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
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
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
