Constipation: Cases and Answers

If you got to go, go now. – Bob Dylan

LEARNING OBJECTIVES:

1.  Recognition of and appropriate intervention for common presentations of constipation in infancy, childhood and adolescence

2.  Familiarity with pharmacologic, dietary and behavioral interventions for constipation

3.  Recognition of some of the more common organic causes of constipation

A normal bowel pattern is believed by many to be a sign of good health, and constipation is a common complaint in general pediatric practice.  Unfortunately, treatment is often sought when symptoms have been long-standing.  Constipation can be simply defined as infrequent or painful defecation, or classified as:

INFANT DYSCHEZIA:

CASE #1:  A three month old turns red, cries, and seems to be in pain when trying to pass a stool.  She has one or two soft stools a day.  The baby is feeding and growing well, has no medical issues, and her physical exam is normal. 

What is the definition of infant dyschezia?:  At least ten minutes of straining and crying before successful passage of soft stools in an otherwise healthy infant <6 months.

This condition is felt to be due to a lack of coordination between increased intra-abdominal pressure and relaxation of the pelvic floor, and resolves spontaneously with no intervention

FUNCTIONAL CONSTIPATION:

CASE #2:  A two year old has a bowel movement about twice a week, and his stools are extremely hard.  He cries when he passes a stool and mother has occasionally noted a small amount of bright red blood when she cleans him.  He appears well nourished but his diet consists of eight bottles of cow’s milk a day, rice and chicken.  He is a picky eater who won’t eat beans and dislikes all fruits and vegetables.

What is the definition of functional constipation?:  At least two weeks of hard, rock-like, infrequent (<2 times a week) stools in infants and pre-school children.

This type of constipation usually has its onset when breastfeeding is discontinued or when cow’s milk is introduced to the diet.

FUNCTIONAL FECAL RETENTION:

CASE #3A:  Five year old Jose had been having normal BM’s until about two years of age, when after passing a very hard stool, he became “afraid of pooping”.  He started stiffening and crossing his legs when he felt the urge to have a BM.  At first his mother thought he was trying to push the stool out but then realized he was trying to hold it in.  He began having less frequent BM’s and now moves his bowels about once a week.  Sometimes there is stool soiling his underwear.

CASE #3B:  A mother brings in her seven year old son because at a recent family gathering he had an episode of stool leakage, which greatly embarrassed her.  She believes this was intentional and she punished him after the event.  History reveals that for a long time his pattern has been to pass a large stool about once or twice a week that is described as filling the toilet.  At his school students are discouraged by staff from using the toilets (or there are no doors on the stalls, or there is no toilet paper available).  Two years ago his sister was born at 24 weeks gestation and mother has had to spend a lot of time at the hospital with her.

What is the definition of functional fecal retention?:  At least 12 weeks of passage of large diameter stools at intervals  <2 times a week; retentive posturing, avoiding defecation using pelvic floor and gluteal muscles.

Most children with constipation have no underlying pathology.  Constipation usually develops when the child associates pain with defecation, and defers defecation until a larger and harder stool is passed, which is even more painful and leads to further stool withholding.  The interval between bowel movements lengthens, and the rectum gradually accommodates until decreased rectal sensitivity to distension develops, with loss of the normal urge to defecate and development of impaction.  Unformed stool may pass around the impaction and leak out because the internal sphincter is relaxed due to long-standing distension.  Many children have a cycle of soiling, anorexia, decreased physical activity, followed by the passage of a huge BM, after which they feel better, are more active, and have a better appetite.

CONSTIPATION IN ADOLECENTS:

CASE #4:  An 18 year old female is concerned because she has seen some blood on the toilet paper after having a bowel movement, and feels a little ball outside her rectum.  She has to push very hard to pass a stool.  She is taking no medications, and has no other medical issues.  You review her diet, which is low in fiber and fluids.  On exam, you note a hemorrhoid. 

How does constipation present in adolescence?:  Adolescents with constipation are more likely to be female, and report straining with defecation; some may present with hemorrhoids.  Diet is usually low in fiber.  

HIRSCHPRUNG’S DISEASE:

CASE #5:  A six month old infant male who is a recent immigrant from the DR presents with constipation “since birth”.  He has always been difficult to feed despite frequent formula changes.  He vomits a lot and was prescribed zantac for suspected GERD after presenting to the ER.  On exam you note that his abdomen is distended and his weight plots at the 5^th percentile. 

