GI Infections Flashcards
What are the main sterile sites of the body?
- Peritoneal space (ascitic fluid)
- Pancreas
- Gall bladder
- Liver
What are the main non-sterile sites of the body?
- Mouth
- Oesophagus
- Stomach
- Small bowel
- Large bowel
Colonisation of body sites;
What is angular cheilitis?
Acute or chronic inflammation of the skin and contiguous labial mucosa at the corners of the mouth.
How does angular cheilitis typically present?
- erythema
- maceration
- scaling
- fissuring
- pain
- lesions are often bilateral
What are the 2 major causes of angular cheilitis? Which organisms can be responsible?
- Excessive moisture and maceration from saliva
- Secondary infection with C albicans or S aureus
Angular cheilitis can be 2ary to infection with which organisms?
- S. aureus
- C. albicans
What are the risk factors for angular cheilitis?
- Older age (typically seen in eldery)
- Dentures (ill-fitting)
- Dry mouth
- Intraoral fungal infection
- Poor oral hygiene
- Thumb sucking/drooling
How does HSV-1 present?
Cold sores
What is hairy leukoplakia? Who is it commonly seen in? What virus is it caused by?
- What –> A white patch on the side of the tongue with a corrugated or hairy appearance
- Who –> Immunocompromised (HIV)
- Virus –> Epstein Barrv virus
What are the 3 major types of dentoalveolar infections?
- Caries (cavity)
- Pulpitis (infection of innermost part of tooth - the pulp)
- Periapical abscesses (abscess at base of tooth following infection)
How can a tooth infection cause;
a) demineralisation of bone?
b) swelling and pain?
a) Acid produced by bacteria is believed to erode the enamel and bone
b) Bacteria move within the tooth and cause inflammation within the pulp, resulting in swelling and acute pain
Common bacteria responsible for dentoalveolar infections?
Oral commensals such as Streptococci and anaerobes
Treatment for caries?
Filling
Treatment for pulpitis?
Root canal
What can excess buildup of plaque beneath the gingivial margin lead to?
Peri-dontal infections
What is the gingival margin?
The terminal edge of gingiva (gums) that surrounds the teeth is known as the gingival margin (marginal gingiva).
What is gingivitis? How does it present?
Inflammation of the gums; red, swollen, painful, bleeding gums
How can gigivitis progress?
- Gingivitis
- Peridontitis
- Periodontal abscess
- Acute necrotising ulcerative gingivitis
- Orofacial space infections (severe)!
What is periodonitis?
Progression of gingivitis with progressive loss of dental support structure function. May require antibiotics.
What is a periodontal abscess?
- Focal or diffuse red, fluctuant swelling of the gingiva which is extremely tender to palpation
- Abscesses always communicate with a periodontal pocket from which pus can be readily expressed after probing
- Requires surgical drainage
What is Vincent angina? What is it caused from?
A life-threatening infection of the oral mucosal membranes is also known as trench mouth/acute necrotising ulcerative gingivitis (ANUG).
How does acute necrotising ulcerative gingivitis (ANUG) present?
Tissue appears eroded with superficial gray-ish pseudomembranes.
Risk factors and treatment for peri-dontal infections?
- Risk factors include inadequate oral hygiene
- Treatment includes improved cleaning, antibiotics
What is quinsy? What is it a complication of?
- Quinsy is a peritonsillar abscess –> unilateral swellings of the tonsil.
- The abscess forms between one of your tonsils and the wall of your throat.
- A rare and potentially serious complication of tonsillitis.
Causative organism of peritonsillar abscess?
S. pyogenes (Group B Strep)
Symptoms of quinsy?
- Painful swallowing
- Unilateral sore throat
- Earache
- Muffled voice
- Deviation of uvula towards unaffected side
- Oral airway may be compromised!
Treatment of quinsy?
Drainage and antibiotic management
What is suppurative inflammation?
Suppurative inflammation involves the production of large amounts of pus
Causative organism of acute suppurative parotitis?
S. aureus
What is parotitis?
Inflammation of the parotid glands
Risk factors for acute suppurative parotitis (non mumps)?
Poor oral hygiene, dehydration
Presentation of acute suppurative parotitis?
