Neuropathies

Question 1

Lower back pain

Answer 1

Although common, take full Hx and O/E

Question 2

What are the tendon reflex nerve roots?

Answer 2

Biceps- C5/6
Suprinator- C6
Triceps- C7
Fingers- C8

Knee L3/4
Ankle- S1/2

Question 3

Peripheral neuropathy

Answer 3

O/E
Inspection- thenar + hypothenar eminences
Pes cavus? Muscle wasting or fasciculations?
Neuropathic ulcers or deformed joints? Charcots joints

Tone- normal or ⬇️
Power- if motor or sensorimotor- weakness distal usually
Reflexes- ⬇️ or absent
Sensation- pin prick, vibration, proprioception check.

Inv- 1.Bloods-> FBC( macrocytosis), U+Es, ESR, B12, folate, glucoses, VDRL, ANCA, ANA, ENA, Rheumatoid factor, plasma electrophoresis.

2. Nerve conduction studies- demyelination or axonal?
3. LP to look for ⬆️ protein(GBS) (CIDP)
4. Possible nerve biopsy if vasculitis suspected or diff dx.

DDx
Metabolic- B12/folate def, diabetes, uraemia
Inflammatory- Guillan Barre(GBS) , chronic inflammatory demyelinating polyneuropathy( CIDP)
Toxic- alcohol, lead, mercury
Vascular- vasculitis
Drugs- phenytoin, Vincristine, vinblastine
Inherited- Charcot-Marie-Tooth, Friedricks ataxia
Neoplastic-paraprotein asssc
Infective- syphillis
Idiopathic

Question 4

What are demyelinating neuropathies?

Answer 4

Slowing velocities on nerve conduction- due to myelin loss
If onset acute/subacute-GBS common
CIDP- is a chronic form of GBS- treatable w/ steroids + IV immuniglobulin.

Question 5

What are axial neuropathies?

Answer 5

Show loss of amplitude on nerve conduction studies- preserved velocities because of loss of axons.

B12 def + vasculitis are aquired axonal neuropathies.
Because axons do not regrow, unlike myelin sheaths, they do not improve w/ tx.

Question 6

What cases give mainly a sensory neuropathy?

Answer 6

Diabetes
B12
Alcohol

Question 7

What causes give main,y motor neuropathies?

Answer 7

Lead

Inflammatory neuropathies

Question 8

What are the red flags for cauda equina syndrome?

Answer 8

Bilateral or unilateral sciatica
Bladder or bowel dysfx
Saddle anaesthesia or paresthesia in perianal region/ buttocks
Gait disturbance
Sexyal dysfx

Refer pt urgently if these apparent.

Question 9

Whats Horners syndrome?

Answer 9

Caused by damage to sympathetic NS (oculosympathetic palsy)

Obsereve: ptosis, acuity + fields normal. 
Pupils small (miosis) but reacts to light and accomodation

Movements: nystagmus if brainstem disease
Fundi- normal
Extras: Eyes- heterochromia of iris- less pigmented affected eye
Neck: lymphadenopathy, carotid aneurysm, scars, ipsilateral carotid bruit (dissection)
Lungs: Apical Pancoasy tumour- T1 muscle wasting + sensory loss

Brainstem: CVA, MS, syringomyelia, look for nystagmus, bulbar palsy, sensory loss.

Idiopathic in young women.

Question 10

What are the anatomical courses of the sympathetic supply to the pupil?

Answer 10

Midbrain->Medulla-> T1 cord-> T1 root-> thoracic DRG-> ascending preganglionic fibers-> carotid plexus-> long ciliary nerve-> short ciliary nerve-> radial pupillodikator muscle/ Muller m

Question 11

What is the classical triad for Horners syndrome?

Answer 11

Ptosis, Miosis, Anhidrosis.

The little Jack Horner for a small pupil with a sunken eye.