Pontine hemorrhage

Pontine haemorrhages are are a common form of intracerebral haemorrhage, and usually are a result of poorly controlled long-standing hypertension, although also have other causes. When due to chronic hypertension, the stigmata of chronic hypertensive encephalopathy are are often present (see cerebral microhaemorrhages). It It carries a very poor prognosis.

Epidemiology

Primary pontine haemorrhage accounts for ~7.5% (range 5-10%) of haemorrhagic strokes and has an incidence of ~3 per 100,000 people ⁶.

Clinical presentation

Patients present with sudden and precipitous neurological deficits. Depending on the speed at which the haematoma enlarges and the exact location,. The clinical presentation may include ^1,2:

• decreased level of consciousness (most common)

• long tract signs including tetraparesis

• cranial nerve palsies

• seizures

• Cheyne-Stokes respiration

Pathology

As is the case with penetrating arteries into the basal ganglia, the penetrating arteries from the basilar artery extending into the pons are subject to lipohyalinosis as a result of poorly-controlled hypertension ¹. This renders the vessel wall prone to rupture. The larger paramedian perforators are more commonly the culprit vessels ¹.

Haemorrhage into the pons can of course also be secondary to underlying lesions including:

• vascular malformations

  • cavernous malformations

  • arteriovenous malformations

• tumours

  • neuroepithelial (primary) brain brain tumours

  • metastases

• central downward transtentorial herniation (Duret haemorrhages)

• supratentorial surgery (remote haemorrhage)^3,4

Radiographic features

CT

CT of the brain is usually the first, and often the only, investigation obtained upon presentation. Features typical of an acute intraparenchymal haemorrhage are noted, usually located centrally within the pons (on account of the larger paramedian perforators usually being the site of bleeding).

The haematoma more frequently extends in a rostrocaudal direction along the traversing long tracts rather than laterally into the middle cerebellar peduncles. Usually the haematoma does not extend beyond the pontomedullary junction inferiorly and the inferior midbrain superiorly ¹. These These haematomas frequently rupture into the 4^th ventricle ¹.

There are many predictors of haematoma expansion potentially evident on CT, which are discussed in depth in the main intracerebral haemorrhage article article.

MRI

The appearance of haemorrhage on MRI varies with time and to some degree the size of the haematoma (see ageing blood on MRI). In patients who have small volume bleeds and who are thought to possibly have an underlying lesion, MRI may be of use (e.g. identification identification of a vascular malformation), ideally after resolution of the acute haemorrhage.

Treatment and prognosis

Pontine haemorrhages have a poor prognosisOverall, with large bleeds being almost universally fatalmanagement does not differ for other causes of intracerebral haemorrhage - please see the article on intracerebral haemorrhage for further discussion ⁷. OpenNotably, open surgical evacuation of the clot is usually not performed, although stereotactic clot aspiration has been advocated by some ⁵.

In smallerPontine haemorrhages have a poor prognosis, medical management and treatment of hydrocephalus with extraventricular drains may be life-saving, however, often with significant residual neurological deficits.

large bleeds being almost universally fatal. Overall mortality ranges between 30% and 90% ⁶, with the overall volume of the bleed and initial GCS being related to outcome ².

Differential diagnosis

The main differential is between a primary pontine haemorrhage and haemorrhages resulting from underlying lesions (see above). Usually, patients present suddenly with severe impairment and the diagnosis is not difficult to make.

In patients where the presentation is not known (e.g. in the exam setting) it is worth considering:

• unruptured/asymptomatic vascular malformations

  • asymptomatic cavernous malformations (these can periodically have small bleeds resulting in repeated symptoms)

  • arteriovenous malformation

    • usually little if any mass effect

    • serpentine irregular density isodense to intravascular blood elsewhere

  • developmental venous anomaly

    • linear, no mass effect

    • density isodense to intravascular blood elsewhere

• haemorrhagic metastases

  • melanoma, renal cell carcinoma, thyroid carcinoma, etc.

Video

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