clinical picture
CSF characteristics (clear, WCC raised with lymphocytes,etc)
Viral menigitis is often managed with supportive treatment and less severe than bacterial, which virus might be treated with an antiviral, and what is the antiviral of choice?
Aciclovir can be used to treat suspected or confirmed HSV meningitis.
Complications of meningitis?
Hearing loss is a key complication
Seizures and epilepsy
Cognitive impairment and learning disability
Memory loss
Focal neurological deficits such as limb weakness or spasticity
Calculation of GCS
Eye opening:
Spontaneous – 4
To speech – 3
To pain – 2
None – 1
Motor response:
Obeys commands – 6
Localizes pain – 5
Normal flexion (withdrawal) – 4
Abnormal flexion (decorticate) – 3
Extension – 2
None – 1
Verbal response:
Orientated – 5
Confused conversation – 4
Inappropriate words – 3
Incomprehensible sounds – 2
None – 1
What is the sign Argyll-Robertson pupil specific for?
Neurosyphillis
A patient with signs of an oculomotor nerve palsy (cranial nerve 3) with pupillary signs (mydriasis)
should be assumed to have what until proven otherwise?
A patient with signs of an oculomotor nerve palsy (cranial nerve 3) with pupillary signs (mydriasis)
should be assumed to have an aneurysm of their ipsilateral posterior communicating artery until
proven otherwise. This is due to the close proximity of the oculomotor nerve to the posterior
communicating artery before it enters the cavernous sinus. Extrinsic compression by an aneurysm
affects the more superficial parasympathetic fibres of the oculomotor nerve, causing pupillary
signs as well as ophthalmoplegia. This is different from ischaemic or diabetic palsies of the
oculomotor nerve which tends to only cause an ophthalmoplegia and no pupillary signs
Positive rhombergs test is caused by what
Deficits in propioceotive pathaars
35 y/o M usually fit and well, very active.
5/7 paresthesia in toes
3/7 days unsteaddieness, numbeness
Sent by GP
Peripheral weakness
Preceded by
Ascending motor and sensory disturbance following a recent gastric symptoms.
Neuro presentations: Anatomical Differential Diagnsois
Brain (left or right) - problems with higher mental function, visual pathways, distribution: hemiparesis or hemisensory symtpoms
Brainstem - cranial nerve, cerbellar conncections, motorpathways to limbs, sensation from limbs, sympathetic pathways (horners syndrome)
Cerbellum
Spinal Cord - para/quadraperisis - sensory level - usually trunk
Motor pathway - mixed lower and motor neurone lesions
Nerve Roots - dermatomal sensory loss, myotomal motor weakness, very painful
Plexus - downstream very complex picture
Peripheral Nerve - indivudal: compression - specific patterns of weakness, sensory loss and reflex changes length dependent peripheral neuorpathy (diabetes, alcohol, B12 def) glove and stocking sensory loss, LMN signs, distal weakness
Neuromuscular junction - fatigeabilty, no signifcant sesnory involvement
Muscle - weakness without sensory involvement
What would you expect to see in a cord lesion vs a peripheral neuropathy?
Spinal cord lesion?
UMN signs
Sensory level
Peripheral neuropathy
LMN
Glove and stocking distrubtion of sensory loss.
What is bulbar palsy?
Speech and swallowing difficulties
Lower cranial nerves (speech and swallow) emerge from bulbar portion on braintsem
LMN problem
(Involvement of corticobulbar fibres - pseudobulbarpalsy UMN)
Dysphagia types
Expressive - Non-fluent
Receptive- Fluent
Associated with higher mental function problems
Probelms with speech and language quality?
Dysarthia - articulation problem
Dysphonia - volume problem
Movement disorders
Hyperkinetic - involuntary additional movements: tremor, chorea, dystonia, ballism, myclonus, tic
Hypokinetic - stiffness, slowness
Tics vs. Myoclonus
Both are jerks, can be repetitive
Tics - small, often facial. Compulsion a feature
simple - repetitive, single muscle group
multiple - associated grunts noise, vocalization - Tourette’s
Cerebellar signs
Ataxic gait
Speech - scanning
Nystagmus
Limb ataxia - dysidadochokinaesia
Reduced tone
Pendular reflexes
How to asses for dysdiadochokinaesia?
Finger nose teesting
Heel shin testing
What is ME
Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME).
