The document provides information on the anatomy and physiology of the peritoneum and abdominal viscera. It describes the layers of the peritoneum and peritoneal cavity. Various peritoneal folds are described such as the greater omentum. Causes of acute abdomen and peritonitis are outlined. Intestinal obstruction is discussed including causes, pathophysiology, and classifications based on speed of onset, site of obstruction, and nature of obstruction. Common causes by age group are also summarized.

1. The Abdomen
Joseph Mwale
BSc CM, MSc (MPH) Epi St

2. Many thanks:
•Dr Yotham Phiri MMed(Surg)

3. Course Content
UNIT 1: INTRODUCTION TO SURGERY
1. Applied anatomy & physiology of the peritoneum
and abdominal viscera
2. Surgical history taking and physical examination
3. Appropriate laboratory & radiological
investigations

4. The Peritoneum
•The peritoneum is the largest serous membrane forming
the lining of the abdominal cavity.
•It covers most of the intra-abdominal organs
•it consists of a layer of simple squamous epithelium
(mesothelium) with an underlying supporting layer of
areolar connective tissue.
•This peritoneal lining supports many of the abdominal
organs and serves as a conduit for their blood vessels,
lymphatic vessels, and nerves.

5. The Peritoneum
•The peritoneal cavity is the potential space between the
parietal peritoneum and the visceral peritoneum i.e. the two
membranes that separate the organs in the abdominal cavity
from the abdominal wall
•The peritoneal fluid is present in between the visceral and
parietal membrane

6. The Peritoneum
•There is normally about 50 ml of sterile
peritoneal fluid, it has anti-inflammatory
properties - antibodies, immunoglobulins and
the white cells
•It lubricates the organs in the peritoneal cavity

7. The Peritoneum
•The parietal peritoneum lines the walls of the abdominal
cavity
•The peritoneum covering continues around the
abdominal viscera as the visceral peritoneum.
•The space in between the visceral and parietal
portions of the peritoneum is called the peritoneal
cavity.

8. The Peritoneum
•In certain diseases, the peritoneal cavity may
become distended by the accumulation of
several litres of fluid, a condition called ascites

9. The Peritoneum
•The peritoneum contains large folds that weave
between the viscera.
•The folds bind the organs to one another and to the
walls of the abdominal cavity
•These also contain blood vessels, lymphatic vessels,
and nerves that supply the abdominal organs.

10. The Peritoneum
•There are five major peritoneal folds:
–the greater omentum
–falciform ligament
–lesser omentum
–mesentery
–mesocolon

11. Extensions of the parietal peritoneum

15. The Peritoneum
•The greater omentum, is the largest peritoneal fold, drapes
over the transverse colon and coils of the small intestine like a
“fatty apron”
•The many lymph nodes of the greater omentum contribute
macrophages and antibody-producing plasma cells that help
combat and contain infections of the GI tract, i.e. hence it has
been called the “policeman of the abdomen”

17. The Peritoneum
•In the male, the peritoneal cavity is completely closed
•in the female it is perforated by the openings of the
uterine tubes which constitute a possible pathway of
infection from the exterior.

18. Acute Abdomen

19. Acute Abdomen
•A serious condition within the abdomen characterized by
sudden onset, pain, tenderness, and muscular rigidity,
and usually requiring emergency surgery
•an acute intra-abdominal condition of abrupt onset,
usually associated with pain due to inflammation,
perforation, obstruction, infarction, or rupture of
abdominal organs, and usually requiring emergency
surgical intervention.
•Its also called the surgical abdomen.

20. Major Common Causes
• Acute cholecystitis
• Acute appendicitis
• Meckel’s diverticulitis
• Acute pancreatitis
• Ectopic pregnancy
• Diverticulitis
• Peptic ulcer disease
• Pelvic inflammatory disease
• Intestinal Obstruction
• Gastroenteritis
• Acute intestinal
ischaemia/infarction or vasculitis
• Gastrointestinal haemorrhage
• Renal colic or renal tract pain
• Acute urinary retention
• Abdominal aortic aneurysm
• Testicular torsion

21. Major Common Causes
•This list is far from exhaustive but is a useful aide-
memoir for those conditions commonly seen in the
community
•Non-surgical disease, e.g. myocardial infarction,
pericarditis, pneumonia, sickle cell crisis, hepatitis,
inflammatory bowel disease, opiate withdrawal, typhoid,
acute intermittent porphyria

