TRAINING DAYS

11/04/07 Afternoon session - Prof Seth Love: Cerebrovascular and Demyelination

These are my own notes from the session and I cannot therefore vouch for their accuracy! They are mainly for my own use and hence they are very much "note form"

No microscope slides were provided with this presentation but there may be a powerpoint presentation available soon

Reasons for examining the brain at autopsy

1 Genetic implications for the family eg. amyloid angiopathy (usually haem stroke), multiple cavernous haemangiomas (common in some countries)

• slide of recurrent cerebral haemorrhage in a 50 yr old (amyloid angiopathy)
• amyoid A beta slide
• sirius red stain
• AV malformation macro - subarachnoid or intracerebral not normal inherited
• cavernous haemangioma - accumulation of abnormal bvs
• histology of above
• histology of 50yr old male with multiple ischaemic stroke - accumulation media granular eosinophilic material (gom) = CADASIL

2 Educating clinicians

has treatable disease been missed? eg. aneurysms, AV malformations, tumour associated bleeds, coagulopathy associated stroke, primary angiopathy of the CNS

• slide - macro of stroke post SBE
• micro of same showing infective aneurysm
• gram +ve cocci
• macro haemorrhagic stroke with midline shift andd subfalcine herniation
• micro perivascular inflammation - prim angiitis of CNS

3 Potential medicolegal implications

Can miss traumatic lesions without microscopy

• slide - macro of large 2 day old R MCA infarct
• micro of dissection of ICA proving traumatic cause
• fat embolism shown by oil red O stain of frozen sections

How to perform adequate autopsy

Like any autopsy your approach will depend on the history.. you must think carefully about what you are expecting to find depending on clinical scenario before you start!

Asymmetry

Remember to look carefully at the major intracranial vessels

INFECTIONS OF CNS

Case 1 - Alcoholic  with Pneumococcal pneumonia meningitis (most common in elderly and debilitated). History of splenectomy, cranial trauma or surgery (these may have other bugs eg. E coli).

CSF aspirate for culture - get from lateral cerebral ventricles even after brain has been removed.

Swab if you see a purulent exudate

Case 2 - Meningitis immunosuppressed patient

Toxoplasmosis. In immunosuppressed patients don't get cyst formation, organisms free in parenchyma and in macrophages (pseudocycts)

HSV encephalitis

macro symmetrical exudate 

lymphocytic rich inflammatory infiltrate, typical HSV nuclei, indisciminate in cell types affected

immunostain

DEMYELINATING DISEASES

Most due to MS

A few cases due to other immunological disease process

Toxic/metabolic

Compression (eg. demyelination of vascular compression in trigeminal neuralgia) or ischaemia

Multiple sclerosis

irrreg shaped lesions of grey discolouration of white matter. Prediliction for certain areas. Prediliction for periventricular wm, optic nerves and chiasm, brain stem and spinal cord. There is also demyelination in the grey matter but obviously more difficult to detect. Need immunostain for myelin.