What features of this case raise suspicion for Hirschprung’s Disease  (aganglionosis)? Delayed passage of meconium, and history of constipation from early infancy are characteristic.    

WHAT ARE SOME IMPORTANT POINTS IN THE HISTORY?

When was first stool passed? (delay might suggest Hirschprung’s)

What is the caliber of the stool? (ribbon-like stools characteristic of Hirschprung’s)

Is there pain with defecation?

Is there bleeding with defecation?

Precipitating event, i.e.,

   Following a transition in diet

   Following an illness associated with dehydration, diarrhea or severe diaper dermatitis

   At the time of school entry, with a change in routine (i.e., travel)

Straining? (may actually be withholding)

Diarrhea?  (may actually be leakage or encopresis)

WHAT SHOULD BE NOTED ON THE PHYSICAL EXAM?

Presence of sausage-like mass in left lower quadrant

Abnormalities of the lower spine

Location of the anus on perineum (normally halfway between posterior forchette/base of scrotum and tip of coccyx) looking for anterior displacement

Presence of fissures, hemorrhoids, tags

Elicit anal wink – stroke perineal skin with applicator; the subQ portion of the external sphincter should contract and pucker at the anal margin

Digital rectal exam – note size of rectum, size of canal, masses, empty or full (with Hirschprung’s usually empty and small, with functional constipation usually enlarged and stool palpable)

WHAT WORK-UP IS INDICATED?

Plain x-ray in some cases to look for presence of stool

Barium enema if considering Hirschprung’s

Stool test for occult blood in infants and in children with abdominal pain, failure to thrive

If specific organic etiology suspected, i.e., thyroid hormone, electrolytes, lead level, celiac serology

WHAT IS THE TREATMENT OF CONSTIPATION?

Educating and engaging the family in the management of constipation is key.  It is important to get the point across that treatment is long-term and relapses may occur. At the beginning of treatment, in order to eliminate the pain associated with defecation, sufficiently aggressive and persistent laxative treatment must be recommended in order to consistently produce soft stools.

1.  Clean out – Impaction is suggested by palpable stool on abdominal exam, large amount of stool in a dilated rectum, or x-ray findings.  It is preferable to use oral medications for disimpaction, but it sometimes can be difficult to get children to ingest sufficient quantities of oral cathartics, necessitating the use of enemas and/or suppositories. (in infants it is preferable to use glycerin suppositories rather than enemas).

2.  Maintenance - Start chronic laxative therapy to prevent reaccumulation of stool.  Modify diet to increase fluids and fiber.  The goal is to produce one to two soft stools a day.  Continue laxatives for several months.

3.  Establish regular bowel habits by instituting a routine of sitting on the toilet one or two times a day for five to ten minutes, usually after a meal to take advantage of the gastrocolic reflex.  This time should be as relaxed and undisturbed as possible.  The toilet seat should be comfortable with feet flat on the floor or a box or a stepstool.

4.  For relapse after discontinuing treatments, use laxatives intermittently.

WHO SHOULD BE REFERRED TO A SUBSPECIALIST?

Consider referral to a pediatric gastroenterologist when treatment fails, or the patient has multiple relapses, or diagnosis is unclear and management complex.

WHAT IS THE DIFFERENTIAL DIAGNOSIS OF CONSTIPATION?

Anatomic:  anal stenosis, anteriorly displaced anus

Metabolic:  hypothyroidism, hypercalcemia, hypokalemia,

Neuropathic:  spinal cord abnormalities, CP

Medications:  Phenobarbital, antacids, anticholinergics, opiates, antidepressants, diuretics, methylphenidate

Other:  cow’s milk sensitivity/intolerance, lead poisoning, botulism, cow’s milk protein intolerance

Attachments:

Constipation Formulary

(Anti)Constipation Diet

References:

1.  Youssef NN, Di Lorenzo C:  Childhood Constipation, J Clin Gastroenterol 2001:33(3):199-205

2.  Evaluation and treatment of constipation in infants and children:  recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition.  J Pediatr Gastroentol Nutr 2006 Sep 43(3):e1-13