PATHOLOGY - Diarrhoea Flashcards
How do you approach the investigation of diarrhoea?
- Assess history, signalement and clinical signs
- Clinical examination
- Diagnostic testing
- Management/treatment
Which history questions are useful to ask when investigating diarrhoea?
- Is the diarrhoea acute or chronic?
- Is the diarrhoea constant or intermittent?
- Describe the appearance of the diarrhoea?
- Has there been any recent dietary or environmental changes?
- Is the patient a scavenger?
- Are any of the animals the patient is in contact with also experiencing diarrhoea?
- Anthelmintic and vaccination history?
- Is the patient systemically unwell? (such as PUPD, jaundice, signs of endocrine disease, lethargic, etc.)
- Has the patient been vomiting?
- How is the patient’s appetite?
When is diarrhoea classified as chronic?
When diarrhoea has been going on for over two weeks, it is classified as chronic
Why is it important for the client to describe the appearance of the diarrhoea?
The appearance of the diarrhoea can help to distinguish if the diarrhoea is originating from the small or large intestine
What are the characteristic features of small intestinal diarrhoea?
Normal to large volumes of diarrhoea
Normal to mildly increased frequency of defaecation
Meleana
Concurrent weight loss
Concurrent vomiting
Ascites
Why do you get concurrent weight loss with small intestinal diarrhoea?
The small intestine is the site of nutrient absorption so you can see concurrent weight loss with small intestinal diarrhoea as the small intestine will be unable to absorb nutrients properly
When would you see ascites with small intestinal diarrhoea?
You can see ascites with small intestinal diarrhoea if there is a protein-losing enteropathy
What are the characteristic features of large intestinal diarrhoea?
Small volumes of diarrhoea
Increased frequency of diarrhoea (usually associated with urgency)
Mucus
Haematochezia
Concurrent faecal tenesmus
Concurrent dyschezia
What are the two main aims of the clinical examination when investigating diarrhoea?
Determine if there are any clinical signs that can help discriminate the cause of the diarrhoea and determine the clinical status of the patient
What should you assess in detail during the clinical examination when investigating diarrhoea?
Signs of systemic disease
Pyrexia
Signs of hepatic disease (jaundice)
Signs of kidney disease
Signs of malnutrition (low BCS)
Assess if the abdomen is painful
Palpate for any abdominal masses
Ascites
Assess for dehydration
Assess for hypovolaemia
What can be indicated by pyrexia when investigating diarrhoea?
Pyrexia can be indicative of an infectious cause of diarrhoea
What can be indicated by malnutrition when investigating diarrhoea?
Malnutrition can be indicatibe of a chronic malabsorptive or maldigestive disorder resulting in diarrhoea
What can be indicated by ascites when investigating diarrhoea?
Ascites can be indicative of diarrhoea secondary to a protein-losing enteropathy
What are the gastrointestinal causes of acute diarrhoea?
Abrubt dietary change
Dietary indiscretion
Infectious disease
Acute colitis
Acute haemorrhagic diarrhoea syndrome
Abdominal catastrophe
What are some of the viral causes of acute diarrhoea?
Parvovirus
Distemper
Coronavirus
Rotavirus
What are some of the bacterial causes of acute diarrhoea?
Salmonella
Campylobacter
Clostridia
E. coli
Which two strains of clostridia cause acute diarrhoea?
Clostridia pefringens
Clostridia difficile
What are the systemic causes of acute diarrhoea?
Acute pancreatitis
Acute hepatobiliary disease
Acute kidney disease
Peritonitis
Endocrine disease
Toxicity
Which endocrine disease can cause acute diarrhoea?
Hypoadrenocorticism (Addison’s disease)
What are the differential diagnoses for acute haemorrhagic diarrhoea?
Parvovirus
Coronavirus
Salmonella
Campylobacter (not always haemorrhagic)
Clostridia
E. coli
Acute haemorrhagic diarrhoea
Abdominal catastrophe
How do you narrow down the differental diagnoses for acute diarrhoea?
Exclude systemic, extra-intestinal causes of diarrhoea
Exclude infectious causes or diarrhoea
Which diagnostic tests can be done when investigating acute diarrhoea?
Haematology
Biochemistry
Diagnostic imaging
Faecal analysis (faecal parasitology and faecal culture and sensitivity)
What are the aims of haematology and biochemistry when investigating acute diarrhoea?
Haematology and biochemistry can be used to identify systemic disease as well as gather more information on the patient’s clinical status
What should you be aware of when assessing liver enzymes when investigating acute diarrhoea?
You should be aware that acute diarrhoea can cause mild to moderate increases in liver enzymes as a consequence of there being increased toxic substances in the intestines which will be drained by the hepatic portal vein to be detatoxified by the liver which can put stress on the liver, resulting in increased liver enzymes
What is a distinctive feature of hypoadrenocorticism (Addison’s disease) on biochemistry?
High potassium levels and low sodium levels
Which additional test can be done to diagnose acute vomiting secondary to hypoadrenocorticism (Addison’s disease)?
ACTH stimulation test
Why is it so important to do diagnostic imaging when investigating acute diarrhoea?
It is important to do diagnostic imaging when investigating acute diarrhoea to rule out abdominal catastrophe
Describe the structure of parvovirus
Parvovirus is an enveloped DNA virus
Describe the pathogenesis of parvovirus
Parvovirus has a tissue tropism for rapidly diving cells such as intestinal epithelial cells and haematopoietic cells. Parvovirus damages the intestinal epithelial cells, resulting in severe acute haemorrhagic diarrhoea and impairment of the intestinal mucosal defences, allowing for the translocation of bacteria, causing sepsis. Parvovirus also targets haematopoietic cells which can result in neutropenia, which also increases the risk of sepsis. Sepsis can result in disseminated intravascular coagulation (DIC) which can be fatal
Which signalement is prone to parvovirus infection?
Unvaccinated dogs