Disturbance in digestion Flashcards
eructation
burp
diarrhoea
- increase in volume, fluidity, or frequency of bowel movements
- relative to their usual
What factors are necessary for the formation or normal stools and normal defecation?
- food quantity, quality, fluid
- ability to swallow
- integrity of all digestive system (liver, gall bladder and pancreas)
- peristaltis, enzyme, hormone, surface area
- blood supply, innervation (& spinal cord)
- willingness to defecate
What are the common causes of diarrhoea?
- laxative abuse
- gastroenteritis (rotavirus, Campylobacter jejuni, Salmonella sp, Vibrio cholera, giardia, helminths)
- food poisoning
- coeliac, lactose
- spurious (faecal impaction or obstruction)
- IBS
- drugs (magnesium containing antacids, antibiotics), diet, stress
What are some other less common causes of diarrhoea?
- colonic causes (carcinoma of colon, diverticular disease, inflammatory bowel disease, dysentery, pseudomembranous colitis)
- malabsorption states
- endocrine (hyperthyroidism, diabetes mellitus, Addison’s disease, carcinoid syndrome, Zollinger-Ellison syndrome)
- Non-Hodgkin’s lymphoma
- AIDS
List the classifications of diarrhoea?
1) osmotic - lower water reabsorption
2) secretory - electrolytes
3) motor
4) exudative -movement of fluid and cells from wall
What is motor diarrhoea?
• increased motility of bowel
- > faecal mater less time contact with bowel wall
- > decreased water reabsorption
• drugs, infective, hyperthyroidism, IBS
What is osmotic diarrhoea?
• decreased water reabsorption into bowel wall
- > more water in faecal material
- > loose stools
- less viable surface
- excessive non-absorptive molecules in bowel lumen
What is secretory diarrhoea?
Increase secretion of electrolytes from bowel wall into lumen
- > water follows electrolytes
- > increased fluid in stools
• cholera
What is exudative diarrhoea?
Excessive movement of cells and fluid from the intestinal wall into the lumen
-> pus and excess fluid in faecal mater +/- blood
- ulcerative colitis
- shingellosis
Which electrolytes are usually measured in a standard biochemistry screen?
- Sodium
- Potassium
- Chloride
- Bicarbonate
- Calcium (sometimes)
- Urea (a waste product, not an electrolyte)
- Creatinine (a waste product, not an electrolyte)
What is measured in “liver function tests”?
- Bilirubin-total, con-/uncon-jugated
- ALT
- Alkaline phosphatase
- Gamma-glutamyl transferase
- Total protein and Albumin
- prothrombin line
What are common causes of constipation?
- Low fibre, fluid, exercise
- Laxative abuse
- Aged and invalids
- Poor defecation habits
What are the other less common causes of constipation?
- IBS, IBD
- anxiety
- drugs
- acute diverticulitis
- intestinal obstruction
- neuromuscular disorders
- painful defecation (haemorrhoids, anal fissures)
- connective tissue disorders
- electrolyte disturbances (hypokalaemia, hypocalcaemia, hypercalcaemia)
- chronic lead poisoning
- typhoid fever
What are the mechanisms by which constipation occurs?
- diminished motility of colon (drug, hypothyroidism, low exercise)
- pain with defecation-avoiding poop (anal fissure, haemorrhoids)
- small faecal mass -> low stimulus by faeces on wall -> low defecation (low fibre)
- hard dry stools -difficult elimination (low fluid)
- repetitively delaying response to urge -> lower sensitivity of rectum receptors (kids)
- mechanical blockage
What is a colonoscopy?
• Uses a fibre-optic endoscope
• Can visualise as far as caecum
• Requires thorough preparatory bowel cleansing
• Can visualise, aspirate fluids, biopsy, perform endoscopic surgery etc
• Indications for use include the diagnosis of:
- Tumours of colon
- Inflammatory disorders of colon
- Source of GIT bleeding
- Diverticular disease
What is bilirubin?
- breakdown product of haem
- unconjugated is carried in plasma to the liver where it is conjugated to form ‘conjugated bilirubin’
- then excreted in bile
- gives colour
Nausea
- unpleasant sensation vaguely referred in epigastrium and upper abdomen
- unpleasant feeling of impending vomit
Vomit
- forcible ejection of some digestive system contents (usually stomach) through the oesophagus and mouth
- voluntary or involuntary
- often associated with nausea
Explain the pathophysiology of jaundice by relating these to the possible disturbances in the bilirubin pathway?
Old RBCs + precursors in bone marrow + heme in liver
- > biliverdin -> unconjugated bilirubin
- > conjugated in canaliculi
- > some excreted by kidney OR most excreted by liver via hepatic ducts
- > common bile duct
- > cystic duct OR small intestine
- > cystic duct -> gall bladder -> bit excreted in urine
- > small intestine -> deconjugated by flora -> excreted in faeces
What is the pathophysiology of nausea?
