Ch 86 Peritoneum Flashcards
Peritoneum
- Serous membrane composed of squamous epithelium (mesothelial origin) and a connective tissue stroma
- Covers the walls of the abdominal cavity and the organs
- Primary function is to reduce friction so that abdominal contents can move freely
- The peritoneum of the visceral surface of the diaphragm has fenestrations of the basement membrane
- These fenestrations and special lymphatic collecting vessels, the lacunae, are important in clearance of fluid and particles from the peritoneal cavity.
What lines the pelvic and peritoneal cavities?
Transversalis facia and mesothelium
- mesothelial cells are supported by collagen fibers, macrophages, lymphocytes, mast cells, glycosaminoglycans, and adipose cells.
Embryology
- lateral mesoderm > give rise to the somatic (parietal) and splanchnic (visceral) mesoderm.
- Somatic > formation of the body wall.
- Splanchnic > formation of the wall of internal organs
- The space enclosed by the somatic and splanchnic mesoderm is the coelom
- Separation of pericardial cavity from the common pleuroperitoneal cavity > growth of the common cardinal veins
- Formation of the diaphragm > separates pleural from peritoneal.
- embryological Malformations: peritoneopericardial, pleuralperioneal or Umbilical hernia
anatomy
- the right and left cranial quadrants and the right and left caudal quadrants
natural openings
- diaphragm > abdominal cavity: esophageal hiatus, caval hiatus and aortic hiatus
- caudal abdomen: inguinal canal and vascular lacunae
- Paired slit-like openings dorsal to the diaphragm
peritoneum
- lines the abdominal, scrotal, and pelvic cavities
- Parietal lines the cavities
- visceral peritoneum covers the abdominal organs
- Connecting peritoneum consists of double sheets
- peritoneal folds comprise mesenteries, omenta, and ligaments
- Additional peritoneal folds are associated with the urogenital organs
retroperitoneum
- covered on only one surface by peritoneum
- kidneys, ureters and adrenal glands
- aorta, caudal vena cava, and lumbar lymph nodes
Paired slit-like openings dorsal to the diaphragm and ventral to the psoas > may be clinically significant in direct extension of certain disease processes (pneumothorax/pneumoperitoneum, pyothorax/septic peritonitis, chylothorax/chylous ascites)
What is the Cullens sign?
A characteristic ring of SQ haemorrhage around the umbilicus often seen with haemoperitoneum or peritonitis bu direct extension from the abdominal cavity to the SQ
omentum
Greater omentum
- three portions, each a double peritoneal sheet.
- bursal portion = largest and attached greater curvature of the stomach
- omental bursa is closed sac except opening, the epiploic foramen, bounded dorsally by the caudal vena cava and ventrally by the portal vein
- superficial ventral layer (paries superficialis) and a deeper dorsal layer (paries profundus).
- splenic portion = hilus of the spleen to form the gastrosplenic ligament
- veil portion = left limb of the pancreas
lesser omentum
- between the lesser curvature of the stomach and porta hepatis
Omental milky spots
- source of neutrophils, macrophages, and lymphocytes
- important components of peritoneal defense mechanisms
physiology
Peritoneal fluid
- provide lubrication (Surfactant produced by mesothelial cells)
- peritoneum is a bidirectional semipermeable membrane > allows free exchange between peritoneal fluid and plasma
- forms as a dialysate of plasma.
- Normal peritoneal fluid lacks fibrinogen and does not clot
- Normal peritoneal fluid is relatively acellular
Lymphatic drainage
- via diaphragmatic lymphatics > mediastinal lymph node > thoracic duct into the systemic circulation
- particles cleared appear quickly in the systemic circulation and lungs. As a result, bacteraemia is an early and consistent finding in bacterial peritonitis
- Simultaneous diaphragmatic contraction and decreased intrathoracic pressure during expiration moves fluid through the lymphatics.
- factors affecting clearance include particle size, respiratory/diaphragmatic movement, intestinal activity, and intraperitoneal pressure
Intraperitoneal Circulation
- general cranial movement within the peritoneal cavity toward the diaphragm.
- circulation is dynamic and spreads matter throughout the cavity
- influenced by material type and clearance mechanisms
Intraabdominal Pressure
- measured indirectly through urinary bladder catheter.
- Increased intraabdominal pressure results from altered abdominal compartment compliance. The muscles of the abdominal wall and diaphragm as well as intraabdominal factors contribute
- Acute increase: cardiovascular, respiratory, and abdominal organ dysfunction.
- results in tachycardia, hypertension, decreased CO, decreased mesenteric arterial blood flow, decreased intestinal mucosal blood flow, and increased bacterial translocation.
- Marked increase in intraabdominal pressure = acute abdominal compartment syndrome
How would you classify peritoneal fluid as normal, transudate, modified transudate and exudate basd on cell count and protein concentration?
cells/uL and Protein g/dL
What is the predominant cell type in normal peritoneal fluid?
Macrophage
What rate of fluid absorption is the peritoneal cavity capable of?
3-8% BW per hour
What is normal intraabdominal pressure in dogs?
2-7.5 cmH2O
Healing of Peritoneal Injury
mesothelial regeneration
- Peritoneal mesothelium is easily injured but heals rapidly
adhesions
- Inflammatory cells and fibrin exude into the peritoneal cavity dt surgery or dz.
