Peritoneum and retroperitoneum Flashcards
In a study by Snipes 2023 in JAVMA, what were 3 risk factors for the presence of pre-operative AKI in dogs with septic peritonitis? Was AKI a risk factor for survival?
Decreased blood pressure, increased respiratory rate, increased BCS.
Yes. AKI decreased the odds of survival. 21% of dogs did not survive to discharge (75% of these being dogs with AKI).
In a study by Sevy 2024 in JAVMA, what was the agreement between findings at exploratory laparotomy and abdominal CT scan?
97%
What is the diagnosis based on the following image from Hennessey 2022 in VRU? What was the suspected underlying cause?
Abscess of the hypaxial musculature characterized by well-defined fluid attenuating noncontrast enhancing areas with a contrast enhancing rim.
Migrating foreign body was suspected. Other common CT findings were periosteal reaction and lysis of vertebrae, and retroperitoneal effusion.
In a study by Parry 2023 in JVECC, was abdominal CT scan a reliable indicator of malignancy versus benignancy for cases of non-traumatic hemoabdomen?
No - benign v. malignant neoplasms were not accurately identified.
In a study by Anderson 2019 in Vet Surg, which of the following laparoscopic abdominal entry techniques was associated with the lowest rate of complications?
1) Veress needle
2) Modified Hasson
3) Ternamian
Ternamian method (cannula entry under endoscope guidance) was associated with the lowest number of complications (9%, compared to 26% [or 5 x risk] for Hasson, and 60% [or 28 x risk] for Veress).
Complications were 12 times more likely in paramedian rather than midline entry.
What is the clinical significance of paired slit like openings dorsal to the diaphragm and ventral to the psoas muscles covered by only a thin layer of fascia?
Potentially allow direct extension of disease processes between the thorax and abdomen. Allow for passage of the sympathetic trunk and splanchnic nerves.
What is the Cullen sign?
A characteristic ring of subcutaneous hemorrhage around the umbilicus in cases of hemoperitoneum or peritonitis.
What are different portions of the omentum?
Greater omentum, comprised of three portions:
1) Bursal - creates the omental bursa.
2) Splenic - gastrosplenic ligament
3) Veil - contains the left limb of the pancreas.
Lesser omentum: gives rise to the hepatoduodenal and hepatogastric ligaments.
What organs are considered retroperitoneal?
Kidneys, ureters, adrenal glands, aorta, caudal vena cava, lumbar lymph nodes.
What are the peritoneal stomata?
Fenestrations in the basement membrane of the visceral surface of the diaphragm. Important in the clearance of fluid and particles from the peritoneal cavity.
What is the predominant cell type of the peritoneal fluid?
Macrophages. Peritoneal fluid is a dialysate of plasma. Normal peritoneal fluid has <3 g/L of protein.
What is the primary route of lymphatic drainage from the peritoneum?
Through the diaphragmatic lymphatics to the mediastinal lymph nodes and then into the systemic circulation (via the thoracic duct). This allows for rapid bacteremia in instances of bacterial peritonitis (rapid clearance of particles <10 um in diameter).
Which side of the diaphragm has a greater concentration of lymphatics?
Right
Aside from particle size, what other factors can affect particulate matter clearance?
Gravity, respiratory movements, diaphragmatic movement, intestinal activity, intraperitoneal pressure.
What is the normal intraabdominal pressure in a dog?
2 - 7.5 cm H2O
What organ systems are affected by abdominal compartment syndrome?
Acute pulmonary failure secondary to atelectasis, increased pleural and pericardial pressures and decreased venous return, acute renal failure with marked oliguria, intestinal ischemia and bacterial translocation, hepatic ischemia, increased ICP.
What causes abdominal adhesion formation?
Fibrin is exuded in response to surgical manipulation or disease. This is normally degraded by fibrinolysis within 3-4 days unless concurrent ischemia is present, in which case fibrin is converted to collagen by fibroblasts. This is worsened in instances of serosal dessication, endotoxemia, and intestinal manipulation.
What techniques can be used to minimize abdominal adhesion formation?
Prevention of tissue dessication, gentle tissue handling, meticulous hemostasis, precise suturing, complete removal of blood clots and foreign debris, thorough lavage.
What are known adjuvants for peritonitis?
Gastric mucin, bile salts, hemoglobin, barium.
Bile results in hemolysis and release of hemoglobin which impairs phagocytosis and lymphatic drainage. May also provide iron required by bacteria for survival.
What are the systemic manifestations of peritonitis?
Hypovolemia and hypoproteinemia (from third spacing of fluid into the abdomen and bowel secondary to reflex ileus), respiratory acidosis and hypoxemia due to diaphragmatic rigidity and increased intraabdominal pressure (which also exacerbates hypovolemia), acute renal failure, release of myocardial depressant factors from the hypoxic pancreas and cardiovascular alterations. Changes to bile flow causes hepatic enzymopathy and icterus. All these changes can be further exacerbated by sepsis or endotoxemia.
