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Case Report |
Address correspondence to Stephen E Vernon, M.D., Department of Pathology, University of Miami/Jackson Memorial Hospital, East Tower Rm 2042, 1611 NW 12th Ave., Miami, FL 33136, USA; tel 305 585 5935; fax 305 585 1029; e-mail svernon{at}med.miami.edu.
Abstract
A 31-yr-old man presented to his general physician complaining of pain and swelling in the soft tissue of both hips. He initially denied knowledge of the etiology, but after elemental mercury droplets were expressed from the skin wounds by manual manipulation, he admitted that the source was self-administered sc injections. He did not provide a reason for this or give the time-frame of the injections. The areas of skin discoloration and soft tissue induration were completely excised and the wounds healed uneventfully. Blood levels of mercury declined gradually after excision. Examination of the resected skin and subcutis revealed subcutaneous abscesses containing droplets of elemental mercury, released easily when the abscesses were sectioned. Sections showed dark droplets of metallic mercury associated with necrosis and microabscess formation, with areas of foreign body giant cell reaction. Disposal of the residual tissues and mercury by incineration would release the volatile elemental mercury into the atmosphere, where it would subsequently be returned to earth in rain water, be converted to methyl mercury by microorganisms, and enter the food chain. The US Environmental Protection Agency has recommended caution in consuming foods containing methyl mercury and has provided guidelines for consuming foods believed to contain increased amounts of mercury. Mercury is readily available in the United States by over-the-counter sales to consumers, and in some cultures elemental mercury is used in ritualistic practices. Skin injection cases are infrequent, but histopathology laboratories should recognize this phenomenon and be prepared to dispose of Hg-contaminated tissues in an environmentally sound manner.
(received 16 September 2004; accepted 10 November 2004)
Keywords: elemental mercury injection, mercury disposal, laboratory safety
Introduction
Mercury is widely used in industry (eg, fabrication of batteries, switches, and high intensity lighting) and has also formerly been used in agriculture (as methyl mercury) as an antifungal agent. Mercury compounds have a history of medicinal use (eg, for treatment of syphilis and as diuretics). Minute amounts of mercury can be found in Chinese and Ayurvedic medicines and are said to be rendered non-toxic by extensive processing before use. Mercuric salts are used in products such as mercurochrome. The dental profession has long used mercury in preparing amalgam dental fillings. The sale of elemental mercury is unrestricted in the United States, and it is readily available in religious shops, or "botanicas," for use as a talisman or in various rituals [1]. Although there has been considerable concern over the real and potential toxicity of mercury, mercury and its compounds are still ubiquitous in the modern world.
Accidental injection of elemental mercury, usually from broken thermometers, has been reported [2–4]. Therapeutic or self-injection of elemental mercury has also been described [5,6]. The following case report is an example of self-injection of elemental mercury, resulting in soft tissue abscesses and elevated blood Hg levels.
Case Report
A 31-yr-old man presented to his general physician complaining of swelling and pain in the soft tissues over both hips. After initially denying knowledge of the cause, he later admitted to injecting himself with elemental mercury (the source was not verified, but is believed to have come from broken thermometer bulbs). The patient gave no history of recreational drug use, and did not report any nausea, vomiting, or diarrhea. He had no chest pain or shortness of breath. Physical examination revealed a healthy-appearing male with stable vital signs and no acute distress. The general examination was unremarkable. On both hips there were 3 x 5 cm areas of induration with round foci of skin discoloration, greater on the right side than the left, approximately 3–5 mm in diameter. There was no adenopathy. Neurologic examination was normal.
Laboratory results were as follows: serum sodium 141 mmol/L, potassium 4.4 mmol/L, chloride 108 mmol/L, CO2 2 mmol/L, urea nitrogen 17 mg/dl, creatinine 0.8 mg/dl, total protein 6.9 g/dl, albumin 3.7 g/dl, bilirubin 0.7 mg/dl, and liver function tests normal, blood WBC 16,000 (70% neutrophils), blood hemoglobin 15.3 gm/dl, urine screen for drugs of abuse negative, and blood mercury level 120 µg/L (normal <10). Urine mercury analysis was not performed.
