Mercury Toxicity Differential Diagnoses

Updated: Nov 05, 2018
  • Author: David A Olson, MD; Chief Editor: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS  more...
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Diagnostic Considerations

Mercury poisoning can be misdiagnosed because of the insidious onset and nonspecific signs and symptoms. Without a complete history, mercury toxicity, especially in elderly individuals, can be misdiagnosed as Parkinson disease, senile dementia, metabolic encephalopathy, depression, or Alzheimer disease.

Testing for mercury exposure is warranted if examination findings are consistent with Minamata disease, particularly if the disease occurs in multiple patients without clear etiology. This is especially true in populations in whom fish is a major part of their diet.

Consider mercury intoxication in the differential diagnosis when unexplained neuropsychiatric disturbances are coupled with renal abnormalities.

Conditions to consider in the differential diagnosis of mercury toxicity include the following:

  • Adverse effects of therapeutic medication (eg, lithium, theophylline, phenytoin)

  • Alzheimer disease

  • Cerebellar degenerative disease or tumor

  • Delayed neuropsychiatric sequela of carbon monoxide poisoning

  • Ethanol or sedative hypnotic drug withdrawal

  • Lacunar infarction

  • Metabolic encephalopathy

  • Parkinson disease

  • Senile dementia

Conditions to consider in the differential diagnosis of inorganic mercury toxicity (mercury salts) include the following:

  • Acid ingestion

  • Alkali ingestion

  • Arsenic toxicity

  • Iron toxicity

  • Phosphorus toxicity

  • Similar to the causes of acute gastroenteritis

Conditions to consider in the differential diagnosis of organic mercury toxicity in neonates include the following:

  • Cerebral palsy

  • Intrauterine hypoxia

  • Teratogenic effects in the embryo

Differential Diagnoses