A 42-year-old woman with a history of myasthenia gravis is admitted to the Emergency Department. She is currently taking pyridostigmine but there has been a significant worsening of her symptoms following antibiotic treatment for a chest infection. On examination she is dyspnoeic and cyanotic with quiet breath sounds in both lungs.
Other than respiratory support, what are the two treatments of choice?
Correct Answer E: This patient is having a myasthenic crisis. Opinions vary as to whether plasmapheresis or intravenous immunoglobulins should be given first-line. Plasmapheresis usually works quicker but involves more expensive equipment.
Myasthenia gravis:
Myasthenia gravis is an autoimmune disorder resulting in insufficient functioning acetylcholine receptors. Antibodies to acetylcholine receptors are seen in 90% of cases*. Myasthenia is more common in women (2:1).
The key feature is muscle fatigability - muscles become progressively weaker during periods of activity and slowly improve after periods of rest:
Associations:
Investigations:
Management:
Management of myasthenic crisis:
*Antibodies are less commonly seen in disease limited to the ocular muscles.
Which one of the following anti-epileptic drugs is most likely to cause visual field defects?
Correct Answer D: V for Vigabatrin - V for Visual field defects.
Vigabatrin
Key points:
A 55-year-old man presents complaining of visual disturbance. Examination reveals a right congruous homonymous hemianopia with macula sparing.
Where is the lesion most likely to be?
Correct Answer D:
Visual field defects:
The main points for the exam are:
A congruous defect simply means complete or symmetrical visual field loss and conversely an incongruous defect is incomplete or asymmetric. Please see the link for an excellent diagram.
Homonymous hemianopia:
Homonymous quadrantanopias*:
Bitemporal hemianopia:
*This is very much the 'exam answer'. Actual studies suggest that the majority of quadrantanopias are caused by occipital lobe lesions. Please see the following link for more details: http://www.ncbi.nlm.nih.gov/pubmed/9109741
A 65-year-old female is admitted with a right hemiparesis. Examination reveals she is in atrial fibrillation. CT confirms an ischaemic stroke and aspirin 300mg is commenced.
If the patient is well and develops no new problems at what point should warfarin be started?
Correct Answer A: The 2004 RCP guidelines recommend that anti-coagulation should be commenced 14 days after an ischaemic stroke. Earlier anti-coagulation may exacerbate any secondary haemorrhage.
Stroke: management:
The Royal College of Physicians (RCP) published guidelines on the diagnosis and management of patients following a stroke in 2004. NICE also issued stroke guidelines in 2008, although they modified their guidance with respect to antiplatelet therapy in 2010.
Selected points relating to the management of acute stroke include:
Thrombolysis:
Thrombolysis should only be given if:
NICE also published a technology appraisal in 2010 on the use of clopidogrel and dipyridamole.
Recommendations from NICE include:
With regards to carotid artery endarterectomy:
*the 2009 Controlling hypertension and hypotension immediately post-stroke (CHHIPS) trial may change thinking on this but guidelines have yet to change to reflect this
**SIGN recommend a window of 4.5 hours
***European Carotid Surgery Trialists' Collaborative Group
****North American Symptomatic Carotid Endarterectomy Trial
Which one of the following statements regarding restless legs syndrome is incorrect?
Correct Answer E: Males and females are thought to be equally affected, with only one study showing a slightly increased incidence in females.
Restless legs syndrome:
Restless legs syndrome (RLS) is a syndrome of spontaneous, continuous lower limb movements that may be associated with paraesthesia. It is extremely common, affecting between 2-10% of the general population. Males and females are equally affected and a family history may be present.
Clinical features:
Causes and associations:
The diagnosis is clinical although bloods to exclude iron deficiency anaemia may be appropriate.
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