Duodenitis-proximal jejunitis (DPJ), also known as anterior enteritis or proximal enteritis, is an acute inflammatory condition of the proximal small intestine (duodenum and proximal jejunum) characterized by ileus, massive nasogastric reflux, and...
Overview and Clinical Importance
Duodenitis-proximal jejunitis (DPJ), also known as anterior enteritis or proximal enteritis, is an acute inflammatory condition of the proximal small intestine (duodenum and proximal jejunum) characterized by ileus, massive nasogastric reflux, and systemic signs of toxemia. This condition is frequently tested on the NAVLE due to its clinical importance, diagnostic challenges, and potential for life-threatening complications.
DPJ occurs sporadically in horses and can be difficult to differentiate from surgical conditions such as small intestinal strangulation or obstruction. Understanding the pathophysiology, clinical presentation, and appropriate management is essential for equine practitioners and critical for board examination success.
| Agent |
Evidence Level |
Key Points |
| Clostridium difficile |
STRONGEST - Experimental reproduction achieved |
Toxins A and B cause epithelial damage; isolated from 10/10 DPJ cases in one study; experimental toxin administration reproduced disease |
| Clostridium perfringens |
Moderate - Association reported |
Type D predominant in DPJ cases; alpha and epsilon toxins may cause damage; isolated from 70% of cases in one study |
| Salmonella spp. |
Weak - Anecdotal reports |
Limited evidence; experimental inoculation did not reproduce DPJ; likely not a primary cause |
| Mycotoxins (Fumonisins) |
Weak - Single study |
High doses caused duodenal/jejunal inflammation but not classic DPJ; may play contributory role |
Terminology and Synonyms
This condition has multiple names in the literature, which may appear on board examinations:
- Duodenitis-proximal jejunitis (DPJ) - most accurate anatomically
- Anterior enteritis - commonly used clinical term
- Proximal enteritis
- Hemorrhagic fibrinonecrotic duodenitis-proximal jejunitis
- Acute ileus syndrome
- Gastroduodenojejunitis
- Acute gastric dilatation
High-YieldOn NAVLE, the term 'anterior enteritis' is frequently used interchangeably with DPJ. When you see a question about a horse with massive nasogastric reflux (greater than 8-10 L) and signs that improve after gastric decompression, think DPJ first!
| Factor |
Details |
| Geographic Distribution |
Most common in Southeastern United States; also reported in Canada, UK, Europe, Brazil, Colombia. Cases in SE USA tend to be MORE SEVERE |
| Age |
Typically greater than 2 years; average 5-10 years |
| Breed/Sex |
No consistent predisposition; one study showed female overrepresentation (59%) |
| Dietary Risk Factors |
High concentrate diets; pasture grazing; recent diet changes (83% in one study were on high concentrate diets) |
| Prevalence |
3-22% of small intestinal colic cases; approximately 13% of all colic cases in some regions |
| Other Factors |
Stress (recent foaling, training changes); sporadic occurrence; often no identifiable trigger |
Etiology and Pathogenesis
The exact etiology of DPJ remains idiopathic in most cases, though several agents have been proposed and studied:
Proposed Etiologic Agents
Proposed Pathogenesis
The proposed pathogenesis based on C. difficile involvement involves the following sequence:
- Spore Ingestion: C. difficile spores are ingested and pass through the stomach to reach the duodenum
- Germination: Bile acids (especially taurocholate, which is abundant in horses) stimulate spore germination into vegetative cells
- Toxin Production: Vegetative cells multiply and produce toxins A (TcdA) and B (TcdB)
- Epithelial Damage: Toxins inactivate Rho GTPases, causing cytoskeleton disruption, tight junction breakdown, and cell death
- Inflammation and Ileus: Mucosal inflammation leads to functional ileus, hypersecretion of fluid into intestinal lumen
- Fluid Accumulation: Fluid backs up into stomach due to ileus, causing massive gastric distension and reflux
- Systemic Effects: Endotoxin absorption leads to systemic inflammatory response and potential complications
NAVLE TipHorses lack a gallbladder and secrete bile continuously. Their bile has high taurocholate (a germination stimulant) and low chenodeoxycholate (a germination inhibitor) compared to other species. This may explain why horses are susceptible to C. difficile-associated intestinal disease.
