Diagnosis of Constipation, Diarrhea & Pill-Induced Esophagitis

ANCHOR QUESTION — SLIDE 1

Clinical Vignette

A 36-year-old woman is evaluated for constipation. Her constipation has recently worsened despite daily laxative therapy. She has a history of hemorrhoids and has had intermittent, painless rectal bleeding for the past 3 months. She has lost weight. She does not have a family history of colorectal cancer. Medications are polyethylene glycol and methylcellulose.

On physical examination, vital signs are normal. Scleral pallor is noted. Rectal examination reveals small, nonbleeding external hemorrhoids. There are no palpable masses in the distal rectal vault.

Laboratory studies:

Hemoglobin

10 g/dL

Mean corpuscular volume

76 fL

Which of the following is the most appropriate test to perform next?

Anorectal manometry

Colonoscopy

Fecal immunochemical testing

Flexible sigmoidoscopy

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 2 — ANSWER + EXPLANATION

Correct Answer

B. Colonoscopy

Blood in the stool

Sudden change in bowel habits

Unexplained anemia

This patient has:

Intermittent painless rectal bleeding

Worsening constipation

Microcytic anemia

Weight loss

These findings require full colonic evaluation, not testing for functional constipation

Why the Other Answers Are Incorrect

A

Anorectal manometry

Used to evaluate dyssynergic defecation

Reserved for symptoms that do not respond to laxative therapy

Not the next step when alarm features are present

C

Fecal immunochemical testing

Used for colorectal cancer screening in average-risk patients

Not used to evaluate active bleeding or anemia

D

Flexible sigmoidoscopy

Evaluates only the distal colon

Does not provide the complete evaluation needed in this patient

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 3

C O N S T I P A T I O N

ALARM FEATURES

MKSAP Alarm Features That Change the Evaluation

Hematochezia

Suggests possible structural colonic disease. Requires more than empiric treatment or functional testing.

Unintentional Weight Loss

Raises concern for malignancy or other serious pathology.

Unexplained Anemia

Especially important when iron deficiency is present. Supports need for endoscopic evaluation.

Acute Constipation in Older Patients

More concerning for obstructing lesion or secondary cause.

Family History of Colorectal Cancer

Increases concern for significant colonic pathology.

Age >45 With No Prior Colonoscopy

Makes colonoscopic evaluation more important.

KEY POINT: When alarm features are present, the evaluation shifts away from functional constipation and toward structural investigation

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 4

Constipation: Diagnostic Approach

History and Examination Are the Foundation

History Should Identify

Secondary Causes

A careful history identifies most causes of secondary constipation

Medication History

Focus on: which medications the patient is taking, and whether constipation began after the medication was started

Alarm Features to Look For

Bleeding

Weight loss

Anemia

Change in bowel habits

Anorectal Examination

What It May Identify

Anatomic causes

Functional causes of an evacuation disorder

Digital Exam + Valsalva Maneuver

Can help assess for anorectal dysfunction

GENERAL PRINCIPLE

Start with history and physical examination before moving to specialized physiologic testing

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 5

DIAGNOSTIC

TESTING

for Constipation

When Testing Is Needed, Choose It Based on the Clinical Scenario

Colonoscopy

Indicated with blood in the stool, sudden change in bowel habits, unexplained anemia.

Used to evaluate colonic causes.

Flat-Plate Radiography

Not routinely needed to quantify stool burden.

May be used when fecal impaction or obstruction is suspected.

Additional Labs / Imaging

Only if clinically indicated.

Physiologic Testing

Reserved for refractory constipation.

Includes: colon transit testing, anorectal manometry, balloon expulsion testing, defecography.

KEY POINT: In refractory constipation without alarm features, physiologic testing helps define the subtype of functional constipation

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 6

Diarrhea: Classification by Duration

First Step in Diagnosis

ACUTE DIARRHEA

< 2 Weeks

Usually infectious in origin

PERSISTENT DIARRHEA

2 to < 4 Weeks

Often still suggests an infectious cause, especially parasites

CHRONIC DIARRHEA

≥ 4 Weeks

Usually noninfectious. Broader differential diagnosis applies.

WHY THIS MATTERS

Duration helps narrow the likely cause before stool studies or endoscopy are considered. Acute diarrhea is approached differently from chronic diarrhea because the differential diagnosis is different.

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 7

CHRONIC

DIARRHEA

Diagnostic Categories

MKSAP Organizes Chronic Diarrhea by Mechanism

Osmotic

Caused by poorly absorbed substances.

