Changes

===Organ function===

===Organ function===

There are several classes of drugs that are nephrotoxic, and any underlying condition which reduces renal blood flow or known renal failure will increase the toxic effect of the substance. Several classes of antibiotics are to be nephrotoxic - aminoglycosides (particularly neomycin and  streptomycin, sulphonamides, Amphotericin B and Oxytetracycline (cattle and dogs seem particularly susceptible). The coccidiostat Monensin which is commonly added to cattle and chicken feeds is nephrotoxic to horses - it damages muscle tissue too. Other organs which can be specifically affected by drugs include ototoxicity associated with Gentamicin, and liver toxicity from aflatoxins produced by ''Aspergillus'' species that grow in certain cereal grains, most notably corn.

There are several classes of drugs that are nephrotoxic, and any underlying condition which reduces renal blood flow or known renal failure will increase the toxic effect of the substance. Several classes of antibiotics are nephrotoxic - [[Aminoglycosides|aminoglycosides]] (particularly neomycin and  streptomycin, [[sulphonamides]], [[Antifungal Drugs#Polyene Antifungals|Amphotericin B]] and [[Tetracyclines|Oxytetracycline]] (cattle and dogs seem particularly susceptible). The coccidiostat Monensin which is commonly added to cattle and chicken feeds is nephrotoxic to horses - it damages muscle tissue too. Other organs which can be specifically affected by drugs include ototoxicity associated with [[Aminoglycosides#Gentamicin|Gentamicin]], and liver toxicity from aflatoxins produced by ''Aspergillus'' species that grow in certain cereal grains, most notably corn.

==Specific Poisons==

==Specific Poisons==

[[Ragwort Toxicity]]

[[Ragwort Toxicity]]

==Clinical approach to a suspected poisoning case==

==Clinical approach to a suspected poisoning case==

**maintain respiratory function using oxygen cages and drugs if necessary

**maintain respiratory function using oxygen cages and drugs if necessary

**monitor and correct acid base balance abnormalities

**monitor and correct acid base balance abnormalities

**monitor CNS signs and treat using drugs (for example Diazepam) if required

**monitor CNS signs and treat using drugs (for example [[Benzodiazepines#Diazepam|Diazepam]]) if required

**reduce pain - use cautiously drugs that have profound effects on cardiovascular and respiratory function such as opioids if these systems are showing compromise already  

**reduce pain - use cautiously drugs that have profound effects on cardiovascular and respiratory function such as [[opioids]] if these systems are showing compromise already  

*Provide a specific antidote where the poison is certain and a known antidote available (adder bites, rat bait ingestion)

*Provide a specific antidote where the poison is certain and a known antidote available (adder bites, rat bait ingestion)

==Sudden death cases==

==Sudden death cases==

[[File:anthrax.jpg|right|thumb|150px|<small><center> Photomicrograph of ''Bacillus anthracis'' bacteria using Gram-stain technique. (CDC, Wikimedia commons)</center></small>]]

[[File:Bacillus anthracis Gram.jpg|right|thumb|150px|<small><center> Photomicrograph of ''Bacillus anthracis'' bacteria using Gram-stain technique. (CDC, Wikimedia commons)</center></small>]]

Investigation of sudden death cases in large animals '''MUST''' start with a check for [[Anthrax#Diagnosis|'''ANTHRAX''']] before any further examination is carried out.  

Investigation of sudden death cases in large animals '''MUST''' start with a check for [[Anthrax#Diagnosis|'''ANTHRAX''']] before any further examination is carried out.  

Try and examine the animal in the place where it fell so that you can look for signs of a struggle/convulsions or any obvious poisons nearby such as yew trees. Look for evidence of lightning strikes too, such as a damaged tree nearby. Check food and water troughs carefully for signs of any contamination. Where groups of animal are affected, examine all the animals present carefully using a full clinical examination as you may get a whole range of symptoms and abnormalities from individual animals which will increase the accuracy of your final diagnosis.  Make very careful notes as your findings may well become crucial at a later date if any further investigation (or court case) is required. Approach these cases as a search for clinical disease or accidental death as this is far more likely than poisoning statistically. As always, take a full clinical history from the owner.  

Try and examine the animal in the place where it fell so that you can look for signs of a struggle/convulsions or any obvious poisons nearby such as yew trees. Look for evidence of lightning strikes too, such as a damaged tree nearby. Check food and water troughs carefully for signs of any contamination. Where groups of animal are affected, examine all the animals present carefully using a full clinical examination as you may get a whole range of symptoms and abnormalities from individual animals which will increase the accuracy of your final diagnosis.  Make very careful notes as your findings may well become crucial at a later date if any further investigation (or court case) is required. Approach these cases as a '''search for clinical disease or accidental death''' as this is far more likely than poisoning statistically. As always, take a full clinical history from the owner.  

 

===Pathological Examination===

===Pathological Examination===

Note any signs of struggle and check the mouth carefully to check for substances such as yew. Check for external sign of trauma or burning (lightning). Open the carcass carefully noting any unusual smells present. Phosphorous poisoning gives a faint smell of garlic, metaldehyde poisoning causes a formalin smell, phenol poisoning smells like carbolic soap and cyanide poisoning created a 'silver polish' smell. These are quickly lost once the carcass has been opened. Check the mucous membranes - bright red membranes can suggest cyanide poisoning, brown membranes are associated with nitrate poisoning. Check for evidence of internal bleeding, and examine the entire GI tract carefully. Some plant toxins such as ragwort demonstrate delayed toxicity so are not detected in the GI tract at time of death. Examine all internal organs, recording the condition of target organs such as the gut, liver, kidneys lungs, heart and CNS. Take the time to contact your regular laboratory and ask them for advice on what samples to collect for laboratory analysis. Always collect duplicate samples in case of any postal delivery problems and label fully at the time of collection. Fresh (or frozen if necessary) samples are often required for analysis of poisons, and faecal and urine samples should be free from preservative. Use glass rather than plastic pots and record all the samples collected. Formal saline samples are indicated where histology is required.

Note any '''signs of struggle''' and '''check the mouth''' carefully to check for substances such as yew. Check for '''external sign of trauma''' or burning (lightning). Open the carcass carefully noting any unusual '''smells''' present. Phosphorous poisoning gives a faint smell of garlic, metaldehyde poisoning causes a formalin smell, phenol poisoning smells like carbolic soap and cyanide poisoning created a 'silver polish' smell. These are quickly lost once the carcass has been opened. Check the '''mucous membranes''' - bright red membranes can suggest cyanide poisoning, brown membranes are associated with nitrate poisoning. Check for evidence of '''internal bleeding''', and examine the entire '''GI tract''' carefully. Some plant toxins such as ragwort demonstrate delayed toxicity so are not detected in the GI tract at time of death. Examine '''all internal organs''', recording the condition of target organs such as the gut, liver, kidneys lungs, heart and CNS. Take the time to contact your regular laboratory and ask them for advice on what samples to collect for laboratory analysis. '''Always collect duplicate samples''' in case of any postal delivery problems and label fully at the time of collection. Fresh (or frozen if necessary) samples are often required for analysis of poisons, and faecal and urine samples should be free from preservative. Use '''glass rather than plastic pots''' and record all the samples collected. Formal saline samples are indicated where histology is required.