Sudden onset of swelling from cheek to angle of jaw
Treatment of acute suppurative parotitis?
Drainage and antibiotic management
What is Ludwig’s angina?
- Bilateral infection of the submandibular space
- Aggressive, rapidly spreading cellulitis without lymphadenopathy
Complications of Ludwig’s angina?
Airway obstruction, asphyxia, aspiration pneumonia
What do pretracheal space infections most commonly arise as a consequence of?
- Perforation of the anterior oesophageal wall
- Occasionally through contiguous extension from a retropharyngeal space infection
- As a consequence of prolonged tracheostomy
Clinical presentation of a pretracheal space infection?
- severe dyspnoea
- hoarseness
- dysphagia
- regurgitation of fluids from nose
Where does the pretracheal space lie?
Immediately anterior to the trachea
Treatment of a pretracheal space infection?
drainage and antibiotic management
Where is the prevertebral space located?
In the neck
Where does a prevertebral space infection usually originate from?
Usually continuation of cervical spine infection
Why can parapharyngeal space infections be life threatening?
- Carotid sheath involvement
- Complications: compression on carotid sheath components, airway impingement, septicaemia
What is suppurative jugular thrombophlebitis? What is it also known as?
- Lemierre’s syndrome
- A venous thrombosis due to the infectious involvement of the carotid sheath vessels with bacteria and is seen in association with intravenous catheters or with certain deep neck infections
What is the ‘danger space’?
The danger space is a deep compartment of the head and neck located behind the true retropharyngeal space, extending from the skull base to the mediastinum.
Clinical importance of the danger space?
The connection of the danger space to the mediastinum allows for the spread of infections from the oral cavity to the thoracic cavity.
What is mucositis?
Inflammation of the mucous membranes of the GI tract (can be oral or intestinal or both)
What is mucositis most commonly induced by?
Chemotherapy
Risk factors for mucositis? What is required before starting chemo?
Caries, periodontal diseases –> dental review before chemotherapy.
What is Boerhaave syndrome/Effort rupture? What can it be caused by?
A spontaneous perforation of the oesophagus that results from a sudden increase in the intraoesophageal pressure combined with negative intrathoracic pressure e.g. severe straining or vomiting
Potential complications of an effort rupture?
- Contamination of the mediastinal cavity (leak of fluid into mediastinal space)
- Chemical mediastinitis
- Mediastinal emphysema and inflammation
- Bacterial infection and mediastinal necrosis
Risk factors for an effort rupture?
- Common in alcoholics
- History of severe retching and vomiting
Diagnosis of an effort rupture?
- Crepitus in chest (subcutaneous emphysema)
- Mediastinal cracking (mediastinal emphysema)
What is crepitus?
Crepitus is the abnormal popping or crackling sound in either a joint or the lungs
Management for an effort rupture?
- Avoid oral intake
- Nutritional support – parenteral
- Antibiotics
- Intravenous PPI
- Drainage of fluid collections/ de-bridgement of infected and necrotic tissue
Mechanism behind H. pylori infection?
- Bacterial urease hydrolyses gastric luminal urea to form ammonia
- Gastric acid neutralised to form a protective cloud around the organism, enabling it to penetrate the gastric mucus layer
Transmission of H. pylori?
- Person-person via faecal/oral or oral/oral exposure
- Primates and domestic cats
Complications of H. pylori?
- Peptic ulcer disease
- Pain, bleeding, perforation
Treatment of H. pylori?
Triple antibiotic treatment; 2x antibiotics and 1 PPI
Diagnostic tests for H. pylori?
- Urease breath test
- Faecal antigen test (most effective)
- Serology (IgG)
- Culture and sensitivity
What is cholangitis?
Cholangitis is an inflammation of the bile duct system
Most common cause of cholangitis?
Enterobacteriacae infection secondary to:
- Stone
- Stenosis
- Stents
- Surgery
- Cancer
ANYTHING THAT CAUSES OBSTRUCTION
Triad of symptoms for cholangitis?
Charcot’s cholangitis triad is the combination of;
- jaundice
- fever (usually with rigors)
- right upper quadrant abdominal pain (RUQ pain)
Investigations for cholangitis?
