Peritoneum, mesentery,

omentum and retroperitoneum

PeritoneumPeritoneum is a membrane located within the

abdominopelvic cavity that covers the surface of both the organs that lie in the abdominal cavity and the inner surface of the abdominal cavity itself.

• Serosa, or visceral peritoneum:

covers organs within peritoneal cavity, pain insensitive

• Parietal peritoneum:

lines inner surfaces of body wall, very pain sensitive

Peritoneal Fluid

• Is produced by serous membrane lining

• Provides essential lubrication

• Separates parietal and visceral surfaces

• Allows sliding without friction or irritation

Mesentery

• Tissue between mesothelial surfaces:

– Provides an access route to and from the digestive tract for passage of blood vessels, nerves, and lymphatic vessels

– Stabilize positions of attached organs

– Prevents entanglement

• Is a thick mesenterial sheet

• Provides stability

• Permits some independent movement

• Suspends all but first 25 cm of small intestine

• Initial portion of small intestine (duodenum) and pancreas fused with posterior abdominal wall, locking structures in position

The Mesentery Proper

Omentum• Greater and lesser omenta are peritoneal

folds that pass from stomach to the liver, transverse colon, spleen, bile duct, pancreas and diaphragm.

• They are separated via the foramen of Winslow and Epiploic foramen

• Originates from dorsal and ventral midline mesenteries of embryonic gut.

Bacterial Peritonitis

Intra-abdominal infections result in 2 major clinical manifestations

• Early or diffuse infection results in localized or generalized peritonitis.

• Late and localized infections produces an intra-abdominal abscess.

2 Major Types

• Primary: Caused by the spread of an infection from the blood & lymph nodes to the peritoneum. Very rare < 1%

• Usually occurs in people who have an accumulation of fluid in their abdomen (ascites).

• Also seen in septicemia.

• The fluid that accumulates creates a good environment for the growth of bacteria.

• Secondary: 1. Direct Infection

• Caused by the entry of bacteria or enzymes into the peritoneum from the gastrointestinal or biliary tract.

• This can be caused due to an ulcer eroding through stomach wall or intestine when there is a rupture of the appendix or a ruptured diverticulum.

• Also, it can occur due to a burst intestine or injury to an internal organ which bleeds into the internal cavity.

2. Local Extension

• From an inflamed organ

• Migration through gut wall

• Via Fallopian tubes

Both cases are very serious &

can be life threatening if not

treated properly!!!

• Post op Peritonitis

• Steroid Induced Peritonitis

• Biliary Peritonitis

• Meconium Peritonitis

• Pneumococcal Peritonitis

• Post Abortion

• Starch Peritonitis

Special variants

Meconium Peritonitis

Histopathology of typical flask-shaped ulcer of intestine

Complications of Peritonitis

• Acute intestinal obstruction due to adhesions.

• Paralytic Ileus

• Residual Abscess 1. Pelvic

2. Sub Phrenic

Intestinal Obstruction

Signs & Symptoms

• Swelling & tenderness in the abdomen

• Fever & Chills

• Loss of Appetite

• Nausea & Vomiting

• Breathing & Heart Rates

• Shallow Breaths

• Hypotension

• Oliguria and renal shutdown

• Inability to pass gas or feces

Contd…

• An acutely ill patient of peritonitis tends to lie “very” still because any movement causes excruciating pain.

• They will lie with there knees bent to decrease strain on the tender peritoneum.

Examination & Evaluation

• Check vitals of patient first. Check for difficulty breathing, low blood pressure & signs of dehydration.

• Feel & press the abdomen to detect any swelling & tenderness in the area as well as signs of fluid has collected in the area.

• Listen to the bowel sounds.

• The abdomen may be rigid and boardlike.

• Accumulations of fluid will be notable in primary due to ascites

• The usual bowel sounds made by the active intestine will be absent on auscultation, because the intestine usually stops functioning.

Evaluation cont:

Exams cont..:• Blood Tests

• Erect or lateral decubitus X-rays of chest and abdomen.

• USG abdomen

• CT Scan

Plain erect x-ray showing Gas DIAPHRAGM

Perforated Gastric Ulcer

• Antibiotics are prescribed to control the infection & intravenous therapy (IV) is used to restore hydration.

• Morphine for pain.

• Mainstay is surgery…an exploratory laparotomy is often necessary to remove the source of infection and to treat underlying cause.

Treatment

Tubercular Peritonitis

• Acute• Mimics acute bacterial peritonitis• Tubercles studded all over.

• Chronic• Origin

– Tubercular mesenteric nodes– Ileocecal TB– TB PYOSALPINX– PULMONARY/ MILIARY

Presentations

• Ascitic

• Encysted/ Loculated

• Plastered

• Purulent

Treatment

• Antitubercular drugs are mainstay.

• Surgical intervention in cases of tense ascites, perforations, adhesions leading to bowel obstruction.

• Nutritional support

Peritoneal Tumors• Carcinoma Peritonei:

– due to metastases from GI Tumors, ovarian, breast, bronchus.• Discrete Nodules, Plaques, Diffuse Adhesions(Plastered

abdomen)

• Pseudomyxoma Peritonei– Ruptured mucinous cyst of ovary,mucocoele of appendix

– Locally malignant, no metastases

• Mesothelioma– Highly malignant, mimics prostatic carcinoma, ??asbestos

– cytoreduction, chemotherapy (pemetrexed and cisplatin)

Peritoneal Calcifications

Pseudomyxoma Peritonei

Pseudomyxoma Peritonei

Mesenteric Cysts• 3 major types

– Chylolymphatic

– Enterogenous (arises from diverticula on mesenteric border)

– Dermoid/ Teratoma

• Symptoms– Usually painless; sometimes Chr. Intermittent pain, can

become acute excruciating when there is torsion/ hemorrhage

• “Tillauxs” sign- lateral mobility of cyst• CT scan is investigation of choice• Rx- surgical resection is sufficient but enterogenous

type requires resection and anastomosis.

Chylogenous Mesenteric Cyst

Dermoid Cyst Enterogenous Cyst

USG CT Scan

Retroperitoneal Fibrosis• Primary

– Ormonds d/s• Due to antibodies to CEROID( lipoprotein)

• Men> Female, involves retroperitoneum below renal arteries first and then spreads all over.

• Secondary– Drugs (methysergide, hydrazaline, B blockers)

– Malignancies( Ca Prostate, NHL,

– Autoimmune disorders( SLE, AS)

• Presents with features of the organ involved.• CT scan is Investigation of choice.• Surgical debulking and corticosteroids, cyclosporine,

azathioprione and tamoxifen chemotherapy.

Retroperitoneal Fibrosis