Peritoneal pathology Notes

NOTES NOTES PERITONEAL PATHOLOGY GENERALLY, WHAT IS IT? PATHOLOGY & CAUSES ▪ Conditions affecting peritoneal cavity (e.g. serosal membrane inflammation, gas) CAUSES Peritonitis ▪ Spontaneous bacterial peritonitis ▪ Leakage of gastrointestinal (GI) contents ▪ Presence of foreign material ▫ Bile, blood, contrast material ▪ Endometriosis ▪ Peritoneal dialysis Pneumoperitoneum ▪ Perforation of anterior duodenal ulcer ▪ Iatrogenic ▪ Increased intrathoracic pressure SIGNS & SYMPTOMS Peritonitis ▪ Fever, chills, tachycardia ▪ Ascites, abdominal distention, abdominal rigidity, spider angiomata, jaundice ▪ Anorexia, nausea, vomiting, diarrhea ▪ Encephalopathy; delirium, confusion, cognitive decline ▪ Absent bowel sounds, ileus Pneumoperitoneum ▪ Abdominal pain, rigidity ▪ Absent bowel sounds, ileus DIAGNOSIS DIAGNOSTIC IMAGING X-ray ▪ Peritonitis ▫ Supine, upright abdominal films ▪ Pneumoperitoneum ▫ Upright chest radiography ▫ Subdiaphragmatic free gas; cupola sign ▫ Rigler’s sign, football sign ▫ Lateral decubitus X-ray CT scan ▪ Pneumoperitoneum ▫ Small quantities of air LAB RESULTS Paracentesis ▪ Peritonitis ▫ If ascites present Complete blood count (CBC) Blood chemistry TREATMENT MEDICATIONS ▪ Systemic antibiotics SURGERY ▪ Exploratory laparotomy OSMOSIS.ORG 351

PERITONITIS osms.it/peritonitis PATHOLOGY & CAUSES DIAGNOSIS ▪ Inflammation of serosal membrane lining abdominal cavity, organs (AKA peritoneum). ▪ Neutrophilic infiltration, formation of fibrinopurulent exudate DIAGNOSTIC IMAGING CAUSES LAB RESULTS ▪ Spontaneous bacterial peritonitis ▫ Bacterial migration from GI lumen; more common in people with ascites/cirrhosis ▫ E. coli, Klebsiella, Pseudomonas, Proteus, Gram-negatives ▪ Leakage of GI contents; most common; perforated viscera ▫ Proximal GI tract perforation → Grampositive bacteria ▫ Distal GI tract perforation → Gramnegative bacteria ▪ Foreign material ▫ Bile, blood, contrast material ▪ Endometriosis ▪ Peritoneal dialysis Supine, upright abdominal films ▪ Subhepatic/subdiaphragmatic free air, abscesses in case of perforated viscus ▪ Leukocytosis, acidosis Paracentesis ▪ If ascites present ▪ Serum ascites albumin gradient (SAAG) ▫ > 1.1 in spontaneous bacterial peritonitis ▪ Neutrophil count > 250 cells/microliter TREATMENT MEDICATIONS Systemic antibiotics ▪ Third generation cephalosporins/quinolones SIGNS & SYMPTOMS ▪ Fever, chills, tachycardia ▪ Ascites, abdominal distention, abdominal rigidity, spider angiomata, jaundice ▪ Anorexia, nausea, vomiting, diarrhea → hypovolemia, renal failure ▪ Absent bowel sounds, ileus ▪ Early stages ▫ Dull, poorly localized abdominal pain ▪ Late stages ▫ Severe, localized abdominal pain; acute abdomen ▪ Encephalopathy; delirium, confusion, cognitive decline 352 OSMOSIS.ORG Figure 41.1 The histological appearance of tuberculous peritonitis, a rare kind of peritonitis. There are numerous epithelioid macrophages and giant cells infiltrating the peritoneal biopsy.

Chapter 41 Peritoneal Pathology Figure 41.2 An abdominal CT scan with oral contrast in the axial plane demonstrating severe peritonitis. There is diffuse peritoneal thickening and large amounts of radiodense fluid. On laparotomy this was discovered to be pus. PNEUMOPERITONEUM osms.it/pneumoperitoneum PATHOLOGY & CAUSES ▪ Abnormal collection of gas within peritoneal cavity. CAUSES ▪ Most common ▫ Perforation of anterior duodenal ulcer secondary to peptic ulcer disease ▪ Iatrogenic ▫ Abdominal surgery; resolves spontaneously ▪ Increased intrathoracic pressure (mechanical ventilation, chest compressions) SIGNS & SYMPTOMS ▪ Abdominal pain, rigidity ▪ Absent bowel sounds, ileus DIAGNOSIS DIAGNOSTIC IMAGING CT scan ▪ Small quantities of air Upright chest radiography ▪ Subdiaphragmatic free gas; Cupola sign (free intraperitoneal air, well-defined superior border formed by diaphragm) Supine abdominal X-ray ▪ Rigler’s sign (double wall sign): both sides of abdominal wall visible ▪ Football sign (massive pneumoperitoneum): ellipsoid shape of abdominal cavity outlined by gas Lateral decubitus X-ray ▪ Free gas between liver, abdominal wall OSMOSIS.ORG 353

TREATMENT SURGERY Exploratory laparotomy ▪ Repair perforated viscus Figure 41.3 A CT scan in the axial plane demonstrating air in the peritoneal cavity. The air has also tracked along an umbilical hernia. Figure 41.4 An erect chest radiograph demonstrating a sub-diaphragmatic air bubble, diagnostic of pneumoperitoneum. 354 OSMOSIS.ORG