IntraCerebral Haemorrhage (ICH), also known as intraparenchymal cerebral haemorrhage is acute accumulation of blood within the parenchyma of the brain.

This module focuses on non-traumatic ICH.

Most common cause of ICH (c.1/3 of all ICH)

Risk factors include age, hypertension, and diabetes.

Top 4 areas in order of frequency:

• Basal ganglia (especially the putamen)
• Thalamus
• Pons
• Cerebellum

ICH is usually caused by ruptured vessels that are degenerated due to long-standing hypertension.

Long-standing poorly controlled hypertension leads to prominent degeneration of the media and smooth muscles of arteries

Fibrinoid necrosis of the sub-endothelium with micro-aneurysms and focal dilatations is seen

Often starts with microaneurysms of small perforating arteries (Charcot-Bouchard aneurysms)

The lenticulestriate branches of the middle cerebral artery have right angulations that can lead to a non-laminar and disturbed blood-flow, given time, the junction with hypertensive effects turns this an especially susceptible area for aneurysm formation and rupture. These branches supply most of the basal ganglia and the thalamus, but Charcot–Bouchard aneurysms can also appear in deep arterioles that irrigates the brainstem and cerebellum, all at risk for rupture when exposed to acute elevations of blood pressure.

Second commonest cause of ICH (1/5 of all ICH)

Characterised by deposition of amyloid proteins in small to medium-sized vessels in brain and leptomeninges, weakening vessel wall structure and increasing the risk of bleeding.

CAA risk increases with age.

CAA typically causes peripheral lobar haemorrhage rather than deeper structures like hypertensive vasculopathy.

Represents 15% of ICH

Anticoagulants include:

• Warfarin
• Heparin
• DOACs
• Thrombolysis

Tumour

Primary: Glioblastoma, lymphoma

Secondary: Melanoma, choriocarcinoma, renal cell carcinoma, bronchogenic carcinoma

ArterioVenous Malformations (AVM)

These are abnormal vascular structures arising from the brain tissue, where arterial systems drain directly into the venous system without an intervening capillary network.

The high flow and shear stress predisposes to aneurysmal formation and thus intracerebral haemorrhage.

The annual spontaneous haemorrhage rate from an AVM is 2-3%

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Dural Arteriovenous Fistula (AVF)

An AVF is a pathological anastomosis between an arterial and venous system, but differs from an AVM in that it arises from the dura

AVFs are classified into low or high grade depending on their site of venous drainage – higher grade if draining into a venous sinus

This stratifies their risk of precipitating an ICH

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Coagulopathy from systemic disease predisposes to ICH

Considered a separate aetiology as treatment and prognosis differs.

Causes of coagulopathy are myriad

In one study, chronic liver disease and thrombocytopenia from other causes were the most frequent cause of ICH

REF

About 20% of ICH with have no cause identified

> Cerebral venous sinus thrombosis

• Important not to miss on initial imaging as treatment paradoxically involves anti-coagulation

> Vasculitis

Typical findings on angiography. serology and LP helps diagnose.

Usually caused by polyarteritis nodosa or lupus, but may also occur with ANCA vasculitis, rheumatoid arthritis, sarcoidosis, drug-induced vasculitis, primary central nervous system vasculitis or Henoch-Schonlein purpura.

> RCVS

> CNS Infection

• Especially fungal
• Herpes Simplex Encephalitis
• Granulomas

> Pregnancy and Puerperium

• Up to 6 weeks post partum
• Risk 1/9500 births
• Usually with pre-eclampsia or eclampsia

> Moyamoya disease

• Haemorrhage is typically in the basal ganglia