A 2½-year-old boy has progressive anorexia, weight loss, and a severe, itchy rash
A mother brings her 2½-year-old son to you for consultation. She explains that her family moved to your community about 7 months ago when her husband changed jobs. Over the past month and a half, the boy has developed progressive anorexia and weight loss. He has also suffered from an increasingly severe and itchy rash. Although normally very active and pleasant, he has become ill-tempered and, for the past couple of days, he refuses to walk around, preferring to lie in bed or be carried. He rubs his knees and cries periodically throughout the day. Neither the parents nor the child's grandmother, who lives with them, has been ill.
The boy's medical history has been unremarkable. His birth was at full-term by a normal spontaneous vaginal delivery without complications. His height and weight have been consistently in the 25th percentile for his age. He is on a regular toddler diet, and all developmental milestones have been appropriately met. His immunizations are up-to-date. He is not taking any medications. He had been taking a multivitamin with iron at the correct dosage as prescribed by his doctor. The mother denies any other family use of dietary supplements or herbal medicines. The family history is negative for blood transfusions and use of illicit drugs, human immunodeficiency virus (HIV) infection, and metabolic or genetic diseases. A review of systems and a brief assessment of how the family functions are noncontributory. No one in the family has been traveling in a foreign country.
Physical examination reveals an irritable, pale child with photophobia. His height is 35½ inches (90.17 centimeters [cm]) and his weight is 27.7 pounds (12.6 kilograms), both of which are in the 25th percentile for his age. (His mother remembers that he weighed 30 pounds the last time he was checked by his pediatrician, just before they relocated.) The child's head circumference is 15.2 inches (38.6 cm), also in the 25th percentile. His temperature is 98.3°F (36.8°C), blood pressure is 125/75 mmHg (90th percentile for his age is 105/69), heart rate is 96 breaths/min, and respiratory rate is 30 breaths/min. His skin and mucous membranes are dry. His trunk and face have an erythematous papulovesicular rash with signs of excoriation, but no petechia. His neck is supple without enlarged nodes, masses, or thyromegaly. No other adenopathy is noted. Head, eyes, ears, nose, and throat (HEENT) are within normal limits. Lungs are clear to auscultation. Heart rate is regular without murmurs. His abdomen is soft and is not distended or tender to palpation. No hepatosplenomegaly is noted. His joints have full range of motion and no signs of inflammation. His hands and feet are pink, sweaty, and scaling. Neurologic examination reveals a tongue tremor, diffuse muscle weakness, and unsteady gait, but no focal abnormalities.
During the day, the child stays at home with his mother or grandmother. The mother works part-time as a bookkeeper-clerk in a local dry cleaning facility. The father works as a production manager in a mercury thermometer factory. The mother states that both parents are concerned about environmental contaminants, specifically those that might be associated with their workplaces, and whether or not these contaminants can put their family at risk. The parents have heard neighbors' and co-workers' comments about ailments associated with mercury exposures. The parents also mention recent reports of a group of teenagers in the community taking elemental mercury over the past several months from the local junior high school chemistry lab and the resulting ongoing investigation by the environmental division of the state health department. One of the teenagers who reportedly took mercury from the lab helped with odd jobs around the parents' house, including indoor house-cleaning. The mother expresses the family's concern and asks for your help.
On further questioning, you learn that the family lives in a converted loft apartment in a building that was once part of a jewelry factory complex. No additional remodeling or interior painting has occurred since the conversion 2 years ago. Drinking water is supplied by the city. Each apartment has its own natural gas heating system. The bedrooms and living room are carpeted. The family does not have a garden, but the child often plays at a park and playground within walking distance. The family has no pets. The parents have no more information regarding the teenager, although they have been trying to contact her since the report came out this past week regarding the ongoing investigation conducted by the environmental division of the state heath department.
The child is hospitalized for further evaluation and workup. Baseline laboratory tests include
white blood cell count with differential;
blood smear;
electrolytes, with blood urea nitrogen and creatinine;
