CNS pathology Third year medical students. Dr Heyam Awad 2018 Lecture 7: Non traumatic brain haemorrhage

Transcription

1 CNS pathology Third year medical students Dr Heyam Awad 2018 Lecture 7: Non traumatic brain haemorrhage

2 ILOS To list the causes of intracranial haemorrhage. To understand the pathogenesis of each cause. to apply the above knowledge in clinical scenarios.

3 intracranial haemorrhage

4 Intracranial haemorrhage Can be: Traumatic: due to external trauma non- traumatic: due to natural diseases affecting the brain vessels or due to hypertension. Today s lecture is about non-traumatic haemorrhage.

5 Brain haemorrhage according to site 1.Parenchymal haemorrhage: 2. Subarachnoid 3. Epidural 4. Subdural. Parenchymal and subarachnoid haemorrhages can be traumatic or non traumatic, whereas epidural and subdural are almost always traumatic.

6 Causes of non- traumatic intracranial haemorrhage 1. primary brain parenchymal haemorrhage. 2. hypertensive cerebrovascular disease 3. vasculitis ا ل د ا ء ا ل ن ش و ا ن ي=.4 cerebral amyloid angiopathy = ت م د د ك ی س ي د م و يaneurysms.5 ruptured 6. vascular malformation 7. Bleeding disorders 8.Drug related: anti-coagulants 9.Cocaine use 10. Tumors.. Can encroach on a vessel and cause bleeding Note: we will discuss causes 1-6 in this lecture.

7 1. Primary brain parenchymal haemorrhage - Primary = spontaneous = non-traumatic. - caused by non-traumatic rupture of a small intraparenchymal vessel -Peak 60 years -Mostly due to rupture of a small intra-parenchymal vessel. -Hypertension is the leading cause. - Most affected sites: basal ganglia, thalamus, pons and cerebellum. - Outcome depends of the site and extent of haemorrhage - Can be fatal if large area affected but if small area involved it can be clinically silent.

8 Why hypertension causes parenchymal haemorrhage? Hypertension causes hyaline arteriolo-sclerosis. This results in weak arterioles, so the arterioles can rupture especially if there is sudden or sustained increase in blood pressure. Minute aneurysms can form (Charcot- Bouchard micro aneurysms) because of the weak vascular walls and these also can rupture.

9 Hyaline arteriolosclerosis Homogeneous pink hyaline thickening of the arteriolar walls with luminal narrowing and loss of underlying structural detail. Occurs due to leakage of plasma components across injured endothelial cells into vessel wall and increased extracellular matrix production by smooth muscle in response to chronic hemodynamic stress.

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12 Symptoms of parenchymal brain haemorrhage 1. neurological symptoms related to the area affected 2. symptoms of increased intracranial pressure

13 morphology Extravagated blood. With time.. Resolution and cavity formation

14 Brain haemorrhage

15 Cavity.. Old infarct or old hemorrhage; both will end up with a cavity!

16 2. Hypertensive cerebrovascular disease. Hypertension affects the brain in several ways: primary intracranial haemorrhage, which is already discussed. Lacunar infarcts. Rupture of small penetrating vessels causing tiny haemorrhages. Acute hypertensive encephalopathy

17 Vessel rupture Small penetrating vessels may rupture. Cause small haemorrhages = slit haemorrhages.

18 Lacunar infarcts Small infarcts, mostly in deep grey matter ( basal ganglia and thalamus), internal capsule, deep white matter and pons. Caused by occlusion of penetrating branch of a large cerebral artery. Effect: depends on site

19 Lacunar infarct

20 Acute hypertensive encephalopathy Happen with sudden sustained rise of diastolic more than 130. Increased intracranial pressure, global cerebral dysfunction ( headache, confusion, vomiting, convulsion, or coma) Rapid intervention to decrease intracranial pressure is essential.

21 3. vasculitis vasculitis= inflammation of the blood vessels. It weakens the vessel wall so it can rupture.\ It can be a localised inflammation of the brain vessels or the brain vessels might be inflamed as part of a systemic diseases causing systemic vasculitis.

22 Causes of cerebral blood vessels vasculitis Infectious arteritis: previously seen with syphilis and TB. Now in association with: CMV, herpes, aspergillosis.. immunosuppression Polyarteritis nodosa. Primary angiitis of CNS cause diffuse encephalopathy with cognitive dysfunction.

23 4. Cerebral amyloid angiopathy Amyloid deposition in the walls of arteries Causes weakness in vessel wall Bleeding, usually in the lobes of cerebral cortex (lobar haemorrhage)

24 Amyloidosis - deposition of extracellular fibrillar proteins - These abnormal fibrils are produced by the aggregation of misfolded proteins (which are soluble in their normal folded configuration).amyloid is deposited in the extracellular space in various tissues and organs of the body - These fibillary proteins are responsible for tissue damage and functional compromise

25 Congo red stain showing apple green colour of amyloid.

26 By electron microscope - All types of amyloid consist of continuous, non-branching fibrils with a diameter of approximately 7.5 to 10 nm. With a cross-βpleated sheet conformation

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28 Chemical Properties of Amyloid Proteins - Amyloid is not a single chemical entity. - Several types exist

29 5. Ruptured aneurysm Mainly causes subarachnoid haemorrhage but also can cause haemorrhage within brain.

30 Subarachnoid haemorrhage Most common cause: ruptured berry aneurysm. Other causes: vascular malformations, trauma, tumours, haematological disturbances. Patients have severe headache described as the worst headache I had in my life = called thunderclap headache followed by loss of consciousness

31 Subarachnoid haemorrhage Ruptured berry ( secular) aneurysm is the most common cause

32 Ruptured berry aneurysm Rupture happens usually due to increased intracranial pressure. Sudden severe headache followed by loss of consciousness 25-50% die Survivors: risk of recurrent bleeding

33 Berry aneurysm 90% in the anterior circulation Near major arterial branching points Multiple in % of cases

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35 morphology Berry aneurysm: thin walled outpouching of an artery

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38 6. Vascular malformations Arteriovenous malformations Cavernous malformations Capillary telengectasia Venous angioma

39 AV malformation Most common type of vascular malformation Males more than females Present at years of age Symptoms: seizures and intracranial haemorrhage

40 Morphology of AV malformation Network of disorganised vascular channels

41 Summary 1/2 Intracranial haemorrhage can traumatic or non traumatic. Intracranial haemorrhage can be intra-parenchymal, subarachnoid, epidural or subdural; the first two can be traumatic or non traumatic whereas the last two are usually traumatic. the most common cause of intraparenchymal haemorrhage is spontaneous haemorrhage which occurs in older individuals who are hypertensive. Hypertension causes haemorrhage via weakening blood vessel walls through hyaline arteriolosclerosis or micro-aneurysm formations. Hypertension also uses slit haemorrhages, lacunar infarcts and acute hypertensive encephalopathy.

42 SUMMARY 2/2 Other causes of intraparenchymal haemorrhage include: amyloid antipathy, infections, autoimmune vasculitis, arteriovenous malformations and other causes. Subarachnoid haemorrhage can be traumatic but is mainly caused by a ruptured aneurysm.

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