Intrabdominal infections Flashcards
define intrandominal infection
presence of micro-organism in normally sterile sites within the abdominal cavity e.g. peritoneal cavity and hepatobillary tree.
why is gastroenteritis not classed as a intrabdominal infection
bowel lumen is not sterile
which areas of the stomach and small intestine are sterile
stomach
proximal small intestines- bile and acid from stomach kill all pathogens.
what is the normal amount of flora in the large intestine ? 10 ^
10^9-11
what pathogens mainly occupy the large intestine flora
anaerobic bacteria (95-99%)
3 main sources of intrabdominal organs
GI contents, blood, external
defien intrapertioneal.
• Translocation of micro- organisms from gastrointestinal tract lumen to peritoneal cavity
define billary tract infection
• Translocation of micro-organism along a lumen- up to liver
define haematogenous spread
• Translocation of micro-organism from a extra-intestinal source- penetrating trauma
how can traslocation of an organism across a wall occur
- Perforation-Perforated appendix, perforated ulcer, perforated diverticulum, malignancy
- Loss of integrity- Ischemia, strangulation (herniation of bowel)
- Surgery- Seeding at operation, anastomotic leak (as it is incomplete or it has broken down).
how can traslocation of an organism along a lumen occur
• Blockage- Cholecystitis, cholangitis, hepatic abscess
– Gall bladder is not normally sterile but bile keeps it sterile, so blockage will mean that no bile can pass so organisms can harbour
• Iatrogenic- Instrumentation (e.g. ERCP)- endoscopic retrograde cholangio pancreatography.
causes of obstruction of lumen of vermiform appendix.
example of translocation across a wall- appendicitis
– Lymphoid hyperplasia, faecal obstruction, stagnation of luminal contents, bacterial growth and recruitment of inflammatory cells.
– Build up of intraluminal pressure may result in perforation
– Escape of luminal contents into peritoneal cavity is “peritonitis”
symptoms of appendicitis
temperature, severe generalised pain.
treat for appendicitis
appendicecectomy and cefuroxime, and metronidazole for 5 days.
what form of intra abdominal infection is appendicitis
translocation across wall
what form of intraabdominal infection is perforated diverticula
translocation across wall
define perforated diverticulum
• Herniation of mucosa and sub mucosa through muscular layer
common complication of bowel cancer
Intraperitoneal and/or bloodstream infection
what organism cause Intraperitoneal and/or bloodstream infection in bowel cancer
clostridium septicum and streptococcus gallolyticus
symptoms of bowel cancer
weight loss, alteration of bowel habits, and blood in stool.
what causes ischaemia of the bowel
– Strangulation
– Arterial occlusion
– Post operative
– E.g. Aneurysm repairs.
• Interruption of intestinal blood supply
how does ischaemia result in translocation of lumina contents
lack of blood supply results in gut wall loses structurally and integrity
causes of post operative infections
• Seeding at operation
– Incidence is reduced due to bowel preparation with prophylactic antibiotics- prior to surgery.
• Anastomotic leak- due to breakdown or due to non formed anastomosis
• Acute infection- abdominal pain and tenderness, shock
• Intraperitoneal abscess- walled off abscess, more indolent condition (presents some weeks after surgery).
define cholecystitis
inflammation of the gall bladder
symptoms of cholecystitis
fever, right upper quadrant pain, mild jaundice.
clinical presentation of empyema in the gallbladder
severe pain, High fever, Chills and rigors.
empyema of the gallbladder is a complication of what condition
cholecystitis
define cholangitis
• Inflammation/infection of biliary tree
causes of cholecystisis and cholangitis
– Mainly obstruction of common bile duct
– Can follow instrumentation (e.g. endoscopic retrograde cholangio-pancreatography, ERCP)
symptoms of cholangitis
– Fever (rigors), jaundice and right upper quadrant pain
define pyogenic liver abcesss
collection of pus in liver.
routes for infection which causes pyogenic liver abcesses
biliary obstruction, direct from intrabdominal infections, Haematogenous- from mesenteric infections via hepatic portal vein, from systemic intravascular infection- hepatic artery
predisposing factors to intrarittoneal abcessess
– Perforation-Peptic ulcer, Perforated appendix, Perforated diverticulum – Cholecystitis – Mesenteric ischemia/bowel infarction – Pancreatitis/pancreatic necrosis – Penetrating trauma – Postoperative anastomotic leak
common areas for intraperitoneal abcess to form
– Subphrenic, subhepatic, paracolic, pelvic
symptoms of intrapertioneal abcess
non specific
Sweating, anorexia, wasting, High swinging pyrexia (high then low)
symptoms of subphrenic abcess
– Pain in shoulder on affected side, persistent hiccup, intercostal tenderness, apparent hepatomegaly (liver displaced downwards, ipsilateral lung collapse with pleural effusion (collapse where ulcer is and effusion is due to blood)
symptoms of a pelvic abcess
– Urinary frequency
– Tenesmus- need to release bowels.
common aerobic bacteria gram -ve bacilli
E .coli
common anaerobic bacteria gram -ve bacilli
Bacteroides
common aerobic Gram-positive cocci
Enterococcus spp.
Occasionally milleri-group streptococci
common anaerobic Gram-positive bacilli
clostrisium
common features of liver abscesses.
polymicrobial
what can cause a liver abcess
haematogenous spread or trauma may not involve normal GI flora
Hepatobiliary tract infections usually involve lower GI flora, despite
what blood investigations are carried out for intraabdominal infections
- Full blood count: neutrophilia/neutropenia
- C-reactive protein: raised
- Liver function tests: abnormal in hepatobiliary disease
what is imaging used for intraabdominal infections and why is it used
Chest x-ray – Consolidation, pleural effusion adjacent to infected area (e.g. subphrenic abscess) Abdominal ultrasound – Abdominal masses – Free fluid – Dilated bile ducts Abdominal CT scan – Higher definition than ultrasound
what microbiological investigations (excluding bloods) are carried out for intraabdominal infections
– Peritoneal fluid
– Ultrasound/CT guided drainage fluid
– Microscopy, culture and sensitivity testing
most common treatment for Intraperitoneal abcess
drainage
how are antibiotics used to treat intrabdominal abcesses
• Start smart ….
– best guess(empirical) antibiotics.
– Intestinal source- coliforms and anaerobes.
o Cefuroxime & metronidazole (
