Abdominal symptoms Flashcards
What is gastroenteritis
Inflammation of the GI tract (stomach, small and large intestine)
Causes of gastroenteritis
Viral
bacterial
parasitic
non-infective
What does viral gastroenteritis typically present with
watery diarrhoea
cramping / abdominal pain
nausea and vomiting
sometimes low grade fever
how to prevent viral gastroenteritis
improved sanitation
behavioural change / infection control
vaccination (rotavirus)
Treatment for gastroenteritis
no specific treatment
need to make sure they are kept hydrated
How is diarrhoea defined
passage of three or more loose or liquid stools per day (or more frequent passage than normal)
frequent passing of normal stools is NOT diarrhoea
what is diarrhoea usually a symptom of
an infection of the intestinal tract
three clinical types of diarrhoea - define them
acute watery diarrhoea - lasts several hours or days, and includes cholera
acute blood diarrhoea - also called dysentery
persistent diarrhoea - lasts 14 days or more
4 most common causes of viral gastroenteritis
rotavirus - commonest cause pre-vaccine
calicivirus (norovirus and sapovirus)
Adenovirus
Astrovirus
fact about adenovirus (one of the viruses that cause gastroenteritis)
second most common cause of infantile diarrhoea in temperate climates
global epidemiology of viral gastroenteritis
considered benign but second leading cause of death in developing countries in children under 5
yet preventable and treatable
transmission of viral gastroenteritis
faecal - oral spread
natural defences of GI tract
lysozyme in saliva
gastric acid pH 2
mucus in GIT traps microbes
bile salts - duodenum, disrupt some cell surfaces
normal flora - modify environments with metabolites , nutrient competition, natural antibiotics
mucosal immunity - cell mediated immunity, and secretory IgA
Motility - vomiting and diarrhoea probably important in clearing pathogens
describe the transmission of viral gastroenteritis
infectivity high ( as few and 10 virions)
virus excretion high - up to 10 >8 virions/mL faeces
environmental survival good - no viral envelope, survives heating, drying, gastric acid secretions, and bile salts
general clinical features of viral gastroenteritis
dehydration causing hypotension, tachycardia and oliguria
distended abdomen - in some cases muscle guarding and hyperactive bowel sounds
Risk groups of viral gastroenteritis
Children - never been exposed before (no immunity), poor hygiene, high SA to volume ratio (susceptible to dehydration)
Elderly - frailty (low reserves), Co - morbidities
Immunosuppressed - suboptimal immune response and immune memory, prolonged shedding/infectivity
since rotavirus vaccination what causes the most cases of viral gastroenteritis in the UK and USA
norovirus
define incubation period
time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent.
incubation period of rotavirus
1-3 days
norovirus incubation period
10-50 hours
astrovirus incubation period
3-4 days
signs of severe dehyrdation
apathy/lethargy/unconscious/unable to drink easily
deep sunken eyes, no tears, parched mouth, cold/mottled appearance
tachycardia (bradycardia if extreme), weak pulse, deep breathing, prolonged capillary refill, skin recoil >2 secs, minimal urine output
pathogenesis if vomiting is main cause of fluid loss
metabolic alkalosis and hypercholeramia (elevated chloride ions)
pathogenesis if diarrhoea is main cause of fluid loss
acidosis more likely