- absence of tissue ischemia, fibrinolysis occurs within 3 to 4 days, and adhesions do not form.
- injury is accompanied by vascular damage, fibrin is infiltrated by fibroblasts producing collagen, which converts fibrinous adhesions to firm fibrous adhesions.
What is required for adhesion formation?
Fibrinous exudate (from surgical manipulation or many diseases)
and vascular damage/ischaemia
In the absense of ischaemia, fibrin undergoes fibrinolysis. When accompanied by vascular damage, fibrin is infiltrated by fibroblasts while produce collagen and form firm adhesions
In addition to ischaemia, what else increases the liklihood of adhesion formation? (5)
- Endotoxaemia
- Intestinal manipulation
- Bowel distention
- Dessication of serosal surfaces
- Foreign body contamination (lint, cotton fibers, glove powder, antibiotic powder may result in granuloma formation)
List some methods of reducing the liklihood of adhesion formation (6)
- Prevention of dessication
- Gentle tissue handling
- Meticulous haemostasis
- Precise suture placement
- Complete removal of blood clots anf foreign debris
- Thorough lavage
Pathophysiology
defences, infalmmatory reaction, omentum, ileus
Peritoneal Defenses
- innate immune mechanisms + mechanisms to absorb and localize infection.
- Peritoneal fluid has innate antibacterial activity = complement system
- Peritoneum-associated lymphoid + omental lymphoid tissue = immunoglobulin production
Inflammatory Response
- injury/contamination elicits inflammatory reaction.
- initial influx of protein-rich fluid from the vascular space accompanied by macrophages and neutrophils.
- There is activation of humoral opsonins, antibodies, and complement
- mesothelial cells produce (IL-8) in response to macrophage-derived (TNF-α) and (IL-1-β), augmenting neutrophil emigration by chemotaxis
- result in fluid rich in complement, immunoglobulins, clotting factors, and fibrin
- adjuvants gastric mucin, bile salts, hemoglobin, and barium worsen SIRS and prognosis
- local effects lead to systemic effects
omentum
- isolate and seal the source of contamination
- absorbs bacteria and particulate matter
- brings a rich blood supply, high absorptive capacity
ileus
- inflammation induces ileus by sympathoadrenergic reflex inhibition
- detrimental effects = source of bacteria by translocation across intact bowel wall
reflex ridigity
- reflex rigidity of the abdominal and diaphragmatic muscles.
- Reduced lymphatic clearance
systemic effects of peritonitis
hypovolemia and hypoproteinemia
- result from movement of protein-rich fluid from the vascular space > peritoneal cavity.
- Sequestration of fluid within the bowel lumen secondary to reflex ileus
- Increased intraabdominal pressure exacerbates hypovolemia by reducing cardiac venous return and cardiac output.
- leads to hypotension and impaired organ perfusion
Respiratory acidosis and hypoxemia
- result from reflex diaphragmatic rigidity and increased intraabdominal pressure
Impaired renal perfusion
- leads to renal insufficiency compounded by decreased renal clearance of toxins, resulting in acute renal failure.
severe catabolic state
- from a 25% increase in metabolic rate + massive protein loss into the peritoneal cavity.
septic shock
- adrenergic stimulation + injured mucosal barrier of the gut > translocation of gut bacterial flora
- Exoenzymes of anaerobic bacteria cause inflammation, necrosis, and suppuration
- septicaemia/bacteriaemia can lead to sepsis (SIRS due to infection) and spetic shock
- development of disseminated intravascular coagulation.
- DIC indicator of poor prognosis and leads to MODS
Multiple organ dysfunction syndrome
- septic peritonitis secondary to gastrointestinal tract leakage (retrospec study)
- mortality rate was 70% with MODS vs 25% for those without the syndrome
List some methods of peritoneal defense
Release of complement (C3a, C5a) which stimulates neutrophil chemotaxis and degranulation of basophils and mast cells
Diaphragmatic lymphatics
Resident leucocytes and macrophages
Abscess formation
Resident natural killer cells
What is the major proinflammatory mediator produced by mesothelial cells?
What stimulates its production?
IL-8
Stimulated by TNFa and IL-1B from macrophages
What substances are know adjuvants in septic peritonitis??
(Intraperitoneal substances which enhance bacterial growth)
Gastric mucin polysaccharide
Bile salts
Haemoglobin
Barium
Peritoneal fluid volume
What are the broad classifications of peritonitis?
Primary or secondary
Acute or chronic
Localised or generalised
Septic or aseptic
Primary peritonitis
spontaneous bacterial peritonitis
- spontaneous inflammation of the peritoneum in the absence of intraabdominal infection or penetrating injury
- postulated to be primarily hematogenous +/- GIT translocation or PSS
- Compromised immunocompetency may play a role
- feline coronavirus infection resulting in FIP
- primary bacterial peritonitis: monobacterial infection 56% canine and 100% feline cases
- most gram positive infections
Secondary peritonitis (aseptic and septic)
septic
- Secondary generalized septic peritonitis is the most common form of peritonitis in dogs.