What is the mortality rate in dogs with MODS secondary to peritonitis?
70% (compared to 25% without). DIC can lead to MODS due to formation of microthrombi.
What are the functions of the omentum?
Rich blood supply, high absorptive capacity, pronounced angiogenic activity. Also helps to isolate contamination through formation of adhesions.
How does peritonitis result in GI ileus?
Sympathoadrenergic reflex inhibition. Ileus helps to decrease the spread of contaminants but can result in bacterial translocation.
What are the classifications of peritonitis?
Primary or secondary, can be further classified into septic or aseptic.
Primary: no obvious source (i.e. FIP), normally monobacterial.
Secondary: most common form in dogs, normally secondary to loss of integrity of the GI or direct innoculation.
Describe the pathophysiology of peritonitis in small animals.
What are some causes of secondary peritonitis?
What is the cause of starch granulomatous peritonitis? What is the treatment?
Suspected hypersensitivity reaction to starch or corn (talcum power no longer used in gloves as could cause significant peritonitis).
Treatment is with corticosteroids.
What are common causes of chemical peritonitis?
Bile, urine, gastric fluid, pancreatic enzymes.
Bile and urine tend to be minimally inflammatory unless concurrent bacterial infection.
Pancreatic fluid is intensely inflammatory.
What is sclerosing encapsulating peritonitis?
A chronic form of peritonitis where the organs become encased in thick layers of collagenous tissue.
Surgical exploration and biopsy from multiple sites is recommended.
Corticosteroid therapy may help to slow progression.
In dogs undergoing GI surgery what were risk factors for development of septic peritonitis (4)?
H - intraoperative hypotension
A - hypoalbuminemia
P - hypoproteinemia
S - preoperative septic peritonitis
Presence of a foreign body is variably a risk factor or protective.
In what percentage of septic peritonitis is concurrent pancreatitis observed?
50%
What is the most common cause of septic peritonitis?
Leakage from the GI tract
What factor drastically affects survival in patients with bile peritonitis?
Concurrent infection (survival of 27% with septic bile peritonitis in one study, compared to 100% when sterile).
Are upper or lower GI perforations associated with a higher mortality rate?
Lower GI due to higher bacterial load and greater proportion of anaerobic bacteria.
What two bacterial species predominate in cases of septic peritonitis caused by bowel perforation?
E. coli and Bacteroides fragilis.
E.coli causes early mortality due to release of endotoxins (specifically alpha hemolysin), B.fragilis enhances the lethality of E.coli.
What volume of peritoneal fluid can be detected on abdominal ballottement?
10 ml/kg
What are the physical examination parameters of SIRS for dogs?
What are the physical examination parameters of SIRS for cats?
What are some common radiographic signs of peritonitis?
Loss of serosal detail, ground glass appearance (with large volumes of fluid only), free peritoneal gas.
How much higher is the mortality in cases of bicavitary effusion?
3 times increased risk of mortality. Most often caused by infectious agents or pancreatitis.
What are some common ultrasonographic signs of peritonitis?
Corrugation of the small intestines, fluid, gas.
Note: 20% of dogs had residual air or fluid in the peritoneum 10 days following uncomplicated GI surgery in one study.
In what percentage of dogs are single abdominal paracentesis results positive with 3ml/kg of fluid?
20%. This increases to 80% for 10 ml/kg of fluid
Which of the following techniques has the highest diagnostic accuracy for detection of peritonitis?
1) Needle paracentesis
2) Catheter paracentesis
3) Diagnostic peritoneal lavage
Needle: 43%
Catheter: 83%
Peritoneal lavage: 95%
How is diagnostic peritoneal lavage performed?
20 - 22 ml/kg of saline is instilled into the abdomen, the animal is rolled for 10 minutes and a large aliquot of fluid is recovered.
Describe the parameters for diagnosis of septic inflammation, uroperitoneum, and chyloperitoneum based on abdominocentesis.
What findings on cytologic examination of peritoneal fluid warrant surgical exploration?
Toxic and degenerate neutrophils, bacteria or plant material.
What level of peritoneal fluid bilirubin is indicative of free intraperitoneal bile?
2 x the serum bilirubin concentration. May see a green granular pigment cytologically or basophilic mucinous material.
What do peritoneal lipase and amylase concentrations in excess of serum concentrations indicate?
Intestinal ischemic injury and pancreatic injury or inflammation.
How does anemia affect blood glucose on point-of-care glucometer?
Will falsely increase blood glucose. Care when interpreting results for diagnosis of septic peritonitis.
What blood-to-fluid lactate difference is indicative of septic peritonitis?
- 2mmol/L (or a total peritoneal lactate >2.5 mmol/L also suggests sepsis).
These indicators are not reliable in cats.
How accurate is cytology in the diagnosis of septic peritonitis?
87%
What are the goals of fluid resuscitation for CVP and urine output in patients with septic peritonitis?
