Exposure to mercury can occur from breathing contaminated air, from eating foods that have acquired mercury residues during processing, from exposure to mercury vapor in mercury amalgam dental restorations, and from improper use or disposal of mercury and mercury-containing objects, for example, after spills of elemental mercury or improper disposal of fluorescent lamps.All of these, except elemental liquid mercury, produce toxicity or death with less than a gram. Mercurys zero oxidation state (Hg0) exists as vapor or as liquid metal, its mercurous state (Hg+) exists as inorganic salts, and its mercuric state (Hg2+) may form either inorganic salts or organomercury compounds.Consumption of whale and dolphin meat, as is the practice in Japan, is a source of high levels of mercury poisoning. Tetsuya Endo, a professor at the Health Sciences University of Hokkaido, has tested whale meat purchased in the whaling town of Taiji and found mercury levels more than 20 times the acceptable Japanese standard.Human-generated sources, such as coal-burning power plants emit about half of atmospheric mercury, with natural sources such as volcanoes responsible for the remainder. A 2021 publication investigating the mercury distribution in European soils found that high mercury concentrations are found close to abandoned mines Almadén (Castilla-La Mancha, Spain), Mt. Amiata (Italy), Idrija (Slovenia) and Rudnany (Slovakia)] and coal-fired power plants. An estimated two-thirds of human-generated mercury comes from stationary combustion, mostly of coal.
Causes
It is important to distinguish association and causation. The vast majority of trigger digits are idiopathic, meaning there is no known cause. Some speculate that repetitive forceful use of a digit leads to narrowing of the fibrous digital sheath in which it runs, but there is little scientific data to support this theory. The relationship of trigger finger to work activities is debatable and there are arguments for and against a relationship to hand use with no experimental evidence supporting a relationship. Diagnosis
Diagnosis is made on interview and physical examination. More than one finger may be affected at a time. It is most common in the thumb and ring finger. The triggering more often occurs while gripping an object firmly or during sleep when the palm of the subject’s hand remains closed for an extended period of time. Upon waking, the affected person may have to force the triggered fingers open with their other hand. In some, this can be a daily occurrence. Treatment
Corticosteroid injections can cure trigger digits. Treatment consists of injection of a corticosteroid such as methylprednisolone often combined with a local anesthetic (lidocaine) at the A1 pulley in the palm. The infiltration of the affected site is straightforward using standard anatomic landmarks. There is evidence that the steroid does not need to enter the sheath. The role of sonographic guidance is therefore debatable. Injection of the tendon sheath with a corticosteroid is effective over weeks to months in more than half of people.