Functional and infective pathology of the lower GI tract: diarrhoea and constipation Flashcards
What is the suggested definition of diarrhea according to the World Health Organization?
‘The passage of three or more loose or liquid stools per day (or more frequent passage than is normal for the individual).’
How is acute diarrhea defined?
Diarrhea lasting 0-14 days.
What is the definition of persistent diarrhea?
Diarrhea lasting 14 days to 4 weeks.
How is chronic diarrhea defined?
Diarrhea lasting 4 or more weeks.
Why is diarrhea considered one of the most common symptoms people seek medical attention for?
Because it is one of the most common symptoms people experience and consider significant enough to consult a healthcare professional.
What is the estimated number of cases of acute diarrhea per year in the UK?
Approximately 17 million cases of acute diarrhea occur each year in the UK, potentially affecting up to 25% of the UK population.
How many annual GP consultations are attributed to acute diarrhea in the UK?
There are approximately 1 million GP consultations per year in the UK related to acute diarrhea.
What percentage of the US population is estimated to have chronic diarrhea?
Chronic diarrhea is estimated to affect 7-14% of the US population.
What are the potential consequences of diarrhea in terms of morbidity and mortality?
Diarrhea can cause a significant amount of morbidity (illness) but generally has low mortality (death) rates.
What is a major concern associated with diarrhea?
Dehydration is a significant concern due to the fluid loss caused by diarrhea.
Which populations are at an increased risk of life-threatening illnesses due to diarrhea?
Young children and older adults are at an increased risk of developing life-threatening illnesses as a result of diarrhea.
What are some potential effects of diarrhea on electrolyte balance?
Diarrhea can lead to electrolyte imbalances, including sodium (Na), potassium (K), and bicarbonate (HCO3) levels.
How can diarrhea contribute to acidosis?
Prolonged diarrhea can lead to acidosis, an imbalance in the body’s acid-base equilibrium.
How can chronic diarrhea impact individuals’ well-being?
Chronic diarrhea can have negative effects on well-being, mental health, daily activities, dietary choices, and may contribute to social isolation.
What is the mechanism of action for osmotic diarrhea?
Osmotic diarrhea occurs when non-absorbed hypotonic compounds in the lumen of the intestine increase fluid loss. Examples include ingestion of magnesium-containing antacids, sorbitol, general malabsorption (e.g., pancreatic insufficiency), and specific absorptive defects (e.g., lactose intolerance).
What is the mechanism of action for secretory diarrhea?
Secretory diarrhea is characterized by increased secretion of substances and ions into the intestinal lumen, coupled with decreased uptake. Examples include enterotoxins (Cholera, E. coli, C. difficile), VIP (Vasoactive Intestinal Peptide), and colonic bile salts and fatty acids following ileal resection.
What is the mechanism of action for inflammatory diarrhea?
Inflammatory diarrhea occurs when there is an inflamed mucosa, leading to the loss of fluid and blood into the intestinal lumen and decreased absorption of fluid and ions. Examples include Shigella infection, Crohn’s disease, and ulcerative colitis.
What is the mechanism of action for abnormal motility diarrhea?
Abnormal motility diarrhea is characterized by increased gastrointestinal motility. It can be caused by functional disorders, diabetes, and hyperthyroidism.
What is the mechanism of action for overflow/mechanical diarrhea?
Overflow/mechanical diarrhea occurs when an obstructing body allows liquid to pass through while solid feces accumulate. Examples include chronic constipation, impaction, and neoplasms.
What are some common viral causes of acute diarrhea?
Viral causes of acute diarrhea include norovirus and rotavirus.
Which bacterial pathogens can cause acute diarrhea?
Bacterial causes of acute diarrhea include Salmonella, Campylobacter, Clostridium difficile, and cholera.
What are some examples of parasitic causes of acute diarrhea?
Parasitic causes of acute diarrhea include Giardia lamblia and Cryptosporidium parvum.
Which medications can potentially cause diarrhea?
More than 700 medications can cause diarrhea, including laxatives, antibiotics (especially macrolides), and allopurinol.
What is meant by “acute presentation of chronic pathology” in the context of diarrhea?
It refers to cases where an underlying chronic condition presents with acute episodes of diarrhea, such as in acute appendicitis, intestinal ischemia, or after radiotherapy.
