Most clinicians are aware of the condition known as pica. The term is derived from a Latin word for magpie, a bird known for its peculiar eating behaviors. The Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) defines pica as “the persistent eating of nonnutritive substances for a period of at least one month, without an association with an aversion to food.” To date, no one has been able to explain a physiologic basis for pica or why certain persons will voraciously consume such substances as ice (pagophagia), clay (geophagia) or starch (amylophagia). Rose and colleagues recently reviewed the published literature on pica. They performed a MEDLINE and PSYCH-Lit search from 1964 to 1999. For the search, they used the key words “pica,” “obsessive-compulsive disorder,” “iron-deficiency anemia” and “nutrition.”
Estimates of the prevalence of pica vary depending on the patient population studied and the criteria used. The condition occurs more often in pregnant women, adults of lower socioeconomic status and children. Although it has been thought of as a symptom of iron deficiency, it is more commonly discovered in patients who are not anemic.
The cause of pica remains unknown, and a variety of theories are discussed in the literature. These theories include associations from a nutritional, neuropsychiatric, cultural, psychologic, sensory and physiologic perspective. The latter two theories are based on findings from patients with pica who profess to actually enjoy the taste, texture or smell of the items they consume. Family stress has been found to cause pica in some persons. Other studies note an association between pica and addiction or addictive behaviors. A more recent review suggests that pica is part of the obsessive-compulsive disorder (OCD) spectrum of diseases.
Complications of pica include: inherent toxicity; intestinal obstruction (such as that occurring with trichophagia, or hair eating); excessive caloric intake (such as that occurring with starch); nutritional deprivation; parasitic infections; and dental injury. In many cases, complications do not occur or are not recognized, making the diagnosis of pica difficult. Moreover, many patients are unlikely to self-report such habits because of embarrassment or ignorance that the behavior could have medical significance.
Most commonly, the diagnosis of pica is made after a patient is found to have iron deficiency anemia, lead poisoning, intestinal obstruction or another metabolic abnormality (see accompanying table). Clinicians should query parents about eating behaviors when discussing dietary habits at well-child visits. Adults or children who have a diagnosis of OCD should also be asked about pica. The medical evaluation of a patient suspected of having pica should include a complete blood count, peripheral smear for eosinophilia, determination of iron, ferritin and lead levels, electrolytes and liver function. An obstruction series or plain abdominal radiographs may be necessary to distinguish obstruction from parasites or bezoars. The authors note, however, that the diagnosis will remain in doubt unless the child or adult admits to the suspected eating behavior.
|Type of complication||Specific examples|
|Inherent toxicity||Metabolic abnormalities, such as heavy metal poisoning, hypokalemia or hyperkalemia, iron and zinc deficiency, other vitamin deficiency|
|Obstruction||Gastric or intestinal obstruction from bezoar, foreign body, feces or parasites, with subsequent perforation, peritonitis and death|
|Excessive caloric intake||Starch eating, excessive cravings for food items|
|Nutritional deprivation||Failure to thrive, achlorhydria|
|Other||Dental injury, parasitic infestations|
Treating the patient diagnosed with pica is challenging. Management should include education about general nutrition and may require iron therapy if a deficiency of this mineral is uncovered. Diagnosing and treating any underlying medical condition or complication such as lead poisoning is also important. Fortunately, in many cases pica will remit with time. However, the use of selective serotonin reuptake inhibitors, referral for counseling and a formal mental health consultation may be warranted in patients with severe or refractory pica.