Gastrointestinal Disorders: Anatomy, Physiology, and Clinical Considerations

Overview of the Abdominal Cavity

The abdominal cavity houses several vital organs, each occupying specific anatomical regions known as quadrants. Understanding these locations is essential for clinical assessment and diagnosis of gastrointestinal disorders.

• Right Upper Quadrant (RUQ): Liver, gallbladder, duodenum, head of pancreas, right kidney & adrenal gland, part of ascending & transverse colon.

• Left Upper Quadrant (LUQ): Stomach, spleen, left lobe of liver, body of pancreas, left kidney & adrenal gland, part of transverse & descending colon.

• Right Lower Quadrant (RLQ): Cecum, appendix, right ovary & tube, right ureter, right spermatic cord.

• Left Lower Quadrant (LLQ): Part of descending colon, sigmoid colon, left ovary & tube, left ureter, left spermatic cord.

Anatomical Considerations: Infants & Children

Infants and children have unique anatomical features that influence gastrointestinal assessment and function.

• Newborns: The umbilical cord is prominent, containing two arteries and one vein. The liver is proportionally larger, and the urinary bladder is positioned higher in the abdomen.

• Early Childhood: The abdominal wall is less muscular, making organs easier to palpate. The urinary bladder remains higher in the abdomen compared to adults.

Anatomical Considerations: The Older Adult

Aging affects the structure and function of the gastrointestinal system, leading to increased risk of certain disorders.

• Musculature: Abdominal wall muscles relax with age.

• Salivation: Decreases, causing dry mouth and reduced taste sensation.

• Gastric Function: Esophageal emptying and gastric acid secretion are delayed.

• Gallstones: Incidence increases with age.

• Liver: Size decreases, but most functions remain normal; drug metabolism may be impaired.

• Colon Motility: Slows down, especially with reduced mobility and medication use, increasing constipation risk.

• Bowel Sensation: Reduced urge to defecate and diminished ability to distinguish between passing solids, liquids, or gas.

Normal Bowel Function, Constipation, and Bowel Obstruction

Understanding normal and abnormal bowel function is crucial for diagnosing and managing gastrointestinal disorders.

• Normal Bowel Function: Defined as passing a bowel motion as often as three times per day or as infrequently as once every three days, without straining and with a sense of complete evacuation.

• Constipation: Difficulty passing stools or infrequent bowel movements (less than two stools per week). Can be:

  • Functional: Normal transit constipation.

  • Mechanical: Obstructive emptying (e.g., inflammatory bowel disease).

• Bowel Obstruction: Partial or complete blockage of the bowel lumen, which can occur in the small or large intestine and may be functional or mechanical in nature.

Common Causes of Constipation in Older Adults

Constipation is prevalent in older adults due to a combination of physiological and lifestyle factors.

• Decreased physical activity

• Inadequate intake of water

• Low-fibre diet

• Side effects of medications (e.g., opioids)

• Irritable bowel syndrome

• Bowel obstruction

• Hypothyroidism

• Inadequate toilet facilities or difficulty ambulating, leading to stool retention

Constipation: Signs & Symptoms

Recognizing the clinical features of constipation aids in timely intervention.

• Abdominal distension

• Abdominal discomfort

• Reduced appetite

• Headache

• Indigestion

• Trouble passing stool

• Change to usual bowel routine (more infrequent)

• Passing hard stools

• Straining when trying to pass stool

• Passing only small amounts of faeces

• Feeling of incomplete evacuation after bowel motion

Constipation Management

Management of constipation involves lifestyle modifications, dietary changes, and documentation for monitoring.

• Fibre Intake: Recommended daily intake is 30 mg for men and 25 mg for women. Documentation via food intake chart.

• Fluid Intake: Women should consume at least 2 litres, and men 2.6 litres of fluid per day. Documentation via fluid balance chart.

• Physical Activity: Increasing activity (e.g., walking, swimming) promotes bowel motility.

• Documentation: Use of bowel charts, Bristol stool chart, and integrated progress notes to monitor bowel motions.

Additional info:

• Bristol Stool Chart: A clinical tool used to classify the form of human faeces into seven categories, aiding in the assessment of bowel health.

• Obstructive vs. Functional Constipation: Obstructive constipation is due to a physical blockage, while functional constipation is related to motility or transit issues without a physical obstruction.