Subjective sensation due to:
• (-) stomach muscle tone and activity
• (+) duodenum muscle tone
• Reflex of chyme/juices from duodenum to stomach
• ANS activity (sweating, salivation, pallor, (-) HR, (-) BP)
What are the triggers of vomiting?
Triggered by any event or situation which stimulates the medullary vomiting centre, and may be from:
1) Digestive tract.
2) Cerebral cortex
3) Labyrinthine structures
4) Medullary chemoreceptor trigger zone (gets stimuli from whole body and drugs)
One there is a trigger for vomiting, then what happens?
• stimulus integrated within medullary vomiting centre
• transmission of nerve impulses via:
1) Phrenic nerve -> diaphragm contraction
2) Spinal nerves -> abdominal wall muscles contraction
3) Visceral efferent nerves -> pylorus contraction, and fundus & gastroesophageal sphincter relaxation
4) Inhibition of respiration
5) Elevation of the soft palate
6) Closure of the glottis
What are the possible causes of vomiting?
- Disorders from the intra- abdominal structures
- Intracranial disorders
- Metabolic disorders and endocrine disorders
- Motion sickness
- Labyrinthine disorders
- Pregnancy
- Toxins: drugs, withdrawal, alcohol, poisons
- Cardiovascular disorders
- Psychogenic
- Acute systemic infections
- Intense pain
What section of the GIT does a colonoscopy see?
only up until ascending colon
-doesn’t see terminal ilium
How does the duration of a diarrhoea help find the diagnosis?
- some diseases are self-limiting
- cholera short duration
- Crohn’s long duration
- long duration gives chance to modify diet or find alleviating factors
What is the aetiology of diarrhoea within 6hrs of a “suspect” meal of dairy products, creamed fillings or mayonnaise?
staph aureus
What is the aetiology of diarrhoea at least 14hrs after eating eggs or poultry?
salmonella
What is the aetiology of diarrhoea at least 14hrs after eating seafood?
vibrila
What is the aetiology of diarrhoea 8-14hrs after eating meat kept warm for a long period of time?
clostridium
What is the possible cause of diarrhoea with mucus?
- disentry type
- salmonella
- Crohn’s
- ulcerative colitis
What is the possible cause of bloody diarrhoea?
- crohn’s
- ulcerative colitis
- bleeding in GIT
What is the possible cause of diarrhoea appearing black?
melon from upper GIT
What is the possible cause of diarrhoea appearing green?
infective organism
What is a nervous colon?
spastic colon
IBS
What are the 2 types of colonoscopy?
Endoscope up anus: examen and take specimen
Swallow camera: virtual colonoscopy
What is the meaning of stools that are frothy and watery?
osmotic diarrhoea -> lactose intolerance
What is the significance of a healthy appetite BUT weight loss?
malabsorption, maldigestion, malmetabolism
What are the possible causes of alternating diarrhoea and constipation?
- IBS
- Crohn’s
- colon or rectum carcinoma
- diverticular disease
- faecal impaction
- laxative abuse
What is the significance of angular stomatitis and diarrhoea?
vitamin deficiency
What is the significance of smooth red tongue and diarrhoea?
vitamin deficiency
What is the significance of oedema with diarrhoea?
Decreased absorption albumin
- > low serum albumin
- > low osmotic pressure
- > oedema
What are the possible causes of protuberant abdomen?
- fat
- flatus
- faeces
- fulminating neoplasm
- foetus
- fluid
Which diseases have diarrhoea and anal lesions?
Crohn’s
ulcerative colitis
What does a prolonged prothrombin time mean?
bleeding tendency
What are the big 2 causes of constipation in elderly adults ?
- colorectal cancer
* diverticular disease
What are the pros and cons of a colonoscopy in the elderly?
Pros:
• prove diverticular disease
• find early carcinoma
Cons:
• very invasive
• elders most likely have many comorbidities
Depends on mental state and health of patient
What is hydrochlorothiazide?
diuretic medication to treat hypertension
What are the types of jaundice?
Pre-hepatic
• hypersplenism
Hepatic
• obstruction of canaliculi
• from swelling of liver
Post-hepatic
• obstruction of common bile duct
Why do we ask a patient with jaundice about arthritis, pruritus, urticaria?
looking for systemic causes of the jaundice
Explain the pathophysiology of dark urine and pale stools in jaundice?
Bilirubin gets conjugated by canaliculi, but it is blocked by swelling of hepatocytes
- > can’t be excreted by hepatic duct into common bile duct into small intestine
- > most excreted into urine
asterixis
flapping wrist extension
Babinski sign
sign of UMN lesion
How do you get Hepatitis A?
faecal oral
What are the clinical features of chronic liver failure?
