A 60-year-old patient attended the emergency department because, according to the family, on waking up after 15 hours of sleep, he presented a picture of disorientation, difficulty in articulating language, with preserved speech and comprehension, blurred vision and vertical double vision. He had no loss of consciousness, palpitations, chest pain or fever.
The patient's medical history included being an ex-smoker for 15 years, hypertensive on treatment with enalapril and dyslipidaemic on treatment with simvastatin.
Examination revealed paresis of the fourth cranial nerve of the right eye, as well as incomplete involvement of the third bilateral nerve and the sixth right nerve, predominantly inferior, manifested in the form of vertical binocular diplopia. The rest of the cranial nerves were normal. There was no evidence of associated motor or sensory deficits, negative Romberg, no dysmetria and no meningeal signs. There was evidence of gait disturbance with a tendency to lateropulsion to the right.
In addition to the basic emergency protocol, haemogram, biochemistry, coagulation study, simple chest X-ray and electrocardiogram, which were normal, a 64-channel cranial computerised tomography (CT) scan was performed prior to admission to the Neurology Department, which was reported as a scan with no apparent pathological findings.

During admission, diplopia persisted, which was corrected with alternating monocular occlusion, and instability and gait disturbance persisted.
On the third day of admission, an encephalic MRI study was completed with Philips 1.5 T MRI, with the result of solitary microinfarcts in the deep white matter, as well as acute ischaemic lesions of paramedial location in both thalami and anterior midbrain, compatible with obstruction of Percheron's artery3. Flair sequences and the use of diffusion are particularly useful for observing these lesions.

The case was referred to the cardiology department and, given the embolic origin of the symptoms, it was decided to start oral anticogulation with Dabigatran due to the high risk of recurrence. The patient's evolution was favourable and, with rehabilitation treatment, gait autonomy was achieved, with progressive improvement in diplopia.