CFS/ME is characterised by persistent and disabling fatigue, post-exertional malaise (PEM), unrefreshing sleep, cognitive dysfunction and headaches.
The symptoms in CFS/ME are not related to other medical or psychiatric conditions; however, symptoms are often preceded by a viral illness.
There are no curative medications or treatments for chronic fatigue; instead, the primary goal of treatment is to manage symptoms and improve functional capacity.
Therefore, initial treatment should include counselling and supportive care, helping patients to understand their condition and implement techniques to improve exercise tolerance.
What is Huffman’s sign
Hoffman’s sign is elicited by loosely holding the hand and flicking the nail of the middle finger downwards. It is positive when the thumb flexes and adducts. This is considered by some as the Babinski test of the upper limb, although not as reliable for upper motor neuron (UMN) lesions because it is positive in a proportion of healthy people. Healthy people tend to be Hoffman’s positive in both right and left hands, so it is more likely to be pathological if it is unilateral.
What type of nerve injury can cause wrist drop?
Weakness of metacarpopgalangeal joint extension of all digits, weakness of wrist extension due to radia nerve injury (mid humeral fracture - radial groove)
Types of dyskinesia
Chorea
Tics
Tremor
Myoclonus
What is Wernicke’s encephalopathy
Wernicke’s encephalopathy - an acute but reversible condition caused by severe thiamine (vitamin B1) deficiency. This can be caused by a combination of factors, including poor intake, low vitamin content in alcohol, low liver storage capacity, decreased intestinal absorption, impaired conversion of thiamine to its active form (thiamine pyrophosphate), and increased demand to metabolise the carbohydrates in alcohol.
Suggestive features in patient history include a history of alcohol misuse and the presentation of acute cognitive dysfunction, ataxia, impaired balance and nystagmus.
It is important to note that the classic triad associated with Wernicke’s encephalopathy - mental status changes, ophthalmoplegia and gait dysfunction - is only present entirely in approximately 20% of patients.
How might autonomic neuropathy commonly present?
Autonomic neuropathy, a common complication of poorly controlled diabetes, may present as postural hypotension and gastroparesis
What is Charcot-Marie Tooth Disease?
Charcot-Marie-Tooth disease is an inherited disease that affects the peripheral motor and sensory nerves.
There are various types of Charcot-Marie-Tooth with different genetic mutations and different pathophysiology.
They cause dysfunction in the myelin or the axons.
The majority of mutations are inherited in an autosomal dominant pattern.
Symptoms usually start to appear before the age of 10 years but the onset of symptoms can be delayed until 40 or later.
Classical features of Charcot Marie Tooth disease?
High foot arches (pes cavus)
Distal muscle wasting causing “inverted champagne bottle legs”
Weakness in the lower legs, particularly loss of ankle dorsiflexion
Weakness in the hands
Reduced tendon reflexes
Reduced muscle tone
Peripheral sensory loss
Causes of peripheral neuropathy?
ABCDE
A - alcohol
B - B12 deficiency
C - Cancer and Chronic Kidney Disease and CMT
D - Diabetes and Drugs (e.g. isoniazid, amiodarone and cisplatin)
E- every VASCULITIS
How is Charcot Marie Tooth disease managed?
Neurologists and geneticists to make the diagnosis (gene testing, nerve conduction studies)
Physiotherapists to maintain muscle strength and joint range of motion
Occupational therapists to assist with activities of living
Podiatrists to help with foot symptoms and suggest insoles and other orthoses to improve symptoms
Orthopaedic surgeons to correct disabling joint deformities
What is Neurofibromatosis?
Genetic condition causing neuromas (nerve tumors) to develop throughout the nervous system
Benign but can cause neurological and structural problems
. There are two types of neurofibromatosis with different features.
Neurofibromatosis type 1 is more common than type 2.
What type of neurofibromatosis is more common?
Type 1
What is the NF1 gene and what is its inheritance pattern?
The neurofibromatosis type 1 gene is found on chromosome 17.
It codes for a protein called neurofibromin, which is a tumour suppressor protein.
Inheritance of mutations in this gene is autosomal dominant.
