Causes and classifications of stroke

The list of causes of stroke and intracranial haemorrhage can be massive. Causes of ischaemic stroke have thus far been neglected, but in Question 25 from the first paper of 2014, the college asks for differentials  to explain the CT finding of "a hyperdensity in keeping with an intracerebral haematoma".

Classifications of stroke

This classification can be made even more granular, but  for the purposes of this chapter these categories are sufficient.

Ischaemic stroke (80%)

• Thrombosis (can be of small or large vessels)
• Embolism
• Global hypoperfusion

Haemorrhagic stroke (20%)

• Intracerebral haemorrhage
• Subarachnoid haemorrhage

Causes of ischaemic stroke

This can be divided further into small or large vessel disease. Of course, systemic hypoperfusion is possible as a cause.

Causes of large vessel stroke

• Atherosclerosis
• Arterial dissection
• Vasospasm (SAH)
• Vasculitis:
  • Takayasu arteritis
  • Giant cell arteritis
  • Moyamoya syndrome

Causes of small vessel stroke

• Lipohyalinosis and stenosis, hypertension-related

Causes of embolic stroke

A better way to name this category would be "causes of intracardiac thrombus". For stroke purposes, it doesn't matter whether its an infective or non-infective embolus.

A list of causes should include:

• Atrial fibrillation
• Valvular disease
• Replaced valves
• Recent myocardial infarction (within one month)
• Dilated cardiomyopathy (i.e. stagnant blood in the LV)
• LV aneurysm
• Infective endocarditis
• Atrial myxoma
• CABG
• Septal defect

Causes of intracerebral haemorrhage

The causes of a spontaneous intracerebral haemorrhage are:

• Hypertension
  • Potentially associated with abuse of stimulants, eg.cocaine
• Amyloid angiopathy
• Arteriovenous malformation
• Intracranial aneurysm (though there is no subarachnoid blood)
• Cavernous angioma
• Venous angioma
• Dural venous sinus thrombosis
• Haemorrhage into the intracranial neoplasm
• Haemorrhage into an ischaemic stroke (haemorrhagic transformation)
• Vasculitis

This list of differentials was retrieved from an excellent 2001 NEJM article by Adnan Qureshi.

Causes of stroke in the Younger Person

Risk factors:

• dyslipidemia
• smoking
• hypertension

Aetiological causes:

• Arterial dissection
• Vasculitis
• Cardiac septal defect
• Pregnancy (particularly associated with dural sinus thrombosis)
• hypercoagulable states eg. antiphospholipid syndrome
• Infective endocarditis
• Sickle cell disease
• Hyperviscosity, eg. myeloma or HONK

Inherited disorders to look for:

• Moyamoya syndrome
• Factor V Leiden mutation
• Protein C deficiency
• Protein S deficiency
• Antithrombin III deficiency
• Prothrombin gene mutation
• Elevated lipoprotein(a)
• Elevated homocysteine
• MELAS syndrome