Question 15

a) List six clinical features associated with myotonic dystrophy. (30% marks)

b) List five clinical signs of severity in chronic aortic regurgitation. (25% marks)

c) List three causes of coma with bilateral miosis. (15% marks)

d) List six clinical features of lateral medullary syndrome. (30% marks)

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College answer

Not available.

Discussion

a) Question 30.1 from the first paper of 2017 also asked for six clinical features of myotonic dystrophy. Fourtunately, there's plenty to choose from:

Neuromuscular phenomena

Myotonic facies
Wasting of facial muscles, sternocleidomastoids, muscles of distal extremities
Ptosis
Myotonic spasms (e.g. delay in opening fingers after making a fist)
"Warm up phenomenon" - grip strength increases with repeated contractions
Slurred speech (pharyngeal myotonia)
Percussion myotonia
Absent reflexes

Other features

Frontal baldness
Cardiomyopathy
Cardiac conduction defects
Cataracts / lenticular opacities
Testicular atrophy
Intellectual impairment
Insulin insensitivity

One might expect that features suggestive of severity in chronic AR would be mainly features related to the effect of AR on cardiac function, not just generic features of AR

LV dilatation (displaced apex, diffuse hyperdynamic impulse)
Congestive cardiac failure (low blood pressure, peripheral oedema)
Poor exercise tolerance
Signs of widened pulse pressure (see below)
An S3, suggestive of poor LV function

Generic features of AR are as follows:

Chacteristic auscultatory findings:
- Soft S1
- Soft A2
- An S3 if LV function is severely depressed
- A systolic ejection sound due to abrupt aortic distension
Signs of widened pulse pressure:
- Corrigans sign
- de Musset's sign
- Quincke's sign
- Duroziez's sign
- Traube's sign
- Mueller's sign
- Becker's sign
- Hill's sign
- Mayne's sign
- Rosenbach's sign
- Gerhard's sign

From the wording of the question, it is not clear that the trainees were expected to know what these signs were; i.e. to list the eponyms would have been enough to pass. Their meaning is discussed elsewhere, in case anybody is interested

c) Bilateral miosis with coma:

Bilateral pontine lesions
Bilateral thalamic lesions
Metabolic encephalopathy
Cholinergic drugs
- Organophosphates
- Myasthenia gravis drugs (the 'stigmines, eg. pyridostigmine)
- Alzheimers nootropics (the 'pezils, eg. donepezil)
- Sarin gas
Non-cholinergic drugs:
- Opiates
- Barbiturates
- GHB
- Clonidine
- GHB
- Chloral hydrate
- Valproate
- Atypical antipsychotics
- Phenothiazines

d) The latery medullural syndrome (Wallenberg syndrome) consists of the following classical findings:

On the side of the lesion:
- Facial sensory loss
- Nystagmus
- Horner's syndrome
- Loss of gag reflex
- Ipsilateral ataxia with a tendency to fall to the ipsilateral side
On the contralateral side:
- Pain and temperature sensory loss in the extremities
Generally:
- Vertigo
- Nausea
- Dysphagia

References

Mudge, Barbara J., Peter B. Taylor, and Abraham FL Vanderspek. "Perioperative hazards in myotonic dystrophy." Anaesthesia 35.5 (1980): 492-495.

Turner, Chris, and David Hilton-Jones. "The myotonic dystrophies: diagnosis and management." Journal of Neurology, Neurosurgery & Psychiatry 81.4 (2010): 358-367.

Sato, Hiromasa, Kosuke Naito, and Takao Hashimoto. "Acute isolated bilateral mydriasis: case reports and review of the literature." Case reports in neurology 6.1 (2014): 74-77.

Thomas, P. D. "The differential diagnosis of fixed dilated pupils: a case report and review." Critical Care and Resuscitation 2.1 (2000): 34.

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