What is the most likely diagnosis?

Q. What is Iain’s most likely diagnosis? Select true or false for each of the options listed below.

A hypoglycaemic attack – False – although hypoglycaemia could cause these symptoms he is not on any medication likely to cause a low blood sugar.

Migraine with a neurological aura – False – this is unlikely because he does not have a past history of migraine, there was no headache, nausea, or flashing lights in his vision. It is unusual to develop migraine at this age.

A Transient Ischaemic Attack (TIA) affecting the brainstem (i.e a posterior circulation TIA) – False – isolated weakness of the hand or arm is more likely to be due to dysfunction in the cerebral hemisphere. It may turn out to be a TIA but his symptoms have not yet resolved.

An ischaemic stroke affecting the right cerebral hemisphere – True – isolated weakness of a left hand or arm is most likely to indicate a right hemisphere problem affecting the motor cortex.

A brain haemorrhage – False – this is possible but less likely than an ischaemic stroke. However, as the symptoms are persisting this will need to be excluded with a brain scan.

A trapped nerve in the neck – False – one would often get pain with a root lesion and it is unlikely to come on like this. A radial nerve palsy can cause a “wrist drop” which may mimic a stroke but there is usually a story which might suggest trauma to the nerve e.g. sleeping in a chair or trauma to the upper arm.