Constipation Flashcards
What is constipation?
Condition where there is difficulty emptying the bowels, often associated with hardened stool
What is primary constipation?
Constipation as a result of disordered or ineffective regulation of colonic and anorectal neuromuscular function or brain-gut neuroenteric function.
= slower transit of stool through large bowel and difficulty evacuating the faeces
What is secondary constipation?
Constipation as a result of factors, such as:
- Medications (opiates, antipsychotics)
- Metabolic disturbances (hypercalcaemia, hypothyroidism)
- Neurological disorders
- Primary diseases of the colon
What are the risk factors for constipation?
Female sex: 2:1 risk compared to men
Age: greater risk in over 65 years of age
Black ethnicity
Lower socioeconomic status
Medication use: opiates, calcium channel blockers, antipsychotics
Metabolic disturbances: hypothyroidism, hypercalcaemia
Neurological conditions: Parkinson’s disease, spinal cord lesions
Diabetes mellitus
Colonic disease: Hirschprung’s disease, anal stricture, colorectal cancer, anal fissure
Functional disorders: irritable bowel syndrome, dyssynergic defecation
Sedentary lifestyle
Reduced dietary fibre
What are the symptoms of constipation?
Difficult defecation: prolonged attempts
Infrequent stools <3 per week
Unsatisfactory of incomplete emptying
Excessive straining
Hard stools
Overflow diarrhoea
What are the signs of constipation?
Abdominal mass: stool may be palpable in right or left lower abdominal quadrants
Anorectal lesions: haemorrhoids, fissures
Abnormality on PR examination - hard stool, anal spasm, anal mass, anal stricture
Signs of underlying medical causes e.g. parkinsonism, hypothyroid appearance
Urinary retention
Delirium - common in elderly population
What are the primary investigation for constipation?
Abdominal examination - masses, distention, palpable colon
PR examination - masses, stool, fissures, haemorrhoids, prolapse, rectocele
What are the secondary investigations for constipation?
FBC: anaemia may suggest underlying malignancy
TFTs: hypothyroidism as a cause of constipation
U+Es: hypokalaemia, hypomagnesaemia may cause constipation
Bone profile: hypercalcaemia as a cause of constipation
Blood glucose: diabetes can potentiate constipation
Abdominal x-ray: faecal impaction, abdominal masses
Colonoscopy: intraluminal masses or obstruction
What is the first line management of short duration constipation (<3 months)?
Investigate, exclude or treat secondary cause
Lifestyle advice - increase daily fibre intake, increase exercise, increase fluid intake
Bulk forming laxative - fybogel (ispaghula husk), methylcellulose
What is the second line management of short duration constipation (<3 months) for hard stool that is is difficult to pass?
Osmotic laxative - macrogol, lactulose
What is the second line management of short duration constipation (<3 months) for soft stool or inadequate emptying?
Stimulant laxatives - senna, bisacodyl
What is the management for chronic constipation when at least two laxatives from different classes have been tried at the highest recommended doses for at least 6 months and failed to relieve symptoms?
Prucalopride: prokinetic which stimulates gastrointestinal motility
What is first line for a faecal impaction?
Oral macrogol +/- stimulant laxative
What is second line for faecal impaction?
Suppository: bisacodyl, glycerol
What is third line for faecal impaction?
Enema: sodium phosphate
What is a faecal impaction?
A patient is said to have faecal impaction when the constipation becomes so severe that they are unable to clear it out. All the poo in their bottom clumps together to form a large mass, which the patient is unable to pass. New poo will keep forming in the colon but cannot get past the blockage, so it just builds up.
What are the complications of constipation?
Pain: abdominal bloating and tenderness
Delirium: elderly patients at high risk
Anal fissure: passing of hard stool can cause trauma
Haemorrhoids: as a result of long term straining
Rectocele
Rectal ulcer syndrome
Megarectum and megacolon: as a result of severe faecal impaction
What is a rectocele?
A rectocele is a type of prolapse where the supportive wall of tissue between a woman’s rectum and vaginal wall weakens.
What is Rectal Ulcer Syndrome?
SRUS is a chronic, benign, disorder characterized by single or multiple ulcerations of the rectal mucosa, with the passage of blood and mucus, associated with straining or abnormal defecation
