Endoscopy & Colonoscopy Expert Witness
Medicolegal | Gastroenterology
Independent expert opinion on gastrointestinal endoscopy, including colonoscopy complications, perforation, bleeding, polypectomy, consent and post-procedure management
CPR 35 Compliant | Currently practising NHS Consultant Gastroenterologist | JAG-accredited Endoscopist | FRCP (London) | Listed in the UK Register of Expert Witnesses
Professor Mohid Khan is a currently practising NHS Consultant Gastroenterologist and JAG-accredited endoscopist who accepts claimant and defendant instructions relating to gastrointestinal endoscopy. His expert-witness work includes questions of breach of duty and causation arising from colonoscopy, gastroscopy, polypectomy, procedural complications, consent, post-procedure deterioration and the interpretation of clinical records.
Written by Professor Mohid Khan
Consultant Gastroenterologist & Endoscopist
Honorary Professor, Cardiff University
Last reviewed: October 2026
A recognised complication of colonoscopy or endoscopy is not, by itself, evidence of negligent care.
Perforation, bleeding and other adverse events can occur despite appropriate endoscopic care. Expert assessment requires consideration of the indication for the procedure, consent, technical conduct, recognised complication rates, the clinical response when a complication occurs and the causal consequences of any alleged breach of duty.
What types of endoscopy cases can require expert gastroenterology opinion?
Medicolegal questions can arise at different stages of an endoscopic episode of care. An instruction may concern whether a procedure was appropriately indicated, the information given beforehand, the conduct of the procedure itself, or the response to a subsequent complication. My scope may include cases involving:
Colonoscopy & flexible sigmoidoscopy
Diagnostic and therapeutic endoscopy
Polypectomy
Post-procedural bleeding
Missed/incomplete examination
Follow-up and communication
Gastroscopy / OGD Perforation
Consent and communication of risk
Post-procedure deterioration
Procedural documentation
Does a complication mean that the endoscopy was negligent?
No. The occurrence of a recognised complication does not, by itself, establish negligent care.
Complications such as perforation or bleeding can occur even when a procedure has been appropriately indicated and performed to an acceptable standard.
The relevant questions are usually more specific. These may include whether the decision to undertake the procedure was reasonable, whether material risks and reasonable alternatives were appropriately discussed, whether the procedure was performed to an acceptable gastroenterological standard, and whether any subsequent complication was recognised and managed appropriately.
The occurrence of a complication and a breach of duty are therefore not synonymous.
Colonoscopy perforation and polypectomy
Perforation during diagnostic colonoscopy
Colonic perforation is a recognised complication of colonoscopy. In an individual case, an expert assessment requires more than establishing that a perforation occurred.
Relevant issues may include:
- The indication for colonoscopy
- Patient-specific risk factors
- Previous surgery or altered anatomy
- Diverticular disease or other underlying pathology
- Technical difficulty encountered during the procedure
- The extent of the examination
- The contemporaneous endoscopy report
- Whether there was evidence of perforation during the procedure
- Subsequent symptoms and clinical observations
- The timing of recognition, investigation and escalation
The clinical record and chronology are important when determining whether the complication arose despite acceptable care or whether aspects of the procedure or subsequent management require further scrutiny.
Perforation following polypectomy
Therapeutic endoscopy introduces considerations beyond those of diagnostic colonoscopy.
Where perforation occurs following polypectomy, relevant issues may include:
- The site, size and morphology of the lesion
- The planned endoscopic intervention
- Recognition of requirement of a repeat procedure
- The technique used
- Mechanical or thermal treatment where relevant
- Procedural documentation and images
- Events recognised during the procedure
- Advice and safety-netting provided afterwards
- Subsequent symptoms and presentation
- Recognition and management of the complication
The fact that a perforation followed polypectomy does not, on its own, determine whether there was a breach of duty. The procedure and subsequent management need to be assessed in their full clinical context.
Bleeding and other post-endoscopy complications
Bleeding may occur during or after therapeutic endoscopy and, like perforation, is not necessarily evidence of negligent care.
Assessment may require consideration of the procedure performed, the nature of any intervention, relevant medication such as anticoagulant or antiplatelet therapy, management during the procedure, and the advice given afterwards.
In cases of delayed bleeding or other subsequent deterioration, the issues may extend beyond the original procedure. The response to new symptoms, reassessment, investigation, escalation and subsequent treatment may need to be considered separately.