- dt gastrointestinal tract and direct inoculation of the peritoneal cavity with endogenous bacterial flora
- Immunocompetency and host defense mechanisms are generally considered
Aseptic Peritonitis
- Generalized peritonitis in the absence of identifiable bacterial, viral, fungal, or other infectious pathogens
aseptic peritonitis
- Barium (chemical)
- Bile peritonitis (chemical)
-
Uroperitoneum (chemical)
(bile and urine produce little inflammation unless infected with bacteria) -
Peritoneal foreign body / Mechanical
(retained surgical sponge gossypiboma, <15um particles are cleared. larger result in granuloma or localized abscess)
survey abdominal radiographs and sonography enabled detection of retained surgical sponges in six of seven dogs (86%) in one study
*Starch granulomatous peritonitis
(surgical glove powder, dx by iodine staining or polarized light microscopic examination of peritoneal fluid. Tx corticosteroids)
- Sclerosing encapsulating peritonitis
What is sclerosing encapsulating peritonitis?
What is the recommened treatment?
- chronic form where abdominal organs become encased in thick, “cocoon-like” layers of collagenous connective tissue.
- Peritoneal fluid large numbers of RBCs, macrophages with erythrophagia, mixed inflammatory cells, reactive mesothelial cells, and fibroblasts
- etiologic agents and pathogenesis not apparent
- Successful combined surgical and medical treatment > was unresponsive to corticosteroid treatment alone but was successfully treated with aggressive surgery and the addition of tamoxifen.
- abdominal radiographs reveal hypersegmented, gas-filled intestines gathered in the central abdomen = considered a characteristic sign
septic peritonitis causes
- most common source = leakage from GIT (60% of dogs and 47% of cats
- STUDY: 46% had undergone abdominal surgery within 14 days before
- causes include GIT surgery dehiscence, FB, neoplastic, nsaid perforation, GDV, necrosis
- pancreas may be the source of bacterial peritonitis (abscess rupture) and - pancreatitis may occur as a result of peritonitis
- pyometra
- Biliary effusion > commonly the result of traumatic disruption of the biliary tract/gall bladder
- Bile is a known adjuvant and will likely progress to septic bile peritonitis.
- Postoperative peritonitis appears to be the most lethal form
- Penetrating wounds associated with gunshots, foreign body and bite wounds
- major complication of peritoneal dialysis
risk factors for septic peritonitis after surgery
often with contradictory results reported
- preoperative septic peritonitis,
- hypoproteinemia,
- hypoalbuminemia
- intraoperative hypotension
- presence of a foreign body (risk or protective depending on the study)
pathophysiology
- The severity of peritonitis is related to the site of leakage along GIT
- Increased bacterial load and increased proportion of anaerobic bacteria > considered responsible for the increased mortality rate associated with large bowel
- stomach and proximal small intestine contain low numbers and no anaerobes.
- colon has very dense bacterial concentration, with obligate anaerobes in excess of aerobes by approximately 1000:1.
- Virulence enhancement factors = substances that enhance bacterial growth, bile salts, gastric mucin, hemoglobin, and barium
- Septic peritonitis is most commonly polymicrobial.
- Early mortality commonly caused by Gram-negative aerobic
- bowel perforation, two species predominate: E. coli and Bacteroides fragilis
- α-Hemolysin (exotoxin) of E. coli postulated to play a key role in facilitating pathogenicity
What are the two most common bacteria isolated with bowel perforation?
E.Coli
Bacteroides fragilis
presentation
- Clinical signs quite variable.
- Peritoneal effusion consistent finding (difficult to detect on palpation if small volume)
- Most are systemically ill. Anorexia, vomiting, depression, general malaise, and other nonspecific signs of illness
- Cats more commonly hypothermic
- SIRS initially injected mucous membranes, tachycardia, and fever > progresses to hypovolemia and shock
- Lack of bowel sounds on abdominal auscultation
Diagnosis
RADs
- loss of serosal contrast = free fluid
- Free peritoneal gas may indicate GIT disruption, gas-producing organism, or penetrating injury
- pneumoperitoneum > present in 20% of dogs 10 days after surgery
- Positive contrast studies may be indicated, Iodinated water-soluble only
ultrasound
- free air and small quantities of free peritoneal fluid.
- may ID abnormal organs
- guided FNA
CT
- diagnosis of intraabdominal abscess, penetrating injuries (in humans)
Bloodwork
- CBC, biochem, total protein and albumin, urea nitrogen, electrolytes, glucose, serum lactate, and blood gas
abdominal centesis
- single most useful diagnostic test
- Cytological evaluation was reported to be 71% sensitive in 1 study.
Bicavitary effusion was associated with a 3.3 times increased risk for death
Comparative tests for diagnosis
- difference in peripheral blood glucose and peritoneal fluid glucose (BG:FG) with blood Glu >20mg/dL higher diagnostic
- difference in peripheral plasma lactate and peritoneal fluid lactate concentrations (PL:FL), with >2 mmol/L difference diagnostic
- both are reported to be 100% sensitive and 100% specific for diagnosing septic peritonitis
Abdominal Paracentesis and Lavage
- single tap should be performed on the ventral midline 1 to 3 cm caudal to the umbilicus
- positive in 80% of animals with a 10 mL/kg effusion volume
- accuracy: 43% for needle vs 82.9% for catheter vs 94.6% for lavage
- Diagnostic peritoneal lavage involves intraperitoneal infusion of 20 to 22 mL/kg of a warmed, sterile isotonic saline solution
- examined grossly, cytologically, biochemically, and microbiologically
- peritoneal effusions: ascites vs aseptic(surgical) vs septic vs uro/bile vs chylo
- aerobic and anaerobic culture and sensitivity testing
- False negative results in local peritonitis
pleural fluid interpretation
- complicated by normal response of peritoneum to surgical insult.
