Overview
Definition:
Functional constipation is defined by the Rome IV criteria as the presence of 2 or more of the following symptoms for at least 1 day per week in the preceding 3 months: infrequent stools, hard or lumpy stools, straining during defecation, sensation of incomplete evacuation, sensation of blockage or obstruction, and use of manual maneuvers to facilitate defecation
Long-term maintenance dosing refers to the ongoing use of laxatives to prevent recurrence and maintain regular bowel movements after initial treatment of an acute episode.
Epidemiology:
Functional constipation is a common problem in childhood, affecting an estimated 0.7% to 29.6% of children globally
It is most prevalent in toddlers and preschool-aged children
Recurrence rates are significant, highlighting the need for effective long-term management strategies.
Clinical Significance:
Untreated or inadequately managed functional constipation can lead to significant morbidity in children, including pain, abdominal distension, fecal impaction, urinary tract infections, enuresis, and behavioral issues
Chronic constipation can impact quality of life for both the child and their family, and proper long-term maintenance is crucial for preventing these complications and promoting healthy bowel habits.
Clinical Presentation
Symptoms:
Infrequent stools (<3 per week)
Hard, large, or difficult-to-pass stools
Straining or pain during defecation
Fecal soiling (encopresis) due to overflow incontinence
Abdominal pain or cramping
Reduced appetite
Nausea
Palpable fecal mass in the abdomen
History of withholding stool.
Signs:
Abdominal distension
Palpable, firm stool in the lower abdomen or rectum on digital rectal examination
Fecal soiling on underwear
Perianal excoriation from soiling or wiping
Rectal prolapse (less common)..
Diagnostic Criteria:
Diagnosis is typically based on the Rome IV criteria for functional constipation in children
Specific criteria include: 2 or more of the following symptoms for at least 1 day per week in the preceding 3 months: infrequent stools, hard or lumpy stools, straining, sensation of incomplete evacuation, sensation of blockage, manual maneuvers used to facilitate defecation
Loose stools are not present
Sufficient criteria for irritable bowel syndrome are not met
Absence of organic disease upon medical history and physical examination
For children younger than 4 years, symptoms must have begun at least 6 months prior to diagnosis and have occurred at least 1 time per week
For toilet-trained children aged 4 years and older, symptoms must have occurred at least 1 time per week
Red flags that suggest organic pathology include: onset of constipation in the first month of life, failure to thrive, bilious vomiting, abdominal distension, rectal bleeding beyond mild anal fissure bleeding, family history of Hirschsprung disease or celiac disease, abnormal neurological signs, or abnormal abdominal examination (e.g., a large mass)..
Diagnostic Approach
History Taking:
Detailed history of bowel habits, including frequency, consistency, and ease of passage of stools
Timing of onset of constipation
Toilet training history
Dietary intake (fiber and fluid intake)
Medications (e.g., calcium supplements, anticholinergics)
Presence of abdominal pain, nausea, vomiting, or poor appetite
History of fecal soiling or encopresis
Presence of red flags suggestive of organic causes: onset in infancy, failure to thrive, bilious vomiting, neurological deficits, sacral dimple, or abnormal anal tone
Family history of gastrointestinal or endocrine disorders.
Physical Examination:
General appearance: assess for failure to thrive or signs of systemic illness
Abdominal examination: assess for distension, tenderness, and palpable fecal mass
Rectal examination: assess for anal tone, presence of stool in the rectal vault, anal fissures, or prolapse
In girls, assess for labial adhesions
Neurological examination: particularly if red flags are present, to assess for spinal cord abnormalities or neuromuscular disorders..
Investigations:
In most cases of functional constipation, investigations are not required if red flags are absent and the diagnosis is clear based on history and physical examination
If red flags are present or if the diagnosis is uncertain, investigations may include: Complete blood count (CBC) to rule out anemia
Electrolytes, calcium, phosphate, and alkaline phosphatase to assess for metabolic causes
Thyroid function tests (TSH) to rule out hypothyroidism
Celiac serology (anti-TTG antibodies)
Abdominal X-ray to assess for fecal loading and impaction (not routine)
Rectal manometry or anorectal manometry if Hirschsprung disease or functional defecation disorder is suspected
Contrast enema or rectal biopsy if Hirschsprung disease is strongly suspected
Biofeedback therapy may be indicated for children with functional defecation disorder
For maintenance, routine investigations are not typically needed unless symptoms change or red flags emerge.
Differential Diagnosis:
Hirschsprung disease
Anal stenosis or stricture
Hypothyroidism
Hypercalcemia
Celiac disease
Neurological disorders (e.g., cerebral palsy, spinal cord lesions)
Irritable bowel syndrome
Inflammatory bowel disease (less common cause of constipation)
Lead poisoning
Meconium ileus (in neonates)..
Management
Initial Management:
The initial management involves disimpaction, followed by a regular maintenance regimen
Disimpaction may be achieved with oral osmotic laxatives (e.g., polyethylene glycol 3350) in higher doses, or through rectal administration of enemas or suppositories if oral therapy is insufficient
Education of parents and child regarding constipation, toilet training, and the importance of consistent bowel movements is crucial.
