Clinical lectures Week 9 Flashcards
How do motor neuron problems first present?
with a weakness of something
What are the 6 pathologies that can cause muscle weakness?
- UMN - stroke, tumour
- LMN - MND, root damage, peripheral neuropathy, single nerve damage
- Neuromuscular junction - myasthenia
- Muscle fibre - myopathy
- Non-specific - systemic illness
- Functional - poor effort, pain, hysteria
In UMN weakness, what happens to:
- Tone
- Reflexes
- Plantars
- Tone increased –> muscles more stiff
- Reflexes increase / brisk
- Plantars increase
In LMN weakness, what happens to:
- Tone
- Reflexes
- Plantars
- Decrease - muscles more flaccid
- Reflexes decrease (will be absent or depressed)
- Plantars decrease
What are some causes of UMN disorders?
stroke, infection, tumour, degeneration
What are the clinical findings in UMN disorders?
weakness
mild atrophy of muscles
brisk reflexes
upgoing plantars
What are the clinical findings in LMN disorders?
weakness
mild atrophy of muscles
depressed or absent reflexes
down going plantars
What are the two types of LMN lesions?
- Axonal loss (if its affecting axons)
2. Demyelination (if its affecting myelin sheath)
What are the clinical features of myopathy? (disease of muscle)
- progressive weakness (rapid or slow), usually proximal normal sensation
- normal reflexes
- normal tone
- moderate wasting
What are the causes of myopathy?
- congenital
- inherited
- metabolic
- toxic
- mitochondrial
- acquired
What is myasthesia gravis a disorder of?
neuromuscular junction
What are the clinical features of myasthesia gravis?
- weakness
- fatigability
- worse as the days go bye –> symptoms are transient
- normal sensation as its an NMJ disorder
- can see problems with speech and swallowing
What are repetitive nerve stimulation studies?
we stimulate motor nerves to see the action potentials and see if they look similar
How can nerve pathologies be divided?
into focal and generalised
Give an example of a focal nerve pathology
Carpal Tunnel syndrome:
- focal median neuropathy at the wrist
- median nerve is compressed at the wrist, resulting in numbness or pain
What are the symptoms of peripheral neuropathy?
- numbness (especially in arms and legs)
- stabbing pain
- burning pain
- sensitivity to touch
- co ordination difficulties
- muscle weakness
- bladder/bowel problems
What is the most common cause of polyneuropathy?
diabetes
What is radiculopathy?
- pinching of nerve at spinal cord level
- will feel sensory and motor symptoms at distributions of specific nerve roots
What is motor neuron disease?
- disease of motor neurones (UMN & LMN)
- idiopathic, progressive motor deficit
- median survival 3-5 years
What are the clinical features of MND?
- painless
- progressive bulbar palsy - weakness in the tongue, face and palate
- dysphasia, dysarthria, nasal regurgitation and aspiration
- progressive muscle weakness
What is electromyography?
fine needle is inserted into a bicep muscle and we record from motor units in the muscle –> this activity is known as motor unit action potentials and is seen when a patient starts contracting
-for LMN function analysis
What is a motor unit?
the number of muscle fibres which are supplied by a single motor neurone
What will you see on an electromyography in a patient with denervated muscle?
- reduced interference pattern
- high amplification but more gaps between MUAP
What will you see on an electromyography in a patient with myopathy?
- full interference pattern
- MUAP are small (low amplification)
What is the presentation of an intracranial tumour?
- raised ICP
- epilepsy
- neurological dysfunction
- incidental
What is the presentation of raised intracranial pressure?
- headaches (early morning)
- vomiting
- blurred vision
What are the causes of raised ICP?
- tumour mass
- surrounding oedema
- obstructive hydrocephalus
What is MRS?
- Magnetic resonance spectrometry
- can be used to look at tumours and see what chemical signals might give you an idea of the type of tumour
What are the main categories of brain tumours?
- Glial tumours
- high grade glioma
- low grade glioma - Benign tumours
- meningiomas
- pituitary adenomas
- schwannomas - Paediatric
- medulloblastoma
- germ cell
- ependymoma
What does the tumour grade tell us?
How aggressive the tumour is –> mitotic rates, proliferative, differentiation
How do brain tumours present?
- pressure symptoms (headache, N&V, confusion, reduced concious level)
- seizures
- focal symptoms due to location e.g weakness, dysphasia
What is expressive aphasia?
can understand but can’t speak
lesion in brocas area
What is receptive aphasia?
can’t understand language spoken to you
What are the side effects of taking steroids in high doses?
insomnia weight gain high BP hyperglycaemia irritability osteoporosis
What are the acute, intermediate and late effects of cranial radiotherapy?
- Acute effects
- cerebral oedema causing raised ICP
- hair loss
- scalp/ear erythema - Intermediate effects
- severe tiredness and exacerbation of exisitive neurological symptoms - Late effects
- damage to sensitive structures e.g lens (cataracts), pituitary (hypopituitarism) and cerebral hemispheres (memory loss)
What is the commonest brain tumour?
brain metastases
What are the 5 types of tumour of the nervous tissue?
- Glial (glioma)
- Meningeal (meningioma)
- Neuronal (gangliocytoma)
- Primitive (PNET)
- Nerve sheath (schwannoma)
What are the 3 types of gliomas?
- Astrocytoma
- Oligodendroglioma
- Ependymoma
What are the WHO grades of brain tumours
I: Benign, no recurrence, no/very slow progression
II: low grade, progressive
III: high grade, rapid progression
IV: aggressive