Criteria for NF1
At least 2/7 of CRABbING
CAFE AU LAIT SPOTS (6 or more) measuring ≥ 5mm in children or ≥ 15mm in adults
RELATIVE with NF1
AXILARY OR INGUNAL FRECKLES
BONY DISPLASIA SUCH AS BOWING of a long bone or sphenoid wing dysplasia
IRIS HAMARTOMAS (Lisch nodules) (2 or more) are yellow brown spots on the iris
NEUROFIBROMAS (>1) or 1 plexiform neurofibroma
GILOMA of the optic nerve
How is neurofibromatosis investigated and diagnosed?
Diagnosis is based on clinical criteria (2/7 or more features for NF1) and no investigations are required to make a definitive diagnosis.
Genetic testing can be used where there is doubt.
Xrays can be used to investigate bone pain and bone lesions.
Imaging with CT and MRI scans can be used to investigate lesions in the brain, spinal cord and elsewhere in the body.
There is no treatment of the underlying disease process in neurofibromatosis type 1, or to prevent the development of neurofibromas or complications.
Management is to control symptoms, monitor the disease and treat complications.
What complications might occur?
Migraines
Epilepsy
Renal artery stenosis causing HTN
Learning and behavioural problems such as ADHD
Scoliosis
Vision loss (secondary to optic nerve gilomas)
Malignant peripheral nerve sheath tumours
Gastrointestinal stromal tumour (a type of sarcoma)
Brain tumours
Spinal cord tumours with associated neurology such as paraplesia
Increased risk of cancer (e.g. breast cancer)
Leukaemia
What is the NF2 gene and how is it inherrited?
The neurofibromatosis type 2 gene is found on chromosome 22.
It codes for a protein called merlin, which is a tumour suppressor protein particularly important in Schwann cells.
Mutations in this gene lead to the development of schwannomas (benign nerve sheath tumours of the Schwann cells).
Inheritance is autosomal dominant.
What is NF2 most associated with
Neurofibromatosis type 2 is most associated with acoustic neuromas. These are tumours of the auditory nerve innervating the inner ear. Symptoms of an acoustic neuroma are:
Hearing loss
Tinnitus
Balance problems
Schwannomas can also develop in the brain and spinal cord with symptoms based on the location of the lesion.
Surgery can be used to resect tumours although there is a risk or permanent nerve damage.
What is tuberous sclerosis?
Tuberous sclerosis is a genetic condition that causes features in multiple systems.
The characteristic feature is the development of hamartomas.
These are benign neoplastic growths of the tissue that they origin from.
What is a hamartoma?
Benign neoplastic growth of the tissue they orginate from.
They can cause problems based in the location of the lesion commonly:
Heart
Brain
Skin
Kidneys
Eyes
Lungs
Tuberous sclerosis is caused by mutations in which genes (and what are the responsible for)?
Either of:
TSC1 gene on chromosome 9, which codes for hamartin
TSC2 gene on chromosome 16, which codes for tuberin
Why do mutations in the TSC1 gene (coding for hamartin) and TSC2 gene (coding for tuberin) cause hamartoma formation?
Hamartin and tuberin interact with each other to control the size and growth of cells. Abnormalities in one of these proteins leads to abnormal cell size and growth.
Skin signs in tuberous sclerosis?
ASH LEAF SPOTS are depigmented areas of skin shaped like an ash leaf
SHAGREEN PATCHES are thickened, dimpled, pigmented patches of skin
ANGIOFIBROMAS are small skin coloured or pigmented papules that occur over the nose and cheeks
SUBUNGUAL FIBROMATA are fibromas growing from the nail bed. They are usually circular painless lumps that grow slowly and displace the nail
CAFE AU LAIT SPOTS are light brown “coffee and milk” coloured flat pigmented lesions on the skin
POLIOSIS is an isolated patch of white hair on the head, eyebrows, eyelashes or beard
Neurological features of tuberous sclerosis?
Epilepsy
Learning disability and developmental delay
Features of tuberous sclerosis?
Skin: cafe au lait spots, poliosis, subungual fibromata, angiofibromas, shagreen patches, ash leaf spots
Neurological: epilepsy, learning disability and developmental delay
Gilomas
Rhabdomyomas in the heart
Polycystic kidneys
Lymphangioleiomyomatosis (abnormal growth in smooth muscle cells, often affecting the lungs)
Retinal hamartomas
What is the typical presentation of tuberous sclerosis?
The classical presentation is a child presenting with epilepsy found to have skin features of tuberous sclerosis. It can also present in adulthood.
