Constipation

Overview

Definition

Constipation is a symptom generally defined as bowel movements < 3 times per week; stools are frequently difficult to pass.

Epidemiology

• Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency:
  • 15% of the population is affected by chronic constipation
  • Most common digestive complaint in the general population
• Sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria: women > men (3:1)
• Age:
  • Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency of adult constipation increases with age, especially in those ≥ 65 years
  • Pediatric constipation Pediatric constipation Constipation is a common complaint in children that is relatively defined for individual age groups based on the frequency and difficulty of defecation and stool consistency. The majority of constipation cases are functional or non-organic. Clinical presentation may vary, from insufficient evacuation noted by the parents, to complaints of abdominal pain, to secondary incontinence. Pediatric Constipation affects up to 30% of children, most commonly in the preschool age group.
• Race/ethnicity:
  • ↑ Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency in non-White as compared with White Americans
  • ↑ Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency in White as compared with Black Africans
  • Rare overall in Africa and India, where stool weight is 3–4 times greater than in Western countries

Classification

Constipation can be classified as either primary or secondary, as well as by duration (acute or chronic).

• Primary constipation (also known as idiopathic Idiopathic Dermatomyositis or functional constipation Functional Constipation Pediatric Constipation) is constipation not caused by a medical disorder or medication; it is divided into 3 subtypes:
  • Normal colonic transit constipation:
    • Stool passes through the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy at a normal rate, but patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship find it difficult to pass it.
    • Most common subtype
  • Slow colonic transit constipation:
    • Characterized by infrequent bowel movements, ↓ urgency, and/or straining to defecate
    • Impaired phasic colonic motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology activity (e.g., no increase in motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology activity after meals)
  • Outlet constipation (also known as pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy dyssynergia)
    • Difficulty expelling stool from the anorectum owing to dysfunction of the pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy and/or anal sphincter 
    • Results in prolonged straining, feeling of incomplete evacuation, use of perineal or vaginal pressure during defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility to allow the passage of stool, or digital evacuation of stool
• Secondary constipation: constipation due to a medical disorder (structural or systemic) or medications
• Acute constipation: present ≤ 12 weeks
• Chronic constipation: present > 12 weeks

Etiology

Primary constipation

Primary constipation, also known as functional constipation Functional Constipation Pediatric Constipation, is when there are no identifiable medical disorders. Primary constipation may be due to:

• Habits:
  • Low-fiber diet
  • Inadequate water intake
  • Sedentary lifestyle
  • Overuse of coffee, tea, or alcohol
• Irritable bowel syndrome Irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome ( IBS IBS Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome) with constipation
• Pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy dysfunction

Secondary Constipation

Secondary constipation is constipation due to a medical disorder or medication.

Pathophysiology

The pathophysiology of constipation varies depending on the etiology, but in general, there are 2 primary mechanisms that cause constipation: altered stool consistency Consistency Dermatologic Examination and altered bowel motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility.

Altered stool consistency Consistency Dermatologic Examination

• Factors that can alter stool consistency Consistency Dermatologic Examination:
  • External factors:
    • ↓ Fiber intake
    • ↓ Fluid intake
    • ↓ Exercise
  • Internal factors: changes within the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy or rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
• Process by which altered stool consistency Consistency Dermatologic Examination leads to constipation:
  • External / internal factors → 
  • Slow passage of stool → 
  • ↑ Absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption of water by bowel mucosa → 
  • Dry, hard stool Hard stool Appendicitis → 
  • Painful or irregular defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility, sensations of incomplete defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility → constipation 

Altered bowel motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility

Altered bowel motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility leads to ineffective peristalsis Peristalsis A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction. Gastrointestinal Motility and difficulty passing stool regardless of its consistency Consistency Dermatologic Examination, leading to sensations of incomplete and irregular bowel emptying. Altered bowel motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility may arise from a number of mechanisms, including:

