Definition and Introduction
Pica is the diagnostic term used to denote children with a specific form of eating disorder characterized by the persistent ingestion of non-nutritive (or nonfood) substances without an accompanying aversion to food, at an age in which this behavior is developmentally inappropriate. This should persist at least for 1 month to be considered abnormal.
The term pica is usually held to come from the Latin word for magpie (picus) referring to the indiscriminate feeding habits of these birds. This eating disorder commonly includes ingestion of dirt, clay, pebbles, chalk, paper, string, ashes, crayons and plastic objects. Ingesting sharp objects such as nails, screws or potentially toxic substances such as medicine, dishwashing fluid can lead to far more serious and potentially life-threatening consequences.
According to some studies, 10–32% children in the age group of 1–6 years exhibit pica, although an Indian study reported 2% occurrence in those younger than 3 years. The early developmental habit of mouthing objects as an exploratory behavior disappears by 2 years of age.
Mental disorders found to have persistent pica more commonly associated with them include pervasive developmental disorders, intellectual disability, schizophrenia, Kleine-Levin syndrome.
Children who continue to eat non-food substances on a consistent basis after their 2nd birthday should be evaluated for pica, as well as the presence of developmental disability and a variety of medical conditions with the serious health risks that accompany chronic ingestion of nonfood substance.
Cause of pica is unknown. To describe this behavior various have been proposed:
- Cultural, ethnic and familial theory
In some cultures there is a custom of eating soil for different illnesses, e.g., morning sickness, which leads to the perception that there is nothing wrong with pica.
- Organic or nutritional theory
Some studies have shown that iron and zinc deficiency increase the craving for nonfood substances. These children get involved in pica to satisfy the craving. However, the prevalence of dietary and mineral deficiencies in children with pica is similar to those without this habit.
- Neuropsychiatric theory
There is a higher incidence of pica among children with many developmental disabilities.
Pica is the most common eating disorder in children with developmental disability. It is most frequently observed in those with severe and profound intellectual disability. Children may learn to engage in pica because it provokes adult attention (positive reinforcement) or allows escape from a non-preferred activity (negative reinforcement). Pica is also perceived as a sensory activity that the child experiences as stimulating or pleasant.
- Organic hypothesis
Pica may also be explained by this hypothesis whereby genetic disorders such as Prader-Willi syndrome increase the risk of ingesting nonfood substances. Anxiety disorders such as hysteria and obsessive compulsive disorder also have been implicated.
It is important to distinguish between stereotyped mouthing of objects by very young children who accidentally ingest them and pica as a behavioral disorder.
There can be immediate and long-term effects on health due to pica. The potential for parasitic infections with sequelae of myocarditis, encephalitis and hepatomegaly, and brain damage by intoxicants such as lead from paints and mercury from paper is of immediate concern. Obstruction from an indigestible mass that may cause choking or perforate the stomach or intestine and result in peritonitis is also a possibility.
Except in circumstances involving children and adolescents with autism spectrum disorder and intellectual disability, most cases of pica are easily diagnosed from history from parents. Children may be afraid of disclosing pica because of embarrassment or fear of being punished.
Educating the parents and child about the dangers associated with placing objects in the mouth is the basic step. Along with this, close supervision of the child by the parents, and making sure that the home-environment is safe for the child are additional measures.
There is no specific medical treatment and the condition often remits spontaneously. Medical management is multimodal in nature.
Investigations need to be individualized but may include complete blood count (especially eosinophil count), peripheral smear, serum electrolytes, liver function tests, iron and calcium studies and lead levels. An X-ray abdomen, barium studies or ultrasonography of the abdomen may be occasionally necessary to diagnose obstruction from parasites or bezoars.
Children with lead poisoning may require chelation therapy. Dietary supplements for mineral deficiencies like iron and zinc, if identified, should be addressed, although limited success has been seen in decreasing the behavior. Specific therapies for parasitic infection may be given when required. In cases of obstruction, surgery may be needed.
Multidisciplinary approach involving psychologist, social worker and developmental pediatrician may be required.
Psychological interventions are done to modify the behavior. Various behavioral strategies have been described, and very rarely, external devices restricting placement of objects in the mouth may be required for resistant cases.
Children with underlying anxiety disorder or obsessive compulsive disorder may need appropriate referrals and medications.
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