Hirschsprung’s Disease — Clinical Documentation Guide (2026)

🔍 Definition

Hirschsprung’s disease (HD) — also known as congenital aganglionic megacolon — is a congenital developmental disorder of the enteric nervous system in which ganglion cells fail to migrate fully from the neural crest during fetal development (weeks 4–12 of gestation). The result is a segment of distal bowel that is permanently devoid of myenteric (Auerbach’s) and submucosal (Meissner’s) plexus ganglion cells, causing tonic contraction of the affected segment, functional intestinal obstruction, and progressive proximal colonic dilatation (StatPearls – Hirschsprung Disease).

The aganglionic segment always begins at the internal anal sphincter and extends proximally for a variable distance. In approximately 80% of cases only the rectosigmoid colon is involved (short-segment disease); in 15–20% the aganglionosis extends to the descending or transverse colon (long-segment disease); and in roughly 5% the entire colon — and occasionally portions of the small bowel — lack ganglion cells (total colonic aganglionosis, TCA) (American Academy of Family Physicians – AFP 2006; PubMed – Outcome of TCA, 2022).

HD occurs in approximately 1 per 5,000 live births with a 4:1 male-to-female predominance in short-segment disease (the sex ratio approaches 1:1 in total colonic forms). Associations include trisomy 21 (Down syndrome) in ~10–15% of cases, Waardenburg syndrome, and multiple endocrine neoplasia type 2A (RET proto-oncogene mutations are found in 35% of sporadic and ~50% of familial HD cases) (World Journal of Pediatric Surgery, 2025).

ICD-10-CM classifies HD under Q43.1 — Hirschsprung’s disease, which captures aganglionosis and congenital aganglionic megacolon. Code Q43.1 may be applied to patients of any age; a congenital condition persisting throughout life retains its Chapter 17 congenital code per FY2026 ICD-10-CM Official Guidelines, Section I.C.17.

🗂️ Alternative Terminology

🩺 Signs & Symptoms

Presentation varies with age and segment length. Key clinical findings include (StatPearls; AAFP AFP 2006):

Neonates / Infants:

• Failure to pass meconium within 48 hours of birth — present in up to 90% of affected neonates; strongest early indicator
• Abdominal distension; bilious emesis
• Explosive discharge of gas and stool upon rectal examination (“squirt sign”)
• Tight anal sphincter on digital exam
• Poor feeding, vomiting, obstipation
• Hirschsprung-associated enterocolitis (HAEC): fever, foul-smelling bloody or watery diarrhea, toxic appearance, abdominal tenderness; most dangerous complication (17–50% incidence)

Older Children / Adults (delayed diagnosis):

• Chronic progressive constipation refractory to laxatives
• Recurrent fecal impaction
• Failure to thrive, poor weight gain, malnutrition
• Overflow diarrhea (often misdiagnosed as functional constipation or IBS)
• Abdominal distension; palpable fecal mass

🧭 Differential Diagnosis

📋 Clinical Indicators for Coders/CDI

The following clinical indicators support coding of Hirschsprung’s disease and related complications. CDI specialists should look for all of these in the medical record:

🦴 Anatomy & Pathophysiology

Normal enteric nervous system (ENS): The ENS comprises two ganglion cell plexuses within the bowel wall — the myenteric (Auerbach’s) plexus between the circular and longitudinal smooth muscle layers, and the submucosal (Meissner’s) plexus in the submucosa. Together they coordinate peristalsis and the rectoanal inhibitory reflex (RAIR), allowing the internal anal sphincter to relax in response to rectal distension (World Journal of Pediatric Surgery, 2025).

Pathophysiology of HD: During weeks 4–12 of gestation, vagal neural crest cells (NCCs) migrate craniocaudally along the intestine. Disruption of NCC migration, proliferation, or differentiation results in failure to colonize the distal bowel. The aganglionic segment lacks inhibitory neurons (VIP, NO-producing), leaving unopposed cholinergic (acetylcholine) excitatory tone — the bowel segment is tonically contracted and does not relax. Stool accumulates proximally, leading to progressive dilation of the normally innervated proximal colon (StatPearls).