• Problems with bowel innervation → ineffective peristalsis Peristalsis A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction. Gastrointestinal Motility; may be due to:
  • Disease or defects in the intrinsic myenteric plexus Myenteric plexus One of two ganglionated neural networks which together form the enteric nervous system. The myenteric (Auerbach’s) plexus is located between the longitudinal and circular muscle layers of the gut. Its neurons project to the circular muscle, to other myenteric ganglia, to submucosal ganglia, or directly to the epithelium, and play an important role in regulating and patterning gut motility. Gastrointestinal Neural and Hormonal Signaling or extrinsic sympathetic and parasympathetic nerves
  • Central neurologic disorders
• Endocrinopathies:
  • Changes in hormone levels (e.g., thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types, estrogen Estrogen Compounds that interact with estrogen receptors in target tissues to bring about the effects similar to those of estradiol. Estrogens stimulate the female reproductive organs, and the development of secondary female sex characteristics. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds. Ovaries: Anatomy) → ↓ bowel motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus: can result in neuropathies Neuropathies Chédiak-Higashi Syndrome
• Hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia and hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia → ↓ the neuromuscular excitability Excitability Skeletal Muscle Contraction of the smooth muscle cells within the bowel leading to hypotonicity Hypotonicity Volume Depletion and Dehydration
• Megacolon Megacolon Megacolon is a severe, abnormal dilatation of the colon, and is classified as acute or chronic. There are many etiologies of megacolon, including neuropathic and dysmotility conditions, severe infections, ischemia, and inflammatory bowel disease. Megacolon and/or megarectum secondary to chronic fecal retention → ↑ rectal compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology and elasticity Elasticity Resistance and recovery from distortion of shape. Skeletal Muscle Contraction and ↓ rectal sensation
• Outlet obstruction prevents effective defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility; may be due to:
  • Rectal prolapse Rectal prolapse Rectal prolapse, also known as rectal procidentia, is the protrusion of rectal tissue through the anus. The tissue may include just the mucosa or the full thickness of the rectal wall. Common risk factors include chronic straining, constipation, bowel motility disorders, and weakening of the pelvic floor muscles. Rectal Prolapse or rectocele Rectocele Herniation of the rectum into the vagina. Pelvic Organ Prolapse
  • Tumors
  • Functional obstruction: failure to relax the puborectalis Puborectalis Vagina, Vulva, and Pelvic Floor: Anatomy and external anal sphincter External anal sphincter Rectum and Anal Canal: Anatomy muscles required for defection (i.e., dyssynergic defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility)
• Drugs: can lead to autonomic outflow dysfunction and abnormal bowel muscle contraction

Clinical Presentation

History and symptoms

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may be asymptomatic, or they may present with the following symptoms:

• Infrequent bowel movements (< 3/week)
• Stool:
  • Difficult to expel, passed with straining
  • Bristol Stool Scale Scale Dermatologic Examination forms 1 and 2: hard and/or lumpy
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways:
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways with defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility
  • Abdominal pain Abdominal Pain Acute Abdomen relieved by defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility
  • Abdominal cramping Abdominal cramping Norovirus
  • Low back pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Bloating
• Rectal bleeding
• Overflow diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea
• Tenesmus (cramping rectal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways leading to sensations of needing to evacuate the bowels)

Examination

• Abdominal distention Abdominal distention Megacolon
• On anorectal area examination:
  • Possible fissures
  • Possible hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids
  • An absent anal wink reflex suggests pathology (e.g., sacral nerve injury Nerve Injury Surgical Complications).
• Findings consistent with secondary causes of constipation (e.g., abnormal neurologic findings)

Diagnosis

Diagnostic criteria

Constipation is a clinical diagnosis. The Rome IV diagnostic criteria for functional constipation Functional Constipation Pediatric Constipation are used in cases with normal transit time.

Criteria:

At least 2 of the following must have occurred in ≥ 25% of defecations during the past 3 months, with the onset of symptoms ≥ 6 months ago:

• Passage of stool < 3 times/week
• Passage of hard or lumpy stool (Bristol Stool Scale Scale Dermatologic Examination form 1 or 2)
• Straining during attempts to defecate
• Sensation of anorectal obstruction 
• Sensation of incomplete defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility
• Using manual maneuvers to evacuate stool
• Note: There must also be insufficient criteria for IBS IBS Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome

Indications:

Indications for further workup include:

