Pica

Pica is an eating disorder characterized by a desire or recurrent compulsion to eat substances that are nonnutritive and not food. These compulsions and ingested substances are inappropriate for age or culture. Pica manifests most commonly during childhood and pregnancy and, therefore, carry a high risk for malnutrition and anemia. Patients usually present with nutritional deficiencies or complications from ingesting nonfood substances. Management aims are to stabilize patients medically and then provide appropriate behavioral therapy as a 1st-line option.

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Overview

Definition

Pica is an eating disorder of unclear etiology characterized by a desire or compulsion to eat substances that are not food in a context that is not developmentally, socially, or culturally appropriate. 

The specific substances that are craved vary:

  • Geophagia (earth ingestion):
    • Common
    • Leads to constipation, hypokalemia with myopathy, and nutritional deficiencies
    • Can be a source of parasites
    • Lead poisoning can be a serious complication with clay ingestion.
  • Pagophagia (ice ingestion):
    • Associated with iron deficiency
    • Tooth decay and sensitivity
  • Amylophagia (excessive starch ingestion):
    • Iron deficiency
    • High blood sugar and obesity

Epidemiology

  • Incidence is challenging to estimate:
    • Diverse clinical definitions
    • Underreported 
  • The highest prevalence seen in:
    • Children
    • Pregnant women
  • Boys and girls equally affected
  • Risk  factors: nutritional deficiency
    • Iron deficiency
    • Zinc deficiency
    • Pregnancy
    • Stress
    • Low socioeconomic status
    • Intellectual disability
    • Child neglect
    • Underlying mental health disorder:
      • Schizophrenia
      • OCD
      • Trichotillomania

Clinical Presentation and Diagnosis

Clinical presentation

  • Patients self-present or are brought in by caregivers when abnormal eating habit is noticed.
  • May also present with complications:
    • Toxicity and poisoning (e.g., lead poisoning if ingesting paints or clay)
    • Hypokalemia (clay ingestion)
    • GI obstruction (bezoar ingestion)
    • Parasitic infection (sand, mud, clay ingestion)
  • Patients do not have self-harm/suicidal intention; distinguish from intentional intoxication/overdose.

Diagnosis

Diagnosis of pica is clinical, based on observed patterns of behavior:

  • Recurrent episodes of eating nonfood, nonnutritional substances (e.g., chalk, clay, cloth, coal, dirt, gum, hair, metal, paint, paper, pebbles, soap, string, or wool)
  • Eating behavior is inappropriate to the patient’s developmental level and is not culturally supported or socially normal.
  • Lasts at least 1 month
  • Exclude autism spectrum disorder, developmental delay, and intellectual disability.

Further testing should be directed by etiology, symptomatology, and ingested substances:

  • Blood cell counts and iron studies to diagnose anemia
  • Lead testing if patient ingests paint
  • Basic metabolic panel to identify hypokalemia in clay ingestion 
  • Testing for parasitic infections that may occur with ingesting soil 
  • Abdominal X-rays to identify intestinal obstruction by bezoars
Geophagia

Abdominal X-ray of a patient with pica:
Patients with pica have a compulsion to ingest nonnutritive material. Some patients fixate on eating earth, which can cause bowel blockage. Abdominal X-rays can help identify the ingested foreign substance (bright material seen in the pelvis of the patient).

Image: “Silica in the soil that has been eaten by a woman” by SuSanA Secretariat. License: CC BY 2.0

Management

Prevention

  • Identifying at-risk individuals
  • Removing patient from area of exposure 
  • Providing food substances with similar texture and color to replace ingested nonfood material

Medical management

  • Assess and treat underlying nutritional deficiencies:
    • Iron deficiency anemia
    • Zinc
    • Potassium
  • Psychotherapy:
    • CBT (1st-line therapy) 
    • Nutritional rehabilitation
    • Mild aversion therapy
  • Treat complications:
    • Medical/surgical bowel clean-out
    • Antiparasitic therapy
    • Treat potential toxicity.

Differential Diagnosis

Pica is classified as an eating disorder and can have features in common with other such disorders.

  • Anorexia nervosa: eating disorder characterized by intense fear of gaining weight, restrictive dietary habits, and distorted body image: Patients affected by anorexia nervosa are usually underweight and are reluctant to seek medical help. Treatment involves CBT with antidepressant medication as an adjunct. Extreme cases may require hospitalization.
  • Bulimia nervosa: anxiety-driven eating disorder defined by recurrent episodic binge eating paired with recurrent inappropriate compensatory behavior (inducing vomiting, laxative abuse, and excessive exercising): The BMI of patients with this condition may be normal or even elevated. Patients with bulimia nervosa are more likely to seek help. Treatment involves a combination of CBT and selective serotonin reuptake inhibitor (SSRI) medication.
  • Binge-eating disorder: eating disorder marked by recurrent episodes of binge eating without inappropriate compensatory behavior: Binge-eating disorder results in fluctuating body weight. Episodes occur at least weekly for 3 months. Treatment consists of a combination of psychotherapy and pharmacotherapy.
  • Rumination disorder: repeated regurgitation of food (which may be re-chewed, re-swallowed, or spit out) that is not due to a general medical condition (e.g., GERD): Treatment involves multiple CBT techniques, including biofeedback psychotherapy as well as medication when appropriate (e.g., proton pump inhibitors).

References

  1. American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-5). Arlington, VA: American Psychiatric Association.
  2. McNaughten B, Bourke T, Thompson A. (2017). Fifteen-minute consultation: the child with pica. Arch Dis Child Educ Pract Ed. https://pubmed.ncbi.nlm.nih.gov/28487433/
  3. Call NA, Simmons CA, Mevers JE, Alvarez JP. (2015). Clinical outcomes of behavioral treatments for pica in children with developmental disabilities. J Autism Dev Disord. https://pubmed.ncbi.nlm.nih.gov/25636679/

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