Dr. Denis Marleau – Gastroenterologist | Montréal, QC

Dr. Denis Marleau is a dedicated Gastroenterologist specializing in the diagnosis and treatment of a wide array of disorders affecting the digestive system in adult patients, and may also see older adolescents for certain conditions. Practicing at CHUM, Médecine hépatologie in Montréal, QC, he is a key member of the local medical community. He provides comprehensive care for a wide range of digestive system disorders, including conditions affecting the esophagus, stomach, intestines, liver, and pancreas, utilizing diagnostic and therapeutic endoscopy. His practice is committed to delivering patient-centered digestive health care within a supportive environment, emphasizing accurate diagnosis and effective management.

Dr. Marleau holds a Medical Degree from a recognized institution and has been practicing as a Gastroenterologist since 1972, bringing over 52 years of specialized experience. He has completed extensive post-graduate training and holds the necessary certifications to practice Gastroenterology (Comprehensive Care for Digestive System Disorders) in Québec, in accordance with the standards set by the Collège des médecins du Québec (CMQ). His credentials affirm his commitment to maintaining the highest standards of medical practice and patient safety.

Driven by a philosophy of evidence-based, personalized care, Dr. Marleau prioritizes patient education on digestive conditions and lifestyle modifications that can improve health outcomes. He is dedicated to early and accurate diagnosis through advanced diagnostic procedures and offers tailored treatment plans aimed at optimizing each patient's quality of life. Fluent in French, he is committed to providing accessible and compassionate care to the Montréal community.

Dr. Denis Marleau diagnoses and treats a wide range of digestive system disorders, including:

Esophageal, Stomach & Upper GI Disorders

• Dysphagia (Difficulty Swallowing) & Odynophagia (Painful Swallowing): Symptoms requiring investigation to determine underlying causes, which can range from structural abnormalities and motility disorders to inflammatory conditions or tumors.
• Gastroesophageal Reflux Disease (GERD) / Acid Reflux / Heartburn: Chronic condition where stomach acid frequently flows back into the esophagus, causing heartburn, regurgitation, chest pain, and potential complications like esophagitis.

Small & Large Intestine (Colorectal) Disorders

• Small Intestinal Bacterial Overgrowth (SIBO) & Intestinal Methanogen Overgrowth (IMO): An abnormal increase in the bacterial population in the small intestine, or an overgrowth of methane-producing archaea, leading to symptoms like bloating, gas, abdominal pain, and altered bowel habits.
• Gastrointestinal Bleeding (Obscure & Overt): Bleeding anywhere along the digestive tract, which can be visible (overt) or hidden (occult/obscure), requiring investigation to identify and treat the source.

Functional Gastrointestinal & Motility Disorders

• Functional Dyspepsia & Epigastric Pain Syndrome: Persistent or recurrent pain or discomfort centered in the upper abdomen (dyspepsia) or specifically in the epigastric region, without an identifiable structural cause after investigation.
• Pelvic Floor Dysfunction & Anorectal Disorders (e.g., Dyssynergic Defecation): Inability to correctly relax and coordinate pelvic floor muscles to facilitate a normal bowel movement, often requiring specialized testing like anorectal manometry and biofeedback therapy.

This list is not exhaustive. For personalized advice regarding your specific digestive condition, please consult with Dr. Denis Marleau.

• Colonoscopy (Screening, Diagnostic, Surveillance) & Polypectomy: Comprehensive examination of the entire colon (large intestine) using a colonoscope to detect and remove precancerous polyps, screen for and diagnose colorectal cancer, evaluate symptoms, and diagnose other colonic conditions like colitis or diverticular disease.
• Gastrointestinal Motility Disorder Evaluation & Management Coordination: Initial evaluation of symptoms suggestive of GI motility disorders (e.g., gastroparesis, achalasia, chronic intestinal pseudo-obstruction), with coordination for specialized testing like esophageal manometry, antroduodenal manometry, wireless motility capsule, or gastric emptying studies, and subsequent management strategies.
• Endoscopic Hemostasis for Acute & Chronic GI Bleeding: Various endoscopic techniques (e.g., injection therapy, thermal coagulation/APC, mechanical clips, hemostatic sprays) used to stop acute or recurrent bleeding from ulcers, varices, angiodysplasias, or tumors in the GI tract.
• Enteroscopy (e.g., Double-Balloon, Single-Balloon, Spiral Enteroscopy): Advanced endoscopic techniques allowing deep visualization, biopsy, and therapy within the small intestine, beyond the reach of standard endoscopes, for conditions like obscure bleeding or small bowel tumors.
• Irritable Bowel Syndrome (IBS) Comprehensive Diagnosis & Management (including subtypes IBS-D, IBS-C, IBS-M): Multifaceted approach to managing IBS symptoms (abdominal pain, bloating, diarrhea, constipation, mixed pattern) including thorough exclusion of other conditions, dietary modifications (e.g., low FODMAP diet), lifestyle changes, stress management, and targeted medications.
• Flexible Sigmoidoscopy with Biopsy: Examination of the lower part of the colon (sigmoid colon and rectum) using a flexible sigmoidoscope, often for evaluation of rectal bleeding, diarrhea, or as part of some screening protocols.
• Diagnosis & Management of Small Intestinal Bacterial Overgrowth (SIBO) & Intestinal Methanogen Overgrowth (IMO): Utilizing glucose or lactulose breath tests for diagnosis and providing targeted antibiotic/antimicrobial therapy, prokinetics, and dietary advice for SIBO and IMO.