Genetics: HD is multigenic. Mutations in the RET proto-oncogene account for 35% of sporadic cases and ~50% of familial HD. Other implicated genes include GDNF, EDNRB, endothelin-3 (EDN3), SOX10, and PHOX2B. HD can occur as isolated or syndromic (10% with trisomy 21; associations with Waardenburg-Shah, Mowat-Wilson, Goldberg-Shprintzen, and central hypoventilation syndromes) (World Journal of Pediatric Surgery, 2025).

Disease extent and transition zone:

• Short-segment HD (~80%): Aganglionosis limited to rectosigmoid junction
• Long-segment HD (~15–20%): Aganglionosis extends proximal to sigmoid colon
• Total colonic aganglionosis (TCA) (~5%): Entire colon affected; may extend into small bowel; complex surgical management; higher risk of short bowel syndrome

The transition zone (TZ) — the point where normal ganglionated bowel transitions to aganglionic bowel — appears radiographically as a “funnel” or “cone” on contrast enema, though the histological TZ extends 2–4 cm beyond the radiographic one, requiring intraoperative frozen sections to confirm clear margins (APSA Pediatric Surgery Library).

💊 Medication Impact / Treatment

Hirschsprung’s disease is fundamentally a surgical condition — no pharmacological agent corrects aganglionosis. Medical management is supportive and directed at complications, particularly HAEC.

Pre-operative / Bridging management:

• Rectal irrigations (bowel washouts): Daily saline rectal irrigation decompresses the obstructed colon, prevents acute HAEC, and prepares the bowel for pull-through surgery. Typically administered by trained parents or nurses.
• Nasogastric decompression: For acute obstruction episodes.
• Nutritional support: Parenteral nutrition (PN) or enteral feeding in neonates with severe obstruction or TCA; coding impact: Z79.01 (long-term PN) if applicable.

Treatment of HAEC:

• Grade I (possible HAEC): Outpatient oral metronidazole, oral fluids/electrolytes
• Grade II–III (definite/severe HAEC): Inpatient admission; IV fluid resuscitation; broad-spectrum IV antibiotics (metronidazole + vancomycin or ampicillin + gentamicin); rectal irrigations every 6–8 hours; ICU for septic shock; emergent colostomy if refractory (StatPearls)

Post-operative pharmacology:

• Prophylactic rectal irrigation post-pull-through to reduce HAEC recurrence
• Botulinum toxin A (Botox) injection into the internal anal sphincter for persistent post-pull-through obstructive symptoms (internal anal sphincter achalasia) — CPT 46505
• Stool softeners (polyethylene glycol, lactulose) for post-operative constipation
• Loperamide for high-stool frequency post-TCA pull-through

Preview ends here. The full guide continues with FY2026 ICD-10-CM code sets, CPT surgical coding, MS-DRG mapping, reimbursement guidance, CDI query templates, and an audit checklist — all available to CCO Members.

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📘 ICD-10-CM Guidelines (FY2026)

The following guidelines from the FY2026 ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) apply to Hirschsprung’s disease and related conditions:

Chapter 17 — Congenital Malformations (Q00–Q99), Section I.C.17:

• Codes from Chapter 17 may be used throughout the life of the patient. Q43.1 is not restricted to pediatric encounters — it may be assigned to adults of any age who have ongoing, uncorrected, or residual Hirschsprung’s disease.
• If a congenital malformation has been surgically corrected, assign a personal history code (Z87.898 — personal history of other congenital malformations) rather than Q43.1, unless complications or residual effects are still present.
• Although present at birth, HD may not be diagnosed until later in life (delayed presentation in adults). Assign Q43.1 whenever the provider documents the diagnosis, regardless of patient age.

Chapter 16 — Perinatal Conditions (P00–P96), Section I.C.16:

• For newborns with intestinal obstruction, neonatal codes (P76.x) take precedence on the birth admission when the underlying cause has not yet been established or when the obstruction is the clinical focus.
• Once HD is confirmed by biopsy, Q43.1 becomes the appropriate principal or primary diagnosis code.
• P78.0 (Perinatal intestinal perforation / meconium peritonitis) may be assigned as an additional code when meconium peritonitis is present as a complication of prenatal or perinatal bowel obstruction.