- Liver test abnormalities with elevations in serum alkaline phosphatase (ALP)
- gamma-glutamyl transpeptidase (GGT)
- bilirubin (predominantly conjugated)
What is cholecysitis?
Inflammation of the gallbladder
What is Murphy’s sign?
- Ask the patient to take in and hold a deep breath while palpating the right subcostal area
- If pain occurs on inspiration, when the inflamed gallbladder comes into contact with the examiner’s hand, Murphy’s sign is positive.
Symptoms of cholecystitis?
- Abdominal pain
- Fever
- History of fatty food ingestion one hour or more before the initial onset of pain (as more bile is secreted after large or high fat meals)
Investigations for cholecystitis?
- Elevation in serum total bilirubin and ALP.
- Positive Murphy’s sign.
- Radiological, endoscopic, surgical
Most common cause of cholecystitis?
Gallstones
Associated symptoms of overgrowth of bacteria on small bowel?
- Malabsorption
- Chronic diarrhoea
Causes of bacterial overgrowth on the small bowel?
- Achlorhydria (after gastric surgery) –> absence of hydrochloric acid in the gastric secretion
- Impaired motility
- Blind loops of bowel
- Surgery
- Radiation damage
Treatment for bacterial overgrowth in small bowel?
- Dietary changes
- Surgery
- Motility
- Non-absorbable antibiotics
What is Whipple’s disease?
Infection causing white plaques in distal duodenum, representing engorged lymph;
- A rare bacterial infection that most often affects your joints and digestive system
- Interferes with normal digestion by impairing the breakdown of foods, and hampering your body’s ability to absorb nutrients, such as fats and carbohydrates
Causative organism of Whipple’s disease?
Tropheryma whipplei
Where is Tropheryma whipplei commonly detected?
- Bacteria has been detected in the sewage
- More prevalent in faeces of sewage workers
Risk factors for Whipple’s disease?
- Caucasian
- Male
- European
- Hereditary: likely rare immune defect
Symptoms of Whipple’s disease?
- Joint pain
- Chronic diarrhoea
- Malabsorption
- Weight loss
- Abdominal pain
Investigations for Whipple’s disease?
Upper GI endoscopy with biopsies of the small intestine
Which organism are liver abscesses most commonly caused by?
Entamoeba histolytica (parasite)
Entamoeba histolytica is a parasite that exists in two forms, what are these?
- Cyst
- Trophozite
How is the cyst form of Entamoeba histolytica acquired?
- Infective form
- Ingested via contaminated food or water but can be associated with venereal transmission through faecal-oral contact
What is the invasive disease causing form of Entamoeba histolytica?
Trophozoite form
Where are high rates of Entamoeba histolytica seen?
- India, Africa, Mexico and parts of Central/South America
- Common in travellers for more than 4 days, but more commonly if people are travelling for months
Pathogenesis behind liver abscess?
- Ascending biliary tract infection (coliforms, streptococci, anaerobes)
- Portal vein after peritonitis or colonic perforation
- Haematogenous e.g. endocarditis
Which organisms are responsible for ascending biliary infection causing liver abscess?
Coliforms, Streptococci, anaerobes
Which organisms are responsible for haematogenous spread from endocarditis causing liver abscess?
S. aureus
Investigations for liver abscess?
- Serum alkaline phosphatase is elevated in 67 to 90 percent of cases and serum bilirubin
- Aspartate aminotransferase concentrations are elevated in about one-half of cases
What is a hydatid cyst? Causative organism?
- The hydatid cyst develops in the liver, lungs, brain, or other organ.
- Parasite –> Echinococcus tapeworm
Transmission of hydatid cysts?
- Zootrophic infection: usually confined to dogs and cattle/sheep
- Transmission
- Ingestion of dog faeces
How can M. tuberculosis affect the GI tract?
- Non healing oral ulcers
- Gastric ulcers
- Gastric outflow obstruction
- Enterocutaneous fistulas
Most common site of GI tract that M. tuberculosis affects? What can this be confused with?
Ileo-caecal TB is the most common site (may be confused with a colonic malignancy)
Risk factors for M. tuberculosis to affect the GI tract?