What are some other factors that can cause acute diarrhea?
Other causes of acute diarrhea include anxiety, food allergies, and gastrointestinal inflammation (e.g., acute appendicitis, intestinal ischemia, and radiotherapy).
What is the most common cause of infectious diarrhea?
Most infectious diarrhea cases are caused by viral infections and are self-limiting.
How long does the majority of infectious diarrhea cases last?
Approximately 50% of infectious diarrhea cases last less than 1 day.
What is the typical duration of viral infectious diarrhea?
Viral infectious diarrhea typically lasts for 2-3 days.
How long does untreated bacterial infectious diarrhea typically last?
Untreated bacterial infectious diarrhea usually lasts for 3-7 days.
What is the expected duration of untreated protozoal infectious diarrhea?
Untreated protozoal infectious diarrhea can persist for weeks to months.
Is it always necessary to conduct investigations for acute diarrhea?
Investigations may not be needed if the patient is well and the symptoms are short-lived or quickly resolving.
When is stool testing (faecal MC&S) typically recommended?
Stool testing, such as faecal microscopy, culture, and sensitivity (MC&S), is particularly useful if the patient is vulnerable, there may be an unusual cause of diarrhea, or there is a need to exclude an infectious cause for public health reasons.
What blood tests are commonly performed to investigate acute diarrhea?
Blood tests such as a complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), liver function tests (LFTs), urea and electrolytes (U&Es), and iron studies are often conducted to rule out other acute causes of diarrhea.
What is the general management approach for acute diarrhea?
In most cases, no specific treatment is needed for acute diarrhea. Supportive measures focus on maintaining hydration.
How can hydration be maintained in cases of acute diarrhea?
Hydration can be maintained by using solutions such as hypertonic saline/glucose solution (e.g., Dioralyte) to replenish electrolytes and fluids lost through diarrhea.
When might hospitalization be necessary for acute diarrhea?
Hospitalization may be required if the patient is significantly unwell or at risk of dehydration.
When are subsequent diagnostics usually performed for acute diarrhea?
Further diagnostic tests are typically conducted once the acute episode of diarrhea has settled, if deemed necessary.
Are antibiotics commonly prescribed for acute diarrhea, even if it is proven to be an infection?
Antibiotics are seldom needed for acute diarrhea, including cases caused by proven infections, unless the diarrhea is severe.
What is the most common concern in managing acute diarrhea?
Dehydration is the most common concern in the management of acute diarrhea.
How can diet contribute to chronic diarrhea?
Chronic diarrhea can be caused by factors such as malabsorption, artificial sweeteners (with excessive sorbitol), as well as the consumption of caffeine and alcohol.
What are some bowel diseases that can cause chronic diarrhea?
Chronic diarrhea can be associated with bowel diseases such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), microscopic colitis, coeliac disease, pancreatic insufficiency, absorption problems, pancreatic and colorectal cancer, small bowel overgrowth, mesenteric ischemia, fistulae, short gut syndrome, Whipple’s disease, tropical sprue, amyloidosis, and radiation enteropathy.
How can constipation and impaction lead to chronic diarrhea?
Chronic diarrhea can be a result of underlying constipation and impaction, where liquid stool bypasses the impacted stool.
What are some common drugs that can cause chronic diarrhea?
Chronic diarrhea can be caused by various drugs, including macrolides, ACE inhibitors, NSAIDs, metformin, DPP4 inhibitors, proton pump inhibitors (PPIs), selective serotonin reuptake inhibitors (SSRIs), oncology drugs, theophyllines, antiarrhythmics, and furosemide.
Besides drugs, what are some other causes of chronic diarrhea?
Other causes of chronic diarrhea include infections, endocrine disorders, cystic fibrosis, lymphoma, hormone-secreting tumors (e.g., VIPoma, gastrinoma, carcinoid), autonomic neuropathy, and factitious diarrhea (diarrhea intentionally induced).
What are the common tests performed to investigate chronic diarrhea?
The same tests used for investigating acute diarrhea are also conducted for chronic diarrhea. These include stool microscopy, culture, and sensitivity (MC&S), with the addition of parasitology testing to identify potential parasitic causes.