Code-first / Etiology-manifestation conventions:

• Megacolon resulting directly from Hirschsprung’s disease is captured by Q43.1 alone — the congenital code includes the megacolon manifestation. Do not assign K59.39 (other megacolon) in addition to Q43.1 for the same condition.
• Toxic megacolon (K59.31) is a separate, acquired complication and must be documented explicitly by the provider as “toxic megacolon” — it is not automatically implied by HD and is coded additionally when documented.
• Adhesive intestinal obstruction (K56.50–K56.52) following prior HD surgery is coded as a separate condition from Q43.1; the underlying cause is adhesions (postoperative), not active aganglionosis.

Key sequencing rules:

• When HD is the reason for the encounter (e.g., pull-through surgery admission), Q43.1 is sequenced first.
• HAEC: If the patient is admitted for HAEC complicating HD, sequence based on circumstances of admission — typically K52.9/K52.89 as principal if HAEC is the reason for admission, with Q43.1 as secondary; or Q43.1 as principal if surgery is planned during the same admission.
• Assign Z93.3 (colostomy status) as an additional code when a diverting colostomy is present (staged surgical approach), even if not the focus of the current encounter.

🔢 ICD-10-CM Code Set (FY2026)

🔎 Indexing

When searching the FY2026 ICD-10-CM Alphabetic Index, use the following main terms and subterms:

Main Entry: Disease

• Disease → Hirschsprung’s → Q43.1

Main Entry: Megacolon

• Megacolon (acquired) (functional) (not Hirschsprung’s disease) → K59.39
• Megacolon → congenital → Q43.1
• Megacolon → Hirschsprung’s → Q43.1
• Megacolon → toxic → K59.31

Main Entry: Aganglionosis

• Aganglionosis (bowel) (colon) → Q43.1

Main Entry: Obstruction

• Obstruction → intestine → Hirschsprung’s disease → Q43.1
• Obstruction → intestine → newborn → P76.9 (with subcategories P76.0, P76.8)

Main Entry: Enterocolitis

• Enterocolitis → noninfective → K52.9 (additional code with Q43.1 for HAEC)

🏥 CPT (2026)

Surgical intervention is the definitive treatment for Hirschsprung’s disease. CPT code selection depends on the specific procedure, extent of resection, and surgical approach (open vs. laparoscopic). The following codes represent the 2026 CPT code set for HD-related procedures (ACGME Pediatric Surgery Tracked Codes; OSI Coding Colectomy):

🧾 HCPCS (2026)

Following ostomy creation for Hirschsprung’s disease (colostomy or ileostomy), patients require ongoing ostomy supplies. HCPCS Level II codes in the A4361–A4422 range cover these supplies (AAPC HCPCS A4361–A4438):

Billing notes: Ostomy supplies are covered by Medicare Part B (DME) and most commercial plans as medically necessary following ostomy creation. Document ostomy status (Z93.3) on all supply claims. For pediatric Medicaid patients, verify state-specific quantity and frequency limitations for HCPCS supplies.

📚 AHA Coding Clinic (Recent Guidance)

The following AHA Coding Clinic guidance is relevant to Hirschsprung’s disease coding (AHA Central Office — Coding Clinic):

• FY2022 / Q1: Megacolon codes K59.31 and K59.39 — New codes K59.31 (toxic megacolon) and K59.39 (other megacolon) were introduced effective FY2022. AHA Coding Clinic confirmed that megacolon in the context of Hirschsprung’s disease is captured by Q43.1 alone. K59.39 is for acquired, non-congenital megacolon; K59.31 applies to the acute toxic complication. See also FindACode AHA Coding Clinic summary: Megacolon.
• Bowel Obstruction coding update (FY2024): The Excludes1 note at K56 that previously prohibited coding obstruction when an underlying cause was present was removed effective October 1, 2023. Coders may now assign both the underlying condition and an obstruction code (e.g., Q43.1 + K56.x for adhesive obstruction following prior HD surgery) when separately documented. See Health Information Associates – Coding Bowel Obstruction in ICD-10-CM.
• Perinatal vs. Congenital Code Guidance: For neonatal admissions where HD is confirmed by biopsy, the AHA guidelines instruct coders to assign Q43.1 rather than the P76.x newborn intestinal obstruction codes once the specific congenital diagnosis is established. The P76 codes serve as provisional codes before confirmation.
• HAEC (Hirschsprung-associated enterocolitis) coding: No dedicated ICD-10-CM code exists for HAEC. Current guidance supports using K52.9 or K52.89 as an additional code with Q43.1 when the provider explicitly documents “Hirschsprung-associated enterocolitis” or “HAEC.” Infectious enterocolitis (A09, A04.x) should be used only when a specific pathogen is identified. CDI specialists should query for provider documentation of the HAEC diagnosis rather than code from clinical indicators alone.

