Constipation is responsible for up to 5% of pediatric office visits. It is defined as delay or difficulty in defecation.
Normal frequency and consistency of stool varies with children's age, and diet; there is also considerable variation from child to child.
Most (90%) normal neonates pass meconium within the first 24 hours of life. During the first week of life, infants pass an average of 4 to 8 stools/day; breastfed infants typically have more stools than formula-fed infants. During the first few months of life, breastfed infants pass a mean of 3 stools/day, versus about 2 stools/day for formula-fed infants. By age 2 years, the number of bowel movements decreases to slightly < 2/day. After age 4 years, it is slightly > 1/day.
In general, signs of effort (eg, straining) in a young infant do not signify constipation. Infants only gradually develop the muscles to assist a bowel movement.
Etiology of Constipation in Children
Constipation in children is divided into 2 main types:
Organic causes of constipation involve specific structural, neurologic, toxic/metabolic, or intestinal disorders. They are rare but important to recognize ( see Table: Organic Causes of Constipation in Infants and Children Organic Causes of Constipation in Infants and Children ).
The most common organic cause is
Other organic causes that may manifest in the neonatal period or later include
Metabolic disorders (eg, hypothyroidism Hypothyroidism in Infants and Children Hypothyroidism is thyroid hormone deficiency. Symptoms in infants include poor feeding and growth failure; symptoms in older children and adolescents are similar to those of adults but also... read more , hypercalcemia Hypercalcemia Hypercalcemia is a total serum calcium concentration > 10.4 mg/dL (> 2.60 mmol/L) or ionized serum calcium > 5.2 mg/dL (> 1.30 mmol/L). Principal causes include hyperparathyroidism, vitamin... read more , hyperkalemia Hyperkalemia Hyperkalemia is a serum potassium concentration > 5.5 mEq/L (> 5.5 mmol/L), usually resulting from decreased renal potassium excretion or abnormal movement of potassium out of cells. There are... read more )
Functional constipation is difficulty passing stools for reasons other than organic causes.
Children are prone to develop functional constipation during 3 periods:
After the introduction of cereals and solid food
During toilet training
During the start of school
Each of these milestones has the potential to convert defecation into an unpleasant experience.
Children may put off having bowel movements because the stools are hard and uncomfortable to pass or because they do not want to interrupt play. To avoid having a bowel movement, children may tighten the external sphincter muscles, pushing the stool higher in the rectal vault. If this behavior is repeated, the rectum stretches to accommodate the retained stool. The urge to defecate is then decreased, and the stool becomes harder, leading to a vicious circle of painful defecation and worsened constipation. Occasionally, soft stool passes around the impacted stool and leads to stool incontinence Stool Incontinence in Children Stool incontinence is the voluntary or involuntary passage of stool in inappropriate places in children > 4 years of age (or developmental equivalent) who do not have an organic defect or illness... read more (encopresis).
In older children, diets low in fiber and high in dairy may lead to hard stools that are uncomfortable to pass and can cause anal fissures Anal Fissure An anal fissure is an acute longitudinal tear or a chronic ovoid ulcer in the squamous epithelium of the anal canal. It causes severe pain, sometimes with bleeding, particularly with defecation... read more . Anal fissures cause pain with stool passage, leading to a similar vicious circle of delayed bowel movements, resulting in harder stool that is more painful to pass.
Stress, desire for control, and sexual abuse Sexual abuse Child maltreatment is behavior toward a child that is outside the norms of conduct and entails substantial risk of causing physical or emotional harm. Four types of maltreatment are generally... read more are also some of the functional causes of stool retention and subsequent constipation.
Evaluation of Constipation in Children
Evaluation should focus on differentiating functional constipation from constipation with an organic cause.
History of present illness in neonates should determine whether meconium has been passed at all and, if so, when. For older infants and children, history should note onset and duration of constipation, frequency and consistency of stools, and timing of symptoms—whether they began after a specific event, such as introduction of certain foods or a stressor that could lead to stool retention (eg, introduction of toilet training). Important associated symptoms include soiling (stool incontinence), discomfort during defecation, and blood on or in the stool. The composition of the diet, especially the amount of fluids and fiber, should be noted.
Review of systems should ask about symptoms that suggest an organic cause, including new onset of poor suck, hypotonia, and ingestion of honey before age 12 months (infantile botulism Infant Botulism Infant botulism results from ingestion of Clostridium botulinum spores, their colonization of the large intestine, and toxin production in vivo. Symptoms are initial constipation followed... read more ); cold intolerance, dry skin, fatigue, hypotonia, prolonged neonatal hyperbilirubinemia, urinary frequency, and excessive thirst (endocrinopathies); change in gait, pain or weakness in lower extremities, and urinary incontinence (spinal cord defects); night sweats, fever, and weight loss (cancer); and vomiting, abdominal pain, poor growth, and intermittent diarrhea (intestinal disorders).