22. Diagnosis
•An acute abdomen requires immediate evaluation and
diagnosis because it may indicate a condition that calls
for surgical intervention.
•Diagnosis depends on a good history, examination and
investigation

23. History
• This should cover the following points:
• Demographic details, occupation, recent travel, history of recent abdominal trauma
• Pain: (SOCRATES)
– Site (ask patient to point), localised or diffuse
– Onset (including whether new pain or previously experienced)
– Nature (constant/intermittent/colicky)
– Radiation
– Severity
– Relieving/aggravating factors (e.g. if worsened by movement/coughing suspect active
peritonitis; pancreatitis is relieved by sitting forward)

24. History (Cont…)
•Past medical and surgical history/medication
•Gynaecological and obstetric history:
•Contraception (including IUCD use)
•LMP
•History of STIs/PID
•Previous gynaecological or tubal surgery
•Previous ectopic pregnancy
•Vaginal bleeding
•Drug history and allergies - including any complementary
medication

25. Examination
•General Examination (BP/Pulse, pallor,…)
•Abdominal Examination:-
- Inspection
- Palpation
- Percussion
- Auscultation

26. Examination
General Examination
– Pulse, temperature and blood pressure.
– Assess respiratory rate and pattern. Patients with peritonitis
may take shallow, rapid breaths to reduce pain.
– If altered consciousness check GCS

27. Inspection
Inspection:
• Look for evidence of anaemia/jaundice.
• Look for visible peristalsis or abdominal distension.
• Look for signs of bruising around the umbilicus (Cullen’s sign -
can be present in haemorrhagic pancreatitis and ectopic
pregnancy) or flanks (Grey Turner’s sign - can be present in
retroperitoneal haematoma).
• Assess whether patient is dehydrated (skin turgor/dry mucous
membranes).

30. Auscultation
Auscultate abdomen in all four quadrants.
• Absent bowel sounds suggest paralytic ileus, generalised
peritonitis or intestinal obstruction. High-pitched and tinkling
bowel sounds suggest sub-acute intestinal obstruction.
• Intestinal obstruction can also present with normal bowel sounds.
• If there is reason to suspect aortic aneurysm, listen carefully for
abdominal and iliac bruits.

31. Percussion
• Percuss the abdomen to assess whether swelling/distension might
be due to bowel gas or ascites.
• Patients who display tenderness to percussion are likely to have
generalised peritonitis and this should act as a red flag for serious
pathology.
• Assess for shifting dullness and fluid thrill.
• Percussion can also be used to determine size of an abdominal
mass/extent of organomegaly.

32. Palpation
• Palpate the abdomen gently, then more deeply, starting away from the pain
and moving towards it.
• Feel for masses, tenderness, involuntary guarding and organomegaly
(including the bladder).
• Test for rebound tenderness.
• Examine the groins for evidence of herniae.
• Always examine the scrotum in men as pain may be referred from
unrecognised testicular pathology.
• Check supraclavicular and groin lymph nodes.

33. Further examination
•Perform rectal or pelvic examination as needed with an
appropriate chaperone.
•Dipstick urine and send for culture if appropriate.
•In a woman of child-bearing age, assume that she is
pregnant until proven otherwise - perform a pregnancy
test.
•Examine any other system that might be relevant, e.g.
respiratory, cardiovascular.

34. Treatment
Medical
- When the diagnosis points to medical cause
Surgical
- When the diagnosis is surgical

35. •Thank You

36. Peritonitis

37. •Acute peritonitis is the acute or chronic inflammation of
the visceral /parietal peritoneum of the abdominal cavity

38. Aetiology
Bacteria may enter the peritoneum via four portals
1. From the exterior – penetrating wound, infection at laparotomy,
peritoneal dialysis
2. From intra-abdominal viscera:
• Gangrene of a viscus – acute appendicitis, acute cholecystitis,
diverticulitis or infarction of the intestine
• Perforation of a viscus –perforation of a viscus –perforated
duodenal ulcer, perforated appendix, rupture of intestine from
trauma
• Post operative leakage of intestinal suture line

39. Aetiology
3. Via the bloodstream – as part of a septicaemia
(pneumococcal, streptococcal or staphylococcal. This has
sometimes called primary peritonitis, but there is usually
some source
4. Via the female genital tract – acute salpingitis or
puerperal infection.
•Approximately 30% in adults result from post operative
complications, 20% from acute appendicitis ad 10% from
perforated peptic ulcers

