GUJHS. 2008 Dec; Vol. 5, No. 2.
Heavy Metal Toxicity
Journal of Toxicology
Volume 2011 (2011), Article ID 870125, 21 pages
A Quick Review of Mercury Poisoning
- Most human exposure results from fish consumption, dental amalgam, or occupational exposure.
- Approximately 80% of metallic mercury vapor outgassed from amalgams is absorbed through inhalation, compared with about 7 to 10% absorption of ingested metallic mercury, and about 1% absorption of metallic mercury through skin
Important Elemental Forms:
- Mercury vapor: Most toxic form. Transported to the brain, either dissolved in serum or adherent to red cell membranes.
- Metallic mercury: Passes easily through the blood brain barrier and through the placenta. Rapidly oxidized, although not so quickly as to prevent considerable uptake by the central nervous system
- Poisons cellular function by altering the tertiary and quaternary structure of proteins and by binding with sulfhydryl and selenohydryl groups.
- The chief target is the brain, but peripheral nerve function, renal function, immune function, endocrine and muscle function, and dermatitis.
- Low-level exposures: nonspecific symptoms like weakness, fatigue, anorexia, weight loss, and gastrointestinal disturbance
- Higher exposure levels:
- Mercurial tremor: fine muscle fasciculations punctuated every few minutes by coarse shaking.
- Erethism: severe behavior and personality changes, emotional excitability, loss of memory, insomnia, depression, fatigue
- Acute myocardial infarction, carotid atherosclerosis
- Blood and urine levels correlate fairly well to each other, but not to total body burden
- It has not been possible to set a level for mercury in blood or urine below which mercury related symptoms will not occur.
- DMPS: increases in urinary mercury output; evidence of decreased body burden
- Safer than British Anti-Lewisite and more potent than DMSA
Hepatic encephalopathy is a disease that can wreak havoc on both patients and their families. Take a look below at this provocative movie about how HE can transform lives…
With the advent of advanced imaging, we saw the rise of incidental (i.e. asymptomatic) medical findings of unknown significance. This can pose a difficult question for the clinician and the patient. The Wall Street Journal highlights some of the issues surrounding the accidental diagnosis.
JAMA Intern Med. 2014;174(11):1734-1735. doi:10.1001/jamainternmed.2014.3501
Thanks to Dr. Lee for a great talk today. Feel up for the challenge? Take this short quiz on the microbiology of pathogens that cause pneumonia.
There are several trials that explore additional options for the treatment of hepatic encephalopathy. Earlier this month, UT Southwestern researchers (including Dr. Amit Singal, Dr. Jennifer Cuthbert, and other former members of our division of Gastroenterology and Hepatology) published the results of The HELP Randomized Clinical Trial, which compared lactulose to polyethylene glycol (AKA miralax, or golytely!) for the treatment of HE. They concluded that “PEG led to more rapid HE resolution than standard therapy, suggesting that PEG may be superior to standard lactulose therapy in patients with cirrhosis hospitalized for acute HE.” Check out the article at JAMA Internal Medicine.
AMA Intern Med. 2014;174(11):1727-1733. doi:10.1001/jamainternmed.2014.4746.
From the International Journal of Hepatology, here is a more extensive review of the pathophysiology, diagnosis, and treatment of HE.
Z. Poh and P. E. J. Chang, “A Current Review of the Diagnostic and Treatment Strategies of Hepatic Encephalopathy,” International Journal of Hepatology, vol. 2012, Article ID 480309, 10 pages, 2012. doi:10.1155/2012/480309