Basic workup

• Anoscopy Anoscopy Anal Fissure: 
  • An anoscope is a rigid tube, approximately 10 cm in length, that allows for direct visualization of the anal canal and distal rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy.
  • Anoscopy Anoscopy Anal Fissure is an office procedure that allows for the assessment of anal fissures, ulcers, hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids, and local anorectal malignancy Malignancy Hemothorax.
• Colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening: 
  • Endoscopic procedure allowing for direct visualization of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy; used to rule out malignancy Malignancy Hemothorax and/or obtain biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma samples
  • Indicated in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship at high risk for or with symptoms concerning for colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy cancer (e.g., rectal bleeding, weight loss Weight loss Decrease in existing body weight. Bariatric Surgery, or anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types)
• Laboratory: Laboratory evaluation does not play a large role in the initial assessment, but basic studies may provide insight Insight Psychiatric Assessment.
  • CBC:
    • WBC for infection
    • Hemoglobin for anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types from GI bleeding
  • CMP:
    • Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes for parathyroid Parathyroid The parathyroid glands are 2 pairs of small endocrine glands found in close proximity to the thyroid gland. The superior parathyroid glands are lodged within the parenchyma of the upper poles of the right and left thyroid lobes; the inferior parathyroid glands are close to the inferior tips or poles of the lobes. Parathyroid Glands: Anatomy disorders and hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia
    • Glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance for diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia for hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia
  • Thyroid-stimulating hormone Thyroid-stimulating hormone A glycoprotein hormone secreted by the adenohypophysis. Thyrotropin stimulates thyroid gland by increasing the iodide transport, synthesis and release of thyroid hormones (thyroxine and triiodothyronine). Thyroid Hormones (TSH) for hypothyroidism Hypothyroidism Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
  • Fecal occult blood test Fecal occult blood test Colorectal Cancer for blood in stool, which raises concern for cancer
• Imaging studies: used to evaluate for intra-abdominal or systemic problems; may show significant stool burden in the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy
  • X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests
  • CT

Motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility studies

• Colonic transit study:
  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship in whom colonic motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility disorders are suspected
  • Orally administered radiopaque Radiopaque An object of high density that blocks X-rays (looks white) X-rays markers are tracked by daily abdominal X-rays Abdominal X-Rays X-rays. 
  • The colonic transit time is the time it takes for these markers to arrive at the site where they appear to be retained.
    • In outlet obstruction, markers are retained in the left colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy and sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus.
    • In colonic dysmotility, the markers may be retained throughout the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy.
• Anorectal manometry Anorectal Manometry Pediatric Constipation:
  • Assesses rectal sensation, reflexes, tone, and compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology
  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship in whom dyssynergic, myopathic, or neuropathic motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility issues are suspected
  • Consider in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who have primary constipation not responding to fiber supplementation and a trial of osmotic laxatives Osmotic Laxatives Laxatives
• Balloon expulsion test:
  • A physiologic assessment that can help differentiate between dyssynergia and slow transit constipation
  • Simple office test: A balloon filled with water is inserted into the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy and the patient is asked to expel the balloon. 
  • A positive test (i.e., failure to expel the balloon) is suggestive, but not diagnostic, of pelvic dyssynergia. 

Management

The 1st step in management should be to identify and treat any causes of secondary constipation. Next, management should focus on lifestyle changes and use of bulk-forming agents, followed by osmotic laxatives Osmotic Laxatives Laxatives, adding surface-acting agents, and finally using stimulant laxatives Stimulant Laxatives Laxatives.

Initial management

• Lifestyle changes:
  • ↑ Fiber: goal is > 20–35 g/day 
  • ↑ Fluid
  • ↓ Constipating agents, such as dairy products, coffee, tea, and alcohol
  • ↑ Exercise
  • Attempt to defecate after meals
  • Avoid overusing laxatives Laxatives Laxatives are medications used to promote defecation. Most often, laxatives are used to treat constipation or for bowel preparation for certain procedures. There are 4 main classes of laxatives: bulk-forming, stimulant, osmotic, and emollient. Laxatives
• Bulk-forming agents (best option for long-term management of constipation)
• Osmotic agents if needed 
• Manual disimpaction for fecal impaction
• Consider:
  • Rectal enemas, lubricants, and suppositories Suppositories Medicated dosage forms that are designed to be inserted into the rectal, vaginal, or urethral orifice of the body for absorption. Generally, the active ingredients are packaged in dosage forms containing fatty bases such as cocoa butter, hydrogenated oil, or glycerogelatin that are solid at room temperature but melt or dissolve at body temperature. Large Bowel Obstruction 
  • Surface agents/surfactants