| Parameter |
Typical Findings |
Clinical Significance |
| Heart Rate |
60-120 bpm (average 68-70 bpm) |
Tachycardia reflects pain, dehydration, endotoxemia |
| Temperature |
Normal to elevated (25-30% have fever greater than 38.6°C/101.5°F) |
Fever suggests inflammatory/infectious component |
| Gastric Reflux |
4-20 L per decompression; 12-144 L in first 24 hours |
Yellow-green to reddish-brown, fetid; alkaline pH (may be acidic early) |
| Borborygmi |
Decreased to absent (80% have absent gut sounds) |
Reflects ileus |
| Rectal Examination |
Small intestinal distension palpable in 44-80% of cases |
Less tense distension than strangulation |
| Colic Pain |
Mild to moderate; improves significantly post-decompression |
SEVERE unrelenting pain suggests surgical lesion |
Epidemiology and Risk Factors
| Test |
Typical Findings |
Clinical Significance |
| PCV/TP |
Elevated (hemoconcentration) |
Reflects dehydration and splenic contraction |
| Electrolytes |
Hyponatremia, hypochloremia, hypokalemia, hypocalcemia common |
Reflects GI fluid losses |
| Acid-Base |
Variable: metabolic acidosis (common due to hypovolemia) OR hypochloremic metabolic alkalosis |
Anion gap greater than 15 mEq/L = increased mortality risk (OR 6.4) |
| BUN/Creatinine |
Elevated (80% azotemic) |
Pre-renal azotemia from dehydration |
| Liver Enzymes |
GGT, SDH, bilirubin often elevated |
Hepatic injury occurs; may be due to ascending inflammation from duodenum |
Clinical Signs and Physical Examination
Cardinal Features
The hallmark triad of DPJ includes:
- Copious nasogastric reflux (often greater than 8-20 L at presentation; can exceed 48 L in first 24 hours)
- Pain relief after gastric decompression (distinguishing feature from surgical conditions)
- Depression/dullness (often marked between episodes of mild-moderate colic)
Clinical Parameters
High-YieldThe classic DPJ patient presents with mild-to-moderate colic pain that dramatically improves after passing a nasogastric tube and obtaining large volumes of reflux. The horse then appears depressed/dull rather than in pain. If a horse continues to show severe pain despite gastric decompression, suspect a surgical lesion!
| Parameter |
DPJ |
Strangulating Obstruction |
| Total Protein |
Elevated (greater than 2.5-3.5 g/dL) |
Elevated |
| Nucleated Cell Count |
MILD elevation or normal (average 10,000 cells/µL) |
MARKED elevation (average 46,000 cells/µL) |
| Prognostic Value |
TP greater than 3.5 g/dL = 4x increased mortality risk |
Serosanguinous fluid = ischemia |
Diagnosis
Diagnosis of DPJ is based on clinical presentation, exclusion of surgical conditions, and response to medical therapy. Definitive diagnosis can only be confirmed at surgery or necropsy.
Clinicopathological Findings
Peritoneal Fluid Analysis
NAVLE TipKEY DIFFERENTIATING FEATURE: In DPJ, peritoneal fluid shows elevated PROTEIN but relatively normal or mildly elevated CELL COUNT. In strangulating obstruction, BOTH protein AND cell count are markedly elevated. Remember: 'DPJ = Protein up, cells pretty normal'
Ultrasonographic Findings
Transabdominal ultrasound is valuable for differentiating DPJ from surgical conditions:
Exam Focus: Remember: DPJ = 'FAT and FLAT' (thick wall, less distension). Strangulation = 'THIN and TEN' (thin wall, greater than 10 cm distension). Wall thickness greater than 6 mm with moderate distension strongly suggests DPJ over mechanical obstruction.
| Parameter |
DPJ |
Strangulating Obstruction |
| SI Diameter |
5-7 cm (moderate distension) |
Greater than 10 cm (marked distension) |
| Wall Thickness |
INCREASED: Greater than 6 mm (often greater than 10 mm) |
Normal to mildly thickened: 3-5 mm |
| Motility |
Decreased but usually present |
Absent (amotile loops) |
| Luminal Contents |
Hyperechoic or anechoic fluid |
Variable |
Medical Management
DPJ is primarily managed medically. Treatment goals include gastric decompression, fluid and electrolyte replacement, pain control, treatment of ileus, and prevention of complications.