40. Primary Peritonitis
Primary peritonitis occurs when disease causing organism
gain entry into the peritoneal cavity
•Blood borne organisms
•Genital tract organisms
•Cirrhosis with ascites

41. Primary Peritonitis
• Rare condition almost confined to females, below the age of 8.
• It is probably due to retrograde infection via the genital tract.
• The purulent exudate grows either streptococci or pneumococci
(rarely, E. coli) and these children are nearly always thought,
before operation, to have pelvic appendicitis.
• Primary peritonitis occasionally complicates the ascites of
nephrosis.

42. Secondary Peritonitis
Secondary causes are the most common causes of peritonitis
• Ruptured appendicitis
• Trauma to the abdominal organs
• Ruptured diverticulitis
• Pancreatitis
• Perforations
• Peritoneal dialysis
• Post operative complications

43. Pathology
• Peritonitis of bowel origin usually shows mixed faecal flora
(Escherichia coli, strep fecalis, psuedomonas, Klebsiella and Proteus,
together with the anaerobic Clostridium and Bacteroides)
• Gynaecological infections may be chlamydial, gonococcal or
streptococcal.
• Blood-borne peritonitis may be streptococcal, pneumococcal,
staphylococcal or tuberculous
• In young girls there may be a rare gynaecological infection due to
pneumococcus

44. Pathology
The pathological effects of peritonitis are as follows
1. widespread absorption of toxins from the large inflamed
surface
2. The associated paralytic ileus with the following
•Loss of fluids
•Loss of electrolytes
•Loss of protein
3. Gross abdominal distention with elevation of the
diaphragm, which produces liability to lung collapse and
pneumonia

45. Clinical manifestations
• Abdominal pain – quite severe, patients tend to lie still, take
shallow breaths because even the slightest movements can cause
pain
• Irritation of the diaphragm may cause referred pain to the
shoulder tip
• Rigid board like abdomen
• Rebound tenderness
• Decreased peristalsis, abdominal distension, constipation
• Anorexia, nausea and vomiting
• High fever tachycardia and tachypneoa
• Possible poor respiration

46. Investigations
• X-ray of the abdomen – shows dilated loops if there is paralytic
ileus, free air if perforation has occurred, air-fluid levels if there is
a bowel obstruction
• Ultrasound and CT scan may identify the abscesses and ascites
• Peritoneal aspiration – analysis of peritoneal fluid may help
identify blood, bile, pus, bacteria and amylase contents if the
pancreas is involved
• Lab - leucocytosis
• Blood culture

47. Complications
• Dehydration
• Oliguria and possible renal failure
• Hypovolemic shock
• Sepsis – when bacteria enter the blood stream, causing septicaemia and
septic shock
• Intraabdominal abscess formation
• Paralytic ileus
• Bowel obstruction
• ARDS – acute respiratory distress syndrome due to increased
abdominal pressure against the diaphragm from intestinal distention
and fluid shift to the peritoneal cavity

48. Management
•The impulse to rush the patient, who is so obviously
gravely ill, to the operating theatre must be resisted:
•Time wisely spent on preoperative treatment may be life-
saving.

49. Treatment
Non surgical
• Nil by mouth (nil orally, NPO)
• NG tube to suction to decompress the stomach
• Iv fluids – isotonic fluids to replace the fluid lost from the
extracellular compartment
• Antibiotics – broad spectrum, penicillin, gentamicin, or
cephalosporin together with metronidazole
• Analgesics – with opiates, intravenous morphine, pethidine etc
• Oxygen – according to patient’s respiratory status

50. Surgery is indicated for identifying the cause
•Exploratory laparotomy – to remove/repair the inflamed
perforated organ
•Surgery focusses on controlling the contamination or
infection, removing the foreign material from the
peritoneal cavity and draining the pus which may have
collected
•Before abdominal closure irrigation of the peritoneal
cavity with antibiotic solution is done

51. Conservative management
Conservative treatment (‘drip, suck, antibiotics’) is
indicated at least initially,
•when infection has been localised e.g. appendix mass, or
•when the primary focus is irremovable as in pancreatitis
or post-partum infection.
•When the patient is moribund
•Lack of surgical facilities e.g. on board a ship

