TOX 7 - Arsenic Flashcards

1
Q

Arsenic compounds

A

Elemental is basically harmless

forms which enter the body:

  • Inorganic arsenic salts:
  • Trivalent arsenite- highly toxic, poor solute, but can be absorbed through skin
  • Pentavalent - less toxic, more soluble
  • or arsenates
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2
Q

Pharmacodynamics

A

Binds to SH groups (sulfhydryl ) and inhibits enzymes–> interfering with oxidative phosphorylation

Strong capillary poison

Possible carcinogenic

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3
Q

Acute intoxication symptoms

A

initial - nausea, vomiting, dizziness

mid - latency period

late - severe vomiting and diarrhoea (rice water stool) -> severe dehydration

  • gastroenteritis, hematemesis, severe diarrhea → hypovolemic shock; arrhythmias,
  • CNS symptoms (encephalopathy, delirium, coma), pancytopenia
  • weeks later – ascending peripheral neuropathy (may result neuromuscular respiratory failure)
  • month later - transverse white striate on the nails
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4
Q

Treatment of acute intox

A

Gastric lavage

Chelation therapy (dimercaprol)

Supportive treatment

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5
Q

Chronic intoxiaction

A

Skin change, anorexia, cachexia, GI problems etc -> death

  • weakness,
  • peripheral neuropathy (socking-glove pattern),
  • anemia,
  • liver and kidney damage,
  • skin changes - hyperkeratosis, hyperpigmentation, general cachexia
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6
Q

Arsine gas poisoning (ASH3)

A

Very powerful haemolytic agent - fever, icterus, renal damage

Supportive treatment

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7
Q

Most frequent source of intoxication- arsenic

A
  1. industry,
  2. agriculture (herbicides, insecticides),
  3. wood, preservatives,
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8
Q

Major route of absorption - arsenic

A
  1. respiratory and
  2. GI tract
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9
Q

distribution of arsenic

A

Distribution

  1. soft tissues,
  2. first of all liver and kidney,
  3. later skin, hair, nail
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10
Q

Arsenic poisoning mechanism

A

Interferes with over 200 enzymes in the body

  • ATP depletion
  • Carcinogenic: Interfere with base and nucleotide excision repair –> cancer risk increases
  • Oxidative stress
  • Disrupts signal transduction pathways
  • Atherosclerosis
  • Diabetes
  • Acute lethal dose: 70 – 200mg or 1 mg/kg/day
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11
Q

arsenic acute lethal dose

A

• Acute lethal dose: 70 – 200mg or 1 mg/kg/day

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12
Q

arsenic poisoning diagnosis

A

Diagnosis:

  • Measurement of arsenic in blood, urine, hair and fingernails
  • Symptoms
  • Drinking water measurements
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13
Q

treatment of arsenic poisoning

A

Treatment:

  • Supportive treatment
  • Chelation:  Dimercaprol  Dimercaptosuccinic acid
  • Calcium sodium edetate
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