Congenital causes of cerebellar dysfunction (dysdiadochokinesia, ataxia, nystagmus, intention tremor, slurred speech, hypotonia)
Friedrich’s ataxia
The spinocerebellar ataxias
Cerebellar lesions: cerebellar vermis vs cerebellar hemisphere
Lesions to the cerebellar vermis typically cause truncal ataxia and gait instability, with relatively few cerebellar signs in the limbs.
Lesion to the cerebellar hemisphere will cause signs in the ipsilateral limb.
What is a bulbar palsy?
A bulbar palsy is a ‘lower motor neurone’ lesion affecting cranial nerves 9, 10 and 12. This causes impairments in speech and swallowing.
Causes of bulbar plasy?
Motor neurone disease (in particular the progressive bulbar palsy variant)
Myasthenia gravis
Guillain-Barré syndrome
Brainstem stroke (the lateral medullary syndrome) Syringobulbia
Mononeuritis multiplex
Mononeuritis multiplex is simultaneous or sequential involvement of individual non-contiguous nerve trunks. It typically presents with acute or subacute loss of sensory and motor function of individual nerves. The pattern of involvement is asymmetric, however, as the disease progresses, deficit(s) becomes more confluent and symmetrical, making it difficult to differentiate from polyneuropathy.
Gait ataxia is caused by lesions where
Cerebellar vermis
MRC power score of two indicates what
that the muscle can work with gravity removed
Ankle reflex
S1-2
Knee reflex
L3-4
Biceps reflex
C5-c6
Triceps reflex
C7-c8
Syringomyelia presentation
Syringomyelia classically presents with cape-like loss of pain and temperature sensation due to compression of the spinothalamic tract fibres decussating in the anterior white commissure of the spine
Lesions in Bitemporal heminopia
lesion of optic chiasm
upper quadrant defect > lower quadrant defect = inferior chiasmal compression, commonly a pituitary tumour
lower quadrant defect > upper quadrant defect = superior chiasmal compression, commonly a craniopharyngioma
What is Wenicke’s encephalopathy and why does it occur?
Vitamin B1 deficiency may cause Wernicke’s encephalopathy.
Wernicke’s encephalopathy is the triad of:
Confusion
Ataxia
Ophthalmoplegia/nystagmus.
Note that not all 3 signs need to exist in one patient.
The most common cause of Wernicke’s encephalopathy is chronic alcohol abuse.
It is therefore important to prescribe thiamine (vitamin B1) when patients present to hospital/community settings with a background of current excessive alcohol use.
What is Korsakoff’s syndrome and why does it occur?
Untreated, Wernicke’s encephalopathy can progress to Korsakoff’s syndrome.
Korsakoff’s syndrome presents as profound anterograde amnesia with limited retrograde amnesia.
Patients may therefore confabulate (fabricate memories to mask the memory deficit).
Korsakoff’s syndrome is thought to be a result of degeneration of the mammillary bodies. The mammillary bodies are part of the circuit of Papez which plays a role in memory formation.
What is autoimmune encephallitis?
Autoimmune encephalitis (AE) is a form of non-infectious neuroinflammation that has become an increasingly recognized cause of acute/subacute progressive mental status change with a variety of clinical phenotypes.
Clinical features of autoimmune encephalitis
Autoimmune encephalitis can present with a wide range of symptoms, including confusion, seizures, movement disorders, behavioural changes, emotional lability, psychosis, cognitive impairment and reduced conscious level.
It is an important differential diagnosis in young people or adults presenting with an acute onset of new neurological or psychiatric symptoms without a past context of mental health problems.
The onset in young people is often faster than in adults.
Symptoms may fluctuate but usually progress over days to weeks.
Autoimmune encephalitis: subtypes
Autoimmune encephalitis subtypes include definite limbic encephalitis, acute disseminated encephalomyelitis, anti-NMDA receptor encephalitis and Hashimoto’s encephalopathy.
Other differential diagnoses include non-convulsive status epilepticus, space occupying lesion, meningoencephalitis, acute demyelinating encephalomyelitis (which is usually preceded by a systemic viral illness or vaccination), stroke and trauma (including non-accidental injury).
Autoimmune encephalitis: differentials
Other differential diagnoses include non-convulsive status epilepticus, space occupying lesion, meningoencephalitis, acute demyelinating encephalomyelitis (which is usually preceded by a systemic viral illness or vaccination), stroke and trauma (including non-accidental injury).