Treatment Protocol
Nutritional Support
- NPO (nil per os) until reflux decreases to less than 2 L every 4 hours and gut sounds return
- Typically requires 3-7 days of therapy before feeding can resume
- Parenteral nutrition recommended if NPO greater than 3-4 days (horses become cachexic from protein-losing enteropathy)
- Gradual refeeding with small amounts of grass/hay once reflux resolves
High-YieldProphylactic digital cryotherapy (icing the feet) is one of the most important interventions for DPJ patients. Studies show horses treated with continuous cryotherapy have 10 TIMES LOWER odds of developing laminitis. This is a frequently tested concept!
| Treatment |
Protocol |
Notes |
| Gastric Decompression |
Nasogastric intubation every 1-2 hours initially; can leave indwelling tube |
ESSENTIAL - prevents gastric rupture; typically 2-10 L per decompression |
| IV Fluid Therapy |
Balanced polyionic fluids (LRS, Plasmalyte); rates can exceed 8 L/hour initially |
Replace ongoing losses; may need greater than 100 L/day; monitor PCV/TP |
| NSAIDs |
Flunixin meglumine: 1.1 mg/kg IV q12h (analgesic) OR 0.25 mg/kg IV q8h (anti-endotoxic) |
Use cautiously - risk of nephrotoxicity and GI ulceration; ensure adequate hydration first |
| Prokinetics |
Lidocaine: 1.3 mg/kg IV bolus then 0.05 mg/kg/min CRI; Metoclopramide; Bethanechol |
Lidocaine helps 65% stop refluxing within 30 hours; monitor for muscle fasciculations |
| Antimicrobials |
Penicillin +/- Metronidazole (for suspected clostridial involvement) |
Use remains controversial; indicated if sepsis/peritonitis suspected |
| Anti-Endotoxin Therapy |
Polymyxin B: 6,000 IU/kg IV q8-12h; Bio-Sponge (di-tri-octahedral smectite) |
Binds and neutralizes endotoxin; monitor renal function with Polymyxin B |
| Laminitis Prevention |
Prophylactic digital cryotherapy (continuous ice water baths on all 4 feet) |
10x reduction in laminitis risk (OR 0.11); start immediately upon diagnosis |
Surgical Considerations
Most DPJ cases are managed medically, but surgery may be indicated in certain situations:
Indications for Exploratory Celiotomy
- Unable to definitively rule out strangulating obstruction
- Failure to respond to medical therapy after 7 days
- Progressive deterioration despite aggressive medical management
- Peritoneal fluid parameters suggesting ischemic bowel
Surgical Options
- Decompression of distended intestine
- Resection and anastomosis of severely affected bowel
- Gastrojejunostomy or duodenocecostomy (bypass procedures - rarely performed)
NAVLE TipStudies show MEDICAL management has BETTER outcomes than surgical management for DPJ. One study reported 91% survival with medical treatment vs 75% with surgery. Only 25% of horses stopped refluxing after surgery. Surgery does NOT resolve the underlying pathology - the intestine needs time to heal.
| Complication |
Incidence |
Notes |
| Laminitis |
~30% |
Most significant complication; reduces survival rate; prevented by cryotherapy |
| Hepatic Injury |
Common |
Elevated liver enzymes; possibly from ascending bile duct inflammation |
| Thrombophlebitis |
Variable |
From prolonged IV catheterization; monitor catheter sites |
| Cardiac Arrhythmias |
Reported |
Usually resolve with treatment of primary condition; electrolyte related |
| Pharyngitis/Esophagitis |
Common |
From indwelling nasogastric tube; consider intermittent tubing |
| Aspiration Pneumonia |
Rare |
From spontaneous reflux; ensure adequate gastric decompression |
| Gastric Rupture |
Rare if treated |
Fatal; prevented by frequent gastric decompression |
| Septic Peritonitis |
Rare |
From mucosal necrosis and bacterial translocation |
Complications
| Factor |
Impact on Prognosis |
| Reflux greater than 48 L in first 24 hours |
4x increased mortality risk (OR 4.13) |
| Peritoneal fluid protein greater than 3.5 g/dL |
4x increased mortality risk (OR 4.03) |
| Anion gap greater than 15 mEq/L |
6x increased mortality risk (OR 6.43) |
| Development of laminitis |
Significantly reduced survival rate |
| Hemorrhagic reflux |
Increased risk of laminitis and death |
Prognosis
Survival Rates
- Overall survival: 67-94% (varies by geographic location and severity)
- Medical management: ~85-91% survival
- Surgical management: ~63-75% survival
- With intensive 24-hour care: 60-80% survival
Negative Prognostic Indicators