A male patient (HJ, aged 75 in May 2012) was undertaking some DIY work at the front of the house while his wife left for her French class. She was away from 4pm and returned at 7pm to find blood stains in the hallway caused by her husband having suffered a broken nose. He remembered going outdoors, leaning against the ladder and feeling ‘peculiar’. He then remembered falling and losing consciousness. The fall had scratched his face. By the time his wife had arrived he had regained consciousness and had even told his wife that he ‘must have had a stroke.’ She immediately rang the ambulance service.
Hospital
Before this episode the patient had had a history of low grade systemic hypertension controlled by diet and exercise, and no medication had been prescribed by his general practitioner. It appeared that he had lost consciousness on a few occasions that afternoon prior to his fall. His breathing had been normal throughout. He was transferred immediately to hospital and a CT scan (Figure 1) revealed a pontine haemorrhage and this scan was sent to Royal Free Hospital where it was confirmed that no fluid was present and hence there was no need to do a drainage operation. Instead it was decided that the best solution was to monitor the patient closely in hospital.
Two days later, while still in hospital, his blood pressure increased dramatically and another scan was undertaken. This showed no change in the bleed and a second opinion from a neurologist confirmed no significant change and that the blood pressure rise represented a delayed response by the body to the original lesion.
The patient had normal swallowing initially, but a week later was showing signs of food entering the trachea (aspiration pneumonia) and the decision was taken to feed by tube (nil by mouth) and this was still continuing some four months later.
The patient was discharged from hospital three months after admission and sent to a convalescence home where physiotherapy was undertaken prior to controlled release back home. The patient reported double vision and for this he was given a patch to wear on the left eye by the ophthalmology clinic. He also had loss of sight in the left eye along with a left facial palsy. Lubricating ointment was prescribed for the left eye to manage ocular surface exposure. The patient had reported tingling in the right hand during his stay in hospital and it was deemed that he had muscle weakness in the right hand and right leg. This was not confirmed as a hemiparesis.
Optometrist involvement
This patient wanted to attend my practice to ascertain the cause of the double vision and the ‘stroke.’ Patient empathy and rapport from a trusted optometrist may be a useful help for such a patient recovering in a community setting. Patient mobility was poor but his mind was still very active and he was keen to know more about his condition. He brought with him his latest CT scans (Figure 2).
[CaptionComponent="791"]Optometrist examination
Four months after the initial stroke, an eye examination revealed:
• Vision; right eye 6/9 and N5 aided, left eye reduced to counting fingers at 20cms (although no obvious cause was detected)
• Binocular status; 20? left esotropia. This is indicative of a left lateral rectus paralysis
• Motility; left eye failed to adduct or abduct, instead remaining fixed to the centre line. Similarly, saccadic testing revealed the left eye unable to look at a target to the left, suggestive of a right internuclear ophthalmoplegia and, therefore, damage to the medial longitudinal fasciculus. This is likely to be ‘one and a half syndrome’ causing an adduction defect to the contralateral gaze and ipsilateral horizontal gaze palsy when abducting (Figure 3)
• Pupils; a left relative afferent pupillary defect
• Ophthalmoscopy; fundus appeared normal in both eyes suggesting pupil defect linked to damage to the left optic nerve following the bleed.
[CaptionComponent="792"]A left facial palsy, with defective blink reflex of the left eyelid, is linked to a defect of the 7th cranial nerve. Facial expression was absent on the left side.
Contralateral hemiparesis was noted, with his right hand showing weaker reflexes and the right leg being slow to lift and much less mobile than the left leg.
Pontine haemorrhage
10 per cent of all intracranial haemorrhages result from primary pontine haemorrhages. They are typically associated with elderly patients, notably those with a long history of poorly controlled hypertension. Haemorrhages in the pons can be secondary to a number of underlying lesions as follows:
• Vascular malformations, cerebral vascular malformations or arteriovenous malformations. Cerebral vascular haemangioma is a common type of cerebral vascular malformation presenting as a ‘mulberry-like’ cluster of dilated thin-walled capillaries which, on an MRI scan, appear as ‘popcorn’ with a rim of signal loss due to surrounding haemosiderin. They are often asymptomatic and only found incidentally, typically in 40-60 year-olds presenting with seizure or focal neurological deficit. The risk of haemorrhage is 1 per cent per year. Cerebral arteriovenous malformations are congenital malformations with a diagnosis occurring at a mean age of 31 years. They are composed of a tangle (or nidus) of vessels through which arteriovenous shunting occurs. Four per cent of the population is affected and 65 per cent of these present with haemorrhages, 20 per cent with seizures, and the rest with headaches or ischaemic episodes
• Tumours – neuroepithelial primary tumours or metastases from other malignant sites
• Downward herniation – duret haemorrhages (small bleeds within the brainstem)
• Supratentorial surgery.
