Functional Neurological Disorders Flashcards
Symptoms indicating damage of a large fibre motor nerve?
- Weakness, unsteadiness, wasting.
Damage of a large fibre motor nerve will have what effect on power?
Reduced power.
Damage of a large fibre motor nerve will have what effect on sensation?
None - normal sensation.
Damage of a large fibre motor nerve will have what effect on reflexes?
Absent reflexes.
Symptoms indicating damage of a large fibre sensory nerve?
- Numbness.
- Paraesthesia.
- Unsteadiness.
Damage of a large fibre sensory nerve will have what effect on power?
No effect - normal power.
Damage of a large fibre sensory nerve will have what effect on sensation?
Reduction in sensation of vibration and joint position sense.
Damage of a large fibre sensory nerve will have what effect on reflexes?
Absent reflexes.
Symptoms indicating damage of a small fibre nerve?
- Pain.
- Dysethesia.
What is dyesthesia?
Abnormal unpleasant sensation upon being touched, due to damage to peripheral/ small fibre nerves.
Damage of small fibres nerves will have what effect on power?
None - normal power.
Damage of small fibres nerves will have what effect on sensation?
- Reduced sensation of both pin prick and temperature.
Damage of autonomic nerves will have what effect on power?
None - normal power.
Damage of autonomic nerves will produce what symptoms?
- Dizziness (postural hypotension).
- Impotence.
- Nausea and vomiting (gastroparesis).
Damage of autonomic nerves will have what effect on sensation?
None - normal sensation.
Damage of autonomic nerves will have what effect on reflexes?
Reflexes will be present.
Myelinated sensory fibres are responsible for which sensation?
- Touch.
- Vibration.
- Joint position perception.
Thinly myelinated sensory fibres are responsible for which sensation?
- Cold perception.
- Pain.
Unmyelinated sensory fibres are responsible for which sensation?
- Warmth perception.
- Pain.
Thinly myelinated and un-myelinated autonomic fibres are responsible for which functions?
- Heart rate.
- BP.
- Sweating.
- GI tract.
- GU tract.
What is pseudoathetosis?
Abnormal writhing movement - usually of fingers.
https://www.youtube.com/watch?v=g3JTZObWGFA
What causes pseudoathetosis?
Failure of joint position perception (proprioception).
What does pseudoathetosis indicate?
Disruption of proprioceptive pathway from nerve to parietal cortex.
High stepping gait implies what?
Foot drop due to weakness of ankle dorsiflexion.
https://www.youtube.com/watch?v=5T3eHpP6-lM
Differentials of high stepping gait?
- Common peroneal palsy (normal ankle inversion).
- L5 root lesion (weak ankle inversion).
- Motor neuropathies (often bilateral).
What is mononeuritis?
Inflammation of a single nerve/ nerve group e.g. carpal tunnel syndrome.
What is mononeuritis multiplex?
Peripheral nerve disorders of distinctive progressive motor and sensory deficits in distribution of specific peripheral nerves.
What is radiculopathy?
Nerve compression in the spinal column resulting in pain, weakness, numbness and tingling of specific areas.
What is a plexopathy?
Inflammation/damage of nerve plexus resulting in pain, loss of motor control and sensory deficit.
Typically affects lumbosacral or brachial plexus.
How are nerves damages?
- Axonal loss.
- Peripheral nerve demyelination.
What investigation can help to identify a demyelinating neuropathy?
Nerve conduction study.
Give an example of a demyelinating neuropathy.
- Guillain-Barre syndrome.
- Acute inflammatory demyelinating polyneuropathy.
- Chronic inflammatory demyelinating polyradiculopathy.
- Hereditary sensory motor neuropathy. (Charcot-Marie-Tooth disease).
Acute cause (days to weeks) of demyelinating neuropathy?
- Guillain-Barre syndrome.
- Acute inflammatory demyelinating polyradiculoneuropathy.
Chronic cause (months to years) of demyelinating neuropathy?
- Chronic inflammatory demyelinating polyradiculopathy.
- Hereditary sensory motor neuropathy. (Charcot-Marie-Tooth disease).
Symptoms of Guillain-Barre syndrome?
- Progressive paraplegia over days to 4 weeks.
- Sensory symptoms proceed weakness.
- Pain is common.
- Symptoms peak at 10-14 days.
- Examination may be normal in early illness.
- Possible post infectious ass. e.g. Campylobacter.
Complications of Guillain-Barre syndrome?
- 25% require mechanical ventilation.
- 10% die mainly from autonomic failure (cardiac arrhythmia).
Management of Guillain-Barre syndrome?
- Immunoglobulin infusion.
- Plasma exchange.
- Minimal role for steroids.
Variants of hereditary neuropathies?
- Pure motor.
- Pure sensory.
- Sensorimotor.
- Small fibre (congenital insensitivity to pain syndrome).
- Autonomic.
- Demyelinating or axonal.
How can the most common mutations leading to hereditary neuropathies be diagnosed?
Genetic testing e.g. CMT1a.
What is the other name for HMSN type 1?
Charcot-Marie-Tooth syndrome.
Hereditary motor and sensory neuropathy type 1
Symptoms suggestive of HMSN type 1?
Symptom onset typically in childhood or young adulthood.
- Weakness and atrophy in lower legs in adolescence and later weakness in hands.
- Fatigue, pain, lack of balance/ feeling/ reflexes/ sight and hearing which result from muscle atrophy.
What is HMSN type 1?
Neuropathies characterised by atypical neural development and degradation of neural tissue.
What causes axonal neuropathies?
- Idiopathic.
- Vasculitis.
- Paraneoplastic.
- Infection.
- Drugs/toxins.
- Metabolic.
What are the vasculitic causes of axonal neuropathies?
- ANCA +ve.
