Constipation (oxford clin cases) Flashcards
What are some pathophysiological reasons someone might be constipated?
Lack of peristalsis
Hard stools
Patient unable to push stool
Bowel obstruction
What are some differentials that you may have in mind when a patient presents with constipation?
IBS Carcinoma Low fibre diet Dehydration Secondary to drugs
What types of drugs are commonly known to cause constipation?
CCBs Opiates Iron supplements Trycyclic antidepressants Anticholinergics
What is the most common cause of constipation in a hospital setting?
Patients being embarrassed to defecate eg because they are in earshot of others
What is the most common cause of constipation in a GP setting?
Lack of dietary fibre or dehydration
What are some red flags when someone has constipation?
Blood in the stool
Intermittent mucoid diarrhoea
Persistent constipation
Absolute constipation
Previous hx of colonic polyps or colon cancer
Family hx of colonic polyps or colon cancer (especially if they were under 60)
Significant weight loss, anaemia (fatigue) or night sweats
What is absolute constipation?
When the patient is not passing any faeces or flatus
What does absolute constipation suggest is the diagnosis?
Small bowel obstruction
What does hard/lumpy stool suggest is the cause of constipation?
Lack of dietary fibre or dehydration
What does chronic constipation suggest?
A benign cause
What does diarrhoea alongside constipation suggest is the diagnosis?
IBS- especially if the patient is young
Diverticular disease- especially if the patient is old and has left iliac fossa pain
Colorectal cancer- especially if the diarrhoea is mucoid
What diagnosis does mucoid diarrhoea alert you to?
Possible colorectal cancer
What does tenesmus alongside constipation suggest?
Mass in the rectum
What diagnoses does blood in the faeces or on wiping suggest?
Anal fissure
Haemorrhoids
Diverticular disease
Colorectal cancer
What diagnosis does feeling cold, tired and weight gain alongside constipation suggest?
Hypothyroidism
What does polyuria and thirst alongside constipation suggest is the diagnosis?
Hypercalcaemia
What are some signs of hypothyroidism you should look for when examining someone with constipation?
Loss of hair- especially outer 1/3rd of eyebrows Brittle hair Dry skin Puffy eyes Malar flush
What might you look for on examination if someone has constipation and why?
Abdominal masses- could be carcinoma or impacted faeces
Virchows node- suggest GI malignancy
Anal tone- if lax could be neurological pathology
Abdominal distention- bloating due to IBS
Anal fissure or haemorrhoids
Mass on DRE- colon/rectal cancer
What electrolyte imbalances will cause constipation?
Hypercalcaemia
Hypokalemia
What investigations might you do if someone presents with constipation?
FBC- masses may bleed and cause anaemia
U+Es- look for hypercalcaemia or hypokalemia
Thyroid function tests- to rule out hypothyroidism
Colon cancer markers
Faecal occult blood test
What imaging should always be done if someone has iron deficiency anaemia and why?
OGD- to rule out an upper GI bleed as the cause
Up to where is visualised via OGD?
The duodenum
What imagine is done for someone after they have been diagnosed with colorectal cancer and why?
PET-CT to see how far it has spread
Also could do an chest, abdomen and pelvis CT
What lifestyle changes would you suggest to a patient with constipation caused by low fibre, dehydration and an immobile lifestyle?
Increase dietary fibre by eating more fruits and veg, high fibre cereal, wholemeal bread etc
Try to exercise more eg a brisk 30 min walk everyday
Increase fluid intake
What medications can be given for constipation and how do they work?
Osmotic laxatives
Stool softners
Peristalsis stimulants
What is the mechanism of action of osmotic laxatives?
They help retain water in the gut
What are some commonly used osmotic laxatives?
Macrogol
Lactulose
Magnesium salts
What is the most common cause of hypothyroidism in young women?
Hashimoto’s thyroiditis
What are some features of hypothyroidism?
Tiredness Carpal tunnel syndrome Constipation Cold intolerance Weight gain Heavy periods
What are the symptoms of hypercalcaemia and how do you remember them?
Stones, moans, bones and abdominal groans= kidney stones, depression/low mood, aches and pains abdominal pain
What are some causes of hypercalcaemia?
Vitamin D overdose
Bone metastases
Hyperparathyroidism
What might you advise a patient if they tell you they have a family hx of colorectal cancer and want to know how they can reduce their risk of developing it?
Have a good diet- high in fibre
Stop smoking if they do
Exercise adequately and maintain a healthy weight
High dose aspirin has also been found to reduce the risk of colorectal cancer however moderate dose will not make a difference
What scoring system can be used to stage colorectal cancer?
Duke’s criteria
