Change in Bowel Habit Station

Presenting Complaint

• You are quite embarrassed about this, but you have come to the GP today because you have diarrhoea.
• What do I mean by diarrhoea? - Runny and watery stool.

History of Presenting Complaint

• General: Pallor, fatigue
• Respiratory: occasional shortness of breath, started 2 weeks ago, usually when you are walking long distances. It does not stop you from walking.
• Cardiology: You have started to get a little light-headed when you stand up suddenly. This is new and has never occurred before.
• Endocrinology/Neurology: No other relevant symptoms
• Red Flags: as below
  • No fever, no back pain, no rigors or night sweats.
  • You have noticed some weight loss which may be related to your diet. You are unable to quantify your weight loss
  • No rectal bleeding
  • No blood in stools
  • No abdominal or rectal mass

Previous Medical History

• Diabetes
• Only if asked: You have just received your FIT test in the post however you have not had a chance to complete it.
• Only if asked: You have not had a recent course of antibiotics or been admitted to hospital recently. (This is relevant to rule out clostridium difficile infection)

Past Surgical history

• Appendix removal 10 years ago due to appendicitis.

Medications

• Metformin: Only if asked: this was started 1 year ago. This is important to ask as starting metformin can cause GI disturbance.

Allergies

• No known drug allergies

Social History

• Travel History - no recent travel
• You are an ex-smoker of 5 cigarettes a day for 3 years. You stopped smoking 1 year ago.
• You have never taken any recreational drugs.
• You drink red wine socially.
• You are a retired school teacher.
• You live alone

Family History

• You were an orphan and an only child, so you did not know what diseases or cancers your parents had

ICE

• Ideas: You are wondering if this is another episode of food poisoning, however you do feel that it has been going on for too long now so you’re starting to get a little worried.
• Concerns: You’re worried it’s something more serious
• Expectations: Nothing.

Vitals

• BP -  98/60
• Heart Rate - 100
• Respiratory Rate - 12
• SpO₂ - 98 %

Inspection

• General - appears comfortable at rest.
• Hands - No peripheral stigmata of disease. Capillary Refill Time is 3 seconds
• Face - Conjunctival pallor. Mucus membranes appear slightly dehydrated.
• Abdomen - slightly distended.

Palpation

• Soft non-tender abdomen
• No masses palpable.
• No hepatomegaly or splenomegaly.

Percussion

• Normal percussion

1. What are your top 3 differential diagnoses?

• Bowel cancer. The age, change in bowel habit, alongside the symptoms of anaemia and weight loss (albeit may be intentional) all suggest a diagnosis such as colorectal cancer.
• Diverticular disease: commonly presents as diarrhoea, however the absence of pain and blood in stool make this an unlikely diagnosis.
• Inflammatory bowel disease: This is least likely, as there has been no changes in diet, and a lack of systemic symptoms such as mouth ulcers or skin changes. However, some people with IBD do not develop their first flare until they are 60⁽¹⁾.

2. What other investigations would you do?

Examinations:

• PR exam with a chaperone
• Respiratory exam to examine her shortness of breath
• Lying standing blood pressure

Laboratory investigations ⁽²⁾⁽³⁾

• Full blood count to assess for iron deficiency anaemia in case of bleeding from other sites
• Urea and electrolytes to assess for dehydration as patient has had chronic diarrhoea
• Liver function tests including albumin level, as liver pathology can be associated with inflammatory bowel disease, but also to rule out dehydration (albumin is high in dehydration and low in inflammation or malabsorption)
• Calcium – calcium is usually raised in cancer conditions⁽⁴⁾
• Vitamin B12 -to rule out anaemia
• Red blood cell folate – to rule out anaemia
• Ferritin to assess for iron deficiency anaemia
• ESR to assess for inflammatory bowel disease
• CRP to assess for inflammatory bowel disease
• TSH -diarrhoea can also be caused by hyperthyroidism

Referral investigations

• FIT test to check for occult blood in stools.
• Faecal calprotectin to rule out IBD.
• Consider CA125 testing however ovarian cancer is unlikely.
• Consider carcinoembryonic antigen CEA testing ⁽³⁾ (marker for bowel cancer)
• Colonoscopy and biopsy⁽⁵⁾
• Consider stool sample for microbiology examination for ova, cysts and parasites ^(3).
• Consider C.difficile testing
•  

3. What would be your next steps as the GP to manage the patient?

• An unexplained change in bowel habit for adults age >60 years should warrant a 2 week suspected cancer pathway referral for suspected colorectal cancer ⁽⁶⁾.

4. What are the bowel cancer screening guidelines?

• People aged 60-74 years are offered bowel cancer screening using a faecal immunochemical test. Patients with a negative FIT test will return to normal routine testing every 2 years. Patients with a positive FIT test will need a colonoscopy ⁽⁷⁾.  

5. Describe the staging system for colorectal cancer?

• TNM staging system ^{(5) (9)}.
  • T-stage (tumour stage):  shows the depth of the tumour invading the bowel.
  • N-stage (nodes stage): shows the extent of the spread of the cancer to local lymph nodes.
  • M-stage (metastasis stage):  shows whether there has been metastasis from the cancer.

6. What is the most common location for colorectal cancer?

• The proximal colon ⁽⁸⁾.

7. What are the different surgical resections for colorectal cancer?

• Right hemicolectomy for removal of cancers in the caecum, ascending and proximal transverse colon
• Left hemicolectomy for removal of cancers in the distal transverse and descending colon.
• High anterior resection for removing cancers in the sigmoid colon
• Low anterior resection for removing cancers in the sigmoid colon and upper rectum
• Abdomino-perineal resection for removing the rectum and anus
• Hartmann’s procedure: for emergency removal of the rectosigmoid colon ⁽⁹⁾.