Constipation Flashcards
List four mechanisms of constipation.
Abnormal bowel peristalsis
Hard faeces
Bowel obstruction
Patient not able/willing to push
For each of the mechanisms below, list some causes of constipation: Abnormal bowel peristalsis Hard faeces Bowel obstruction Patient not able/willing to push
- Abnormal bowel peristalsis IBS Medications Others: hypothyroidism, hypercalcaemia, hypokalaemia, diabetic neuropathy, multiple sclerosis, Parkinson’s disease - Hard faeces Lack of dietary fibre Dehydration - Bowel obstruction Colorectal carcinoma Sigmoid volvulus - Patient not able/willing to push Haemorrhoids Anal fissure Pelvic floor dysfunction
List some red flag symptoms that may suggest that the constipation has a sinister cause.
Severe constipation that’s unresponsive to treatment
Absolute constipation
Rectal bleeding, tenesmus or intermittent mucoid diarrhoea
Significant weight loss, iron deficiency anaemia, night sweats
Why is it important to ask about the time course of the constipation?
Chronic constipation – usually benign
Recent change – pathology
Describe the type of stools that will be passed in constipation caused by dehydration or a lack of dietary fibre.
Hard and lumpy
List some associated symptoms of constipation.
Weight loss, night sweats, fever Diarrhoea Tenesmus Blood in stools Bloating Hypothyroid symptoms (cold intolerance, weight gain, reduced appetite) Bone pains Polyuria and polydipsia
What might intermittent diarrhoea with constipation suggest?
Young – IBS
Middle-aged – colorectal cancer
Elderly – diverticular disease
What is tenesmus and what does it indicate?
Sensation of having a desire to defecate, which is continuous and recurs frequently, with or without the production of significant amounts of faeces
Suggests that there is a persistent mass in the rectum
Why is it important to take note of any bone pains that the patient is complaining about?
This may indicate the presence of bone metastases, which can lead to hypercalcaemia, which, in turn, can cause constipation
List some major risk factors for constipation.
Past medical history of bowel disease, neurological disorders, back problems or endocrine disease
Family history of bowel disorders
Medications
Diet
List some hereditary disorders that are risk factors for constipation.
Familial adenomatous polyposis (FAP)
Hereditary non-polyposis colorectal cancer (HNPCC)
Peutz-Jeghers syndrome
List some classes of medication that are known for causing constipation.
Opiates Calcium channel blockers Iron supplements Tricyclic antidepressants Anticholinergics
List some features of the abdominal examination that could give clues about the aetiology of the constipation.
Virchow’s lymphadenopathy Abdominal mass Anal fissures or haemorrhoids Mass on DRE Lax anal tone
List some important blood tests that may be useful when investigating a patient with constipation.
FBC – colonic cancers can bleed causing anaemia
U&Es and calcium – check for hypokalaemia and hypercalcaemia
TFTs – check for hypothyroidism
Glucose and HbA1c – check glycaemic control to assess risk of diabetic neuropathy
FOBT is used as a screening test for colorectal cancer. Other than colorectal cancer, what else can give a positive FOBT?
Colonic angiodysplasia
Polyps
Haemorrhoids
Aspirin, warfarin etc.
Which cancers are the following tumour markers associated with:
CEA
CA19-9
CA125
- CEA Colorectal cancer - CA19-9 Pancreatic cancer - CA125 Ovarian cancer
List and provide a brief description of the forms of imaging that may be used to investigate a patient with constipation.
Proctoscopy – visualise anus and rectum
Rigid sigmoidoscopy – visualise as far as the sigmoid colon
Flexible sigmoidoscopy – visualise as far as the splenic flexure and can take biopsies/resect polyps. Requires bowel prep and sedation
Colonoscopy – visualise as far as the ileocaecal valve
Virtual CT colonography – performed in patients who are unable to tolerate colonoscopy
Double contrast barium enema – rarely used now
OGD – if lower GI pathology is not found
Outline the treatment options available for constipation.
Lifestyle – increase fluid intake and dietary fibre Bulk producers Stool softeners Osmotic laxatives Peristalsis stimulants Enemas
Give examples of the following types of laxative:
Stool softeners
Osmotic laxatives
Peristalsis stimulants
- Stool softeners Liquid paraffin Arachic oil enema - Osmotic laxatives Movicol Lactulose Magnesium salts - Peristalsis stimulants Senna Glycerol suppositories Bisacodyl
Describe the typical presentation of a patient with hypothyroidism.
Young woman with reduced frequency of bowel movements Lethargy Reduced appetite Weight gain Cold intolerance Features of carpel tunnel syndrome
What is the most common cause of hypothyroidism in the UK?
Hashimoto’s thyroiditis (autoimmune)
Which antibodies are associated with Hashimoto’s thyroiditis?
Anti-thyroid peroxidase antibodies
Describe the typical presentation of a patient with hypercalcaemia.
Polyuria Polydipsia Aches and pains Abdominal pain Constipation Low mood
What are the four main causes of hypercalcaemia?
Bone metastases
Myeloma
Primary and tertiary hyperparathyroidism
Vitamin D toxicosis
How can you differentiate between myeloma and bone metastases as a cause of hypercalcaemia?
Myeloma has normal ALP because it activates osteoclasts and inhibits osteoblasts
Osteoblasts produce ALP
Describe the action of PTH.
Increase calcium and phosphate release from bone
Increase renal excretion of phosphate
In a hypercalcaemic patient, why is it abnormal to find a serum PTH that is within the normal range?
If calcium is high, PTH should be low because of negative feedback
List some causes of hyperparathyroidism.
Parathyroid adenoma Parathyroid hyperplasia Parathyroid carcinoma PTH-secreting tumour NOTE: PTHrP (PTH-related protein) can be secreted ectopically by some tumours
Describe the effect of vitamin D on the GI tract.
Increase calcium and phosphate reabsorption
Will the PTH be low, normal or high in a patient with vitamin D toxicosis (overdose)?
Low
List some clinical features of bowel obstruction.
Abdominal distension Tinkling bowel sounds Absolute constipation Colicky abdominal pain Nausea and vomiting
What is considered an abnormal diameter of the:
Small bowel
Large bowel
Caecum and sigmoid
Small bowel - 3 cm
Large bowel - 6 cm
Caecum and sigmoid - 9cm
(rule of 3,6,9)
What are the distinguishing features of the small bowel and large bowel on an abdominal X-ray?
Small Bowel – valvulae conniventes
Large Bowel – haustra
What radiological sign is associated with sigmoid volvulus?
Coffee bean sign
What is Rigler’s sign?
When the wall of the bowel is particularly defined due to the presence of air on both sides of the wall
This is caused by bowel perforation causing gas to leak into the peritoneal cavity
It is also called double-wall sign
Outline the management of a patient with bowel obstruction.
‘Drip and Suck’
Nil by mouth to aspirate stomach contents
IV fluids
How is a sigmoid volvulus relieved?
A flatus tube is inserted to untwist and decompress the volvulus
