Pediatric Primary Care Case Studies (74 page)

The abnormal findings in the physical examination include:

•   Decreased activity

•   Central pallor

•   Anterior fontanel borderline large for age

•   Blue sclera

•   Bruising

•   Glossitis

•   Angular stomatitis

•   Splenomegaly

•   Stool palpable in abdomen

Utilizing information from both the history and physical, what are the differential diagnoses to consider for Oswaldo?

The following are the possible differential diagnoses:

•   Iron deficiency anemia

•   Lead poisoning

•   Leukemia/lymphoma

•   Developmental delay, possibly secondary to neurotoxic effects of organophosphates

•   Hypothyroidism

•   Organophosphate toxicity

•   Warfarin ingestion

Before refining the diagnosis by ordering any laboratory or radiologic tests, a review of each of the possible diagnoses will be useful.

Discussion of the Differential Diagnoses

What facts in the history indicate that Oswaldo is at high risk for environmental health hazards?

Oswaldo lives in a household where the parents are migrant workers in an agricultural environment known to use organophosphate pesticides; pesticides are used in his home to eradicate mice; crawling is his primary modality; and he spends much time on the floor playing.

Environmental Toxins and Children

Research conducted in the early 1990s revealed that approximately 75% of U.S. households used at least one pesticide product indoors (American Lung Association, n.d.). Such widespread use of pesticides makes the environmental history an integral aspect of data collection in pediatrics. Unique physical characteristics make children especially vulnerable to accumulating toxins in
their bodies and exhibiting symptoms of both acute and chronic exposures. Children’s bodies are less capable of detoxifying the toxins that get into their bodies due to immature levels of enzymes capable of accomplishing this task. Children spend much of their time close to the ground crawling and playing in the zones where pesticides accumulate. In this pesticide-rich environment, children breathe in fumes and ingest residue through hand-to-mouth activities, further increasing their ingestion of household pesticides.

Considering that the life expectancy of children from the time of toxic exposure is greater than if the exposure occurs in adulthood, there is more time for the development of diseases with long latency periods (Cohen, 2007). A child’s respiratory rate is more than twice that of an adult’s. Children consume seven times the amount of water as an adult in the first 6 months of life, and between ages 1 and 5 years children consume proportionally three times as much food as adults (Shea, n.d.). There are periods during development when certain systems are especially vulnerable, making them more susceptible to harm if exposed to toxins during these times, generally when organs such as the brain are rapidly growing. The timing of the ingestion of neurotoxic elements, such as lead, arsenic, mercury, PCBs, and alcohol, can have a more robust effect than the amount of the toxin itself.

Children’s diets include large amounts of fresh fruits, vegetables, and juices. Breastmilk may also be contaminated. Other factors to consider are that children consume a greater volume of liquids and foods per kilogram than adults, therefore ingesting more toxins per body weight.
Table 19-2
shows various fruits and vegetables and the relative amount of pesticide that is absorbed into the food and found by government testing. It is clear from viewing the list of fruits and vegetables that children are at greater risk for proportionally larger amounts of potential pesticides ingestion than adults.

Lower organophosphate metabolites are noted in the urine of children who ate organic foods, compared to children who did not. Children of agricultural workers repeatedly demonstrate higher organophosphate metabolites than children in other environments. Organophosphate metabolites are transmitted via aerial spraying or transmission from parents’ clothing (Cohen, 2007; Curl et al., 2002; Thompson et al., 2008).

In the realm of acute effects, symptoms reflect the affected organ system: local irritation (skin, eyes, throat), respiratory system (respiratory distress), and the central nervous system (headache, seizure, coma, death). Chronic symptoms can range from birth defects, cancers, and asthma, to neurodevelopmental/ neurobehavioral symptoms. Many pesticides have been demonstrated to have disruptive effects on the endocrine systems.

Organophosphates (OP) are the most widely used pesticides in the United States, and those employed in agriculture experience the greatest levels of exposure. Data exist describing the health effects of both acute and chronic exposures. Repeated low-grade home spraying more often triggers acute toxic reactions than does agricultural exposure. The mechanism for these reactions is
related to inhibition of cholinesterase activity, which results in accumulation of acetylcholine. These toxins target the central nervous system, and among the effects reported are verbal and visual attention problems, motor dexterity, confusion, cognitive deficits, and memory lapses, as well as muscle twitching, seizures, and coma (Fenske, Chensheng, Curl, Shirai, & Kissel, 2005; Karr, Solomon, & Brock-Utne, 2007). Organophosphates demonstrate a predilection for triggering hematologic and solid tumor cancers (Cohen, 2007; Lambert et al., 2005). Toxic symptomatologies can vary greatly between adults and children, with children’s symptoms having a much broader presentation. This makes it imperative for healthcare providers to maintain a high index of suspicion. Other symptoms include anorexia, dyspnea, miosis, salivation, tearing, and sweating. Symptoms can persist long after exposure to organophosphates. The mnemonic I PREPARE can be employed to remember the aspects of an environmental history (see
Table 19-3
).

Oswaldo’s environment is abundant in potential pesticide exposures: his father’s work clothing, the types of foods he ingests, playing on the floor, hand-to-mouth behaviors, and home rat poison. The family history suggests that pesticide exposure may have had an impact on the siblings as well: Maria has a seizure disorder, Ignatio has ADHD, and Miguel has asthma. Further investigation should involve evaluation of the entire family’s exposure level and urinary metabolites as well as other possible toxins. Although these conditions do not necessarily indicate toxicity, but are listed as possible complications, environmental toxins should be explored in Oswaldo’s siblings.

Specific tests would be based on history and symptomatology. Most urinary metabolite tests are nonspecific for the individual organophosphate. Treatment would be based on the agent and whether the poisoning was acute or chronic.

Decontamination of skin, nails, hair, and clothing is paramount because organophosphate absorption increases through breaks in the skin’s integrity. Therefore, open areas should be cleansed first with the water flowing away from the wound.

Anemia

Because only 2% of 1 year olds are found to have iron deficiency anemia (IDA) during routine screening between 9 and 18 months of age, the U.S. Preventive Services Task Force does not find sufficient data to definitely recommend selective screening in the 6- to 12-month age group (U.S. Preventive Services Taskforce, 2006). However, general risk factors for anemia and the populations that should be screened for anemia have been identified.

•   Premature infants (most hemoglobin accumulates in fetus during the last month of pregnancy)

•   Cow’s milk consumed before 1 year of age

•   Low iron formula in infancy

•   Children over 1 year who consume more than 24 ounces of cow’s milk per day

•   Menstruating adolescent females