- Rheumatoid arthritis/ Sjogrens syndrome (ANA/ENA +ve).
What paraneoplastic syndromes are associated with axonal neuropathies?
- Myeloma.
- Antibody mediated e.g. breast cancer, SCLC anti-hu/yo.
What infections are associated with axonal neuropathies?
- HIV.
- Syphilis.
- Lyme.
- Hepatitis B/C (cryoglobulin mediated).
What drugs/toxins are associated with axonal neuropathies?
- Alcohol.
- Amiodarone.
- Phenytoin.
- Chemotherapy (cisplatin/vincristine).
What metabolic syndromes are associated with axonal neuropathies?
- Diabetes.
- B12/ folate deficiencies.
- Hypothyroidism.
- Chronic uraemia.
- Porphyria.
Chronic causes of autonomic neuropathies?
- Diabetes i.e. gastroparesis.
- Amyloidosis.
- Hereditary.
Acute causes of autonomic neuropathies?
- Guillain-Barre syndrome.
- Porphyria.
Management of axonal peripheral neuropathies?
- Treat cause e.g. clear Hep. C.
- Treat symptoms: physio, orthotics, neuropathic pain relief.
- If vasculitic: pulsed IV methylprednisolone + cyclophosphamide.
Management of axonal peripheral neuropathies due to vasculitic causes?
- Pulsed IV methylprednisolone + cyclophosphamide.
Management of demyelinating (inflammatory) peripheral neuropathies?
- IV immunoglobulin.
- Steroids.
- Azathioprine, mycophenalate, cyclophosphamide.
- 70 y/o right handed carpenter.
- 6 week history of pins + needles in inner aspect of right hand. Ass. difficulty with holding cutlery.
- Painless.
- Power: 4 - first dorsal interosseus (FDI) and abductor digiti minimi (ADM).
- Normal reflexes.
- Reduced pin prick, temperature and vibration sense in medial 1 1/2 digits.
Which nerves are damaged?
- Large and small fibre motor.
- Sensory.
- 70 y/o right handed carpenter.
- 6 week history of pins + needles in inner aspect of right hand. Ass. difficulty with holding cutlery.
- Painless.
- Power: 4 - first dorsal interosseus (FDI) and abductor digiti minimi (ADM).
- Normal reflexes.
- Reduced pin prick, temperature and vibration sense in medial 1 1/2 digits.
Where is the nerve damage?
Ulnar territory.
62 y/o retired journalist.
- Painful paraesthesia and “burning” sensation in lower limbs for 4/52.
- Reduced grip strength in right hand.
O/E:
- Left abductor pollicis 4/5.
- Left leg dorsiflexion 4/5.
- Reduced pinprick sensation over left L5.
- Absent left ankle reflex.
Which nerves are damaged?
- Large and small fibre motor.
- Sensory.
62 y/o retired journalist.
- Painful paraesthesia and “burning” sensation in lower limbs for 4/52.
- Reduced grip strength in right hand.
O/E:
- Left abductor pollicis 4/5.
- Left leg dorsiflexion 4/5.
- Reduced pinprick sensation over left L5.
- Absent left ankle reflex.
Where is the nerve damage?
- Right median nerve.
- Left common peroneal nerve.
62 y/o retired journalist.
- Painful paraesthesia and “burning” sensation in lower limbs for 4/52.
- Reduced grip strength in right hand.
O/E:
- Left abductor pollicis 4/5.
- Left leg dorsiflexion 4/5.
- Reduced pinprick sensation over left L5.
- Absent left ankle reflex.
NCS demonstrates axonal picture, how are the nerves damaged?
Mononeuritis multiplex.
62 y/o retired journalist.
- Painful paraesthesia and “burning” sensation in lower limbs for 4/52.
- Reduced grip strength in right hand.
O/E:
- Left abductor pollicis 4/5.
- Left leg dorsiflexion 4/5.
- Reduced pinprick sensation over left L5.
- Absent left ankle reflex.
Nerves are damaged due to ANCA +ve mpo titre of 15iu/L.
How can nerve damage be stopped?
Pulsed steroids +/- cyclophosphamide.
24 y/o female.
- 7/7 abdominal pain admitted under surgeons for normal laparoscopic exam.
- 4/7 history of pins and needles in all four limbs + unsteadiness and requiring assistance of 2 to walk.
PMHx: Carseview admission aged 19 with acute psychosis.
O/E:
- Ataxic gait, absent reflexes throughout.
- 4/5 flexors,
- Sensory loss: patchy pin-prick and temperature, absent vibration sense and reduced joint position sense.
- BP: significant postural drop.
What nerves are damaged?
- Large fibre motor and sensory.
24 y/o female.
- 7/7 abdominal pain admitted under surgeons for normal laparoscopic exam.
- 4/7 history of pins and needles in all four limbs + unsteadiness and requiring assistance of 2 to walk.
PMHx: Carseview admission aged 19 with acute psychosis.
O/E:
- Ataxic gait, absent reflexes throughout.
- 4/5 flexors,
- Sensory loss: patchy pin-prick and temperature, absent vibration sense and reduced joint position sense.
- BP: significant postural drop.
What is the manner of nerve damage?
Length dependent.
24 y/o female.
- 7/7 abdominal pain admitted under surgeons for normal laparoscopic exam.
- 4/7 history of pins and needles in all four limbs + unsteadiness and requiring assistance of 2 to walk.
PMHx: Carseview admission aged 19 with acute psychosis.
O/E:
- Ataxic gait, absent reflexes throughout.
- 4/5 flexors,
- Sensory loss: patchy pin-prick and temperature, absent vibration sense and reduced joint position sense.
- BP: significant postural drop.
NCS demonstrates axonal picture.
Why are the nerves damaged?
Acute porphyria.
