arsenic and mercury Flashcards
Forms of Mercury
The nature of the poisoning syndrome varies depending upon the form of mercury.
1. elemental metal mercury
2. inorganic salts – mercuric chloride (ccause tissue necrosis/ shock)
3. organic mercury – methyl mercury (not corrosive damage)
-must write the type of mercery as answer not just mercury
absorption of mercury
Metal mercury - well absorbed by inhalation
Inorganic mercury – relatively poor absorption
Organic mercury – well absorbed through GIT and skin
- lipophilic in nature
mercury clinical
Two syndromes are seen clinically. Exposure to inorganic mercury will produce a gastric
intestinal and neurological syndrome. Organic forms of mercury produce only a
neurological syndrome
GIT (inorganic only) – anorexia
- vomiting
- salivation
- diarrhea
- stomatitis, ulcer
CNS (organic)
- ataxia, tremors
- blindness
- terminal convulsions
- depression
- paresis or paralysis
kidney: hematura, uremia
skin alopecia
pathology of mercury poisoning
Severe gastrointestinal lesions are observed with inorganic mercury exposure. Both
forms of mercury produce degenerative changes in other organ systems.
GIT (inorganic) – gastroenteritis, stomatitis
- mucosal hemorrhage and edema
- ulcers
Kidney - interstitial nephritis
- tubular necrosis
Lung – edma
- bronchitis
- hydrothorax
Liver – mild necrosis
CNS: encephalomalacia, cerebellar atrophy in utero, degeneration
Treatment of Mercury Poisoning
A long half-life (70 days), plus degenerative changes in many organs limits the treatment
success. Sodium thiosulfate, egg whites, milk, astringents and fluids have been used as
treatments. Chelators, such as, penicillamine or British antiLewisite may be effective
ecomonics of mercury
The insidious nature and irreversible effects of mercury limit livestock treatment options.
Extended milk and meat residues and its highly teratogenic nature encourage most
veterinarians to recommend euthanasia and disposal.
arsenic poisoning
There are two basic forms of arsenic including the organic and inorganic (arsenates,
arsenites) forms. The organic forms are much less toxic. Two distinct clinical
syndromes are observed.
organic: CNS, low mortality
inorganic: 100% mortality, GIT severe
sources of arsnic
- dips, sprays for ectoparasite control
- herbicides
- heart worm medication – thiacetarsamide
- feed additive – arsanilic acid
clinical manifestations of INORGANIC arsnic
Acute Syndrome
- high mortality
- sudden onset
Characterized by vomiting, abdominal pain, weakness, ataxia, recumbancy, shock,
diarrhea, and death within 3 – 4 hours. Terminal convulsions may be observed.
Subacute Syndrome
The disease has a longer duration ranging from 2 – 7 days. There are more neurological
manifestations present.
GIT – colic
- vomiting
- diarrhea, salivation
- grinding teeth
- anorexia, thirst
The animals are usually dehydrated and in shock.
CNS – muscle tremors, sizers
diagnosis of arsnic
Clinical manifestations including GIT and neurological signs may suggest inorganic
arsenic poisoning. Analysis of liver, kidney, hair or food samples may be useful. A
severe gastroenteritis and degenerative changes in most organ systems, may be evident
Treatment of Inorganic Arsenic Poisoning
At high levels of exposure, most animals die. Sodium thiosulfate, British antiLewisite
and astringents may be helpful. Fluid therapy for shock is essential
Differential Diagnosis Inorganic Arsenic
Sudden death, gastrointestinal and neurological symptoms are typically present.
CNS – lead
- mercury
- salt
Organic Arsenic Poisoning
These forms of arsenic are much less toxic. Historically, they have been used as feed
additives.
1. arsanilic acid
2. roxarsone
3. nitrophenylarsonic acid
Improper feed formulation is often the source of the problem.
organic arsnic poisoning clinical
Depending upon the level in the feed, the syndrome may take weeks to develop. Since
the gastrointestinal tract is not affected, animals continue to consume feed until the late
stages of the disease.
Acute Poisoning Organic Arsenic:
With about one week, symptoms begin to appear.
- incoordination, ataxia
- paralysis
- blindness
-NO GI NOT ANOREXIC
Diagnosis of Organic Arsenic Poisoning
A history of exposure and clinical manifestations (neurological) will suggest a tentative
diagnosis of organic arsenic poisoning. Feed analysis is recommended. Since arsenic is
rapidly excreted, tissue analysis should be interpreted with caution. The animals will
usually make an uneventful recovery if the feed is removed early.
Differential Diagnosis
Other agents producing a comparable neurological syndrome include:
1. methyl mercury
2. salt
3. 2, 4-D
ecomonics of arsnenic poisoning
If the poisoning is recognized early, and the feed is withdrawn, the animals recover
rapidly and can be shipped in the near future since withdrawal times are very short.
