Constipation Flashcards
What are the 4 broad causes of constipation
Abnormal bowel peristalsis
Hard stools
Bowel obstruction
Patient not pushing
What are the differentials for constipation caused by abnormal bowel peristalsis
IBS Medications e.g. opiates, iron supplements, CCBs Hypothyroidism Hypercalcemia Hypokalaemia MS, Parkinson's, diabetic neuropathy
What are the differentials for constipation with hard stools
Lack of dietary fibre
Dehydration
What are the differentials for constipation due to bowel obstruction
Colorectal adenocarcinoma
Sigmoid volvulus
Pelvic masses - uterine fibroids, ovarian tumour
Colonic stricture - radiotherapy, Crohn’s, diverticulum
What are the differentials for constipation due to the patient not pushing
Haemorrhoids
Anal fissure
Pelvic floor dysfunction e.g. after hysterectomy
What red flags warrant further investigation of a patient presenting to the GP with constipation
Severe, persistent constipation unresponsive to treatment
Absolute constipation
Rectal bleeding, tenesmus or intermittent mucoid diarrhoea
Significant weight loss, IDA, night sweats
PMHx UC or colonic polyps
Strong FHx of colon cancer of colonic polyps
What should be asked about the constipation itself
Specify what the patient means by constipation
When did it start
What associated symptoms should be asked about in a patient with constipation
Weight loss, night sweats, fevers Diarrhoea Tenesmus Blood on faeces, PR or when wiping Bloating Feeling cold, reduced appetite, gaining weight Bone pain Polyuria, thirst
What do the following symptoms (with constipation) suggest: Weight loss, night sweats, fevers Diarrhoea Tenesmus Blood on faeces, PR or when wiping Bloating Feeling cold, reduced appetite, gaining weight Bone pain Polyuria, thirst
Weight loss, night sweats, fevers: malignancy
Diarrhoea: IBS (younger), colorectal cancer (>45), diverticular disease (>60)
Tenesmus: mass e.g. tumour
Blood on faeces, PR or when wiping: haemorrhoids, anal fissure, diverticular disease, colorectal cancer
Bloating: IBS
Feeling cold, reduced appetite, gaining weight: hypothyroidism
Bone pain: bone mets -> hypercalcaemia -> constipation
Polyuria, thirst: hypercalcaemia
What risk factors should be asked about for constipation
History of bowel disease, neuro disorders, back problems, endocrine disease
FHx of bowel disorders e.g. FAP, HNPCC, Peutz-Jegher’s
Opiate, anticholinergic, TCA, CCB and iron supplement use
Low-fibre diet and dehydration (ask for colour of urine)
What should be looked for on general inspection in an exam for a patient with constipation
Cachexia (malignancy)
Hypothyroidism signs: loss of hair, brittle hair, dry skin, puffy eyes, malar flush
What should be looked for on abdominal exam for a patient with constipation
Virchow’s node (GI malignancy)
Abdominal mass (faeces, tumour, Crohn’s, ovarian)
Anal fissure or haemorrhoids
Mass on digital rectal examination
Lax anal tone (neuro path e.g. diabetic neuropathy or MS)
What blood tests should be ordered to investigated consipation
FBC: anaemia suggests malignancy
U+Es: electrolytes (hypoK and hyperCa) can cause constipation
TFTs: exclude hypothyroidism
Glucose and HbA1c: assess diabetic control
What additional markers may be ordered for suspected colorectal cancer
Faecal occult blood test (FOBT)
CEA (Carcinoembyonic antigen), Ca19-9, Ca-125
What imaging should be ordered for constipation
Proctoscopy Rigid sigmoidoscopy / Flexible sigmoidoscopy Colonoscopy CT colonography Double contrast barium enema OGD
What are bulk producers, fibre supplements and stool softeners
Bulk producers - helps constipation by providing bulk which activates stretch receptors in the bowel
Fibre supplements: methylcellulose tablets, isphaghula husk
Stool softeners: liquid paraffin and arachis oil enemas (short term use)
What are osmotic laxatives
Lactulose, macrogols/polyethylene glucols e.g. movicol, magnesium salts
Retains fluid in the bowel -> osmotic diarrhoea
Patient MUST increase fluid intake to avoid dehydration
Give examples of peristaltic stimulants
Glycerol suppositories
Bisacodyl
Senna
Docusate
How will a patient who is constipated due to dehydration, low fibre diet and immobility present
Long-standing constipation
Hard stools and dark urine
DRE - rectum loaded with hard faeces with normal anal tone
NO pain, rectal bleeding, no other symptoms
Social history - little fluid intake, low fibre diet, immobility
How will a patient who is constipated due to hypothyroidism present
Progressive constipation over months No pain, blood or straining Cold intolerance Weight gain despite reduced intake Fatigue Heavy menstruation Bradycardia , carpal tunnel syndrome
What are common causes of constipation in elderly women
Medications e.g. opiates Hypercalcaemia Immobility Weakness Poor diet and dehydration Megarectum
What is the treatment for sigmoid volvulus
Drip and suck (IV in, NG tube out)
Removal of obstruction by
1. sigmoidoscopy and flatus tube insertion
2. Surgery
why is constipation very common after surgery
Anaesthesia + opiate analgesia + bowel manipulation -> paralysis/ileus
Electrolyte disturbances e.g. hypokalaemia, magnesaemia
Embarrassment of using commode in hospital
Describe Dukes classification
Dukes A - no spread into muscularis propria
Dukes B - invasion beyond the muscularis propria
Dukes C - Spread to lymph nodes
Dukes D - metastases to other organs
