Clinical Cases in Pharmacology Clinical Cases  ·  Psychiatry VIII  ·  Elimination Disorders
Psychiatry VIII, Case 0005 — Elimination Disorders

Nonretentive Fecal Incontinence: When the Laxative Was the Wrong Diagnosis, Not the Wrong Dose

Two years of maintenance laxative therapy haven't helped a child's daytime soiling — because his history was never a retentive constipation picture to begin with, and the drug may have been making his actual problem easier, not harder, to have.

Abbreviations, terms, and other agents mentioned in this case ICCS — International Children's Continence Society  ·  FNRFI — functional nonretentive fecal incontinence  ·  PEG — polyethylene glycol, an osmotic laxative
Presentation

Two years into a laxative regimen that was supposed to fix this, Tyler B.'s mother has started keeping her own private log of something the treatment plan never asked her to track: what her son's accidents actually look like, and what he's doing in the moments before one happens. Tyler, 10, plays travel soccer on Saturdays and has a laptop he isn't supposed to have in his room after nine, and most of his afternoons this school year have ended in a change of clothes he handles himself, quietly, without telling anyone unless someone notices first. He was started on maintenance polyethylene glycol two years ago by a previous provider, on the standard assumption that daytime soiling in a school-age child means retentive constipation until proven otherwise — a reasonable starting assumption, since retentive fecal incontinence accounts for roughly 80 percent of cases like his, on the same ICCS figures discussed below. What his mother's own log actually shows, and what nobody had specifically asked about before, is that his stool is normal-caliber and well-formed, not the smeared overflow around a retained mass a textbook description of his supposed diagnosis would predict — and that he never has any warning beforehand at all, going from fine to already-happened in what he describes as no time whatsoever.

There is also, per exam and history both, no evidence of the mechanism the original prescription assumed: no history of painful defecation, no withholding behavior, and no palpable stool mass. Koppen and colleagues' 2016 International Children's Continence Society recommendations describe exactly this alternative picture under a specific name — functional nonretentive fecal incontinence, found in roughly one in five children presenting with soiling once constipation and other causes are genuinely ruled out — and its own management guidance runs in the opposite direction from what Tyler has been getting: laxatives, in the absence of real retention to treat, offer no mechanistic benefit and can plausibly worsen outcomes by loosening the stool of a child who already has poor voluntary control over the urge to defecate. Two years on a laxative that made his stool looser without ever making his accidents less frequent is exactly the clinical picture that finding would predict.

Tyler B. · 10 Re-evaluation
History
Daytime soiling × 3 years, weekday afternoons; child reports being "surprised" each time; no nocturnal enuresis
Bowel pattern
Normal-caliber, well-formed stool passed involuntarily; no history of withholding or painful defecation
Exam
No palpable stool mass; rectal exam normal caliber and tone
Current therapy
PEG 3350, 0.5g/kg/day × 2 years; no improvement, stools have become looser
Colonic transit study
Within normal range, obtained as part of FNRFI workup
Social impact
Refuses to change soiled clothes at school; skips lunch some days to avoid the bathroom around peers

Reconsidering two years of treatment

Pediatric Gastroenterologist Opening

He doesn't have retentive encopresis, and I don't think he ever did. No withholding history, no palpable mass, normal-caliber stool, and two years of maintenance laxative with zero improvement — that's not a dosing problem, that's the wrong diagnosis. Koppen and colleagues' 2016 ICCS recommendations describe functional nonretentive fecal incontinence as a real, distinct entity, roughly one in five children with soiling once constipation is properly ruled out, and their own guidance is that laxatives offer no benefit here and can worsen outcomes by loosening stool he already has trouble voluntarily controlling. I want the PEG stopped today.

Child Psychologist Response

I agree it should stop, and I don't think anyone here is going to argue for continuing a laxative that's demonstrably not working. What I want to make sure doesn't get lost is what replaces it.

Stopping the PEG isn't itself a treatment plan — the same ICCS recommendations my colleague is citing describe FNRFI as often genuinely difficult to treat, frequently co-occurring with real behavioral and attentional factors, which matches exactly what Tyler's own pattern looks like: soiling specifically during activities absorbing enough to override his attention to the urge. That's a behavioral target, not something that resolves on its own once the laxative is gone. I want a structured toileting program in place the same day the PEG stops, not a wait-and-see gap between one plan ending and another one starting.

Pediatrician Final

I'm not against either of those — stopping the PEG and starting structured toileting support are both right. What I want us to be honest about is how thin the actual evidence behind either move really is. The study the ICCS recommendations lean on for rewarded scheduled toilet sits — Boles, Roberts and Vernberg, 2008 — is a single-participant report: one ten-year-old boy, followed with a multiple-baseline design across home and school. I don't think that's a reason to hesitate, but I do think it's a reason to build in real monitoring rather than assume this is settled: a two-week close follow-up once the PEG stops, tracking whether his stooling pattern and accident frequency hold steady or shift in either direction, before we're confident we've actually got the diagnosis right and not just traded one uncertain plan for another.

Regimen selected
Polyethylene Glycol — Discontinued
Osmotic Laxative · Stopped today
Stopped after 2 years without benefit; no mechanistic rationale in the absence of retention, and a plausible contributor to easier involuntary passage.
Structured Toileting Program
Behavioral, Non-Pharmacologic · Started same day
Scheduled toilet-sits, bowel diary, and a reward system, per ICCS FNRFI management recommendations.
Close Interval Follow-Up
Monitoring · 2 weeks
Confirms his stooling pattern and accident frequency respond as expected once the laxative is stopped, before treating the new diagnosis as settled.
Escalating the PEG Dose — Ruled Out
Not adopted
Two years of non-response at a substantial dose gives no reason to expect a higher dose would succeed where the mechanism itself doesn't apply.
Where this was left

Agreed: PEG discontinued today; structured toileting program (bowel diary, reward system, scheduled sits) started the same day; 2-week follow-up booked to monitor response.

Not agreed: whether Tyler also needs an individual behavioral-health referral for the attention/avoidance pattern specifically, or whether the family-run structured program alone is sufficient to start — the psychologist wants a referral placed now given how thin the evidence is for self-directed programs at this level of chronicity, the pediatrician wants to see the 2-week follow-up data first before adding another appointment.

Educational content only — a composite teaching case, not a real patient encounter or a substitute for clinical guidance. About These Cases →