CVP of 0-5 cmH2O
Urine output of 1-2 ml/kg/hr
What antimicrobial drugs are recommended for empiric antimicrobial selection in patients with septic peritonitis?
Ideally drugs effective against both gram positive and gram negative aerobes and anaerobes. Typically a third generation cephalosporin or ampicillin and an aminoglycoside are recommended.
In one retrospective study only 28% of gram positive organisms and 52% of gram negative organisms were sensitive to fluoroquinolones.
What are the goals of surgical treatment of patients with septic peritonitis?
Elimination or correction of the source of contamination/infection, reduction of the bacterial load, removal of foreign material and inflammatory cells, prevention of persistent or recurrent infection.
What volume of fluid is recommended for pertioneal lavage?
200 - 300 ml/kg, or until the fluid is clear.
Efficacy of lavage for improving clinical outcomes remains uncertain.
What are some surgical methods proposed to help decrease the risk of enterotomy or anastomotic leakage in patients undergoing correction of septic peritonitis?
Serosal patching, fibrin sealant, omentalization.
Why is laparoscopic surgery potentially detrimental in patients with septic peritonitis?
Diffuse damage to the peritoneum occurs secondary to insufflation.
What are the proposed advantages and disadvantages of open peritoneal drainage?
Advantages: increased efficiency of removal of bacteria (may also prevent proliferation of anaerobic bacteria), foreign material and inflammatory mediators.
Disadvantages: nosocomial infection, hypoalbuminemia, hypoproteinemia, anemia.
In humans it is associated with worsening organ dysfunction, amplified inflammation, and greater use of blood component therapy.
Can also be performed using negative pressure wound therapy (vacuum assisted closure).
What are some reported indications for open peritoneal drainage?
Severe systemic manifestations of peritonitis, ineffective drainage with conventional procedures, and extensive suppuration or necrosis of the deep layers of the incision.
What factors are used to determine closure of open peritoneal drainage?
Appearance of the wound and peritoneal effusion, cytology.
What are the most common complications associated with the use of closed suction abdominal drainage?
Hypoproteinemia, anemia, edema. All occurred in around 50% of cases.
Why are epidurals contraindicated in patients with septic peritonitis?
May decrease survival times and decreased cardiac and renal function attributed to abdominal sympathetic blockade.
Is canine or human specific albumin preferred for supplementation in dogs, if required?
Canine. There is a high rate of type III hypersensitivity reactions to human albumin, and significant morbidity and mortality.
What are reported survival rates for dogs with septic peritonitis?
Varied. Range from 50-80% for open peritoneal drainage, closed suction drainage, and primary closure.
What are negative prognostic indicators for survival in septic peritonitis?
Hypotension, CV collapse, respiratory distress, DIC, pre-operative ALT and GGT, plasma lactate >2.5 mmol/L on admission, inability to normalize lactate within 6 hours, preoperative protein C above 60%, antithrombin activity above 42%, ionized hypocalcemia, MODS.
What are indications for surgical exploration of bite wounds to the abdomen?
Persistent hemorrhage, positive diagnostic peritoneal lavage or abdominocentesis, abscessation or necrosis, herniation.
What is the major pathogen in dog and cat bite wounds?
Pasteurella multocida.
Staphylococcus and clostridium were most common in gunshot wounds.
Is urine a adjuvant compound in peritonitis?
No, chemical peritonitis is normally minimal.
Are peritoneal urea concentrations useful in the diagnosis of uroabdomen?
No, they re-equilibriate quickly with the serum.
What is the most common cause of chyloperitoneum?
Neoplastic disease
What is the most common anaerobic organism implicated in abdominal abscess formation?
B.fragilis
What are the most common sources of bleeding in cases of traumatic hemoabdomen?
Spleen, liver and kidneys.
What is the most common primary retroperitoneal neoplasia in small animals?
Lipoma
What is the most common cause of retroperitonitis?
Foreign body migration or ovarian pedicle granuloma after hysterectomy.
What is the difference between a fistula and a sinus tract?
A fistula is between two epithelial surfaces. Because the mesothelium is distinct from epithelium, draining tracts from the peritoneum to the skin surface are termed sinus tracts.
What are some imaging techniques that may be useful in the investigation of sinus tracts?
Radiography +/- positive contrast sinography, ultrasonography, CT, MRI. Most frequently secondary to migrating foreign bodies, often occur in the sublumbar region and are thought to migrate from the respiratory tract following inhalation.
Exposure to what substance is thought to result in mesothelioma in dogs?
Asbestos (75% of dogs diagnosed with mesothelioma in one study had exposure).
How is mesothelioma diagnosed?
Generally requires histopathology, as it is not uncommon to see reactive mesothelial cells in effusions of various causes. Immunohistochemistry may be required.
What is the MST for mesothelioma?
60 days (although longer survival has been reported in some cases - 42 months in one case with repeated abdominal drainage).