Investigation autoimmune encephalitis
Full neurological examination
Blood tests:
- Low sodium is associated with LG1 encephalitis
- Antibodies: LGI1, NMDA receptor, CASPR2
- MRI
- Lumbar puncture (will show increased levels of lymphocytes in the cerebrospinal fluid (‘lymphocytic pleocytosis’))
EEG is sensitive but not specific
Management of autoimmune encephalitis?
The first-line treatment of autoimmune encephalitis includes steroids and intravenous immunoglobulin.
Plasma exchange can also be used as an adjunctive treatment in those who are not fully responding to steroids or immunoglobulin; it is rarely used alone.
The most common complications of plasma exchange are infection, hypotension and electrolyte imbalances due to fluid shifts.
Second-line treatment, if patients are not responding within 2 weeks, includes immunosuppressant therapy with agents such as Rituximab and Cyclophosphamide. First line therapy should be continued during this time.
Autoimmune encephalitis and cancer screening?
Encephalitis can occur as a paraneoplastic syndrome where autoimmune disorders are triggered by tumours.
Therefore, it is important to screen for cancer in patients whom you suspect may have an underlying tumour.
Particular associations:
Anti-Hu: Small cell lung cancer
NMDA receptor antibodies: Ovarian teratoma
Anti-Yo: breast and ovarian tumours
What is transient global amnesia, how does it present?
Transient global amnesia is a neurological condition characterised by a temporary but total disruption of both short and long term memory. Other cognitive functions are preserved.
It can present with patients being found wandering the street far away from their home.
The episode may last for several hours before spontaneously resolving.
Wernicke-Korsakoff syndrome refers to two distinct neurological syndromes resulting from deficiency of what?
thiamine (Vitamin B1)
What is Wernicke’s encephalopathy (WE) and how is it characterised?
Wernicke’s encephalopathy (WE): an acute encephalopathy characterised
by a triad of confusion, ataxia, and oculomotor dysfunction
Wernicke’s encephalopathy (WE) triad of features
Confusion
Ataxia
Oculomotor dysfunction - Nystagmus
This triad of features is only seen in up to one-third of patients.
What is Korsakoff syndrome and what is it characterised by?
Korsakoff syndrome (KS): a chronic amnesic syndrome characterised by defects in both anterograde and retrograde memory
Wernicke-Korsakoff syndrome refers to two distinct neurological syndromes, most commonly seen when?
The syndromes are most commonly observed in chronic alcoholism because of poor dietary intake, although other factors are involved including a possible genetic element.
WKS is not restricted to chronic alcoholism and may be observed in other conditions (e.g. anorexia nervosa).
WKS prognosis
KS is essentially the late neuropsychiatric manifestation of WE if it goes unnoticed or untreated. Once KS has been established, patients rarely recover.
What can be used to prevent permenant neurological damage in WE?
High dose B vitamins (e.g. Pabrinex®) is critical to prevent permanent neurological damage
Causes of Wernicke-Korsakoff syndrome?
From conditions that result in poor dietary intake or malabsorption of thiamine relative to metabolic requirements.
Chronic alcoholism
Prolonged fasting or starvation
Anorexia nervosa
Hyperemesis gravidarum
Systemic malignancy
End-stage renal failure: on haemodialysis or peritoneal dialysis
Gastrointestinal disease & malabsorption
Where does thiamine come from and how is it stored?
Thiamine is an essential cofactor for several metabolic reactions in the body.
Thiamine is present in most foods, but specifically in whole grains, poultry, nuts, peas, brown rice, and fortified food.
Once absorbed from the gastrointestinal tract it is stored in the liver.
However, storage occurs for a maximum of 18 days meaning a moderate consumption of thiamine is needed to maintain stores.
Investigating ?NMS
Bedside: observations, blood glucose, GCS monitoring, ECG, cardiac monitor
Bloods: electrolyte derangements and acute kidney injury may be seen, particularly with the development of rhabdomyolysis (e.g. hypophosphataemia, hypomagnesaemia, hyperkalaemia, metabolic acidosis, sodium disruption). Mildly deranged LFTs and leucocytosis are common. CK is critical in all suspected cases.
Imaging: Cerebral imaging is important to exclude an alternative cause of confusion (e.g. CT head / MRI head)
A lumbar puncture may be needed to exclude a cerebral infection or alternative cause of confusion (e.g. autoimmune encephalitis).
NMS diagnosis
There should be a low index of suspicion for the presence of NMS in patients taking antipsychotics.
