Miscellaneous

Question 1

Presentation of myasthenia gravis

Answer 1

-Fatigability (muscles become progressively weaker during periods of activity and slowly improve after periods of rest)
-Extraocular muscle weakness (diplopia)
-Proximal muscle weakness (face, neck, limb girdle)
-Ptosis
-Dysphagia
-More common in women (2:1)

Question 2

What is myasthenia gravis associated with?

Answer 2

-Thymoma
-Autoimmune (pernicious anaemia, thyroid, rheumatoid, SLE)
-Thymic hyperplasia

Question 3

Investigation of myasthenia gravis

Answer 3

-Single fibre electromyography (high sensitivity)
-CT thorax to exclude thymoma
-CK normal
-Antibodies to acetylcholine receptors positive in around 85-90% of patients
-40% are positive for anti-muscle-specific tyrosine kinase antibodies.

Question 4

Management of myasthenia gravis

Answer 4

-Long-acting acetylcholinesterase inhibitors: pyridostigmine is first-line
-Immunosuppression is usually not started at diagnosis, but the majority of patients eventually require it in addition to long-acting acetylcholinesterase inhibitors: prednisolone initially, azathioprine, cyclosporine, mycophenolate mofetil may also be used
-Thymectomy.
-Myasthenic crisis: plasmapheresis, IV immunoglobulins.
-Exacerbated by beta-blockers, lithium, phenytoin, antibiotics.

Question 5

Risk factors for benign intracranial hypertension

Answer 5

-Obesity
-Female sex
-Pregnancy
-Drugs (combined oral contraceptive pill, steroids, tetracyclines, retinoids/ vit A, lithium)

Question 6

Presentation of benign intracranial hypertension

Answer 6

-Headache
-Blurred vision
-Visual loss
-Diplopia
-Transient visual obscurations
-Enlarged blind spot
-Neck and back pain
-Sixth nerve palsy
-Pulse-synchronous tinnitus

Question 7

Investigation in benign intracranial hypertension

Answer 7

-Visual field testing
-Fundoscopy: papilledema, visual acuity
-MRI (transverse sinus stenosis, exclude secondary causes)
-Lumbar puncture (elevated opening pressures)

Question 8

Management of benign intracranial hypertension

Answer 8

-Weight loss
-Diuretics e.g., acetazolamide/ topiramate
-Repeated lumbar puncture may be used as a temporary measure but is not suitable for longer-term management
-Surgery: optic nerve sheath decompression and fenestration may be needed to prevent damage to the optic nerve.
-A lumboperitoneal or ventriculoperitoneal shunt may also be performed to reduce intracranial pressure.

Question 9

Diagnosis of benign essential tremor

Answer 9

-Bilateral postural tremor worse if arms outstretched
-Improved by alcohol and rest
-Most common cause of titubation (head tremor)
-Problems with fine motor tasks

Question 10

Management of benign essential tremor

Answer 10

-Propranolol
-Primidone sometimes used
-Deep brain stimulation