Dr. Badar Uddin UmarMBBS, M.Phil (Pharmacology)

ARSENIC POISONING

PROPERTIES OF ARSENIC (AS) It is a heavy metallic inorganic irritant poison

Inorganic arsenic compounds are poisonous:

Arsenic trioxide, sodium arsenite, arsenic sulphide, copperarsenite, etc.

Metallic arsenic is non poisonous if ingested because it is not absorbed

MECHANISM OF ACTION

Arsenic ion binds with sulphydryl group (-SH) of enzymes in the liver, lungs, intestinal walls, spleen

It replaces phosphorus in bones where it may remain for years

It also gets deposited in the hairs

SIGNS & SYMPTOMS Arsenic poisoning clinically manifests in three

forms -

1. ACUTE FULMINATING TYPE:

• Symptoms occur within half an hour when heavy dose (3-5 gm) is taken

• Acts on sulphhydryl groups of enzymes and capillaries inhibiting cellular metabolism and causing marked dilation of capillaries and myocardial failure resulting in shock and death

Purging precedes vomiting

Stools are rice water throughout and passed as involuntary jet

No pain in the throat

Voice rough & whistling

Conjunctiva is normal

Vomitus is watery

Vomiting precedes purging

Stools are rice water initially and later turn bloodstained

Pain in the throat

Voice remains unaffected

Conjunctiva is inflamed

Vomitus contains mucus, bile and streaks of blood

2.SUB ACUTE TYPE( GASTROENTERITIS TYPE):

Arsenic poisoning Cholera

• When small doses of arsenic are given at repeated intervals • Resembles case of cholera or food poisoning

3. CHRONIC TYPE:

Gastrointestinal: presents with gradual weight loss, malnutrition, fatigue, loss of appetite

Catarrhal changes: presents with running nose, headache, conjunctivitis, bronchial catarrh

Raindrop pigmentation: known to produce milk & roses complexion initially, followed by patchy brown pigmentation of the skin (especially forehead, neck, shoulders)

Presents with a sequence of 5 different set of manifestations

It might also show hyperkeratosis of the skin of palms and soles

Mees lines: whitish lines 1-2 mm breadth across the nails of fingers and toes

Arsenical neuritis: polyneuritis, optic neuritis, paresthesias, atrophy of extensors resulting in wrist and foot drop

Diagnosis: urinary As level of > 100 mg/24 hrs. Blood levels are not reliable

3. CHRONIC TYPE:

TREATMENT Butter and greasy substances act as demulcents

Gastric lavage with warm water or freshly prepared hydrated ferric oxide solution

Hemodialysis is the line of choice in massive arsenic poisoning

BAL is the specific antidote. (3 – 5 mg/kg 4 hourly deep IM for 2 days followed by 2 – 3 mg/kg 6 hourly for 2 days and then every 12 hours for 7 days)

DMSA, Penicillamine can also be used

Symptomatic therapy

Inj. Vitamin B1 helps in peripheral neuritis

POSTMORTEM FINDINGS Stomach: velvety red or brownish, patchy areas

with ulceration. Gastric contents emit garlicky odor

Heart: subendocardial haemorrhage

Other viscera: fatty degeneration of liver, kidney & heart

Brain may show inflammation with haemorrhagic spots

MEDICOLEGAL IMPORTANCE It was considered as an ideal homicidal poison as it

was-

Cheap

Easy to obtain

Could be easily mixed and given

Symptoms were similar to cholera

Accidental poisoning with those who consume for its aphrodisiac effects

Accidental poisoning with contaminated tube well water is common in Asia