Informed Consent OSCE - Colonoscopy Consent

Case Overview

• Age/Sex: 41-year-old female
• Occupation: Office worker (administrative assistant)
• Setting: Gastroenterology clinic pre-procedure appointment
• Chief complaint: "I'm here to sign the consent form for the colonoscopy"

Patient Script

Who I Am

I'm 41, work in an office doing paperwork and computer work, and I was referred by my GP for a colonoscopy.

What Brings Me In

I'm here because my GP said I need a colonoscopy and asked me to come in to discuss and sign the consent form.

My Story

About six weeks ago I started noticing bright red blood on the toilet paper and a little blood in the toilet after bowel movements. Around the same time I felt more tired than usual and my clothes are a bit looser — I think I've lost a couple of kilos over the past two months without trying. My bowel habits have changed slowly over three months; I have more frequent bowel movements and sometimes looser stools but no severe tummy pains. My GP did some blood tests and said I have a low haemoglobin and low iron, and referred me for a colonoscopy to find out what's causing the bleeding. I'm a bit anxious about the procedure and wanted to go over what will happen before I sign the form.

My Medical Background

• Past medical history: mild asthma (salbutamol inhaler PRN); lifelong external hemorrhoids (flare-ups occasionally)
• Medications: ferrous sulfate 200 mg once daily (started 2 weeks ago), occasional ibuprofen for headaches (2–3 times a month)
• Allergies: none known
• Social: non-smoker, drinks alcohol socially (3–4 units/week), lives with partner, works full-time
• Obstetric/Gyn: 2 children, regular periods, using combined oral contraceptive; last smear normal 2 years ago
• Family history: maternal aunt had bowel cancer in her 70s (distant relative)

What I Think & Worry About

• I think the bleeding might just be from my old hemorrhoids, but the GP seemed worried.
• I'm worried it might be something serious like cancer — I want to know how likely that is.
• I expect the test to tell us what's wrong and to fix it if possible; I don't want to be ill or miss work for long.

If You Ask Me About Other Symptoms...

• Abdominal pain: "I get some mild cramping sometimes, but nothing severe or constant."
• Weight/appetite: "My clothes feel a bit loose; I haven't been deliberately dieting. Appetite okay."
• Bowel movements: "More frequent and a bit looser for a few months; sometimes urgency but no incontinence."
• Fever/night sweats: "No fevers, no night sweats."
• Nausea/vomiting: "No vomiting."
• Medication use: "I take iron tablets; I sometimes take ibuprofen for headaches, but not often."
• Previous procedures: "I've never had a colonoscopy before."
• Pregnancy: "I'm not pregnant and use the pill; I haven't missed periods."
• Anaesthesia history: "I've had a dental extraction under local only; I've never had a general anesthetic."

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Clinical Summary

Examination

• General: alert, mildly pale, well-looking office worker
• Vitals: BP 118/74 mmHg, HR 82 bpm, RR 14/min, SpO2 98% on air, Temp 36.7°C
• Abdominal: soft, non-tender, no palpable masses, no organomegaly
• Perianal/rectal: external hemorrhoids visible; digital rectal exam reveals bright red blood on the glove, no palpable rectal mass

Investigations

• Full blood count: Hb 105 g/L (norm 120–160), MCV 76 fL (microcytic)
• Ferritin: 8 µg/L (low; consistent with iron deficiency)
• CRP: 3 mg/L (normal/low) (norm <5)
• Coagulation (INR): 1.0 (normal)
• Stool faecal immunochemical test (FIT)/occult blood: positive (high concentration of haemoglobin)
• Pregnancy test (urine): negative
• Recent GP referral letter: colonoscopy indicated for investigation of iron deficiency anaemia and rectal bleeding

Diagnosis

Primary diagnosis:

• Indication for colonoscopy: investigation of lower gastrointestinal bleeding with iron-deficiency anaemia (evidence: persistent bright red rectal bleeding for 6 weeks, positive stool test, Hb 105 g/L, ferritin 8 µg/L).

Differential diagnoses to be considered/reasoned:

• External/internal hemorrhoids: plausible given long-standing haemorrhoids and bright red bleeding on wiping; however anemia and positive FIT suggest further investigation is warranted.
• Colorectal neoplasia (polyp or cancer): must be excluded given iron-deficiency anaemia and persistent bleeding despite hemorrhoid history, although age 41 reduces baseline risk compared with older adults.
• Inflammatory bowel disease (ulcerative colitis or Crohn's): possible with change in bowel habit and bleeding, but CRP normal and symptoms are not classic for severe IBD.
• Anal fissure: causes bright red bleeding but usually painful; patient denies severe pain.

Management

• Informed consent process:

  • Explain indication: to identify source of lower GI bleeding and investigate iron-deficiency anaemia; may allow diagnosis and treatment (biopsy, polypectomy).
  • Explain the procedure: colonoscope passed to visualise colon; takes biopsies and removes polyps if needed.
  • Explain benefits: diagnostic clarity, potential therapeutic polypectomy, prevention of future malignancy if polyps removed.
  • Explain key risks with approximate numbers: bleeding after biopsy or polypectomy (common if polypectomy performed), perforation (~0.01–0.1%), cardiopulmonary complications from sedation (rare), failure to complete procedure due to poor bowel prep (variable), and need for further procedures.
  • Discuss alternatives: flexible sigmoidoscopy (limited reach), CT colonography (imaging alternative, no biopsy), or deferring (not advised given anaemia).
  • Address sedation options and requirement for an escort home post-sedation.
  • Confirm understanding and allow questions; document informed consent in notes and obtain signature.

• Pre-procedure practical steps:

  • Review and advise on anticoagulant/antiplatelet use; patient currently only on occasional ibuprofen — advise to stop NSAIDs 3–7 days before as per unit policy, and ask about any regular anticoagulants (none reported).
  • Ensure pregnancy test negative on the day of procedure (done today) and arrange if any uncertainty.
  • Provide clear bowel preparation instructions (split-dose polyethylene glycol or unit standard prep) and fasting instructions (nil by mouth from midnight for solids if morning list; clear fluids allowed until specified time).
  • Arrange transportation home and advise not to drive or work for 24 hours if sedated.
  • Continue iron supplementation as prescribed; consider arranging iron infusion if severe anaemia and rapid correction needed depending on results/haematology advice.
  • Document baseline observations and allergies; check consent for potential polypectomy/biopsy and transfer of specimens to pathology.

• Safety-netting and follow-up:

  • Advise patient to seek urgent care for severe abdominal pain, fever, heavy ongoing bleeding, or collapse after the procedure.
  • Plan follow-up to discuss results and any histology; coordinate with GP for iron therapy and anaemia follow-up.

Key Learning Points

• Informed consent for colonoscopy must cover indication, expected benefits, specific risks (with approximate frequencies), alternatives, and practical pre- and post-procedure requirements (bowel prep, fasting, escort).
• Investigate persistent rectal bleeding and iron-deficiency anaemia even in younger patients; hemorrhoids may coexist but do not exclude more serious pathology.
• Check and manage modifiable peri-procedural risks: pregnancy status in women of childbearing potential, anticoagulant/antiplatelet therapy, and ability to arrange safe transport after sedation.