- Experimentally, total leukocyte counts 1 to 3 days after surgery ranged 500 to 10,500 cells/µL, nondegenerate neutrophils predominate. Dogs with induced peritnitis > Bacteria were seen consistently within neutrophils and free.
- No absolute cell count or differential count can reliably distinguish between a “normal” postsurgical response and postoperative infection.
septic peritonitis
- Bacteria within neutrophils and free
- Cytology of abdominal fluid is <87% accurate in companion animals
- [Glucose]: should be used as supportive, not definitive, evidence of septic peritonitis; interpret with fluid analysis, cytology and clinical findings
- blood-to-fluid lactate difference 2.0 mmol/L > NOT relaible in CATS
other peritonitis
- Peritoneal [creatinine] > serum = uroperitoneum, as is peritoneal fluid [potassium] > serum
- Peritoneal [bilirubin] > 2x serum = free intraperitoneal bile
Fluid and Electrolyte Replenishment
- resuscitation is aimed at restoration of perfusion and hydration while preventing volume overload.
- consider both crystalloids LRS and Hypertonic saline (7.5% NaCl) solution
- Both fluid and protein exude from the plasma into the peritoneal cavity
- oncotic support via FFP
- urine output at least 1 to 2 mL/kg/h to avoid fluid overload and pulmonary edema.
- Alterations of IVFT based on results of serum electrolyte and blood gas
- Aggressive resuscitation may exacerbate the pathological changes to the microcirculation
- There may be a role for CCS in some cases of septic shock (critical illness-related corticosteroid insufficiency)
Antimicrobials
- initiated as soon as peritoneal fluid samples obtained for C&S
- survival benefit of early and appropriate antimicrobial administration documented in humans
- Bactericidal drugs effective against both Gram-positive and Gram-negative aerobes and anaerobes
- cephalosporin or ampicillin plus an aminoglycoside are most commonly recommended
- Prospective clinical trials comparing efficacy of various antibiotic regimens are lacking
- controversy in human medicine if C&S justified
often didn’t result in change of antibiotics
prospective randomized trial comparing triple-drug therapy with single-agent showed no significant differences between treatment groups - trend in humans: “less is best,” with single-drug therapy of short duration.
- Cats that received appropriate empirical antimicrobial therapy were more likely to survive.
surgery goals
aimed at:
- elimination of the source of contamination or infection,
- reduction of the bacterial load,
- removal of foreign material and inflammatory cells/mediators
- prevention of persistent or recurrence
- debride
- lavage
- serosal patching
- omentalisation
- closure/drainage
lavage
- lavage with copious amounts of warm, sterile, physiologic saline
- reducing the bacterial load, eliminating blood clots and debris, and reducing inflammatory cells/ mediators.
- conflicting experimental evidence for efficacy:
» No evidence that lavage reduces mortality or septic complication rates in humans receiving appropriate systemic antibiotic - no definitive effect of peritoneal lavage was seen for the population as a whole.
Kalafut 2018: Comparison of Initial and Postlavage Bacterial Culture Results of Septic Peritonitis in Dogs and Cats JAAHA - pilot study, the number of dogs with decreased postlavage concentration of bacteria was not statistically significant, and the study was unable to show whether lavage had an overall effect on survival
- no benefit for ab’s in lavage fluid
Complications of peritoneal lavage
- hypokalemia,
- hypoproteinemia,
- subcutaneous edema,
- progressive decrease in packed cell volume.
- Nosocomial infection
What is the minimal amount of lavage fluid recommended?
200-300ml/kg or until the fluid is returning clear
Serosal Patching
- Peritonitis is associated with an increased risk for suture line disruption and leakage.
- Strong proteolytic activity in peritonitis degrades collagen and extracellular matrix and may predispose intestinal anastomoses and enterotomies to dehiscence
- Serosal patching of anastomoses and areas of potential leakage from hollow viscera is recommended for patients with peritonitis
- Its effectiveness is controversial, however
- Use of a serosal patch did not protect dogs from either postoperative septic peritonitis or failure to survive in a more recent study.
- efficacy of fibrin sealant has not been evaluated
What is the reasoning behind serosal patching in septic peritonitis?
Strong proteolytic activity in peritonitis degrades collagen and extracellular matrix which may predispose to dehiscense
Omentalisation
- mechanically seal small leaks.
- Omental angiogenesis, growth factors, immunocompetent cells, and inflammatory cells may contribute to improved anastomotic healing
- although direct evidence of its efficacy in this application is lacking.
- A few studies on benefits of omentalising anastomosis performed in the 70’s and in non-peritonitis conditions.
- wrapping omentum 360 degrees around intestine > may cause obstruction
List broad options of coeliotomy closure after treatment of septic peritonitis?
