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Objectives for NS 2: Cytotoxic, osmotic and vasogenic brain edema) Thiamine-responsive polioencephalomalacia of ruminants Thiamine deficiency in carnivores.

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Presentation on theme: "Objectives for NS 2: Cytotoxic, osmotic and vasogenic brain edema) Thiamine-responsive polioencephalomalacia of ruminants Thiamine deficiency in carnivores."— Presentation transcript:

1 Objectives for NS 2: Cytotoxic, osmotic and vasogenic brain edema) Thiamine-responsive polioencephalomalacia of ruminants Thiamine deficiency in carnivores Lead poisoning Salt poisoning Toxin-induced vasogenic brain edema You should be able to define, describe pathogenesis, list lesions and know how to diagnose the following conditions:

2 Increased intracranial pressure Brain swelling (cerebral edema) E. Simko WCVM Response to injury - Brain edema

3 Brain swelling (edema) Intracranial pressure Blood perfusion pressure Ischemic necrosis E. Simko WCVM Response to injury - Brain edema

4 Brain edema Cytotoxic (intracellular) Extra cellular edema Osmotic Vasogenic E. Simko WCVM Response to injury - Brain edema

5 Gross: cerebellar coning (herniation) cerebral herniation flattened gyri Microscopically neuronal necrosis edema is not evident in most cases Diagnosis: E. Simko WCVM Response to injury - Brain edema

6 Polioencephalomalacia (PEM) Thiamine-responsive PEM of ruminants Lead poisoning in ruminants Salt poisoning in pigs & occ. in rumin. Hypoxia

7 Cytotoxic edema (cellular degeneration) Thiamine-responsive polioencephalomalacia in ruminants Disturbance of thiamine production/absorption concentrate ruminal pH change in flora Bacterial thiaminase [sulfur, sulfates, sulfides] in diet or water Etiology E. Simko WCVM Response to injury - Brain edema

8 Pathogenesis Cytotoxic edema - Thiamine deficiency Thiamine interferes with glucose metabolism and Krebs cycle in CNS ATP production Na/K transport is impaired Intacellular H 2 O (hydropic degeneration) Cellular swelling (Cytototoxic edema) Energy exhaustion Intacranial pressure & blood perfusion Ischemic necrosis E. Simko WCVM

9 Lesions Brain swelling (flattened gyri, cerebellar coning) Yellow cortical discoloration (autofluorescence under UV light) Cortical liquefaction and cavitation Histology Laminar cortical necrosis E. Simko WCVM Cytotoxic edema - Thiamine deficiency

10 Diagnosis History Response to thiamine Gross and histologic lesions Rule out the other causes of PEM E. Simko WCVM Cytotoxic edema - Thiamine deficiency

11 Dietary thiamine deficiency in carnivores Dog, cat, mink (Human – Wernicke’s encephalopathy) Depend on exogenous source of vitamin Pathogenesis: diet with thiaminase, sulfur preservativesor exposed to high temperature Lesions: Symmetrical necrosis of thalamic and mid-brain nuclei E. Simko WCVM Cytotoxic edema - Thiamine deficiency

12 Lead poisoning Cattle Waterfowl Source: Old batteries and paint Lead shotgun pellets Lesions: Polioencephalomalacia similar to thiamine resp. PNS degeneration (Esophageal/crop dilation and impaction) E. Simko WCVM Brain edema

13 Pathogenesis in cattle Direct endothelial injury vasogenic edema Damaged metabolism cellular swelling Energy exhaustion Increased intracranial pressure Failure of blood perfusion Ischemic necrosis Brain edema - Lead poisoning E. Simko WCVM

14 Diagnosis Gross and histologic lesions Lead particles in the rumen Lead level in liver and kidney E. Simko WCVM Brain edema - Lead poisoning

15 Osmosis and semi-permeable cellular membrane Hypo Os Hyper Os Hypo Os Hyper Os Swelling Shrinkage

16 Osmotic brain edema H2OH2O E. Simko WCVM Water intoxication ( IV H 2 O, behavioral, ADH) N Edema Dehydr. Brain edema BRAINPLASMABRAINPLASMA H2OH2O N Edema Dehydr.

17 Water deprivation +/- high salt Dehydration t = 0 hr HyperNa Osmotic brain edema - Salt toxicity BRAIN N Edema Dehydr. BRAINPLASMA NaCl N Edema Dehydr. PLASMA Na + Cl - Na + Cl - Na + Cl - Na + Cl - Na + Cl - Na + Cl - H2OH2O Na + Dehydration NormoNa NormoOsHyperOs

18 Equilibration of CNS hyperNa PLASMA HyperNa t = > 36 hr HyperNa Osmotic brain edema - Salt toxicity N Edema Dehydr. BRAIN Cl - Na + Cl - Na + Cl - Na + Cl - Na + Cl - Dehydration PLASMA NormoNaHyperNa N Edema Dehydr. BRAIN AA Na + Cl - Na + Cl - Na + Cl - Na + Cl - Dehydration HyperOs

19 Water access t = > 36 hr H2OH2O Osmotic brain edema - Salt toxicity PLASMA NormoNa N Edema Dehydr. BRAIN AA Na + Cl - EdemaNormal hydr. HyperOsNormalOs PLASMA NormoNaHyperNa N Edema Dehydr. BRAIN AA Na + Cl - Na + Cl - Na + Cl - Na + Cl - Dehydration HyperOs Na + Cl - Na + Cl -

20 Lesions Brain swelling Cerebrocortical necrosis (occ) Histology Laminar cerebrocortical necrosis Perivascular eosinophilic infiltrate (Po) E. Simko WCVM Osmotic brain edema - Salt toxicity

21 Diagnosis History Gross and histologic lesions Na level in the brain E. Simko WCVM Osmotic brain edema - Salt toxicity

22 Vasogenic brain edema The most common type of brain edema Pathogenesis: damaged BBB Examples: Toxins Inflammatory processes (H. somnus) E. Simko WCVM Vasogenic brain edema

23 White matterGrey matter E. Simko WCVM

24 Shigella toxin type II (Edema disease) Po Fibrinoid vasculitis Epsilon toxin (C. perfringens D enterotoxemia) Ov Symmetrical encephalomalacia Fumonisin B1 (Fusarium momiliforme) Moldy corn Equine leucoencephalomalacia Toxins E. Simko WCVM Vasogenic brain edema - Salt toxicity Toxin-induced

25 Necrosis Trauma Thiamine deficiency Lead poisoning Salt poisoning Edema disease Clostridial eterotoxemia Equine leucoencephalomalacia Infarction Response to injury - Necrosis

26 Infarction


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