Medical Management:
Long-term maintenance therapy aims to prevent recurrence and maintain soft, easily passable stools
The cornerstone of maintenance therapy is the use of osmotic laxatives
Polyethylene Glycol 3350 (PEG 3350): This is the first-line agent
Dosing: Typically starts at 0.5-1.5 g/kg/day, not to exceed 17 g/day for children under 2 years, and up to 34 g/day for children over 2 years
The dose is adjusted to achieve soft stools daily or every other day
Once regular bowel movements are established, the dose can be gradually reduced to the lowest effective dose for long-term maintenance
Some children may require continuous daily use for months or even years
Lactulose: A disaccharide laxative
Dosing: Typically 1-2 mL/kg/day, divided into 1-2 doses, with a maximum of 20 mL/day
Similar to PEG 3350, the dose is adjusted to maintain soft stools and then gradually reduced to the lowest effective maintenance dose
It can cause bloating and flatulence
Other agents: Stimulant laxatives (e.g., senna, bisacodyl) are generally reserved for short-term use or severe cases due to potential for dependence and cramping, but can be used cautiously as adjuncts in some maintenance plans under medical supervision
Stool softeners like docusate sodium are less effective for functional constipation maintenance
Mineral oil is generally not recommended due to risks of aspiration and vitamin malabsorption.
Surgical Management:
Surgery is rarely indicated for functional constipation and is typically reserved for cases with underlying structural abnormalities that contribute to chronic constipation, such as severe anal stenosis or Hirschsprung disease that has not responded to medical management
For functional constipation alone, surgical intervention is not an option.
Supportive Care:
Dietary modifications: Increased intake of fiber-rich foods (fruits, vegetables, whole grains) and adequate fluid intake are essential adjuncts to laxative therapy
Behavioral therapy: A regular toileting routine (e.g., sitting on the toilet for 5-10 minutes after meals) can help establish regular bowel habits
Positive reinforcement for successful bowel movements is important
Education: Comprehensive education for parents and children about the chronic nature of functional constipation, the rationale for long-term laxative use, and the importance of adherence is paramount
Regular follow-up with a healthcare provider is necessary to monitor progress, adjust medication as needed, and address any concerns
Regular physical activity also plays a role in promoting bowel motility.
Complications
Early Complications:
Fecal impaction
Rectal prolapse
Abdominal pain and distension
Fecal soiling (encopresis)
Anal fissures
Urinary tract infections (UTIs) due to pressure from impacted stool.
Late Complications:
Chronic pain
Behavioral issues related to soiling and embarrassment
Poor quality of life
Development of psychological distress or anxiety related to bowel function
Potential for decreased bone mineral density if calcium intake is consistently poor due to avoidance of dairy
Long-term reliance on laxatives, though generally safe with osmotic agents.
Prevention Strategies:
Adherence to maintenance laxative therapy at the lowest effective dose
Regular toileting routines
Adequate fiber and fluid intake
Behavioral interventions
Regular medical follow-up to monitor for recurrence and adjust management
Prompt treatment of any fecal impaction or soiling episodes.
Prognosis
Factors Affecting Prognosis:
Adherence to treatment regimen
Family support and education
Presence of behavioral issues or psychological distress
Extent and duration of chronic constipation prior to treatment
Presence of underlying organic causes (though this is functional constipation)..
Outcomes:
With consistent and appropriate long-term maintenance therapy and behavioral support, the prognosis for functional constipation is generally good
Most children achieve regular bowel movements and resolution of symptoms
However, it can be a chronic condition requiring management for several years, with a significant risk of relapse if treatment is discontinued prematurely or if lifestyle factors are not addressed
Long-term maintenance doses can often be gradually reduced over time as children mature and develop more consistent bowel habits.
Follow Up:
Follow-up appointments are crucial, initially every 1-3 months during active treatment and then every 6-12 months once stable
The goal is to ensure continued compliance, monitor for recurrence of constipation or encopresis, assess for potential side effects of laxatives, and reinforce lifestyle and behavioral strategies
Gradual tapering of laxative doses should be attempted periodically under medical supervision
The duration of maintenance therapy varies significantly
some children may require it for months, while others may need it for several years
The decision to discontinue laxatives should be made by a healthcare provider in conjunction with the family, based on sustained symptom-free intervals and established healthy bowel habits.
Key Points
Exam Focus:
Rome IV criteria for functional constipation in children
First-line maintenance laxative: Polyethylene Glycol 3350 (PEG 3350)
Standard maintenance dosing range for PEG 3350 (0.5-1.5 g/kg/day, max 17-34 g/day)
Goal of maintenance therapy: soft, easily passable stools
Importance of disimpaction before maintenance
Role of fiber, fluids, and behavioral modification
Red flags suggesting organic causes
Management of encopresis
Long-term management duration can be variable.
Clinical Pearls:
Always rule out red flags before diagnosing functional constipation
Education is key for adherence: explain to parents that laxatives are not habit-forming in this context and are necessary to break the pain-retention cycle
Start low and go slow when adjusting PEG 3350 dose, aiming for soft stools every 1-2 days
Consider gradual tapering of laxatives only when a child has been symptom-free for several months
Be patient
functional constipation is a chronic condition requiring long-term management
Encopresis management requires a multifaceted approach including laxatives, timed toileting, and behavioral strategies.
Common Mistakes:
Discontinuing laxatives too early, leading to relapse
Underestimating the importance of disimpaction
Insufficient education of parents and child regarding the condition and treatment plan
Relying solely on diet and fluids without pharmacological support for maintenance
Focusing only on stool frequency and not stool consistency and ease of passage
Failing to identify and manage underlying behavioral or psychological factors
Over-reliance on stimulant laxatives for long-term maintenance.