Primary closure
Open peritoneal drainage
Closed peritoneal drainage
Primary Celiotomy Closure
- patient selection for closure versus open not apparent.
- Randomized, prospective clinical trials comparing closure, open and closed drainage are lacking. Small numbers and lack of patient homogeneity in retrospective studies comparing treatments makes interpretation of results difficult
- No significant difference in outcome between animals treated with closed-suction drains vs primary closure (44 dogs)
- mortality 46% in 28 dogs without abdominal drainage
- Retrospective with no diff in survival between groups Open peritoneal drainage versus primary closure
Open Peritoneal Drainage
benefits? (4)
- Open peritoneal drainage was introduced in human patients to try improve outcome
beneficial effects:
- increased removal of bacteria, foreign material, and inflammatory mediators (experimental study in horses)
- decreased abdominal adhesion
- ease of inspection of the peritoneal cavity,
- unfavorable environment for anaerobic bacteria
technique
- Variations whether daily debridement and lavage, the type and frequency of bandaging, the timing of closure
- The linea alba, subcutaneous tissue, and skin of the cranial two-thirds of the wound are left open.
- covered with a sterile bandage.
- Tack omentum to prevent occlusion.
- bandage is changed aseptically once daily or more to prevent strike-through +/- under GA with lavage.
timing of closure:
- gross improvement in color and clarity of drainage fluid,
- progressively decreasing volume of drainage fluid (weight of bandages)
- decrease or absence of cellular toxicity
- absence of bacteria on cytology
complication of open peritoneal drainage (4)
- Nosocomial infection
- hypoproteinemia,
- hypoalbuminemia
- anemia
Vacuum assisted
- Superiority of open peritoneal drainage over closed lacks controlled clinical trials. Has been shown to have no advantage over closed treatments in a prospective trial.
- Randomized prospective clinical trial. Overall survival was 81%. negative pressure therapy is an effective alternative to open dtainage. Clinical outcomes, including survival were comparable between techniques.
Spillebeen 2017
Advantages
- decreased frequency of bandage changes
- continuous removal of fluid
- collection and storage of effusate
- nosocomial infection and hypoproteinemia remain challenges (same as open)
disadvantages
- occlusion of the vacuum by omentum or viscera
- formation of enterocutaneous fistula
- ascending infection
Closed Peritoneal Drainage
- Most drainage methods suffer from ineffective drainage of the entire peritoneal cavity (therefore place multiple)
- Acquired bacterial infection is a potential complication of all methods of peritoneal cavity drainage
- Jackson-Pratt (retrospec 20 dogs): drain duration of 6 days, hypoproteinemia and anaemia in most, 85% survived to discharge
- mortality rate 30% comparable to open abdominal drainage
Mueller 2001: Use of closed-suction drains
advanatges
- decreased risk for nosocomial infection,
- decreased potential for evisceration,
- decreased intensity of postoperative bandage care,
- no need for a second procedure.
disadvanatges
- Occlusion by omentum is a common
- hypoprotienaemia + aneamia still occurs
Criteria for removal:
- largely rely on the clinical judgment of the attending clinician.
- blood-to–peritoneal drain fluid glucose or lactate not a reliable
overall drainage decision
- whether or not to provide drainage and the method remains controversial and at discretion of the surgeon.
- Two described effective methods are active drains and open abdomen.
- There are insufficient data for comparison of vacuum-assisted peritoneal drainage to open or closed peritoneal drainage or primary closure without drainage
- Many authors consider that continued drainage of the abdominal cavity is important: facilitates peritoneal defense = physically removing bacteria and inflammatory mediators from the abdominal cavity.
- One study: closed suction drainage survival rate of 70%
- comparable survival rates 52–89% open
- 54–67% primary closure.
- The advantages of closed drain over open: no evisceration, bandage care, no 2nd surgery to close the abdomen.
- vacuum‐assisted: 2nd surgery was still required to close, difficult to compare if survival advantage
Post-op managment
- Animals with septic peritonitis are often critically ill and require intensive supportive care
- Opiod analgesia and lignocaine
- Cardiovascular support (dopamine or dobutamine) to maintain CO or MAP
- Continuation of fluid therapy (tailored to individual: UO, CVP, eletrolytes, glucose)
- Epidural local anesthesia is contraindicated in patients with septic peritonitis because of decreased survival times
nutritional support
Early enteral or parenteral nutritional support is recommended:
- directly beneficial to enterocytes and decreases bacterial translocation
- associated with significantly shorter length of hospitalization
- Massive protein exudation into peritoneal fluid is expected
- Protein-energy malnutrition leads to impaired immunocompetence, depletion of energy stores, weakness, delayed wound healing, and organ failure
- Feeding tube placement: Nasogastric or nasoenteric feeding tubes, O-tube
- Gastrostomy and jejunostomy > risk in septic environment (Elmenhorst 2020: G-tube associated with a low complication rate)
- open surgical jejunostomy has the highest reported complication rates of 17.5% - 42% in small animals
- ileus, Gastric distention predisposes to vomiting or regurgitation
Transfusion Support
Transfusion of whole blood or blood components or synthetic colloid often used
- Albumin supplementation in severe hypoalbuminemia ( canine-specific, potenitally no survuval benefit even if given)
- Human serum albumin > adverse reactions suggestive of type III hypersensitivity, significant morbidity and mortality)
- Fresh frozen plasma (FFP) may be given to provide albumin and oncotic support
- hydroxyethyl starches (HES): dont improve albumin and associated with risk of AKI
What is considered a conditionally essential amino acid during catabolic illness?
