Arsenic Poisoning

• Arsenious  oxide  (AS₂O₃),  also  known  as  arsenic  trioxide  or arsenious,  is  the  most  common  form  of  arsenic used. Therefore, the  term  arsenic  (or  white arsenic) refers  to  arsenious  oxide.

Other  forms  of arsenic:

1. Copper arsenite  (scheele’s  green),
2. copper acetoarsenite  (paris  green  or emerald  green),
3. arsenic  trichloride  (butter  of arsenic),
4. arsenic  trisulphide  (yellow  orpiment  or hartal)
5. arsenic  disulphide  (red  realgar  or manseel)  are  other  forms  of arsenic.

• Fatal dose of arsenic  is  100-200  mg (0.1  to  0.2  gm)
• Some  people take  arsenic  regularly  as aphrodisiac  or tonic  can  tolerate  up to  0.3  gm.  Dose,  and known  as ‘arsenophagist’.
• Fatal period  is  2-3  hours  in narcotic  form and  12  hours  – 2 days  in  gastrointestinal  form.

Arsenic poisoning  may be  acute  or chronic.

(A)  Acute  arsenic poisoning.

It can  present  in  any of the  two  ways :

1) Gastrointestinal  type:

• It is  the  common form  and  resembles  bacterial  gastroenteritis  (e.g.  cholera).
• There is  garlic odour with hemorrhagic  gastroenteritis  and  necrosis of  intestinal  mucosa.  There is  tenesmus  and  anal  irritation.
• Dehydration  may  cause acute  circulatory  collapse, with hypotension,  oliguria and  acute tubular  necrosis  (ATN).

2)  Fulminant  narcotic  form:

• Large  dose of arsenic is  rapidly  absorbed without producing  GI  symptoms.  These are  giddiness,  headache,  myalgia, formication,  vertigo  and  death  in  2-3  hours.

Treatment:  It includes  stomach  wash and  use  of freshly  precipitated  hydrated ferric  oxide  as an antidote  (which forms  ferric  arsenite  a  harmless  salt).

Postmortem  appearance  include:

• Red velvety  mucosa  of stomach  and  sub mucous  petechial  hemorrhage.
• Subendocardial  petechial  haemorrhage.
• Fatty  degeneration  of liver,  kidney  and heart.

(B)  Chronic  arsenic  poisoning

 Chronic  arsenic  poisoning  has  four  stages  :

1) First  stage  (nutritional  and gastrointestinal  disturbances)  :

• The earliest  sign  is  gradual  emaciation. There is  loss  of appetite,  nausea  and  intermittent  vomiting  and  diarrhea.

2)  Second  stage  (catarrhal  changes)  :

• It resembles common  cold, i.e. conjunctivitis, running nose and eyes, coughing etc.

3) Third  stage  (skin rash)  :

• There is  classical  ‘rain  drop pigmentation’ i.e.  patchy  brown  pigmentation of skin.
• At initial stages,  there  is  a  vesicular  eruption  which  may  resemble  nettle rash.
• Hyperkeratosis  of palms  and soles.

• There  are  white  transverse  bands crossing  the  nails, known  as  Mee’s  line, and  indicate  periods  of  arrested growth  due  to  interference  with normal  metabolism.
• There is  alopecia and exfoliative  dermatitis.

4) Fourth  stage (nervous  disturbance):  :

• There  is  sensory  and  motor  (i.e. mixed)  polyneuropathy‘ with painful Paresthesia of  hands  and feet and  muscle  tenderness.
• There may be evidence  of  liver  (fatty  liver)  and  kidney damage  and bone  marrow  suppression
• causing  anemia  and other  cytopenias.  Heart may  also  be  involved.
• Chronic arsenic  exposure  can  also  cause  ‘black  foot  disease’ form  of  peripheral  vascular  disease,  causing gangrene  of lower  limbs.
• Arsenic  is  carcinogenic,  can cause  cancers  of skin  (squamous  cell  carcinoma and  basal  cell  carcinoma) of lung, Iiver,bladder, kidney,  larynx  and lymphoid  system leukemia).

Investigations  in  As  poisoning  include:

• Excretion  of > 100 mg of arsenic  in  24  hours  urine,
• Atomic  absorption spectroscopy,
• Neutron  activation  analysis.
• Marsh’s  test and Reinschs  test are  obsolete  now.

Postmortem  Appearance

• APPEARANCE:  There  is  emaciation, fatty  degeneration  of  liver,  kidney  and  heart and  congestion  of Gl-tract’
• Arsenic  retard  putrefaction  and  can  be found in  bones  and  nails for several years.
• It  can  be  detected in  completely  decomposed  bodies, charred  bones , or  ashes,
• Hair nails  and  bone  sample  should  be taken  for  analysis.
• Arsenic also  delay  rigor  mortis  which  lasts  longer(In a suspected case of death due to poisoning where cadaveric rigidity is lasting longer than usual, it may be a case of poisoning due to arsenic)

ABSORPTION  AND  DISTRIBUTION  OF ARSENIC

• Arsenicals  are  rapidly  absorbed  from  GIT and  skin’
• Arsenic  is  present in  almost  all tissues.
• After absorption, arsenic  is  found  in  the  greatest  quantity  in  liver  followed  by  kidney and Spleen.
• Brain  consists  of least  amount  as  arsenic  does not cross  BBB.
• In  cases in  which  life  is  prolonged,  it  may be found  in  muscles  (for  a matter of  days),  in  bones  (for  a matter of weeks) and in  keratin  tissues  like  skin,hair and nail  (for  months)

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