In some cases, the central medicolegal question is not whether a complication should ever have occurred, but whether it was recognised and managed appropriately once it developed.
Consent and communication of risk
Consent for endoscopy is a process rather than simply a signature on a form.
Depending on the circumstances, relevant clinical issues may include:
- Why the procedure was being recommended
- The expected benefits
- Material risks relevant to the individual patient
- Reasonable alternatives
- The option of not proceeding
- Particular patient-specific factors
- What was documented in the clinical record
A signed consent form provides evidence of the consent process, but assessment may require consideration of the wider discussion and the information available to the patient when the decision was made.
Questions concerning the legal interpretation of consent remain matters for the Court. My role as a gastroenterology expert is to provide opinion on the relevant clinical practice and information that would reasonably arise within that clinical context.
Recognition and management of post-procedure deterioration
Some cases concern not the technical performance of the original procedure, but what happened afterwards. A patient developing significant symptoms following endoscopy may require reassessment and, depending upon the clinical circumstances, further investigation or escalation.
New symptoms → Clinical reassessment → Investigation → Escalation → Treatment
Relevant issues may include the nature and timing of symptoms, observations, clinical examination, communication between services, the timing of imaging or other investigations, and referral for surgical or other specialist assessment.
An expert report may therefore need to distinguish between two separate questions:
Was the original procedure performed to an acceptable standard?
and
Was the subsequent complication recognised and managed appropriately?
Breach of duty and causation are separate questions
In clinical-negligence work, a potential departure from an acceptable standard of care does not itself establish that the alleged breach caused the eventual outcome.
Breach of duty - Did the relevant gastroenterological care fall below an acceptable standard?
This may concern the indication for investigation, consent, procedural conduct, interpretation of findings, follow-up or the response to complications.
Causation - What would probably have happened had appropriate care been provided?
This may require consideration of the timing and consequences of a complication, subsequent treatment and the counterfactual clinical course.
Where the causation question extends beyond gastroenterology - for example to operative management, oncological outcome or radiological interpretation - an additional expert from the relevant specialty may be required.
My reports distinguish clearly between matters falling within my own expertise and those requiring opinion from another discipline.
What records are usually required?
The records required depend on the allegations, but an initial expert review commonly benefits from:
Core records
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Letter of instruction
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Particulars or summary of the allegations, where available
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Relevant GP records
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Hospital and clinic records
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Referral correspondence
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Endoscopy request and documented indication
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Consent documentation
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Full endoscopy report
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Endoscopic photographs or video where available
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Histology reports
Depending on the case
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Recovery-unit observations
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Nursing documentation
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Emergency department or readmission records
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Blood results
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CT or other imaging
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Surgical records
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Critical-care records
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Local protocols or policies where relevant
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Relevant correspondence with the patient
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An existing chronology, if one has been prepared
A large volume of records is not necessarily a substitute for the relevant records. I can advise at an early stage if further documentation is likely to be required before a reliable opinion can be given.
Endoscopy experience and expert-witness practice
I am a currently practising NHS Consultant Gastroenterologist and JAG-accredited endoscopist, with more than 20 years of medical experience and over 13 years' experience as a consultant.
My clinical work includes gastrointestinal investigation and endoscopy, complex gastroenterology, gastrointestinal cancer and neuroendocrine tumours. I accept instructions from both claimant and defendant solicitors and provide independent opinion within my areas of expertise.
My expert-witness work includes breach of duty and causation, delayed diagnosis, endoscopy-related complications, gastrointestinal cancer, and interpretation of complex clinical records.
Independent expert opinion
An expert witness's overriding duty is to assist the Court within their area of expertise.
I accept instructions from both claimant and defendant solicitors. My opinion is based on the clinical evidence and is independent of the interests of the instructing party.
Reports are prepared with regard to the requirements of CPR Part 35 and the relevant duties of an expert witness.
Why Instruct Me
I combine academic and clinical excellence with real-world understanding of NHS systems, timelines, and pressures. I regularly review cases and understand the nuances of medicolegal opinion writing, balancing clarity, defensibility, and impartiality.
CPR 35 Compliant | Currently practising NHS Consultant Gastroenterologist | JAG-accredited Endoscopist | FRCP (London) | Listed in the UK Register of Expert Witnesses
