Archived case 80 · December 17-December 24, 2010
Metallic Mercury Embolism
Clinical History Withheld
The question posed to readers
What are the pertinent radiologic findings and what is your leading diagnosis?
Images
Imaging findings
Clinical History: Young man withdrew metallic mercury from more than 30 broken thermometers and intravenously injected the material in a suicide attempt (originally withheld) Radiologic Findings: PA (Fig. 1) chest radiograph reveals a multitude of short linear and branching opacities of metallic density, greater than that of the cortical margins of the ribs, extending far out into the periphery of the lungs and more heavily concentrated in the more dependent lower lung zones. Single view of the left forearm (Fig. 2) shows a linear pattern of deposition of the heavy metal in the soft tissues of the forearm at the injection site. Answer Diagnosis: Metallic Mercury Embolism
Diagnosis
Metallic Mercury Embolism
Differential Diagnosis
None
Discussion
The pulmonary embolization of mercury may occur accidentally (e.g., injury from a broken thermometer; venous blood sampling with mercury-sealed syringes) or intentionally after injection by intravenous drug abusers (IVDA) and persons attempting suicide. Self injection of elemental mercury has also been described as a means of improving sexual or athletic performance. Although mercury is relatively viscous in nature, the intravenous injection of mercury readily flows through the veins and is carried to the right heart and then onto the distal pulmonary arterial circuit.
Clinical Findings
Metallic mercury pulmonary embolization may manifest clinically by a metallic taste, gingivitis, excessive salivation, stomatitis, diarrhea, nephrosis, tremor, irritability, excitability, memory loss, and other mental status changes (The Alice in Wonderland’s “Mad Hatter” syndrome). The symptoms are believed to be related to the oxidation of metallic mercury to its more soluble mercuric ion. Pulmonary symptoms may be absent or mild. The mercury deposition in the pulmonary arterial circuit may persist for years after the initial event.
Imaging Findings
Chest Radiography
- Multitude of short linear and branching opacities of metallic density (Fig. 1)
- Usually distributed bilaterally and symmetrically in the distal arterial segments of both lungs (Fig. 1)
- Dependent portions of lung may show a heavier deposition because of the greater blood flow and blood volume (Fig. 1)
- Focal collection of mercury in the right ventricle differentiates embolized mercury from aspirated mercury
KUB (Kidney, Ureter, Bladder Conventional Radiograph)
- Scattered foci of metallic mercury deposits in various solid organs as a result of passage of the mercury from the pulmonary capillaries into the systemic circulation
- Liver
- Spleen
- Kidney
Forearm Radiography (IVDA / Suicide Attempts / Self-Injection)
- Metallic mercury deposition in soft tissues at or along the injection site
Treatment
- Monitor total blood mercury levels (normal < 50 nmol/L)
- Monitor 24-hour urinary mercury excretion (normal < 10 nmol)
- Early surgical debridement of subcutaneous mercury deposits is required to prevent local complications and minimize the risk of systemic absorption and toxicity
- Mixed results with dimercaprol and 2,3-dimercaptosuccinic acid
Prognosis
- Soft tissue collections of metallic mercury can produce local necrosis and may allow for continuous systemic absorption with persistent elevations in blood and urinary mercury levels
- Bronchiectasis may develop as long-term sequela
Selected Readings
- Davey P, Benson M. A Young Man with Heavy Heart. Heart 1999; 82(6): e11.
- Schaumburg HH, Gellido C, Smith SW, et al. Elemental Mercury Neurotoxicity from Self-Injection. Neurology 2009; 72(4): 377-378.
- Soo YO, Wong CH, Griffith JF, Chan TY. Subcutaneous Injection of Metallic Mercury. Hum Exp Toxicol 2003; 22(6): 345-348.
- Wong F, Hung LK, Wong CH, Ho PC. Suicidal Mercury Injection into the Upper Limb: A Case Study. Hand Surg 2004; 9(2): 225-228.
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Original case written by its authors at Virginia Commonwealth University and published at this address as part of a weekly teaching collection. Reproduced here as an archive.