- glucose intolerance
- steatorrhea
- hepatic encephalopathy
- bleeding tendency
- ascites, oedema
- jaundice (dark urine, pale stools)
- vitamin deficiencies (swollen tongue, angular stomatitis)
- mineral deficiencies
- excess hormones (spider nave, palmar erythema, testicular atrophy, gynaecomastia, menstrual irregularities)
- excess glucocorticoids (cushings like symptoms)
- excess mineralocorticoids (salt and water retention)
- increase drug side effects
- infections
- portal hypertension (hematemesis)
- clubbing
What is hepatic encephalopathy?
- sign of chronic liver failure
* buildup of ammonia -> changes blood pH -> damages brain
What are the possible causes of hepatomegaly?
- vascular congestion (H failure)
- biliary duct obstruction
- infiltration: leukaemia, lymphoma, fat, amyloid, iron, granuloma (TB)
- cysts
- inflammatory or infective: hepatitis, mono, typhoid fever, abscess, crohn’s
- cirrhosis
- tumours: hepatoma, metastatic from bowel
What is the consequence of laxative abuse on bowel habits?
diarrhoea but can also be constipation if stopping after long term abuse
What is the consequence of painful anal lesions on bowel habits?
constipation -because unwilling to defecate to avoid pain
What is the consequence of drugs on bowel habits?
constipation or diarrhoea
What is the consequence of IBS on bowel habits?
alternating constipation and diarrhoea
What is the consequence of AIDS on bowel habits?
diarrhoea
What is the presentation of acute appendicitis?
- acute onset of umbilical colicky pain
- vomiting, anorexia, fever
- migrates to R iliac fossa, worse over McBurney’s point
- rebound tenderness
- pain becomes constant
- if retrosecal -> psoas and obturator tests
- high HR, fever
What are the causes of paralytic ileum?
- spinal cord trauma
- drugs
- peritonitis
What is important to think of about the 75 year old demographics?
- malignancies
- degenerative (cardiovascular, joints, brain)
- lifestyle diseases (diabetes, smoking, obesity, alcohol)
- organs not working as well anymore
- more than one problem at once
- ADLs, independence
What is the DDx of a 42yr old male with a 10 year Hx of constipation with intermittent diarrhoea?
- IBS
- Coeliac disease
- Lactose intolerance
- Crohn’s
- Ulcerative colitis
What is the DDx of a 39yr old thin female with a 20yr Hx of intermittent diarrhoea with occasional blood?
- Crohn’s
- Ulcerative colitis
- (NOT IBS because of the blood)
How can you tell the difference between Crohn’s and ulcerative colitis?
colonoscopy
What is the possible cause of watery diarrhea following use of antibiotics, plus abdominal pain?
- overgrowth of pathogenic bacteria
* pseudomembranous colitis
What is the possible cause of diarrhoea with fever?
- infective cause
* neoplastic or ischaemic origin
What is the possible cause of chronic diarrhoea with peri-anal lesions?
Crohn’s
What is the possible cause of diarrhoea with blood and mucus?
- ulcerative colitis
* chronic gastroenteritis
What is the possible cause of diarrhoea with abdominal pain and flatus, relieved by defecation?
- IBS
* distal colon disorder
What is a complication of chronic diverticular disease?
colorectal cancer
What is under the R hypochondrium?
liver
gallbladder
What is the presentation of Hep A?
- spreads by fecal oral route
- starts as a GIT illness
- fever
Compare the presentation of Hep A and mono
Mono:
• looks like Hep A
• BUT starts as URT issue and not GIT
What investigations can we do to confirm a suspected hep A infection?
- urine test for bilirubin
- full blood count (high lymphocytes)
- liver function test (high AST and ALT)
- serology for antibodies against hep A
How can you differentiate which hepatitis it is?
serology for antibodies against that type of hep in the blood
What are the effects of alcohol abuse on the GIT?
- acute gastritis
- increased chance of GIT carcinoma
- fatty liver, cirrhosis, liver failure
- acute or chronic pancreatitis
Which hepatitis may become chronic?
all except for hep A
How do you get Hep B?
- piercing
- unprotected sex
- needle sharing
What are the potential causes of episodic vague upper abdominal pain?
Stomach: diet, GORD, reflux, idigestion
Gallbladder
Pancreatic cancer
Ovarian cancer
What are the potential causes of fainting?
- psychogenic
- pain
- low BP, glucose, O2
- drugs
- alcohol
- seizure
- transient ischaemic attack
- arrhythmia
What can cause upper GI bleed?
- peptic ulceration
- oesophageal varices
- malignancy
- poison
What is the possible significance of dark red blood mixed with the stools?
upper colon bleed
What is the possible significance of bright red blood found on the surface of the stools?
rectum-sigmoid colon bleed
What is the possible significance of bright red blood, predominantly found on toilet paper, rather than stools?
anal lesions
fissure of haemorrhoids
What is orthostatic hypotension and what causes it?
- when blood pressure drops from prone to siting or standing
* dehydration is common cause