52. Intestinal Obstruction

53. Introduction
•Intestinal obstruction happens when there is restriction to
the normal passage of intestinal contents
•It may be divided into two main groups as
Paralytic (adynamic)
Mechanical (dynamic)

54. Mechanical Obstruction
Further classified according to the following
•Speed of onset: acute, chronic, acute on chronic
•Site: High or low
•Nature: simple versus strangulating
•Aetiology – according to the cause

55. Speed of onset
•Acute obstruction – the onset is rapid with severe
symptoms
•Chronic obstruction – symptoms are insidious (gradual,
subtle) e.g. most cases of carcinoma of large bowel
•Acute on chronic – a chronic obstruction that suddenly
becomes complete

56. Site
•High – small bowel obstruction
•Low – Large bowel obstruction

57. According to the Nature of obstruction
•Simple obstruction – when bowel is occluded without
damage to its blood supply
•Strangulated – when the blood supply of the involved
segment of intestine is cut off e.g. strangulated hernia,
volvulus, intussusception or adhesive band. Gangrene
may occur if untreated

58. Aetiology
•Causes in the lumen – fecal impaction, gallstone ‘ileus’,
food bolus, parasites, intussusception, pedunculated
tumour
•Causes in the wall – congenital atresia, tumours,
diverticulitis, Crohn’s disease
•Causes outside the wall – strangulated hernia (external
or internal), volvulus, adhesions

59. Common causes by age groups
•Neonatal – Congenital atresia and stenosis, imperforate
anus, volvulus neonatorum, Hirschsprung’s disease,
meconium ileus
•Infants – intussusception, Hirschsprung’s disease,
strangulated hernia, Merkel’s diverticulum

60. Causes by age (Cont…)
•Young adults and middle age – strangulated hernia,
adhesion and bands, Crohn’s disease
•The elderly – strangulated hernia, Ca colon, colon
diverticulitis, impacted faeces
Hernia is an important cause from infants to old age an
must always be ruled out

63. Strangulated Hernia

74. Pathophysiology
Fluid in the intestines is made up of two sources:
1. what the patient ingests and drinks
2. digestive secretion - saliva, gastric juice, bile,
pancreatic secretion and succus entericus.

75. Pathophysiology
•Bowel distal to the obstruction rapidly empties and
becomes collapsed
•Above the obstruction becomes dilated with gas
(swallowed air) and fluid poured from gastric, biliary and
pancreatic secretions
•Increased peristalsis to overcome obstruction causing
intestinal colic

76. Pathophysiology
Fluid made up of various digestive juices
•Saliva 1000mls/day
•Gastric secretions -2000mls/day
•Bile - 1000mls/day
•pancreatic secretions- 1500mls/day
•Succus entericuss -3000mls/day)

77. Pathology of obstruction
•As bowel distends blood supply becomes impaired with
mucosal ulceration, perforation
•Perforation may occur due to pressure by a band causing
ischaemic necrosis or pressure from within the gut

78. Pathophysiology
•In strangulating obstruction the integrity of the mucosal
barrier is lost due to ischaemia
•Bacteria and toxins can no longer be contained within the
lumen
•Transudation of bacteria into peritoneal cavity takes place
with secondary peritonitis

79. Pathophysiology
Lethal effects of obstruction is due to
•Fluid and electrolyte depletion (shock) due to copious
vomiting and loss into the bowel lumen
•Protein loss into the gut
•Toxaemia due to migration of toxin and bacteria into the
peritoneal cavity

80. Clinical Features
Four cardinal symptoms of intestinal obstruction
•Colicky abdominal pain
•Distension
•Absolute constipation
•Vomiting
NB: Not all may be present

81. Clinical Features
Pain
•Usually the first symptom
•Small bowel obstruction - peri-umbilical
•Distal obstruction – suprapubic
•Post op obstruction - may be disguised by general
discomfort and by opiates given to the patient

82. Clinical features
Distension
•Marked in large bowel obstruction, Sigmoid volvulus
•Not so marked in small bowel obstruction

83. Clinical features
Absolute constipation
•Failure to pass either flatus of faeces
•Its an early feature of large bowel obstruction but late
feature of small bowel obstruction
•Patient may pass one or two motions early after onset of
obstruction
•Partial or chronic obstruction may have passage of small
amounts of flatus

84. Clinical Features
Vomiting
•Early in high obstruction
•Late or absent in chronic or low obstruction
•Late stages - faeculent but not faecal
•Faeculent because of decomposing of stagnant contents
and altered blood transudating into the lumen
•True faecal vomiting only happens in gastrocolic fistula