The patient underwent wide surgical excision of the bilateral hip abscesses, followed by copious irrigation of the site, and primary closure following complete hemostasis. Subsequent blood mercury levels on post-operative days 2 and 22 gave values of 72 and 16 µg/L, respectively. The surgical wounds healed uneventfully. The patient was referred for psychiatric evaluation.
Pathologic Studies
The pathologic specimens consisted of formalin-fixed skin and subcutaneous fat from the right and left hips, submitted separately. These were each about 8 x 5 x 4 cm and showed foci of dusky gray skin discoloration, approximately 3–5 mm in diameter. Sectioning through these areas revealed underlying hemorrhagic and necrotic abscesses, up to 1.5 cm in diameter, which on sectioning exuded specks and droplets of elemental mercury from 0.1 to 1.5 mm in diameter (Fig. 1
).
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Representative sections of skin and subcutis showed dermal abscesses (Fig. 2), often surrounding spherical or irregularly shaped droplets of mercury, which appeared black on microscopic examination (Fig. 3). There were also areas of more granulomatous character, with occasional foreign body type giant cells, histiocytes, lymphocytes, and plasma cells (Figs. 3 and 4). The bacterial and fungal stained sections were negative for microorganisms.
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Mercury is increasingly recognized as a significant toxin and has received considerable attention in the scientific literature and the lay press. Toxicity from contaminated fish in Minamata, Japan, has been widely reported and poisoning from methylmercury has been referred to as Minamata disease [7]. A less publicized but massive poisoning occurred in Iraq in 1971–72 when grain intended for seed (treated with a methylmercurial fungicide) was processed for flour, made into bread, and widely ingested, resulting in >500 deaths and hospitalization of thousands more [8]. Although these cases involved methyl mercury rather than elemental mercury, the eventual fate of atmospheric elemental mercury is conversion by microbes to methylmercury, whereupon mercury enters the food chain and is subject to bioamplification [9]. In a small number of previously reported cases, when elemental mercury was injected directly into tissues, a granulomatous foreign body-giant cell reaction was typically observed, with a mixed inflammatory cellular infiltrate composed of polymorphonuclear leukocytes, lymphocytes, histiocytes, plasma cells, and occasional eosinophils, as in the present case. Metallic mercury in tissue sections appears as dark, opaque globules, usually spherical, and of varying size and number [2–4]. Krohn et al [10] provided clinical guidelines for the surgical removal of tissues injected with mercury.
Dental offices represent a unique environment in which accidental exposure to elemental mercury may occur. The American Dental Association has developed and promulgated mercury hygiene recommendations, eg, periodic atmospheric monitoring and spill clean-up procedures [11]. For a thorough review of the toxicity of mercury, readers may consult publications of Clarkson et al [9,12].
All CAP-accredited clinical laboratories are mandated to have a chemical hygiene plan, with policies and procedures for hazardous waste disposal [13]. Clinical laboratories may produce mercury-containing hazardous wastes during routine operations, eg, the use of fixatives such as "B-5," Zenker’s, and Helly’s solutions. Elimination of these products by introduction of alternative fixatives, non-mercury thermometers, and ion-selective electrodes has been recommended [14].
The US Environmental Protection Agency and the American Hospital Association reached an agreement on mercury reduction, with an announced goal of elimination by the year 2005. Since the sale of elemental mercury remains unregulated and elemental mercury is available to the general public, clinical laboratories may be faced with the disposal of unwanted mercury from patient sources, as in the present case. The author’s laboratory has documented policies for the handling of toxic wastes and has contracted with a licensed toxic waste disposal company to pick up and properly dispose of such wastes, rather than simply discard them with leftover tissue specimens.
References
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