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
how to diagnose viral gastroenteritis
stool enzyme immunoassays
molecular diagnosis - PCR of faeces or vomit (preferred type)
what is jaundice characterised by
elevated bilirubin in plasma causing yellowing of the skin or mucosa
unconjugated bilirubin
excess production cannot be cleared, e.g. haemolysis
what does high conjugated bilirubin mean
liver cell damaged
what is hepatitis
hepatocellular inflammation
causes of hepatitis
infective toxic autoimmune metabolic obstructive
how is hepatitis A transmitted
through faecal oral transmission
how common is hepatitis A cases in the uk
rare
Hepatits A clinical features
spectrum from asymptomatic to acute liver failure
no chronic infection
jaundice incidence increases with age
Four clinical phases of hepatitis A - explained
Incubation/pre-clinical (range 15-50 days) - person is well but infectious for 2 weeks before illness upset
prodromal/pre-icteric (few days to 10 days) - flu like illness and loss of appetite
icteric phase - fever, jaundice (rarely pale stool and dark urine), liver enlargement and tenderness, anorexia, vomiting, fatigue, lasting 1-3 weeks
convalescence (recovering)
rare complications of a hepatitis A infection
fulminant hepatitis
cholestatis
relapsing hepatitis
pathogenesis of jaundice
probably due to immune mediated T lymphocyte destruction of hepatocytes
how to diagnose hepatitis A
clinical suspicion
biochemical features
epidemiological clues (age, risk groups, prior exposure, travel)
however need lab tests -antibody genome (RNA)
management of acute hepatitis A
dont need antivirals
check liver function, clotting and U&Es
if vomiting, dehydrated and altered consciousness then admit (bad signs)
transplant for acute liver failure
what do hepatitis B, D and C have in common
all bloodborne viral hepatitis agents
transmission of hepatitis B
typical blood borne virus so ..
sexually transmitted
mother to child
needle sharing - blood products
acute clinical features of hepatitis B
incubation period of 60-90 days
virtually all children and infants are asymptomatic with 50% adults being so too
ALT up to 2000 IU/L
relevance of hepatitis B surface antigen serology
abbreviation (HBsAg)
relevance - infected, acute or chronic
Acute management of hepatitis B
supportive
antivirals not usually given
check clotting, electrolytes; transplant for acute liver failure
counsel regarding transmission, screen for other blood borne viruses, STDs
management of chronic hepatitis B
assess need for antiviral therapy
most should be treated
Therapy of chronic hepatitis B
achieved by reducing HBV DNA levels - nucleoside antiviral drugs, immunomodulators
Hepatitis B prevention
avoid/reduce risk - safe sex, needle exchange, infection control
screening - blood products, high risk groups, pregnancy
treatment of chronic infections
Vaccine
describe hepatits C virus
Flavivirus, Hepacivirus
positive single stranded RNA
enveloped
what type of virus is hepatitis C
blood borne virus
Who has higher risk of severe fibrosis with hepatitis C
increased alcohol intake age >40yrs HIV co - infection Male Chronic HBV co-infection
management of hepatitis c
counsel on routes of transmission
avoid alcohol
vaccine against HAV and HBV
usually supportive - wait to see if it clears
what is considered change in bowel habit
depends on the patient
change in stool frequency
diarrhoea or constipation
Tenesmus - constant inclination to empty bowels
Bleeding
Steatorrhoea - excretion of abnormal amount of fat with faeces
what is tenesmus
constant inclination to empty bowels
what is steatorrhoea and what does it look like
excretion of abnormal amount of fat with faeces
looks pale and oily - can be especially foul smelling
common causes of altered bowel movement
IBS gastroenteritis medication diet coeliac disease
Less common but important causes of altered bowel movement
malignancy
IBD - inflammatory bowel disease
diverticular disease
bowel obstruction
difference between irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD)
IBS is a disorder of the GI tract whereas IBD is inflammation or destruction of the bowel wall, which can lead to sores and narrowing of the intestines
how can we investigate altered bowel habit
bloods endoscopy capsule endoscopy CT MRI US Stool samples nuclear medicine
blood tests to consider with altered bowel habits
FBC ferritin CRP LFTs GLucose thyroid function tests calcium lipase TTG - tissue transglutaminase
what do stool samples look for
microscopy, culture and sensitivity (MC&S)
faecal calprotectin
helicobacter pylori stool antigen
faecal elastase
differentials for diarrhoea
Drugs infection IBD IBS coeliac disease malignancy diverticultis bile acid malabsorption hyperthyroidism diabetes mellitus constipation (overflow) ischaemic colitis
red flags in abdominal symptoms
PR bleeding weight loss family history colorectal cancer nocturnal symptoms abdominal mass anaemia
difference between ulcerative colitis and crohn’s
UC is limited to the colon whereas crohn’s can occur anywhere between the mouth and the anus
in crohn’s there are healthy parts mixed with inflamed parts whereas UC will be inflamed areas together
causes of small bowel obstruction
adhesions hernia malignancy strictures foreign bodies
causes of large bowel obstruction
primary malignancy
strictures
volvulus
luminal bodies
what is a volvulus
an obstruction caused by twisting of the stomach or intestine
what is paralytic ileus
muscle or nerve problem that stops peristalsis - not a physical blockage
common post-operatively
what is obstipation
severe constipation - i.e. no flatus either
3 things that cause obstipation
small bowel obstruction
paralytic ileus
large bowel obstruction
function of the large bowel
absorb salt and water
absorb short chain fatty acids
store faeces
expel faeces
rectosphinteric reflex
reflex characterized by a transient involuntary relaxation of the internal anal sphincter in response to distention of the rectum.
what is parenteral nutrition and when is it used
it is delivered into a large vein, bypassing the intestine and portal system
it is used if the absorptive function of the intestine is severely impaired
what is the main source of glucose for the brain
gluconeogenesis
what is refeeding syndrome
the potentially fatal shifts in fluids and electrolytes that may occur in malnourished patients receiving artificial refeeding (whether enterally or parenterally5). These shifts result from hormonal and metabolic changes and may cause serious clinical complications
when you start feeding a malnourished patient what need monitoring daily
sodium potassium glucose magnesium phosphate urea creatine
when you start feeding a malnourished patient what needs monitoring twice weekly
LFT (including clotting)
when you start feeding a malnourished patient what needs monitoring weekly
calcium
albumin
FBC
red cell indices
when you start feeding a malnourished patient what needs monitoring every 2-4 weeks
zinc
copper
folate
B12
When you start feeding a malnourished patient what needs monitoring every 3-6 months
Vit D Ferritin iron Mn Se
Type 1 intestinal failure
acute onset, usually self-limiting
most often seen after abdominal surgery
type 2 intestinal failure
less common
acute onset
usually following catastrophic effect (e.g. intestinal ischaemia)
type 3 intestinal failure
chronic
patients are metabolically stable but IV support is required over months - years
may or may not be reversible
what does the proximal small intestine absorb (nutrients)
fats sugars peptides and amino acids iron folate calcium water electrolytes
what does the middle small intestine absorb (nutrients)
sugars peptides and amino acids calcium water electrolytes
what does the distal small intestine absorb (nutrients)
bile acids
vitamin B12
water electrolytes
what is short bowel syndrome
a condition in which your body is unable to absorb enough nutrients from the foods you eat because you don’t have enough small intestine
what causes short bowel syndrome
post operative mesenteric ischaemia Chron's disease trauma neoplasia radiation enteritis