Secondary management

If initial management is inadequate, additional options are available, including:

• Biofeedback Biofeedback The therapy technique of providing the status of one’s own autonomic nervous system function (e.g., skin temperature, heartbeats, brain waves) as visual or auditory feedback in order to self-control related conditions (e.g., hypertension, migraine headaches). Psychotherapy training for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with defecatory dysfunction
• Stimulant laxatives Stimulant Laxatives Laxatives:
  • Daily use of stimulant laxatives Stimulant Laxatives Laxatives may lead to hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia, protein-losing enteropathy Enteropathy IPEX Syndrome, and salt depletion
  • Try to avoid when treating chronic constipation
• Chloride Chloride Inorganic compounds derived from hydrochloric acid that contain the Cl- ion. Electrolytes channel activators
• Prokinetics
• Guanylate cyclase Guanylate cyclase An enzyme that catalyzes the conversion of GTP to 3. Diarrheagenic E. coli C (GC-C) agonists

Pharmacologic options

Complications

• Anal fissures:
  • Passage of hard, lumpy stools causes a tear in the anoderm.
  • Leads to painful defecation Painful Defecation Pediatric Constipation and rectal bleeding
• Hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids:
  • Due to excessive straining with hard, lumpy stools
  • Leads to rectal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, itching, and/or bleeding
• Fecal impaction:
  • Obstruction of the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy with stool
  • Leads to inability to defecate for days or weeks and a tender, distended abdomen
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may feel the urge to defecate but are unable to do so.
  • Management: manual disimpaction → osmotic enema → stimulatory suppository
• Fecal incontinence Fecal incontinence Failure of voluntary control of the anal sphincters, with involuntary passage of feces and flatus. Pediatric Constipation (involuntary defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility):
  • Chronic constipation → formation of a hard stool Hard stool Appendicitis mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast → progressive distention of the anal sphincter complex → patient no longer feels urge to defecate
  • Soft or liquid stool begins to seep around the obstructing stool mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast, causing overflow incontinence Overflow incontinence Symptom of underactive detrusor muscle of the urinary bladder that contracts with abnormally reduced strength or duration resulting in an incomplete and/or prolonged bladder emptying. Urinary Incontinence
• Urinary retention Urinary retention Inability to empty the urinary bladder with voiding (urination). Delirium
• Pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy damage in women
• Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope with straining
• Megacolon Megacolon Megacolon is a severe, abnormal dilatation of the colon, and is classified as acute or chronic. There are many etiologies of megacolon, including neuropathic and dysmotility conditions, severe infections, ischemia, and inflammatory bowel disease. Megacolon (see Differential Diagnosis)

