Neuropath Lecture 3 Flashcards
Inflammation of the brain - not white/gray matter specific
Encephalitis
(Panaencephalits = both)
Inflammation of grey matter
Polioencephalitis
Inflammation of white brain matter
Leukoencephalitis
Inflammation of the spinal cord
Myelitis
(poliomyelitis, leukomyelitis)
Inflammation of the brain and spinal cord
Encephalomyelitis
Inflammation of the meninges
(in general implies involvement of the leptomeninges)
Meningitis
Inflammation of the meninges and brain
Meningoencephalitis
Inflammation of the choroid plexus
Choroiditis
Inflammation of the peripheral nerve
Neuritis
Inflammation of multiple peripheral nerves
Polyneuritis
Inflammation of a nerve root
Radiculoneuritis
5 exudate types
Suppurative
Non-suppurative
Granulomatous
Eosinophilic
Fibrinous
Suppurative exudate
Neutrophils
Bacterial infection
May accompany tissue necrosis
Rarely, neutrophilic infiltrates occur in viral infection
Non-suppurative exudate
Lymphocytes +/- plasma cells, histiocytes
Viral infections
Autoimmune conditions
Certain protozoal/parasitic infections
Granulomatous exudate
Focal accumulations of histiocytic cells
Mycoses (may be pyogranulomatous)
Certain bacteria (mycobacterium), protozoa, metazoans
Idiopathic
Eosinophilic exudate
Certain parasitic infections
May represent species-specific responses to certain categories of non-infectious disease
Porcine salt poisoning
Fibrinous exudate
Reflects a severe vascular insult which may suggest certain infectious agents (chlamydia or FIP)
Pleocytosis
Migration fo leukocytes (especially neutrophils) across the BBB
Perivascular cuffs
General term describing accumulations of cells in teh perivascular area of medium to small sized veins (space of Virchow-Robin) and may be the result of cellular efflux or influx
Infiltrating cells:
Lymphocytes/plasma cells, Eosinophils, Monocytes
Infectious causes of CNS inflammation
Portals of infection into the CNS
Hematogenous (most common)
Neural
Direct extension from surrounding structures
CNS Route of Infection
Hematogenous
Most common
Sites seeded (any/all wherever vascular density is high and vessel caliber is small)
Leptoeninges
Choroid plexus, (sub)ependyma
Neural parenchyma (particularly grey-white junction)
Agents: Bacteria, Virus, Fungi, Parasite, Protozoa
CNS Route of Infection
Neural
Retrograte axonal transport (rabies, human herpesvirus-1)
Ascending neuritis from oral cavity (listeriosis)
CNS Route of Infection
Direct extension from surrounding structures
Nasal turbinates (crytococcosis)
Extension from otiits media/interna (actinomyces pyogenes)
Bacterial Infection
Bacterial meningitis pathogenesis
Bacteria in bloodstream and multiply
High levels of bacteraemia and cross the BBB
Invasion of meninges and CNS
Release proinflammatory and toxic compounds
Increased BBB permeability and Pleocytosis
Increased intracranial pressure and neuronal injury
Bacterial Infection
Host response to bacterial meningitis
Macrophages, microglia, astrocytes, endothelial cells, inflammatory cells exacerbate host response
Resulting in neuronal injury
Bacterial Infection
Suppurative meningitis +/- choroiditis
Secondary to generalized bacteremia
Generally a disease of young immunocompromised animals
(failure of passive transfer of colostral antibody and hypgammaglobulinemia)
(severe combined immunodeficiency)
Primary site of infection is hard to find
Hematogenous dissemination results in seeding of multiple organs
(synovia membranes, serosal membranes, kidneys, meninges, CNS lesions)