Note: This list provides a general overview. Specific procedures and treatments are determined after a thorough evaluation. Discuss with Dr. Marleau for care relevant to your specific condition.

All medical and surgical services (if applicable) are provided in accordance with the standards of practice set by the Collège des médecins du Québec (CMQ) and relevant gastroenterological care guidelines. Contact the clinic or your referring physician regarding new patient intake and referral processes.

Dr. Marleau practices at CHUM, Médecine hépatologie, located in Montréal’s vibrant Ville-Marie East (Quartier Latin, Village) neighborhood. The practice is conveniently situated near Schwartz's Deli, a well-known local landmark. Accessible via the Société de transport de Montréal (STM) with options including the Métro and bus services, the facility is wheelchair accessible to accommodate all patients. Paid parking options are conveniently located nearby, ensuring ease of access for patients arriving by car. The practice is committed to providing accessible, patient-friendly digestive health care in a central and welcoming environment.

Are consultations and procedures like endoscopies with Dr. Marleau, a Gastroenterologist, covered by Régie de l'assurance maladie du Québec (RAMQ) in QC?

Medically necessary consultations with a licensed Gastroenterologist like Dr. Marleau, as well as most diagnostic procedures (e.g., endoscopies for investigating symptoms, biopsies for medical reasons) and treatments for provincially insured digestive conditions (e.g., IBD, celiac disease, screening colonoscopies as per provincial guidelines, liver disease management), are generally covered by Régie de l'assurance maladie du Québec (RAMQ) in QC when a referral from a family doctor or another specialist is in place. Procedures considered purely for screening outside of guidelines, or for non-medical reasons, and some advanced technologies or specific drug therapies might have different coverage. It's crucial to discuss coverage specifics for any proposed treatment or procedure with Dr. Marleau's office, the hospital/clinic's financial services, or Régie de l'assurance maladie du Québec (RAMQ) beforehand.

Do I need a referral from my family doctor to see Dr. Marleau, a Gastroenterologist?

Yes, in nearly all cases, a referral from your family physician or another specialist (such as an internist or surgeon) is required to schedule an appointment with a Gastroenterologist like Dr. Marleau for services covered by the provincial health plan. Gastroenterological issues often require initial assessment and preliminary investigations by your primary care provider. The referral ensures that a specialist consultation is appropriate, helps with prioritizing appointments, and facilitates coordinated care, including the transfer of relevant medical information.

How does Dr. Marleau approach treating functional GI disorders like IBS or functional dyspepsia?

Treating functional GI disorders like Irritable Bowel Syndrome (IBS) or functional dyspepsia often involves a multi-faceted approach tailored by Dr. Marleau to your specific symptoms and triggers. Since these conditions don't have a structural cause seen on tests, management focuses on symptom relief and improving quality of life. This may include dietary modifications (like identifying trigger foods or trying a low FODMAP diet for IBS), lifestyle adjustments (stress management, regular exercise), fiber supplements, over-the-counter remedies, and prescription medications. Medications can target specific symptoms like pain (antispasmodics), diarrhea (anti-diarrheals), constipation (laxatives), or abnormal gut-brain interaction (neuromodulators in low doses). He will work with you to find the most effective combination of strategies.

How does a Gastroenterologist like Dr. Marleau approach the management of Inflammatory Bowel Disease (IBD)?

The management of IBD (Crohn's disease and ulcerative colitis) by a Gastroenterologist like Dr. Marleau is a highly individualized and long-term process. The primary goals are to induce and then maintain remission (control inflammation), alleviate symptoms, prevent complications, and improve the patient's overall quality of life. Treatment strategies often involve a combination of medications, which can include aminosalicylates (5-ASAs), corticosteroids (for acute flare-ups), immunomodulators (e.g., azathioprine, methotrexate), and increasingly, biologic therapies or small molecule drugs that target specific inflammatory pathways. Regular monitoring through clinical assessment, blood tests, stool tests (like fecal calprotectin), and endoscopic procedures is crucial to track disease activity and adjust treatment as needed. Nutritional counseling and lifestyle advice are also integral parts of comprehensive IBD care.

Are there significant risks associated with procedures like gastroscopy or colonoscopy?

Gastroscopy (upper endoscopy) and colonoscopy are generally very safe procedures, especially when performed by an experienced Gastroenterologist like Dr. Marleau. Complications are uncommon. Potential risks can include bleeding, particularly if polyps are removed or biopsies are taken; perforation (a tear in the wall of the digestive tract); infection (rare); or adverse reactions to the sedative medication used. Before your procedure, Dr. Marleau will thoroughly discuss the specific potential risks and benefits based on your individual health and the reason for the procedure, allowing you to make an informed decision.

CHUM, Médecine hépatologie
1000 Rue Saint-Denis
Montréal, QC H2X 0C1

Phone: (514) 890-8000 | Fax: (514) 412-7314

The facility is wheelchair accessible.

Dr. Marleau is a licensed Gastroenterologist regulated by the Collège des médecins du Québec (CMQ) under the Medical Act in QC. A referral from a family physician or appropriate specialist is typically required for consultations with Dr. Marleau for services covered by the provincial health plan.

Verify registration with the Collège des médecins du Québec (CMQ): https://www.cmq.org/en/directory/physicians?number=66074