Symptom Scenario: Tingling Tom Gamble and Jo Swallow 20/11/13

Common Mononeuropathies Describe the presentation and causes of the following: Median nerve (carpal tunnel syndrome) Ulnar nerve Radial nerve Sciatic nerve Lateral cutaneous nerve Common peroneal nerve Tibial nerve Bell’s Palsy Ramsay Hunt

Split into pairs and discuss/research a mononeuropathy

Radial nerve The radial nerve may be damaged anywhere in its course. It is most commonly affected in the upper arm where it winds round the humerus Finger and wrist drop are common, their severity depending upon the site of the lesion. sensory loss on the dorsum of hand and forearm appropriate to the cutaneous distribution - see radial nerve anatomy

Common peroneal nerve terminal of the sciatic nerve, providing motor supply to the muscles of the anterior and lateral leg. most commonly damaged nerve in the lower limb and traverses the lateral aspect of the head of the fibula. foot drop weakness of dorsiflexion and eversion of the foot weakness of extensor hallucis longus inversion and plantar flexion are normal anaesthesia over the lower lateral part of the leg and dorsum of the foot; often with little or no sensory loss all reflexes are intact - the ankle jerk is lost in a sciatic nerve lesion

entrapment of the lateral cutaneous nerve of the thigh is named meralgia paraesthetica Damage to the tibial nerve is uncommon. Most usually, there is paralysis of gastrocnemius which is easily tested by asking the patient to stand on tiptoe

Ramsay hunt The Ramsay Hunt Syndrome is characterised by sensorineural deafness, vertigo and facial paralysis following Herpes Zoster infection. The patient is usually elderly. ?Treatment otalgia - pain in the ear and the mastoid region - often with few signs on examination a vesicular eruption involving the external ear facial paralysis, deafness and vertigo ipsilateral loss of taste in the anterior two-thirds of tongue

Mononeuritis multiplex is a condition which is characterised by multiple individual nerve palsies, for example an ulnar nerve palsy in one arm, a radial nerve palsy in the other arm, and an asymmetrical foot drop due to a lateral popliteal nerve lesion.

Causes of polyneuropathy: Metabolic: Diabetes; renal failure; hypothyroidism; hypoglycaemia; mitochondrial disorders Inflammatory: Guilain Barre; sarcoid Vasculitis: PAN; Rheumatoid arthritis; Wegener’s Malignancy Infection: Lyme disease; HIV; syphilis; leprosy Vitamin deficiency (Vit B1,6,12 – alcoholism) Drugs: alcohol; isoniazid; nitrofurantoin; phenytoin Inherited porphyria; Charcot Marie Tooth

Blood Tests for Polyneuropathy Glucose; FBC; U&E; B12, TFTs +/- LFTs, autoimmune profile,syphilis serology

Polyneuropathy ?Motor – eg guillain – barre ?sensory Painful – eg diabetic, alcoholic, B12 defic Other, demyelenation, axonal

Guillain-Barre Guillain-Barre syndrome is an acute, inflammatory, postinfectious polyneuropathy. A prodromal malaise with vomiting, headache, fever and limb pains is rapidly surmounted by a progressive and ascending paralysis. This can lead to respiratory dysfunction, and as such, the acute presentation can be a neurological emergency. The incidence is 2 per 100 000 per year. Usually within 3 wks of a viral illness Muscle weakness evolves over 3-21 days. It may be generalised, proximal in distribution, or commence distally and ascend

Treatment for Guillain-Barre syndrome is supportive Treatment for Guillain-Barre syndrome is supportive. Early tracheostomy is indicated if there is progressive bulbar and respiratory weakness Specific treatment for Guillain-Barre syndrome consists of high-dose intravenous immunoglobulin (IvIg) or plasma exchange

Myasthenia Gravis Myasthenia gravis is an acquired autoimmune disorder characterised by weakness, typically of the periocular, facial, bulbar, and girdle muscles. serum IgG antibodies to acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction. Classically, the muscles are easily fatigued. It affects 5 people in every 100 000 external ocular muscles - affected in over 90% of cases, and are the muscles first affected in 65% of cases; diplopia or ptosis, often asymmetrical, are typical lower limbs are rarely affected

Management of myasthenia gravis oral anticholinesterase medication, e.g. pyridostigmine or neostigmine thymectomy - required if there is a thymoma because of the risk of local infiltration immunosuppression with corticosteroids +/- cytotoxic agents is also highly effective in inducing remission of disease