QuestionSBA
QuestionChoice
The change is bowel habit is very acute and there are no other red flags in context. It would not be the most likely diagnosis at this point.
61989
b
Colorectal cancer
QuestionChoice
A good differential, however, hard stool in the rectum and history of constipation would go against this. There are no infective symptoms or vomiting to support this.
61990
c
Gastroenteritis
QuestionChoice
Common in this age group; however, you would not expect hard stool on per rectum examination, and might expect a more inflammatory history.
61991
d
Diverticulitis
QuestionChoice
Coeliac disease would classically present younger, more chronically and with general symptoms such as weight loss. There may other auto-immune history.
61992
e
Coeliac disease
QuestionChoice
Severe constipation can lead to diarrhoea as liquid stool flows around immovable solid stool in the bowel.
61988
a
Overflow diarrhoea
Concept
Chapter
# Summary

Constipation is a common gastrointestinal disorder characterised by infrequent bowel movements, hard stools, excessive straining, tenesmus and sometimes necessitating manual evacuation. The disorder can be primary, due to a functional issue, or secondary, due to various causes such as diet, certain medications, and endocrine or neurological disorders. Key investigations include full blood count, electrolytes, thyroid function, blood glucose, and imaging if suspicious of secondary causes. Management is dependent on the underlying cause and may involve lifestyle modifications, a range of laxatives, and referral to a specialist centre for gut motility evaluation if laxatives fail to resolve symptoms.

# Definition

Constipation may involve any or all of the following (Rome IV criteria):

- Fewer than three bowel movements per week
- Hard stool in more than 25% of bowel movements
- Tenesmus (sense of incomplete evacuation) in more than 25% of bowel movements
- Excessive straining in more than 25% of bowel movements
- A need for manual evacuation of bowel movements

It can be categorised as:

- Primary constipation: no organic cause, thought to be due to dysregulation of the function of the colon or anorectal muscles
- Secondary constipation: due to factors such as diet, medications, metabolic, endocrine or neurological disorders or obstruction

# Epidemiology

Risk factors include:

- Advanced age
- Inactivity
- Low calorie intake
- Low fibre diet
- Certain medications
- Female sex

# Aetiology

Causes of constipation include:

- Dietary factors, such as inadequate fibre or fluid intake
- Behavioural factors, like inactivity (common cause of constipation in inpatients) or avoidance of defecation
- Electrolyte disturbances, like hypercalcaemia
- Certain drugs, particularly opiates, calcium channel blockers and some antipsychotics
- Neurological disorders, like spinal cord lesions, Parkinson's disease, and diabetic neuropathy
- Endocrine disorders, such as hypothyroidism
- Colon diseases, like strictures or malignancies. Bowel obstruction can also cause complete constipation (obstipation)
- Anal diseases, like anal fissures or proctitis

# Signs and symptoms

Symptoms and signs of constipation include:

- Infrequent bowel movements (less than 3 per week)
- Difficulty passing bowel motions
- Tenesmus
- Excessive straining
- Abdominal distension
- Abdominal mass felt at the left or right lower quadrants (stool)
- Rectal bleeding
- Anal fissures
- Haemorrhoids
- Presence of hard stool or impaction on digital rectal examination

ALARMS features which may indicate gastrointestinal malignancy include: anaemia, weight loss, anorexia, recent onset, melaena/haematemesis/PR bleeding, swallowing difficulties


# Investigations

### 2-week-wait criteria

- Constipation (or diarrhoea) with weight loss, 60 and over. Consider an urgent, direct access CT scan, or an urgent ultrasound scan if CT is not available, to rule out **pancreatic cancer**

If it a patient does not fit the 2-week-wait criteria above, and the cause is thought to be primary, then it is likely that no further investigations are needed.

However, if there is suspicion over secondary causes of constipation, investigations may include:

Bedside:

- PR exam
- Stool culture – MC&S, ova,cysts,parasites
- FIT testing (if accompanied with new rectal bleeding and signs suggestive of colorectal cancer), faecal calprotectin

Bloods:

- Full blood count (may show an anaemia), U+Es (including calcium), TFTs

Imaging:

- Abdominal x-ray if suspicious of a secondary cause of constipation such as obstruction (may reveal faecal loading)
- Barium enema if suspicious of impaction or rectal mass
- Colonoscopy if suspicious of lower GI malignancy

[lightgallery]

# Management

Conservative:

- Lifestyle modifications such as dietary improvements and increased exercise

Medical:

**Laxatives** are the mainstay of treatment, please see summary table below.

| Class of Laxative  | Drug Name Example         | Indication                                                    | Mechanism of Action                                     | Side Effects                          | Contraindications                                         |
|---------------------|-------------------|--------------------------------------------------------------|---------------------------------------------------------|---------------------------------------|-----------------------------------------------------------|
| Bulking Agents      | Ispaghula Husk    | Used for constipation, especially in individuals who need to increase stool bulk. | Increase faecal mass and stimulate peristalsis          | Contraindicated in dysphagia, GI obstruction, faecal impaction  |    Colonic atony, faecal impaction, intestinal obstruction, reduced gut motility, sudden change in bowel habit that has persisted more than two weeks; undiagnosed rectal bleeding                                                       |
| Stimulant         | Senna, bisacodyl             | Used for short-term relief of constipation.                  | Increase intestinal motility                             | Cramps                                | Contraindicated in acute obstruction or colitis; Prolonged use causes colonic atony (+ melanosis coli)          |
| Stool Softeners     | Sodium Docusate, Macrogol   | Used to soften stool and make bowel movements easier.        | Use in fissures, reduce anticipatory withholding          |     Flatulence, nausea                                  |  Ileus; intestinal obstruction; intestinal perforation; risk of intestinal perforation; severe inflammatory bowel disease; toxic megacolon                                                         | 
| Osmotic Laxatives   | Lactulose         | Used for the treatment of constipation, particularly in cases of hepatic encephalopathy. | Retain fluid in bowel and discourage ammonia-producing microorganisms; First-line for hepatic encephalopathy | Abdominal discomfort, flatulence, diarrhea, electrolyte imbalance | Known hypersensitivity to lactulose, galactosemia, intestinal obstruction                |
| Phosphate Enema     | Phosphate Enema   | Used for rapid bowel evacuation, often before medical procedures or examinations requiring an empty bowel. | Rapid bowel evacuation, need digital rectal examination (DRE) first | Abdominal cramps, electrolyte imbalance, dehydration | Contraindicated in patients with renal impairment, heart failure, electrolyte abnormalities, and those at risk of phosphate nephropathy |


If laxatives fail to resolve symptoms, referral to a specialist centre for evaluation of gut motility may be necessary. 

Surgical:

- If suspicions of colorectal cancer, referral to lower GI/colorectal surgeons
- If concerns over obstruction these patients need to go to A&E for urgent management and imaging

# NICE Guidelines

[NICE: Treatment Summary: Constipation](https://bnf.nice.org.uk/treatment-summary/constipation.html)

# References

[World Gastroenterology Organisation: Constipation](https://www.worldgastroenterology.org/guidelines/global-guidelines/constipation)

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Faecal loading seen on an abdominbal x-ray.
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2439
Constipation
Topic
57
Geriatrics
12459
A 65 year old male presents to GP with 2 day history of diarrhoea and soiling. He denies fevers; he feels nauseous but is otherwise well with no vomiting. Previously he has tended towards constipation and opens his bowels on average three times per week. He denies weight loss or bleeding per rectum.
On examination he has diffuse mild abdominal tenderness, and hard stool in his rectum but no blood.

Which of the following is the most likely diagnosis?
a