Differential Diagnosis

• Appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis: acute inflammation Acute Inflammation Inflammation of the appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy: Symptoms of appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis are periumbilical pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways that migrates to the RLQ, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, anorexia Anorexia The lack or loss of appetite accompanied by an aversion to food and the inability to eat. It is the defining characteristic of the disorder anorexia nervosa. Anorexia Nervosa, nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics, and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia, but appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis can often cause constipation, as well. The diagnosis is clinical, but imaging is used in cases of uncertainty. The standard management is appendectomy Appendectomy Appendectomy is an invasive surgical procedure performed with the goal of resecting and extracting the vermiform appendix through either an open or a laparoscopic approach. The most common indication is acute appendicitis. Appendectomy, though there can be a role for antibiotics in some cases.
• Colorectal cancer Colorectal cancer Colorectal cancer (CRC) is the 2nd leading cause of cancer-related deaths in the United States. Colorectal cancer is a heterogeneous disease that arises from genetic and epigenetic abnormalities, with influence from environmental factors. Colorectal Cancer: 2nd leading cause of cancer-related deaths in the United States. Almost all cases are adenocarcinoma, and the majority of lesions come from the malignant transformation Transformation Change brought about to an organism’s genetic composition by unidirectional transfer (transfection; transduction, genetic; conjugation, genetic, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell’s genome. Bacteriology of an adenomatous polyp Adenomatous polyp Benign neoplasms derived from glandular epithelium. Colon Polyps. Most cases are asymptomatic, so screening Screening Preoperative Care colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening or stool tests are recommended in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship ≥ 50 years of age. Diagnosis is by colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening. Management is based on characteristics of the cancer and usually includes surgery and potentially chemotherapy Chemotherapy Osteosarcoma and/or radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma.
• Large bowel obstruction Bowel obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis: interruption in the normal flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure of intestinal contents through the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy and rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy. The obstruction may be mechanical (due to actual physical occlusion of the lumen) or functional (due to loss of normal peristalsis Peristalsis A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction. Gastrointestinal Motility, also known as pseudo-obstruction). The typical symptoms include intermittent lower abdominal pain Abdominal Pain Acute Abdomen, abdominal distention Abdominal distention Megacolon, and obstipation Obstipation Large Bowel Obstruction. Diagnosis is by imaging. Surgery is needed in the majority of cases.
• Crohn’s disease: chronic, recurrent condition that causes patchy transmural inflammation Transmural inflammation Crohn’s Disease that can involve any part of the GI tract. The terminal ileum Ileum The distal and narrowest portion of the small intestine, between the jejunum and the ileocecal valve of the large intestine. Small Intestine: Anatomy and proximal colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy are usually affected. Crohn’s disease typically presents with intermittent, nonbloody diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea and crampy abdominal pain Abdominal Pain Acute Abdomen. Diagnosis is by endoscopy Endoscopy Procedures of applying endoscopes for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. Transluminal, to examine or perform surgery on the interior parts of the body. Gastroesophageal Reflux Disease (GERD). Management is with corticosteroids Corticosteroids Chorioretinitis, azathioprine Azathioprine An immunosuppressive agent used in combination with cyclophosphamide and hydroxychloroquine in the treatment of rheumatoid arthritis. According to the fourth annual report on carcinogens, this substance has been listed as a known carcinogen. Immunosuppressants, antibiotics, and anti– tumor Tumor Inflammation necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage factor ( TNF TNF Tumor necrosis factor (TNF) is a major cytokine, released primarily by macrophages in response to stimuli. The presence of microbial products and dead cells and injury are among the stimulating factors. This protein belongs to the TNF superfamily, a group of ligands and receptors performing functions in inflammatory response, morphogenesis, and cell proliferation. Tumor Necrosis Factor (TNF)) agents ( infliximab Infliximab A chimeric monoclonal antibody to tnf-alpha that is used in the treatment of rheumatoid arthritis; ankylosing spondylitis; psoriatic arthritis and Crohn’s disease. Disease-Modifying Antirheumatic Drugs (DMARDs) and adalimumab Adalimumab A humanized monoclonal antibody that binds specifically to tnf-alpha and blocks its interaction with endogenous tnf receptors to modulate inflammation. It is used in the treatment of rheumatoid arthritis; psoriatic arthritis; Crohn’s disease and ulcerative colitis. Disease-Modifying Antirheumatic Drugs (DMARDs)).
• Irritable bowel syndrome Irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome: functional bowel disease characterized by chronic abdominal pain Abdominal Pain Acute Abdomen and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of IBS IBS Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome are not well understood, and there are many factors that may contribute. Irritable bowel syndrome Irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome is a diagnosis of exclusion, and organic causes should be ruled out. Dietary modifications and symptom control measures may be instituted.
• Megacolon Megacolon Megacolon is a severe, abnormal dilatation of the colon, and is classified as acute or chronic. There are many etiologies of megacolon, including neuropathic and dysmotility conditions, severe infections, ischemia, and inflammatory bowel disease. Megacolon: severe, abnormal dilatation of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy classified as acute or chronic. There are many etiologies for megacolon Megacolon Megacolon is a severe, abnormal dilatation of the colon, and is classified as acute or chronic. There are many etiologies of megacolon, including neuropathic and dysmotility conditions, severe infections, ischemia, and inflammatory bowel disease. Megacolon, including neuropathic and dysmotility conditions, severe infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage, and inflammatory bowel disease. Common symptoms include abdominal distention Abdominal distention Megacolon, pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, bloody diarrhea Bloody diarrhea Diarrhea, and obstipation Obstipation Large Bowel Obstruction. Management for acute megacolon Acute megacolon Megacolon includes supportive care, decompression, and, potentially, surgery.