💰 HCC / Risk Adjustment (v28)

The CMS-HCC Model V28 (fully operative as of January 1, 2026) governs 100% of Medicare Advantage risk score calculations for payment year 2026. Key points for Hirschsprung’s disease and related codes:

V28 key principles for HD risk adjustment:

• As of PY2026, V28 is 100% operative (phased implementation complete: 33% V28 in PY2024, 67% in PY2025, 100% in PY2026) (RAAPID INC – CMS-HCC V28).
• Q43.1 is a valid V28 diagnosis code among the 268 new codes added to the model. Per Guidewell V28 Congenital Code Changes guidance, it can be assigned to adult patients (e.g., 72-year-old with late-diagnosed HD) and must be supported by current documentation (MEAT criteria).
• All Chapter 17 codes (Q00–Q99) may be used throughout the patient’s lifetime; they are not restricted to pediatric risk adjustment models.
• For pediatric MA and CHIP managed care, verify the child and infant model HCC coefficients for intestinal obstruction (HCC 045) and peritonitis (HCC 042), which carry significantly higher weights in children than in adults.

✍️ CDI Query Templates

The following query templates are designed in accordance with AHIMA and ACDIS compliant query standards — non-leading, multiple-choice format with supporting clinical context provided to the provider.

🧑‍⚕️ Treatments (Clinical)

Definitive treatment of Hirschsprung’s disease is surgical resection of the aganglionic segment followed by pull-through of normally innervated bowel to the anal canal. The approach is tailored to disease extent, patient age, presence of HAEC, and bowel dilation (StatPearls; World Journal of Pediatric Surgery, 2025; Boston Children’s Hospital):

Surgical Approaches:

• Swenson’s procedure: Original open proctectomy with full mobilization and end-to-end anastomosis of ganglionic bowel to anus (0.5–1 cm above dentate line). High historical success rate; technically demanding in pelvis.
• Duhamel’s procedure: Retrorectal pull-through; preserves anterior rectal wall (sensory function); creates a side-to-side anastomosis leaving a rectal “pouch” (blind stump). Preferred in long-segment disease.
• Soave’s procedure (Endorectal pull-through): Strips rectal mucosa, pulls ganglionic colon through muscularis cuff; preserves extrinsic innervation; requires post-operative anal dilations. Widely used.
• Transanal endorectal pull-through (TEPT): Modern single-stage technique; entirely via anal canal without abdominal incision; laparoscopic assistance added for long-segment. Increasingly favored for neonates and infants. Multiple studies confirm comparable outcomes to open procedures (PLOS One, 2026 — TSLPT vs. TEPT comparison).

Staged vs. Single-Stage Surgery:

• Single-stage pull-through: Preferred for neonates with uncomplicated short-segment HD and no enterocolitis or colonic dilation; avoids colostomy entirely.
• Staged repair (2–3 stages): Initial leveling colostomy (Stage 1) → pull-through (Stage 2) → colostomy closure (Stage 3); used for HAEC, dilated colon, long-segment or TCA, or unstable neonate.

