What is the most likely diagnosis and appropriate diagnostic approach for a middle-aged male with chronic constipation, soft stools, incomplete evacuation, straining, chronic anal fissures, grade 2 internal hemorrhoids, rectal bleeding, autoimmune history, peripheral eosinophilia, and chronic active gastritis?

Diagnostic Approach and Management of Chronic Constipation with Suspected Defecatory Disorder

This patient most likely has a defecatory disorder (pelvic floor dysfunction), and anorectal manometry with balloon expulsion testing should be performed first, before colonoscopy, to guide definitive treatment with biofeedback therapy. 1, 2

Clinical Reasoning: Why This is Defecatory Disorder

The symptom pattern strongly indicates pelvic floor dysfunction rather than slow transit constipation:

• Soft stools that are difficult to pass is the hallmark clinical clue for defecatory disorder, as prolonged excessive straining with soft stools or inability to pass enema fluid strongly indicates this diagnosis 1, 2, 3
• Incomplete evacuation sensation is a Rome III diagnostic criterion for defecatory disorders and suggests impaired rectal evacuation 2, 3
• Straining even with formed stools indicates paradoxical pelvic floor contraction or failure to relax during defecation, not a stool consistency problem 1, 2
• Chronic anal fissures can both result from and perpetuate defecatory disorders through a pain-spasm cycle that worsens pelvic floor dysfunction 4, 5

The fact that fiber supplementation and laxatives have failed to resolve symptoms despite achieving softer stools is pathognomonic for defecatory disorder—if this were purely slow transit constipation, softer stools would improve symptoms 1, 6

Diagnostic Algorithm: Anorectal Testing First

Perform anorectal manometry and balloon expulsion test before colonoscopy in this patient. 1, 2, 3

Why Anorectal Testing Takes Priority:

• The American Gastroenterological Association recommends anorectal testing first (manometry and balloon expulsion test) to identify defecatory disorders, especially when patients report straining, sensation of blockage, or need for manual maneuvers 1, 2, 3
• Colonic transit study should only be evaluated if anorectal tests do not show defecatory disorder or if symptoms persist despite treatment of the defecatory disorder 1, 2, 3
• This sequence prevents unnecessary laxative escalation and identifies patients who need biofeedback therapy rather than prokinetic agents 1, 2

When to Perform Colonoscopy:

Colonoscopy with biopsies is indicated in this patient, but can be performed after anorectal testing. 1, 3

The indications for colonoscopy here include:

• Rectal bleeding with bowel movements is an alarm feature requiring colonoscopy 1, 3
• Peripheral eosinophilia (percentage not specified but noted as elevated) combined with chronic active gastritis raises concern for microscopic colitis or eosinophilic gastrointestinal disease 1
• Autoimmune condition history increases risk for microscopic colitis, which can present with constipation (though diarrhea is more common) 1
• However, colonoscopy should not be performed unless alarm features are present or age-appropriate screening has not been done 1, 3

The bleeding is likely from the chronic anal fissures and grade 2 hemorrhoids, but colonoscopy is still warranted to exclude proximal pathology given the autoimmune history and eosinophilia. 1, 4

Treatment: Biofeedback Therapy is Definitive

If defecatory disorder is confirmed on anorectal testing, biofeedback therapy is the first-line definitive treatment with strong recommendation and high-quality evidence. 1, 7, 5, 8

Why Biofeedback Works:

• Biofeedback therapy trains patients to relax their pelvic floor muscles during straining and restores normal rectoanal coordination through a relearning process, with success rates exceeding 70% for dyssynergic defecation 7, 5, 8
• Randomized controlled trials show biofeedback is more effective than laxatives, general muscle relaxation exercises, and drugs to relax skeletal muscles in adults with dyssynergic defecation 8
• The therapy is completely free of morbidity and safe for long-term use 7
• Biofeedback specifically improves rectal sensory perception in patients with reduced sensation, which may explain the incomplete evacuation sensation 7

Treatment Protocol:

• Biofeedback involves using pressure measurements or electromyographic activity within the anal canal to teach patients how to relax pelvic floor muscles when straining to defecate 8
• This is combined with teaching more appropriate straining techniques (increasing intra-abdominal pressure) and having the patient practice defecating a water-filled balloon 8
• The earlier the intervention with biofeedback therapy, the better the recovery of sensory function 7

Role of Chronic Anal Fissures

Yes, chronic anal fissures are likely both a consequence and perpetuating factor of the defecatory disorder. 4, 5

• Anal fissures cause pain during defecation, which leads to voluntary withholding and worsening of pelvic floor dysfunction through a pain-spasm cycle 4
• Most anal fissures are adequately treated by a medical approach using sitz baths, stool softeners, and analgesics 4
• If the anal fissure becomes chronic and is not responsive to medical therapy, pharmacologic treatment with botulinum toxin or nitroglycerin ointment to decrease internal anal sphincter tone has shown promise 4
• Lateral sphincterotomy of the internal anal sphincter is the surgical procedure of choice for refractory cases 4
• However, addressing the underlying defecatory disorder with biofeedback therapy may allow the fissures to heal by normalizing defecation mechanics and reducing straining. 5, 8

Common Pitfalls to Avoid

• Do not continue escalating laxatives indefinitely in patients with defecatory disorders, as this will not address the underlying pelvic floor dysfunction and delays definitive treatment 7, 3
• Do not assume constipation is purely a colonic motility problem, as failure to recognize the pelvic floor component is a frequent reason for therapeutic failure 7
• Do not skip anorectal testing in patients who fail initial conservative measures with fiber and laxatives, as this is essential to identify the specific dysfunction 1, 2, 3
• Do not perform colonoscopy first without considering defecatory disorder, as this may lead to unnecessary procedures and missed diagnosis 1, 3

Specific Diagnostic Sequence for This Patient

1. Perform anorectal manometry and balloon expulsion test to confirm defecatory disorder and assess rectal sensation 1, 2, 3
2. Perform colonoscopy with biopsies to evaluate for microscopic colitis, eosinophilic colitis, and exclude structural pathology causing the rectal bleeding 1, 3
3. If defecatory disorder is confirmed, refer for biofeedback therapy as the definitive treatment 1, 7, 5, 8
4. If anorectal tests are normal and symptoms persist, perform colonic transit study to evaluate for slow transit constipation 1, 2, 3
5. Treat chronic anal fissures concurrently with conservative measures (sitz baths, stool softeners) or pharmacologic therapy (botulinum toxin, nitroglycerin ointment) if they persist despite biofeedback 4