Transcript Normal Edema

Pathologic Basis of
Disease
Neuropathology - 1
Major cells of the CNS
• Neurons
• Glial cells: -astrocytes
-oligodendrocytes
-ependymal cells
-microglial cells
Supporting structures
• Meninges: arachnoid cells
• Choroid plexus
• Blood vessels: blood-brain barrier
Organization of the CNS and disease
• Not all cells in the CNS are ‘equal’: while some
disease processes affect some groups of cells more
than others (‘selective vulnerability’), other
disease processes could affect other areas more.
• Not all areas in the brain are equal: most areas in
the brain have specific functions: a same disease
process in two different areas of the brain, often
give different symptoms.
• Some disease processes are the same in the brain
as elsewhere in the body, while others are unique
to the brain (eg demyelinative disease,
neurodegenerations)
NEURON
• Maturity: G0 phase
• Great metabolic activity requiring a
continuous supply of O2 and glucose
Neuron cell death
• Phagocytosis by macrophages: acute
neuronal death, viral infections
• Apoptosis
• ‘simple atrophy’: loss of cell volume and
ultimately cell death due to metabolic
derangement (often in neurodegeneration).
Protection of neurons from the
bad outside world
• Blood brain barrier: capillaries with
endothelial cells with tight junctions (only
active transport possible), astrocytic
footplates
• Brain CSF barrier: ependymal cells with
tight junctions, and astrocytic footplates.
WHY BBB & BCB
• Controlled external milieu of neurons –
needed for excitability of neurons
• Protection against infections
• Protection against autoimmune responses
• Protection against cerebral oedema (skull is
a closed box-no volume increase possible)
CEREBRAL EDEMA
• Abnormal accumulation of fluids with
increase in cerebral tissue volume
Normal
Edema
Grey matter
White matter
800mg/g
680mg/g
820mg/g
760mg/g
Topography of edema
Localized edema
Generalized edema
Types of edema
• Vasogenic edema: rupture of the bloodbrain barrier
• Cytotoxic edema: pump failure
• Interstitial edema: passage through the
ependymal lining of the ventricles