Four types; 

1. Large vessel disease (e.g. embolism & thrombosis)

2. Small vessel disease (e.g. arteriosclerosis)

3. Venous infarction (e.g. dehydration, thrombophilia sydnromes > increased blood)

4. Global ischaemia (e.g. laminar cortical necrosis/"watershed infarcts"

Comprised of infarcted & penumbra regions 

Can present as; completed stroke (infarct occurrence) or transient ischemic attack (anoxic episode with minimal damage)

- Completed stroke - symptoms rapidly develop and last for >24 hours, hemiplegia of face(contralateral side), confusion, aphasia & epiletic fits

- Transient ischemic attack - symptoms do not persist >25 hours, amaurosis fugax (unilateral blindness), hemiparesis (partial paralysis), paraesthesia, vertigo, diplopia, 

BOTH do not usually result in a lose of consciousness 

2. Epidural haematoma; trauma to temporal region > ruputred middle meningeal artery or branches > concussion, loss of consciousness > regained consciousness (lucid interval) > comatose > death

3. Subdural haematoma; acute (e.g. car accident > cortical vein rupture > raised I.P., herniation, coma or death. Chronic (e.g. falls, birth trauma >cerebral vein tear > delayed symptoms of headache, drowsiness, hemiparesis, seizures, reduced mental capacity > herniation, death (bad prognosis)

4. Subarachnoid haemorrhage; commonly due to vasculature pathology rather than injury (E.g. berry aneurysm) > presents with focal signs/cranial nerves palsies > transient headache, neck stiffness, occipital headache & vomiting (worst prognosis)

5. Intracranial haemorrhage; rupture to lenticulostriate branch > intense headache, vomiting, loss of conciousness, congested face, heavy/laboured brathing, total contralateral hemiplegia > bad prognosis

2. Missile trauma (open head injury); skull damage/injury

-Primary brain damage; Coup lesions (damage to brain/skull adjacent to site of impact) & Contrecoup lesions (diagonally opposite lesions)

Contusions heal by gliosis (haemosiderin depositions > brown straining

-Secondary brain damage; occurs after immediate impact > tearing of blood vessels > secondary hypoxic brain damage & cerebral oedema

- Cerebral haemorrage types; intracerebral haematoma, subarachnoid haemorrhage, subdural haemorrhage, extradural haemorrhage

2. Congenital; arnold-chiari malformation, spina bifida, intrauterine infections, intracranial tumours

3. Acquired; arnold-chiari malformation, infection, tumours

4. Compensatoy; reduced brain volume due to increased I.P.

5. Idiopathic; over-production of CSF by choroid pleux or under absorption by arachnoid granulations

1. Acute suppurative meningitis; different microbials > blood borne infections or direct spread > purulent exudate in subarachnoid space

Symptoms; severe headache, fever, chills, neck stifness, delirium, coma, neurological impairment (E.g. Opisthotonus, Waterhouse-Friedrichsen syndrome)

2. Chronic meningitis; variety of microbes > slow headache onset, malaise, fatigue, low grade fever > poor prognosis

3. Viral meningitis/Aseptic meningitis (no bacteria); virus > sudden headache, fever, neck stiffness > self-limiting & full recovery usually

4. Cerebral abscess; pyogenic microbe > haematogenous spread > space-occupying lesion > raised I.P.

5. Encephalitis; infection (usually viral) > fever, level of conciousness changes, neurological deficits, tremors, rigidity, paralysis, mental retardation, convulsions > occasionally fatal

2. Alzheimer's disease; accumulation of amyloid in the brain > amyloid plaques & neurofibrillary tangles > progressive loss, memory loss, aphagia, cortical dysfunction > mute, immotile > severe brain atrophy

3. Spongiform encephalopathies; associated with prion proteins

4. Creutzfeldt-Jakob disease (CJD); prion proteins act as infectious agent

5. Variant CJD (vCJD); prion cow disease exposure

Diagnosed via; amniocentesis or chorionic villus sampling 

2. Spina bifida; neural tube & spinal canal fusion failure > spina bifida occulta (asymptomatic), meningocoele, meningomyelocoele, syringomyelocoele and myelocoele 

3. Arnola-chiari malformation; Protrusion of ventromedial cerebellum, fourth ventricle & medulla into cervical spinal canal

- Glioblastoma multiforme = most aggressive

2. Oligodendrogliomata; slow growing > may differentiate

3. Ependymomata; present in early childhood > poor prognosis

4. Medulloblastoma; seen in adolescence > IV ventricle obstruction & hydrocephalus > very poor prognosis

5. Meningioma; in adults > raised I.P., non-invasive > good prognosis 

6. Schwannoma; affects acoustic nerve (usually benign) > tinnitus, deafness, ataxia & dizziness

Space occupying lesion = ischaemia/trauma/inflammation/tumours/metabolic disorders > breakdown of BBB

Clinical presentation; headache, vomiting (esp. in morning), papilloedema, later stage coma & epileptic seizures (also herniation through tentorium cerebelli)

Increased intracranial pressure > ventricular atrophy