The diagnosis of NMS is usually made in patients who present with characteristic clinical features who are also taking antipsychotics. A supporting feature includes an elevated creatine kinase (CK) due to muscle rigidity (e.g. >1000-100,000 IU/L). CK may be normal if rigidity is not profound or the patient is early in the presentation.
Pathophysiology of Wernicke-Korsakoff
Wernicke-Korsakoff syndrome, thiamine deficiency leads to neuronal injury.
Deficiency causes areas of the brain with high metabolic activity to undergo neuronal injury that may be precipitated by the administration of intravenous glucose before thiamine supplementation.
On autopsy, typical findings in acute WE include vascular congestion, microglial proliferation, and petechial haemorrhage.
In chronic disease, there is evidence of neuronal loss, most notably in the medial thalamus.
Several other histological findings are typical of the syndrome.
What is Beriberi and why does it occur
Beriberi refers to two classic syndromes known as ‘dry’ and ‘wet’ that result from thiamine deficiency.
Dry vs wet BeriBeri
Dry beriberi: symmetrical motor and sensory peripheral neuropathy
Wet beriberi: causes a high-output cardiac failure (fluid overload, cardiomyopathy, tachycardia, warm extremities) due to peripheral vasodilatation from a build-up of pyruvate and lactate
Nystagmus in ?WKS - differentials
Lateral rectus palsy (CN VI palsy)
Conjugate gaze palsies: inability to move both eyes in a single horizontal
Nystagmus
Memory deficit in Korsakoff syndrome
KS is characterised by profound memory defects. Interestingly, long-term memory is relatively preserved in the condition.
Memory deficit: anterograde and retrograde
Confabulation: stories made up to fill gaps in memory
Poor insight: unaware of their illness
Global cognitive dysfunction: seen in some patients. Significant impairment in mental function with the development of dementia
What is the Cane criteria?
Diagnostic criteria proposed for WE. Based on the presence of ≥2 of the following criteria in patients with chronic alcoholism:
Dietary deficiency
Oculomotor abnormalities
Cerebellar dysfunction
Altered mental status or mild memory impairment
WKS investgations
No specific blood test is useful for the diagnosis of Wernicke-Korsakoff syndrome. Thiamine deficiency can be detected by performing erythrocyte thiamine transketolase activity before and after the addition of thiamine, but this test is not routinely available.
Neuroimaging (e.g. CT/MRI) is commonly performed in patients with Wernicke-Korsakoff syndrome to exclude an alternative cause of confusion. A number of typical findings can be identified on imaging in both conditions
WE complications
Permanent horizontal nystagmus
Inability to walk
Deficits in learning and memory
Korsakoff syndrome
What is seen in normal pressure hydrocephalus
Dilated ventricles disproportionate to cerebral atrophy
Common peroneal nerve lesion
Common peroneal nerve lesion can cause weakness of foot dorsiflexion and foot eversion
Weakness of ankle dorsiflexion and of the extensor hallucis longus associated with loss of sensation on the lateral aspect of the lower leg
Most common autonomic dysreflexia causes
Fecal impaction
Urinary retention
What is Brown-Sequard syndrome
Brown-Séquard syndrome is a rare spinal disorder that results from an injury to one side of the spinal cord resulting in hemisection of the cord. The damage to the corticospinal tract, spinothalamic tract and dorsal columns, results in ipsilateral upper motor neurone signs, contralateral spinothalamic signs, and ipsilateral dorsal column signs respectively.
Loss of corneal reflex
CNV1 palsy
The sensation of fine touch, proprioception and vibration are all conveyed where?
in the dorsal column
Bitemporal heminopia - where is the lesion?
lesion of optic chiasm
upper quadrant defect > lower quadrant defect = inferior chiasmal compression, commonly a pituitary tumour
lower quadrant defect > upper quadrant defect = superior chiasmal compression, commonly a craniopharyngioma
What is Hoffmans sign?
Hoffmans sign is elicited by flicking the distal phalaynx of the middle finger to cause momentary flexion.
A positive result is exaggerated flexion of the terminal phalanyx of the thumb
UMN sign
Horner’s syndrome - anhydrosis determines site of lesion:
head, arm, trunk = central lesion: stroke, syringomyelia
just face = pre-ganglionic lesion: Pancoast’s, cervical rib
absent = post-ganglionic lesion: carotid artery
