Symptom Definitions

In gastroenterology, precise language matters. Differentiating between "bloating" and "distension," or defining exactly what constitutes "constipation," is the first step toward clinical management.

Bloating vs. Distension

While often used interchangeably by patients, these are two distinct clinical symptoms:

Subjective Bloating

The feeling of increased abdominal pressure or trapped gas. The stomach may not look any larger to an outside observer. Often related to visceral hypersensitivity (a heightened pain response in gut nerves).

Objective Distension

A measurable, visible increase in abdominal girth. Often worsens throughout the day. Caused by actual gas volume from fermentation (SIBO) or abnormal diaphragmatic reflexes (abdomino-phrenic dyssynergia).

Constipation

Clinically defined not just by frequency, but by form and effort.

Form: Types 1 or 2 on the Bristol Stool Scale.
Frequency: Fewer than three bowel movements per week.
Effort: Straining during more than 25% of defecations, or a feeling of incomplete evacuation (tenesmus).

Key distinction: Slow-transit constipation (colon moves too slowly) vs. Evacuation disorders (pelvic floor muscles fail to coordinate properly). The latter will not respond to fiber or laxatives.

Diarrhea

Defined by stool consistency and weight, not just frequency.

Form: Types 6 or 7 on the Bristol Scale.
Types:
- Osmotic: Water is pulled into the bowel by unabsorbed substances (e.g., lactose or excessive vitamin C). Stops when fasting.
- Secretory: The bowel actively secretes fluid (e.g., bacterial toxins, cholera). Continues even when fasting.
- Motility-related: Transit is too fast for water reabsorption (e.g., hyperthyroidism).