Mercury poisoning

MERCURY

 1.Elemental mercury

• Quicksilver

2.Inorganic mercury salts

• Mercurous
• Mercuric

3. Organic mercury compounds

• Short chain mercury(methylmercury)
• Long chain mercury compounds
• The most poisonous Mercury salt is chloride
  

Occupational  Exposure 

1.Elemental mercury

• Amalgam makers, Barometer maker, Ceramic workers
• Dentists, Electroplaters, Jewelers, Thermometer makers, Paint makers and Mercury refiners

2.Inorganic

• Dye makers, Explosive makers, Tannery workers ,Disinfectant

3.Organic

• Drug makers, Bactericide makers, Farmers, Fungicide makers, seed handlers, Histology technicians

Nonoccupational  Exposure 

1. Medicinal

• Antiseptic, calomel teething powders, dental amalgam, diuretics
• Laxatives, preservatives

2.  Food

• Fish,grains,seeds(treated)

3.  Others

• Button batteries,Compact fluorescent lamp,Incandescent bulb,Fluorescent lamp

Mechanism of Action

• Mercury ions produce toxic effects by protein precipitation,  enzyme inhibition, and generalized corrosive action
• Binds to sulfhydryl groups as well as to phosphoryl, carboxyl, amide, and amine functional groups.

Clinical Manifestations

• Acute inhalation of elemental mercury
• Acute ingestion of mercuric salts
• Sub acute or chronic inorganic mercury intoxication
• Acrodynia(pinks disease)
• Methyl mercury intoxication

Acute Toxicity(elemental mercury)

• Primary target organs( in case of inhalation are : Lungs , peripheral and central nervous system 
• Initial effects- Pulmonary effects
• Ingestion- Retain in appendix  systemic mercury poisoning
• Injection- Abscess,embolization,granuloma formation

 Chronic Exposure

Inhalation

• Classical triad of Gingivostomatitis, Tremor, Neuropsychiatric illness

 Tremors

•  Resting and intentional( MAD HATTER SHAKE )

Erethism

• Neuropsychiatric symptoms, 
• Memory dysfunction, shyness loss of self confidence

Ophthalmic

• Brown light reflex from anterior capsule of the lens  vascular changes at the corneoscleral junction

 Acrodynia(Pink disease/Feer’s disease)

• Chronic mercury exposure that occurs in infants and children

 General symptoms

•  Excessive sweating,tachycardia,irritability,anorexia,photophobia
•  insomnia
• Tremors
• Paresthesias, decreased tendon reflex and weakness
• Skin

1. Painful pinkish red discoloration of the extremities
2. Rash may be urticarial, vesicular and hemorrhagic
3.  Hyperkeratotic induration of palms soles and face

 Acute ingestion(Inorganic salts)

• Target organs are GIT and kidney(PCT)), nervous system
•  Grayish discoloration of mucous membrane
•  Metallic taste
•  Hematemesis
•  Hematochezia
•  Hemorrhagic gastroenteritis
•  Fluid loss
•  Acute tubular necrosis

 Chronic Intoxication(Organic Mercury)

• Target organs
• Central nervous system, liver and congenital abnormalities

 DELAYED NEUROTOXICITY

•  paresthesia involving lips, nose, and distal extremities
•  Headaches,fatigues,ataxia,dysarthria,visual field  constriction and blindness
•  Severely effected patients lay in mute rigid position  primitive reflexive movements 
•  Dysarthria, ataxia and constricted vision
• GI SYMPTOMS
• colitis that resembles diptheritic colitis
• COARSE  TREMORS
•  RESPIRATORY DISTRESS
•  DERMATITIS

 Diagnosis

Acute

•  Blood ,urine level
•  Abdominal radiography
•  Endoscopy

 Chronic

•  Hair analysis
•  Electromyography and nerve conduction studies

Treatment

Decontamination

•  Inhalation
•  Ingestion
•  Injection

 Chelation

• Disodium EDTA is used as an antidote 
• Succimer is drug of choice in elemental and organic mercury
•  10mg/kg three times daily for five days
• Chelating agent for copper, mercury, lead which is given by oral route is Penicillamine
• BAL (Dimercaprol)
•  First choice in inorganic mercury
•  3-5 mg/kg every 4 hours for first 24 hours
•  Then every 12 hours for second 24 hours, then once a day for 3 days

PostMortem Finding

Acute

• Appearance of corrosive poison if the poison taken in concentrated form
•  The tongue is white and sodden
•  Diffuse grayish white escharotic appearance
•  Mucous membrane of alimentary tract is inflamed and corroded
•  Difficult to remove the organs without rupture
•  Selective action on caecum and large intestine
•  Inflammation ,ulceration, gangrene
•  Liver and heart show fatty degeneration

 Chronic

• Changes in large intestine due to reexcretion
• Tubular nephritis
• Fatty degeneration of the liver and cardiac muscles

 Chronic elemental mercury

• Pleural effusion, pulmonary granuloma, bronchiectasis

 Acute inorganic mercury

• Severe hemorrhagic necrosis of GIT

 Chronic organic mercury

• cortical and cerebellar atrophy
•  Corpus collasum hypoplasia
•  Demyelination of pyramidal tract
•  In addition to routine viscera
•  Bones, teeth ,hairs and nails should also be preserved for chemical analysis