Past medical history should ask about known disorders that can cause constipation, including cystic fibrosis and celiac disease. Exposure to constipating drugs or lead paint dust should be noted. Clinicians should ask about delayed passage of meconium within the first 24 to 48 hours of life, as well as previous episodes of constipation and family history of constipation.
The physical examination begins with general assessment of the child’s level of comfort or distress and overall appearance (including skin and hair condition). Height and weight should be measured and plotted on growth charts.
Examination should focus on the abdomen and anus and on the neurologic examination.
The abdomen is inspected for distention, auscultated for bowel sounds, and palpated for masses and tenderness. The anus is inspected for a fissure (taking care not to spread the buttocks so forcefully as to cause one). A digital rectal examination is done gently to check stool consistency and to obtain a sample for occult blood testing. Rectal examination should note the tightness of the rectal opening and presence or absence of stool in the rectal vault. Examination includes placement of the anus and presence of any hair tuft or pit superior to the sacrum.
In infants, neurologic examination focuses on tone and muscle strength. In older children, the focus is on gait, deep tendon reflexes, and signs of weakness in the lower extremities.
The following findings are of particular concern:
Delayed passage of meconium (> 24 to 48 hours after birth)
Hypotonia and poor suck (suggesting infant botulism)
Abnormal gait and deep tendon reflexes (suggesting spinal cord involvement)
Interpretation of findings
A primary finding that suggests an organic cause in neonates is constipation from birth; those who have had a normal bowel movement are unlikely to have a significant structural disorder.
In older children, clues to an organic cause include constitutional symptoms (particularly weight loss, fever, or vomiting), poor growth (decreasing percentile on growth charts), an overall ill appearance, and any focal abnormalities detected during examination ( see Table: Organic Causes of Constipation in Infants and Children Organic Causes of Constipation in Infants and Children ). A well-appearing child who has no other complaints besides constipation, who is not taking any constipating drugs, and who has a normal examination likely has a functional disorder Functional Constipation is responsible for up to 5% of pediatric office visits. It is defined as delay or difficulty in defecation. Normal frequency and consistency of stool varies with children's age... read more .
A distended rectum filled with stool or the presence of an anal fissure is consistent with functional constipation in an otherwise normal child. Constipation that began after starting a constipating drug or that coincides with a dietary change can be attributed to that drug or food. Foods that are known to be constipating include dairy (eg, milk, cheese, yogurt) and starches and processed foods that do not contain fiber. However, if constipation complaints begin after ingestion of wheat, celiac disease Celiac Disease Celiac disease is an immunologically mediated disease in genetically susceptible people caused by intolerance to gluten, resulting in mucosal inflammation and villous atrophy, which causes malabsorption... read more should be considered. History of a new stress (eg, a new sibling) or other potential causes of stool retention behavior, with normal physical findings, support a functional etiology.
For patients whose histories are consistent with functional constipation, no tests are needed unless there is no response to conventional treatment of constipation. An abdominal x-ray should be done if patients have been unresponsive to treatment or an organic cause is suspected. Tests for organic causes should be done based on the history and physical examination ( see Table: Organic Causes of Constipation in Infants and Children Organic Causes of Constipation in Infants and Children ):
Plain x-rays of lumbosacral spine; MRI considered (tethered spinal cord or tumor)
Serologic screening usually for IgA antibodies to tissue transglutaminase (celiac disease Diagnosis Celiac disease is an immunologically mediated disease in genetically susceptible people caused by intolerance to gluten, resulting in mucosal inflammation and villous atrophy, which causes malabsorption... read more )
Treatment of Constipation in Children
Specific organic causes of constipation should be treated.
Functional constipation is ideally initially treated with
Dietary changes include adding prune juice to formula for infants; increasing fruits, vegetables, and other sources of fiber for older infants and children; increasing water intake; and decreasing the amount of constipating foods (eg, milk, cheese).
Behavior modification for older children involves encouraging regular stool passage after meals if they are toilet trained and providing a reinforcement chart and encouragement to them. For children who are in the process of toilet training, it is sometimes worthwhile to give them a break from training until the constipation concern has passed.
Unresponsive constipation is treated by disimpacting the bowel and maintaining a regular diet and stool routine. Disimpaction can occur through oral or rectal agents. Oral agents require consumption of large volumes of liquid. Rectal agents can feel invasive and can be difficult to give. Both methods can be done by parents under medical supervision; however, disimpaction sometimes requires hospitalization if outpatient management is unsuccessful. Usually, infants do not require extreme measures, but if intervention is required, a glycerin suppository is typically adequate. For maintenance of healthy bowels, some children may require over-the-counter dietary fiber supplements. These supplements require consuming 32 to 64 oz of water/day to be effective ( see Table: Treatment of Constipation Treatment of Constipation ).
Functional constipation accounts for about 95% of cases.
Organic causes are rare but need to be considered.
Delayed passage of meconium for > 24 to 48 hours after birth raises suspicion of structural disorders, especially Hirschsprung disease.
Early intervention with dietary and behavior changes can successfully treat functional constipation.