Glutamine
prognosis: sepsis severity category and survival
There was strong evidence for an association between sepsis severity category and survival, with 8% mortality in the “abdominal infection” group, 55% mortality in the “severe sepsis” group, and 94% mortality in the “septic shock” group
prognosis: survival over decades
Despite advances in diagnosis and critical care management in patients with septic peritonitis, mortality rates remain stubbornly high in animals and humans. There was no significant difference in survival in a retrospective study comparing two different time periods in a single institution (1988-1993 vs. 1999-2003).
prognosis: poor literature
comparison of survival rates among published results of retrospective studies is difficult. Inclusion criteria vary between publications:
- include dogs and cats, despite differences between these species
- grouping various causes, various microbial pathogens, various treatments makes meaningful comparisons of techniques and treatments impossible.
Reported survival rates for dogs
50% and 85%
- regardless of treatment method (open, drain, closed etc)
- must be interpreted with caution because large RCCT are lacking
- Nonsurvivors typically succumb to complications related to dysfunction organ systems in the immediate postoperative period
List some negative prognostic indicators of septic peritonitis (5)
- Refractory hypotension
- Elevated ALT, GGT
- Plasma lactate over 2.5mmol/L or inability to normalise
- Ionised hypocalcaemia
- Multiorgan dysfunction
prognostic factors
recurrence rate?
- Rate of recurrence was 10%
- 3/7 (42.9%) survival after re-op
- Time until surgery didn’t
- age, needing vasopressors, lactate
- Dogs with GI sepsis
- contradictory in literature: presence of a foreign body
- Septic peritonitis is a known risk factor for dehiscence of enterectomy sites
- MODS: renal, cardiovascular, hepatic and coagulation (PT or PTT is prolonged or the platelet count is 100,000/µL or less)
Davies 2018: Influence of preoperative septic peritonitis and anastomotic technique on the dehiscence of enterectomy sites in dogs: A retrospective review of 210 anastomoses
No association was detected between anastomotic technique and IRA dehiscence in dogs without septic peritonitis (stapled 4.2%, hand-sewn 8.1%); however, stapled anastomoses were less likely to dehisce in dogs with peritonitis (stapled 9.7%, hand-sewn 28.9%).
Risk factors for dehiscence
included previoius SP and hand-sewn technique
Septic peritonitis in Cats
- overall similar to dogs but soem difference between species: absence of signs of pain during abdominal palpation, relative bradycardia, spontaneous peritonitis more common
- SP secondary to gastrointestinal leakage still most common etiology
- overall survival rate was 66% (2019)
Scotti 2019: Prognostic indicators in cats with septic peritonitis (2002–2015): 83 cases
prognostic indicators in cats
- overall survival 58/83 (69.9%)
- risk factors for mortality: higher blood glucose on presentation, not receiving empirical antibiotics on admission
Anderson 2021: Outcome following surgery to treat septic peritonitis in 95 cats in the United Kingdom JSAP
- The presence of an abdominal mass or having dehiscence of a previous gastrointestinal surgery did not confer a worse prognosis.
- Intraoperative hypotension was associated with non-survival.
Cats that survived beyond 1 day postoperatively had an improved likelihood of survival (87.5%)
Penetrating Injuries
- bite wounds, gunshot wounds, knife wounds
- Intensive resuscitation and supportive care + early surgical exploration of the abdomen is often required
- damage to abdominal viscera was confirmed in 70% by surgery or necropsy
- diagnostic peritoneal lavage led to accurate diagnosis in 90% (blood, grossly dark bloody or opaque lavage fluid, white blood cell (WBC) count above 500/mm3, bacteria)
- assessment of the integrity of the urinary system may be required b4 sx
- Bacterial contamination may be from: GIT tract, skin contaminants, or oral flora
- cosider imaging to determine (u/s, CT)
Indications for surgical exploration:
- persistent hemorrhage,
- positive diagnostic peritoneal lavage
- abscessation or necrosis
- herniation
What is the most common bacteris isolated from dog and cate bite wounds?
Pasteurella multocida
What are the most common bacteria isolated from gun shot wounds?
Staphylococcus spp
Clostridium spp
Urine Peritonitis
- secondary to trauma to the urinary system.
- The presence of urine in the peritoneal cavity has severe metabolic consequences but is not usually associated with bacterial peritonitis.
- abdominocentesis fluid creatinine or potassium concentrations exceed serum values.
- ratios for creatinine and potassium were greater than 2 : 1 and 1.4:1, respectively.
Sx
- If the urine is infected, early definitive repair or diversion is recommended to decrease risk for diffuse peritonitis.