- Respiratory TB and aspiration
- Chemotherapy
Potential complications of pancreatitis?
- Necrotising pancreatitis (15%)
- Peripancreatic fluid collection
- Pancreatic pseudocyst
- Acute necrotic collection
- Walled-off necrosis
What is a complicated intra-abdominal infection?
Defined as infection that extends beyond the hollow viscus of origin into the peritoneal space and is associated with either abscess formation or peritonitis.
What does complicated intra-abdominal infection commonly follow?
Perforation of;
- Cholecystitis
- Diverticulitis
- Appendicitis
- Gastric/duodenal ulcer
Other causes of complicated intra-abdominal infection;
- Colonic perforation after C diff infection
- Ischaemic colon or malignancy with perforation of bowel
- Colonic fistula communicating with peritoneal space
- Abscess in solid organ communicating with the peritoneal space e.g. liver abscess
What is diverticulitis?
The infection of diverticula (abnormal out-pouches in the colon)
What is the most common cause of left iliac fossa pain in hospital admissions (33%)?
Diverticulitis
Complicated vs uncomplicated diverticulitis?
Uncomplicated diverticulitis is defined as localised diverticular inflammation without complication, whereas complicated diverticulitis consists of inflammation associated with a complication such as abscess, fistula, obstruction, bleeding, or perforation.
What is an intra-peritoneal abscess?
Localised area of peritonitis with build-up of pus.
Locations;
- Sub-phrenic
- Sub-hepatic
- Para-colic
- Pelvic
Predisposing factors for intra-peritoneal abscesses?
- Perforation (of peptic ulcer, appendix, diverticulum)
- Mesenteric ischaemia/bowel infarction
- Pancreatitis/pancreatic necrosis
- Penetrating trauma
- Post-operative anastomotic leak
Treatment of Intra-peritoneal abscess?
- CT/US guided drainage or surgical
- Combined with antimicrobial therapy
Symptoms of intra-peritoneal abscess?
- Non-specific
- Sweating, anorexia, wasting
- Swinging pyrexia
- Localising features e.g. subphrenic abscess will result in pain in shoulder on affected side, persistent hiccup, intercostal tenderness, apparent hepatomegaly (liver displaced downwards, ipsilateral lung collapse with pleural effusion)
- Pelvis abscess: urinary frequency, tenesmus
Management of complicated vs uncomplicated appendicitis?
- Complicated: surgical management + antibiotics
- Uncomplicated: surgical management plus single dose of antibiotic prophylaxis.
What are the 3 types of post-operative infections?
- SSI-S: Superficial Surgical Site Infection
- SSI-D: Deep Surgical Site Infection
- SSI-O: Organ space infection
When do post-operative infections occur?
- Occurs within 30 days of surgery
- Occurs within 1 year of prosthetic implantation
What is spontaneous bacterial peritonitis?
Ascitic fluid infection without an evident intra-abdominal surgically treatable source.
Diagnosis of a spontaneous bacterial peritonitis?
- Positive ascitic fluid bacterial culture
- Elevated ascitic fluid absolute polymorphonuclear leukocyte (PMN) > 250 cells/mm3
Pathogenesis of spontaneous bacterial peritonitis?
- Bacteria in gut lumen cross the intestinal wall into mesenteric lymph nodes –> translocation
- Lymphatics carrying contaminated lymph rupture because of the high flow and high pressure associated with portal hypertension
- Seeding of ascitic fluid via the blood
Complications of spontaneous bacterial peritonitis?
- Advanced cirrhosis
- Ascites
Which organism is associated with colonic malignancy?
Streptococcus bovi/ gallolyticus (causing bacteraemia with bowel cancer)
What else can S. bovis be associated with?
Endocarditis
What does a positive Murphy’s sign indicate?
Acute cholecystitis
What is a root canal treatment?
Root canal treatment (endodontics) is a dental procedure used to treat infection at the centre of a tooth (pulpitis)
Parapharyngeal infections can spread to the ___ and cause ___?
Carotid sheath; can cause septic thrombophlebitis (Lemierre syndrome)
Where is pain from the subphrenic region referred to?
Shoulder on the affected side