Causes:

laxatives, lactose, fructose, sorbitol, mannitol.

Secretory

Active fluid/electrolyte secretion.

Causes:

medications, endocrine causes, bile salt malabsorption, some infections.

Steatorrhea

Maldigestion or malabsorption.

Seen with:

pancreatic dysfunction, bile salt deficiency, celiac disease, small bowel disease.

Inflammatory

Mucosal inflammation or injury.

Seen with:

IBD, malignancy, invasive infection, ischemia, radiation.

Motility-Related

Altered transit.

Seen in:

diabetes, hyperthyroidism, postsurgical states.

Miscellaneous

IBS, functional diarrhea, overflow diarrhea from constipation, fecal incontinence.

MOST COMMON: IBS-D and functional causes are the most common causes of chronic diarrhea (MKSAP)

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 8

Diarrhea: Diagnostic Clues from the History

Stool Pattern and Symptom Behavior Help Identify the Mechanism

Osmotic Diarrhea

Occurs with eating, improves with fasting. Suggests unabsorbed solutes in the intestinal lumen.

Secretory Diarrhea

Does NOT improve with fasting. Suggests ongoing intestinal secretion.

Steatorrhea

Greasy or bulky stools, may be difficult to flush. Suggests fat malabsorption or maldigestion.

Inflammatory Diarrhea

Nocturnal symptoms more suggestive. Blood or systemic features support an inflammatory cause.

IBS-D

Abdominal pain occurs with changes in bowel movements.

Dietary Clues

Lactose, fructose, and artificial sweeteners may point to osmotic diarrhea.

Medication Clues

Always ask about new prescription and nonprescription medications and when they were started.

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 9

STOOL TESTING

and Additional Testing

Testing Depends on the Clinical Scenario

Stool Analysis May Include

Electrolytes

pH

Fat content

Elastase

Blood and leukocytes

Fecal Osmotic Gap

290 − 2 × (stool Na⁺ + stool K⁺)

< 50

Secretory diarrhea

> 100

Osmotic diarrhea

Blood or Leukocytes in Stool

Suggests an inflammatory cause

Elevated Fecal Calprotectin

Supports an inflammatory process

Positive 72-Hour Stool Fat

Confirms steatorrhea

Reduced Fecal Elastase

May suggest exocrine pancreatic dysfunction

Endoscopic Evaluation:

Colonoscopy is the primary diagnostic tool for colonic causes. Colon biopsies from the right AND left colon are needed to exclude microscopic colitis.

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

ANCHOR QUESTION — SLIDE 10

Clinical Vignette

A 68-year-old woman presents with chest pain and odynophagia that began 2 days after starting alendronate. She reports taking the medication at bedtime with minimal water.

Topic

Pill-Induced Esophagitis

Which of the following is the most appropriate next step in management?

Initiate proton pump inhibitor

Discontinue medication and modify administration

Immediate upper endoscopy

Start antibiotics

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 11 — ANSWER + TREATMENT

Correct Answer

B. Discontinue Medication and Modify Administration

Pill-induced esophagitis results from medication-related esophageal injury.

Initial Management:

Stop the offending medication

Prevent additional esophageal exposure

Prevention & Treatment:

Drink sufficient water with medications

Remain upright for 30 minutes after pill ingestion

Why the Other Options Are Incorrect

Initiate PPI

Not the main treatment point — removing the causative agent and correcting administration are the primary steps.

Immediate Upper Endoscopy

Not required in every case. Reserved for severe, persistent, or atypical symptoms (e.g., hematemesis, abdominal pain).

Start Antibiotics

No role in medication-induced esophageal injury. This is a chemical/mechanical injury, not infectious.

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis

SLIDE 12

Pill-Induced Esophagitis

Causes, Risk Factors, and Escalation

Common Medications

Antibiotics (especially tetracyclines)

Bisphosphonates

NSAIDs

Ferrous sulfate

Potassium chloride

Specific Examples:

Alendronate

Quinidine

Tetracycline

Doxycycline

Potassium chloride

Ferrous sulfate

Mexiletine

Medications Associated with Stricture

Alendronate

Ferrous sulfate

NSAIDs

Potassium chloride

Risk Factors

Decreased salivary output

Esophageal dysmotility

Large pills

Medications that increase LES tone (e.g., opioids)

Taking medications in the supine position

When to Perform Upper Endoscopy

Endoscopy is indicated when symptoms are:

Severe

Persistent

Atypical, including:

Hematemesis

Abdominal pain

Diagnosis of Defecation Disorders + Treatment of Pill-Induced Esophagitis