Chylous Peritonitis
- comparison of peritoneal fluid cholesterol and triglyceride concentrations with serum
- not appear to induce an inflammatory response
- spontaneous pleural and peritoneal chyle most often associated with neoplasia and carry a grave prognosis
- may be secondary to lymphanic rupture, thoracic duct ligation
Intraabdominal Abscesses
- associated with organs or lymph nodes, peritoneal or retroperitoneal foreign bodies
- requires the presence of neutrophils and, frequently, anaerobic bacteria
- Anaerobic organisms secrete large amounts of succinic acid, which inhibits neutrophil function in vitro
- neutrophils effector
- protected from normal peritoneal defense mechanisms, and fibrinous exudate prevents penetration of antibiotics.
- mineralization or air density, may be apparent with abscesses on rads
- Surgical treatment of intraperitoneal abscesses is usually required to remove the abscess, omentalize the abscess cavity, or establish drainage.
What is the most common organism isolated from intraabdominal abscesses?
Bacteroides fragilis
Pneumoperitoneum
causes:
- Abdominal surgery (most common)
- from ruptured abdominal viscus,
- infection with gas-forming organisms
- penetrative injury
- abdominal drain site
- leakage of gas through distended stomach
- iatrogenic
- duration of pneumoperitoneum experimentally: 9-25 days
Hemoperitoneum
Common causes: trauma, iatrogenic trauma, neoplasia, coagulopathies, splenic torsion
- acute nontraumatic hemoperitoneum in dogs is malignant neoplasia
diagnosis
- accuracy of needle abdominocentesis is 50% to 62%.
- Blood in contact with peritoneal surface >45 minutes does not clot
- Blood by abdominocentesis that clots is suggestive of inadvertent splenic or vascular penetration
- PCV peritoneal : peripheral PCV, serial measurements
- RBC counts in excess of 100,000/mm3 in diagnostic peritoneal lavage (humans)
- patient’s overall hemodynamic status
Tx
- Autotransfusion and abdominal binding (trauma)
What was the mortality rate of traumatic haemoperitoneum cases which required a blood transfusion?
Mortality 27%
Retroperitoneal Diseases
- Primary retroperitoneal diseases include retroperitonitis, pneumoretroperitoneum, nonneoplastic space-occupying lesions, and neoplasia
- lipoma, fibrosarcoma, lymphosarcoma, myxoma, pheochromocytoma, paraganglioma, osteosarcoma, leiomyosarcoma and Metastatic
- Primary disease of the kidneys, ureters, adrenal glands
- retroperitonitis occurs most commonly secondary to foreign body migration and ovarian pedicle granuloma after ovariohysterectomy.
imaging
- poor definition of the borders of the left kidney and retroperitoneal swelling.
- CT and magnetic resonance imaging (MRI) are useful diagnostic tools in suspected retroperitoneal disease.
sx
-particular attention paid to the location of the ureters during granuloma resection
What is the most common primary retroperitoneal tumour?
lipoma
Sinus Tracts
- Chronic sinus tracts commonly secondary to foreign bodies.
- fistulae defined as abnormal connections between epithelial-lined structures (not sinus)
- lumbar, paralumbar, or flank are often associated with peritoneal or retroperitoneal foreign bodies
- dx: ultrasound, CT or positive-contrast Sinography
- sinography: 87% sensitive and 100% specific
- Radiographic: tissue swelling, periosteal reactions on adjacent bone, gas densities and possible foreign bodie
- ## back pain secondary to lumbar plant foreign bodies > proposed that plant parts were inhaled and then migrated along the diaphragmatic crus
What are the most common caused of retroperitonitis?
FB migration
Ovarian pedicle granuloma
What is a mesothelioma?
What is it often seen in relation to?
Neoplasms arising from the mesothelial lining of the coeliomic cavities (peritoneal, pleural, pericardial)
- Often seen in relation to asbestos exposure
mesothelioma
- Mesotheliomas clinically produce malignant effusions
- dx: histopathologic examination of mesothelial biopsy specimens is required
- Tx: palliative (repeat drainage)
- doxorubicin and intrathoracic cisplatin survived 300 days
Tensile testing in feline ventral
abdominal coeliotomy closure with
different sizes of polydioxanone suture
material: a biomechanical study
PDX 2-0 and 3-0 can be used without reservation for the closure of ventral midline
coeliotomy in cats. Although there was no statistically significant difference between PDX 2-0, 3-0 and 4-0, PDX 4-0
showed a higher probability for suture breakage
Sclerosing encapsulating peritonitis
in cats: a two-case report and
literature review
A thick and diffuse fibrous capsule around the intestine was detected and removed surgically, and biopsies were taken
from the affected organs confirming the SEP. Case 1 recovered well, was discharged some days after surgery and was clinically unremarkable for the next 2 years. Case 2 showed unsatisfactory improvement
Diagnostic and surgical treatment for traumatic
bile peritonitis in dogs and cats
McAlexander 2024
- The most frequent site of rupture was the CBD in dogs and the cystic duct in cats (also gallbladder and hepatic duct)
- common surgeries were cholecystoduodenostomy and CBD repair in dogs and cholecystectomy
- One dog that underwent cholecystectomy experienced recurrent bile peritonitis
- Short-term survival following surgical treatment of traumatic bile peritonitis was excellent and recurrence appears uncommon
Measurement of peritoneal bilirubin should be considered
Abdominal computed tomography and exploratory
laparotomy have high agreement in dogs
with surgical disease
Sevy 2023
100 client-owned dogs
The overall agreement between abdominal CT scan and exploratory laparotomy in all cases was 97%
Abdominal CT scan read by a board-certified diplomate is a sensitive presurgical diagnostic tool for surgical abdominal disease in the dog.