Post-Pull-Through Management:

• Serial anorectal dilations (Soave/TEPT): prevent anastomotic stricture; typically begun 2–3 weeks post-op
• Rectal irrigation: ongoing prevention and treatment of HAEC recurrence
• Botulinum toxin injection into internal anal sphincter: for internal anal sphincter achalasia causing persistent post-pull-through obstructive symptoms
• Redo pull-through: required in ~5–10% of cases for residual aganglionosis, transition zone left behind, anastomotic stricture, or persistent obstructive symptoms (Journal of Indian Association of Pediatric Surgeons, 2018)

Total Colonic Aganglionosis (TCA) — Special Considerations:

• Requires ileoanal anastomosis (pull-through of terminal ileum to anus)
• Risk of short bowel syndrome when small bowel aganglionosis extends >40 cm proximal to ileocecal valve
• Parenteral nutrition dependency in severe TCA with <80 cm of ganglionic small bowel (PubMed – TCA outcome study, 2022)
• Intestinal transplantation may be considered in refractory TCA with liver failure

Outcomes: Mortality has decreased to <3% in developed countries with modern surgical and neonatal ICU care. Fecal continence is achieved in >80% of patients by school age. Long-term issues include bowel dysmotility, constipation, fecal soiling, and recurrent HAEC in the first 2 years post-pull-through.

🎓 Patient Education / Summary

The following summary is suitable for use in patient/family education materials and discharge instructions:

What is Hirschsprung’s disease?
Hirschsprung’s disease is a condition present from birth in which some nerve cells are missing from part of the large intestine (colon). These nerve cells — called ganglion cells — are needed for the intestine to squeeze and move stool forward. Without them, the affected part of the intestine stays tight and blocked, causing stool to back up. It occurs in about 1 in every 5,000 babies and is more common in boys.

How is it diagnosed?
Most babies are diagnosed in the first few weeks of life when they don’t pass their first stool (meconium) within 48 hours of birth. Diagnosis is confirmed by:

• A rectal biopsy — a small tissue sample taken from the rectum and examined under a microscope to confirm the nerve cells are absent
• A contrast enema (barium enema) — an X-ray test that shows the abnormal “transition zone” between normal and affected bowel
• Anorectal manometry — a test that measures pressure reflexes in the rectum and anus

How is it treated?
Hirschsprung’s disease requires surgery to remove the section of intestine without nerve cells. The surgeon then connects the healthy, normal intestine to the anus — a procedure called a “pull-through.” Sometimes this is done in stages, with a temporary colostomy (an opening in the belly where stool exits into a pouch) until the child is ready for the final connection surgery.

What is a colostomy?
A colostomy or ileostomy is a temporary opening in the belly wall where the intestine is connected to a pouching system on the outside of the body. This allows stool to pass while the child heals before or after pull-through surgery. Families will receive training on ostomy pouch care, skin protection, and when to call the doctor. Insurance typically covers colostomy supplies (pouches, skin barriers, etc.) — these are billed using special supply codes.

What is Hirschsprung-associated enterocolitis (HAEC)?
HAEC is a serious intestinal inflammation that can happen before or after surgery. Signs include:

• Fever
• Explosive, foul-smelling diarrhea
• Swollen abdomen
• Vomiting, poor feeding, lethargy

HAEC is a medical emergency — call 911 or go to the nearest emergency room immediately if these symptoms occur. Treatment includes IV fluids, antibiotics, and rectal irrigation.

What can families expect long-term?
Most children with Hirschsprung’s disease lead full, healthy lives after surgery (Cincinnati Children’s Hospital; Johns Hopkins Medicine):

• Most children achieve normal bowel control by school age
• Some children may need help with constipation, bowel training, or managing stool accidents
• Regular follow-up with a pediatric gastroenterologist and pediatric surgeon is important
• HAEC can recur in the first 1–2 years after pull-through — families should know the warning signs
• Down syndrome (trisomy 21) is present in about 1 in 10 children with Hirschsprung’s disease — developmental support services should be coordinated if applicable

Resources for families:

• Boston Children’s Hospital — Hirschsprung’s Disease
• Cincinnati Children’s Hospital — Hirschsprung’s Disease
• Johns Hopkins Medicine — Hirschsprung’s Disease

About this Guide

This Clinical Documentation Guide is published by CCO Academy and is intended for credentialed coding, CDI, and clinical documentation professionals. Content is updated for FY2026 ICD-10-CM (effective October 1, 2025). All code assignments should be verified against the official ICD-10-CM Tabular List, AHA Coding Clinic, and applicable payer-specific policies. This guide does not constitute legal, medical, or compliance advice.

Last reviewed: April 2026 · Next scheduled review: October 2026 (FY2027 update)