Clinical presentation:
Pontine haemorrhages present with:
• Decreased level of consciousness – this is the most common feature at presentation
• Long tract signs – this results from injury to nerves that originate from the brain and travel down the spinal cord and cause tetraparesis (loss of sensation and motor control leading to total or partial paralysis of all the limbs)
• Cranial nerve palsies
• Seizures
• Cheynes-Stokes respiration – an abnormal pattern of breathing whereby there is a temporary cessation of breathing (apnoea) resulting in increased CO2 levels which causes excessive compensatory hyperventilation (heavy breathing) and, in turn, decreased CO2 so restarting the cycle.
Prognosis of pontine haemorrhages
CT scanning is usually the first, and often the only, investigation undertaken on first presentation and even small pontine haemorrhages have been detected with this technique. The prognosis of pontine haemorrhages is related to:
• Size of the haematoma
• Level of consciousness
• Extent of pupillary abnormalities.
Patients with poor prognosis present with haematomas over 20mm in size, and may become comatose within two hours of onset. They usually have dilated, pinpoint or anisocoric pupils.
Better prognosis is associated with alertness or minimal disturbance of consciousness, normal respiration, positive pupil reflexes, normal heart rate and a haematoma less than 2.5mm in size.
Pathology
It is important to understand the anatomy of the vertebrobasilar arteries. The vertebral artery arises at the neck and enters the skull to form the basilar artery. At the top of the pons, the basilar artery divides into two posterior cerebral arteries (PCAs). The vertebral and basilar arteries are large vessels which become occluded by plaques due to atherosclerosis. Smaller vessels which arise from the basilar artery may become occluded and this weakens the vessel walls. Poor control of any systemic hypertension causes these arteries from the basilar artery that extend into the pons to rupture, resulting in focal haemorrhages. The most common site of these lesions is the paramedian pontine region. Almost all intracerebral haemorrhages originate from occlusion of the smaller vessels. Paramedian pontine lesions lead to motor abnormality, most typically dysarthria, a motor speech disorder resulting from neurological injury to the speech system, and contralateral hemiparesis, predominantly of the upper extremities.
Horizontal ‘one-and-a-half’ syndrome
The 6th cranial nerve, the median longitudinal fasciculus (MLF) and the paramedian pontine reticular formation (PPRF) are neighbours in the pons (Figure 4). A median pontine lesion may affect each of these simultaneously. Thus combined damage to the ipsilateral MLF and abducent (6th nerve) nucleus or alternatively to the MLF and ipsilateral PPRF causes the ‘one-and-a-half’ syndrome.
[CaptionComponent="793"]Adduction is impaired during contralateral gaze (the ‘half’), representing an internuclear ophthalmoplegia from medial longitudinal fasciculus damage. There is also ipsilateral horizontal gaze palsy (the ‘one’), which affects eye movements if the 6th nerve is involved.
In the primary position, the eye may be esotropic if the 6th fascicle is involved (as in our patient) or extropic or indeed orthotropic.
The 7th and 5th cranial nerves are also in close proximity to the 6th nerve, MLF and PPRF in the pons. Lesion involving the 7th nerve will give rise to a facial palsy while the paralysis of the 5th or trigeminal nerve may give rise to loss of sensation of the face on the affected side.
Swallowing and aspiration pneumonia
Swallowing abnormalities (dysphagia) are a common functional impairment of acute stroke, affecting as many as 50 per cent of all patients. Not only is this disabling to patients trying to maintain nutritional requirements, but also carries the potential to cause serious complications related to dehydration and aspirational pneumonia.
Read more
Systemic disease: Heteronymous hemianopias
Systemic disease: Acromegaly and its diagnosis
Systemic disease: Vascular disorders with neurological consequence
Systemic disease: Vascular disorders with neurological consequence - part 2
Kirit Patel practises in Radlett, Herts