3% of patients in which the surgical plan changed intraoperatively, as new lesions were identified in surgery.
Association of the origin of contamination and species of microorganisms with short-term survival in dogs with septic peritonitis
Uetsu 2023
AVJ
overall survival rate was 75.9% (n = 44/58).
no association between anatomical
location of leakage (GIT tract, billary), microorganism species and survival although
further studies are warranted
Assessing major influences on decision-making
and outcome for dogs presenting emergently
with nontraumatic hemoabdomen
Menard 2023
QOL scores were significantly higher with surgery versus those with palliative care (P = .007).
Median survival time (MST) was 213 days with surgery and 39 days with palliative care (P = .049).
Survival benefit of surgery was lost when considering only dogs with malignant histopathology (MST, 81 days; P = .305).
> underscores the importance of timely preoperative staging
Owners were more likely to be satisfied when they chose surgery
owners (26%) second-guessed or were unsure of their decision
Acute kidney injury is common in dogs with septic peritonitis and is associated with increased mortality
Snipes 2023
77 dogs that underwent abdominal surgery for septic peritonitis
31 dogs (40.3%) had AKI diagnosed
(23.4%) dogs presented with AKI, (16.9%) dogs developed AKI postoperatively
a significant risk factor for survival to discharge
Diagnostic utility of abdominal ultrasonography
for evaluation of dogs with nontraumatic hemoabdomen:
94 cases (2014–2017)
Sarah E. Cudney 2021
Differences were identified between AUS and surgical or necropsy findings
for 51 of 94 (54%) dogs. Splenic masses were most commonly identified as the cause of hemoabdomen.
Sensitivity of AUS was 87.4%, 37.3%, and 31.3% for masses in the spleen, liver, and mesentery,
the utility of AUS to detect grossly identifiable lesions in dogs with nontraumatic hemoabdomen was limited
Comparison of imaging techniques to detect migrating foreign bodies. Relevance of preoperative and intraoperative ultrasonography for diagnosis and surgical
removal
Blondel 2021
detection of migrating FB in subcutaneous and underlying soft tissue structures.
Retrospective study.
Sample population: Forty-one dogs.
relative sensitivity of preop-US 88% and and preop-CT/MRI was 57.1%
The success rate for FB removal was higher in with intra-op us (89.5%) vs none (59.1%;
Clinical resolution occurred in 90.2% of dogs for a median duration of follow-up of 4.2 years
Intraoperative US should be used in combination with preop-US to increase the likelihood of migrating FB surgical removal in dogs
In our study,
39% of the dogs were presented to a clinician after one or
more surgical treatment had already been attempted
No preop-DI technique is able to identify all migrating
FB
The reported sensitivity of preop-CT ranges between 19% and 75%.
Comparison of Initial and Postlavage Bacterial
Culture Results of Septic Peritonitis in Dogs
and Cats
Kalafut 2018 JAHAA
E coli followed by Enterococcus sp
Culture samples were collected from the peritoneal
surface pre- and postlavage from dogs and cats treated surgically for septic peritonitis
Microbial growth occurred in at least one culture in 88.6% of patients. There was no significant difference in bacterial
isolates or susceptibility profiles pre- versus postlavage. Positive culture pre- or postlavage and appropriate antimicrobial
selection did not significantly affect survival.
no definitive effect of peritoneal lavage was seen for the population as a whole
Limitations of this study include a small sample size, lack of
standardization of surgical technique among surgeons, and lack of
standardization of antimicrobial protocols
Based on these findings, we recommend
obtaining cultures both pre- and postperitoneal lavage, to ensure that
all organisms are identified.
lavage solution used was not standardized
Evaluation of factors associated with
retained surgical sponges in veterinary
patients: a survey of veterinary
practitioners
Lack of specifically scheduled time for
surgery, few theatre staff and lack of sponge counting and documentation may have contributed to the 17 retained surgical sponge cases reported.
Shipov 2022 – surgically treated septic peritonitis in 113 dogs
- overall survival rate 74.3%
- risk factors for mortality:
- at presentation: lateral recumbency, elevated resp rate
- intra-/post-op hypotension, liver and kidney injury
- source of contamination, number of sx and location of GI perforation not associated
- number of sx possibly type II
- serum vs abdominal glucose (delta glucose) not sensitive, no difference in outcome
Selmic 2023 – sx and outcome for septic peritonitis secondary to neoplasia in 86 dogs
- neoplasia, n=12/86 – most common GI lymphoma, hepatocellular adenoma
- not associated with incidence of complications or survival to discharge
- medial overall survival time 604 d
- survival rates: overall 70.9%; neoplasia 58%, other 72%
Fink 2020 – risk factors for recurrent secondary septic peritonitis, n=149 dogs
- recurrence in 15/149 (10.1%) after surgery → 8 euthanasia, 7 re-operation
- 3/7 (42.9%) survival after re-op
- risk factors: low serum albumin at first surgery, high pre-op PCV
GI sepsis and presence of GI foreign body