85. Clinical Examination
•Dehydration
•In pain, may be rolling about with colic
•Tachycardia
•Afebrile, if fever may suggest strangulation
•Abdominal distention
•May have visible peristalsis

86. Clinical Features
During inspection look for
•Strangulated external hernia – inguinal or femoral (may
be difficult in fat people)
•Abdominal scar – previous operation may suggest
adhesions or bands

87. Clinical Features
•On palpation mass may be present (intussusception or
carcinoma)
•Bowel sounds may be accentuated or tinkling
•Rectal examination (DRE, ?PR) – should always be done.
It may reveal a mass in the Pouch of Douglas, the apex of
an intussusception or faecal impaction

88. Clinical Examination
•Digital vagina examination in a female patient is
mandatory.
•This is done before rectal examination with the same
gloved finger
•On auscultation - bowel sounds are increased in early
stages of obstruction but later on decrease and even stops.

89. Special Investigations
•Abdominal X-Rays (Erect and supine). Small bowel -
ladder pattern of dilated loops in central position and by
striations that pass completely across the width of dilated
bowel. Large bowel is peripheral and show haustration of
the taenia coli
•Computerised tomography (CT Scan)
•Water soluble contrast studies

91. • Specific treatment is according to the cause
• Chronic large bowel obstruction, slowly progressing obstruction
can be investigated at some leisure with sigmoidoscopy,
colonoscopy and barium enema and treated electively
• Acute obstruction, of sudden onset, complete and with risk of
strangulation is an urgent problem requiring emergency surgical
intervention
Treatment – General Principles

92. Preoperative Preps in Acute Obstruction
•Gastric aspiration by nasogastric suction – this helps to
decompress the bowel and reduce risk of inhalation of
gastric content during induction of anaesthesia
•Intravenous venous fluid replacement – Hartmann’s
solution or Normal Saline with potassium of renal
function is okay
•Antibiotic therapy if strangulation is likely

93. Management
•Resuscitation- (ABC…)
•Fluids, Blood
•Monitor urine output
•Prepare for laparotomy
•Type of operations depends on the findings

94. Operative treatment
•Affected bowel should be carefully inspected for viability
•Doubtful bowel may recover after relief of obstruction
•If extensive areas of bowel are doubtful second look
laparotomy after 48 hrs
•Small bowel may be resected and primary anastomosis
done

95. Operative treatment
•Large bowel resection with ileocolic anastomosis may be
done
•A colonic primary (colo-colonic) anastomosis is very
liable to leak in the presence of an obstruction
•A defunctioning loop colostomy or ileostomy may be
performed to minimize the complications of anastomotic
leak

96. Conservative Treatment
Conservative treatment is by means of iv fluids and NG
aspiration (‘drip and suck’). This is indicated
•Post operative paralytic ileus
•Repeated episodes of obstruction due to massive intra-
abdominal adhesions
•Chronic large bowel obstruction, remove faeces by
enema, prepare bowel and do elective operation

97. Paralytic ileus
• Functional obstruction most commonly seen after abdominal
surgery
• Also associated with trauma, intestinal ischaemia, sepsis
• Small bowel is distended throughout its length
• Absorption of fluid, electrolytes and nutrients is impaired
• Significant amounts of fluid may be lost from the extracellular
compartment

98. Clinical Features
•Usually history of recent operation or trauma
•Abdominal distension is often apparent
•Pain is often not a prominent feature
•If no nasogastric tube in-situ vomiting may occur

99. Clinical Features
•Large volume aspirates my occur via nasogastric tube
•Flatus will not be passed until resolution of the ileus
occurs
•Auscultation will reveal absence of bowel sounds

100. Investigations
•Plain abdominal x-ray may show dilated loops of small
bowel
•Gas may be present in the colon
•If doubt as to whether there is a mechanical or functional
obstruction
•Water soluble contrast study may be helpful

101. •Prevention is better than cure
•Bowel should be handled as little as possible
•Fluid and electrolyte derangements should be corrected
•Sources of sepsis should be eradicated
Management

102. Management
For an established ileus the following will be required
•Nasogastric tube
•Fluid and electrolyte replacement
•No drugs are available to reverse the condition
•Usually resolves spontaneously after 4 or 5 days

103. Thank You!