A Jar of Mercury at Home: Two Siblings' Severe Mercury Poisoning, Connecticut, 2022

Summary

• Elemental mercury vapor poisoning causes such varied symptoms that it's easily missed, especially when no one mentions the exposure.
• In July 2022, two siblings in Connecticut, aged 5 and 15, developed severe thrombocytopenia — very low platelet counts — about 10 days after playing with a jar of mercury they found at home. Infections and blood disorders were suspected first.
• Both needed chelation to draw the mercury out, and the younger child needed many treatments over weeks. Mercury is still found in glass thermometers, fluorescent lights and other devices, so quick recognition and notifying public health matter.

Two sick children

Three weeks after her family moved into an older single-family home, a 5-year-old girl came to the emergency department at Connecticut Children's with 3 days of a petechial rash, mouth ulcers, sore throat, chills, fever, nosebleeds and weakness. She had a fever of 102.4°F (39.1°C), was breathing and beating fast, and had an enlarged spleen. Her platelet count was below 2,000/μL — normal is 150,000–700,000 for her age — with anemia and signs of inflammation and strain on the heart.

With pets and mice in the home, doctors considered tickborne and other infections and immune thrombocytopenic purpura, and gave antibiotics, a platelet transfusion and intravenous immune globulin (IVIG). Her fever went, but her platelets stayed below 10,000/μL. A bone marrow test on the sixth day was normal and full of platelet-making cells — pointing to platelets being destroyed in the blood.

Her 15-year-old half-brother arrived at the same time with a 4-day history of the same rash and mouth ulcers, plus chills, fatigue and belly pain. He had high blood pressure, fast breathing, an enlarged spleen, platelets below 2,000/μL, and signs of kidney damage — heavy protein in the urine, low albumin and swelling, consistent with nephrotic syndrome. Two platelet transfusions and IVIG didn't help.

Finding the mercury

After 6 days with no answer, doctors called the Connecticut Poison Control Center, whose toxicologists asked about mercury. The boy then told them his sister had found a small jar (6–8 fluid ounces) full of mercury about 10 days before they were admitted. It spilled on the carpet of a second-floor bedroom; he spent about 30 minutes scooping it up with his hands, recovering about half. Nobody else knew. He kept sleeping in the room and she kept playing there, and a week later another family member vacuumed the carpet.

Clearing the house

The state Department of Energy and Environmental Protection and the local health department evacuated the family to temporary housing at once. Mercury vapor measured 174.6 μg/m³ outside the front door, 99.4 outside the back door, and over 999 on the second floor — saturating the meter. Federal guidance treats 1 μg/m³ or more as unacceptable for living in. Exposure was highest in the bedroom where the spill happened. The jar predated the family's ownership, and no one knows what it was for. The house was decontaminated and the family eventually moved back.

Treatment and recovery

Both children received dimercaptosuccinic acid to chelate the mercury (an off-label use).

• The boy went home on day 15 with platelets at 47,000/μL, finished a 19-day course of chelation as an outpatient, and his blood pressure and urine protein returned to normal.
• The girl's platelets stayed low despite two courses of chelation, a steroid pulse and three IVIG infusions. On day 42, doctors started weekly romiplostim (also off-label), which stimulates platelet production; her count rose and she went home on day 46, with mercury down to 39 μg/L. After 7 weekly doses her platelets were normal at 250,000/μL, and stayed normal.

Platelet counts, blood mercury concentrations and treatments for the two siblings. Figure from the CDC report.

What it teaches

• Mercury evaporates at room temperature, so even small spills can fill a room with dangerous vapor — and vacuuming spreads it further. Children are more vulnerable, because of their physiology and because they are closer to vapor from spills on the floor.
• Poisoning can affect the brain, liver, kidneys, blood, skin and heart, which delays diagnosis. Blood effects are rare; these cases likely reflect very high mercury after about 2 weeks of exposure. The boy's kidney disease was likely membranous nephropathy from mercury, which has been reported before.
• When several people in one household fall ill the same way, consider an environmental cause, not only infection.
• Tell public health and environmental agencies promptly about a mercury spill, for safe cleanup and, if needed, relocation. The Agency for Toxic Substances and Disease Registry has guidance on mercury's health effects and disposal.

Sources

Based on Emily W. Hogeland, Tarah S. Somers, Luke Yip and others (Connecticut Children's, the University of Connecticut, the Connecticut Poison Control Center, Yale University and CDC's Agency for Toxic Substances and Disease Registry), "Thrombocytopenia Associated with Elemental Mercury Poisoning in Two Siblings — Connecticut, July 2022," MMWR, Centers for Disease Control and Prevention; published by CDC and in the public domain; rewritten in hubnx's own words.