A 3 year-old girl presents to your clinic with her parents who complain of behavioral changes for about a month (withdrawn, refusing to play, irritable). Recently the child has experienced night sweats, however her parents did not take her temperature.
History for this child includes recurring ear infections during the past winter, which were treated with oral antibiotics, normal growth and development (75th percentile for weight and height), immunizations are up to date, NKA, and no current medications.
During physical examination the girl is uncooperative, crying and complains that her legs “hurt”. She is afebrile, pulse is 130 per minute and regular, respirations are 16 per minute. She is sweating and her nose, fingers, and toes are erythematous; the skin on her fingers and toes are peeling. Her oral pharynx and abdomen appear normal on examination; lungs are clear to auscultation. In bilateral legs, point tenderness is negative, and she has full ROM. No swelling noted in bilateral ankles. Neurological exam is normal; there is no muscular atrophy. Other findings are unremarkable.
Her parents report that normally their daughter enjoys social activities with her family. The family lives in a freshly painted house. Her 6 year-old sibling has not exhibited similar symptoms. Both parents are teachers and report good health. The family has no pets and has not traveled within the last year.
Painful extremities, erythematous and peeling skin on nose, toes, and fingers; personality changes; tachycardia; sweating; and possible intermittent low-grade fever.
Diagnoses to Consider:
Acrodynia. This disease of infancy and early childhood is caused in most, in not all, instances by exposure to mercury. Marked by pain and swelling in, and pink coloration of, the fingers and toes and by listlessness, irritability, failure to thrive, profuse perspiration, and sometimes scarlet coloration of the cheeks and tip of the nose. Acrodynia is also called erythredema polyneuropathy and pink disease.
Acute Rheumatic Fever. Occurs most commonly between the ages of 5 and 15 years when streptotococcal infection is relatively common. Sore joints and fever are characteristic. Leukemia. The most common cancer in young children, and symptoms can include sweats and low-grade fever. This diagnosis would not explain the erythematous and peeling skin of the fingers and toes.
Kawasaki Disease. This patient does not have some of the common signs of this disease: e.g., she does not have bilateral conjunctivitis, lymphadenopathy; a red rash; red and sore lips, mouth, or throat. However, she is under 5 years of age and does have red and tender hands and feet with peeling skin. She may have had a fever, but it is not well characterized. Only 5 to 10 of every 100,000 children acquire Kawasaki disease. Tuberculosis. This patient’s night sweats and possible low-grade fever make this a possibility; however, she has no cough, and tuberculosis is not associated with erythematous and peeling skin on the fingers and toes.
Measles. Although immunized against measles, the patient could have experienced primary vaccine failure. However, she does not have Koplik’s spots, cough, conjunctivitis, coryza, or a typical rash, making this diagnosis unlikely. Boric Acid Poisoning. Irritability and erythema and peeling of the skin and mucous membranes can occur with boric acid poisoning. However, the patient does not exhibit renal toxicity or other common symptoms of boric acid toxicity such as nausea, vomiting, and diarrhea.
Additional diagnoses to consider. Stevens-Johnson syndrome, fifth disease, scarlet fever, rubella, systemic lupus erythematosus, and drug rashes (due to unsuspected ingestion) should be considered.
Blood and hair analysis can be used when acute mercury poisoning is suspected, however, the best test to confirm or rule out chronic mercury exposure is a 24-hour urinary mercury concentration and creatinine clearance. A metal free collection container must be used for the 24-hour urinary mercury collection (ask your laboratory about the provision of containers). The patient should abstain from eating shellfish during the testing period. Urine should be analyzed by cold vapor atomic absorption spectrophotometry. The Reinsch test (a heavy metal screening test) is not sufficiently specific or sensitive. Other tests to exclude other diagnoses include: CBC with differential; erythrocyte sedimentation rate or C-reactive protein; chest and hip X rays; serum creatinine and blood urea nitrogen; urinalysis; tuberculin skin test with controls; streptococcal antibody titers (ASO); and throat culture for streptococcus.
Test results indicate the patient has a high urinary mercury concentration. Chelation therapy should be considered and a physician experienced in it’s use should be consulted. Chelators differ in their efficacy for various forms of mercury, routes of administration, side effects, and routes of excretion. Depending on the chemical to which one has been exposed and the health status of the individual, different chelators may be indicated. Eliminating the source of the mercury exposure is crucial. The county or state health department (in Lancaster County call the Lincoln-Lancaster County Health Department at 441-8000) should be contacted to identify and eliminate the mercury source and to evaluate the potential exposure to members of the community. Chronic mercury exposures in young children are most likely linked to the home. Testing for possible mercury exposure in other family members is needed. Possible mercury sources in this case include off-gassing of paint on interior walls and liquid mercury from a spill embedded in floors or carpets. Possible ingestion sources include contaminated drinking water, mercury-containing medicinals, or folk remedies.
Agency for Toxic Substances and Disease Registry. (1992). Case studies in environmental medicine: Mercury Toxicity. As seen in Environmental Medicine. Pope, A. & Rall, D. (Eds.). Washington, DC: National Academy Press.
Agency for Toxic Substances and Disease Registry. (1999). Toxicological profile for mercury. [On-Line]. Available: http://www.atsdr.cdc.gov/toxprofiles/tp46.pdf.
Children's Environmental Health