acute bowel obstruction

1. ACUTE ABDOMEN Shynal Dutt - s180271
Mashal – s200604

2. Q1 - ACUTE ABDOMEN DEFINITION
• Defined as a sudden onset of severe abdominal pain
• Developing in less than 1 week’s duration
• Requiring admission to hospital for urgent attention and treatment, which has
not been previously investigated or treated’

3. Q2 - Be able to correlate abdominal
anatomy to the presentation of an
acute abdomen.

4. ABDOMINAL
BOUNDARIES
• Superior – diaphragm
• Inferior- pelvic inlet
• Anterior- anterior abdominal wall
• Posterior – lumbar vertebrae, upper part of bony
pelvis, psoas and quadratus lumborum muscles

5. Abdominal quadrants

6. ABDOMINAL
PAIN

7. TYPES OF ABDOMINAL PAIN
1. Visceral Pain- dull and deep-
seated pain usually localized
vaguely to the area occupied by the
viscus during development, and is
referred to the overlying skin of the
abdominal wall
1
2. Parietal Pain (Somatic)- sharp or
knife-like in nature, and is usually
well localized to the affected area.
2
3. Referred Pain – pain/ discomfort
at a site distant from the affected
organ, reflects same
embroyological nerve root.
3

8. Q5 - Be able to correlate the
pathophysiology of appendicitis to
its clinical presentation
• 2-20 cm in length
• <6mm in diameter
• <2mm wall thickness
• Supplied by the appendicular artery ->
ileocecal artery – SMA
• Innervation
• Sympathetic – Nerve fibres from
T10
• Parasympathetic – Vagus nerve

9. Aetiology
Appendicitis – Acute onset of an Inflamed appendix
Primary aetiology that has been proposed is appendiceal (luminal) obstruction
• Children/ young adults – Hyperplasia of lymphoid follicles or initiated by infection
• Adults – Fibrosis/ stricture, fecalith (hard faecal mass), obstructing neoplasm (benign or
malignant)
• Other causes – Parasites or foreign body

10. Pathophysiology
1. Luminal obstruction
2. Overgrowth of bacteria – Occurs within diseases appendix – Invade wall and propagate
further
3. Inflammation and swelling (Lumen becomes mucus filled and distended)
4. Increased luminal and intramural pressure
5. Ischemia due to thrombosis, occlusion of small vessels in appendiceal wall, and stasis of
lymphatic flow
6. Perforation
7. Localised abscess formation or diffuse peritonitis

11. Clinical features
• Highly variable pain
• Sequence of events  Preceding period of anorexia followed by central abdominal
pain then vomiting, and it concludes with pain in the RLQ (Right anterior Iliac Fossa)
• Initially - Gnawing pain in periumbilical region -> Obstruction and inflammation of the
appendix. Mediated through visceral pain [C] fibres as a mid-gut pain
• Post transmural - Serosa of appendix and parietal peritoneum become involved ->
Localised sharp pain which is mediated through somatic pain [A-delta] fibres in the
RIF

12. Clinical features continued
• Tachycardia
• Fever 37.5-38.5 degrees – Generally occurs later
• Furred tongue
• Pt will remain still as best as possible
• Coughing exacerbates pain
• Foetor oris +/- flushing
• Shallow breaths
Atypical presentations – Indigestion, flatulence, bowel irregularity, diarrhea, and generalised malaise

13. Hx and Physical exam
Non-specific – Progressive fever, anorexia, N/V, diarrhoea/ constipation
Abdominal pain – Migratory, dull colicky periumbilical pain or sharp RIF pain
Physical exam – Inspection, palpation, percussion, auscultation + special tests

14. Special tests –
McBurney’s sign
• Guarding and rebound tenderness
present at McBurney’s point – 1/3 the
distance from the anterior superior iliac
spine to the umbilicus on the right side

15. Rovsing sign
• Palpation of the Pt LIF will bring about
pain in the Pt RIF – Indirect tenderness –
Indicative of right-sided local peritoneal
irritation

16. Psoas sign
• Pt in left lateral position – Extension of
the hip will bring about pain in RIF –
Associated with retrocecal appendix
• Psoas borders peritoneal cavity. Stretching/
contracting the muscle causes friction against
the inflamed tissue

17. Obturator sign
• Associated with pelvic appendix – Pts
knee and hip are flexed and then internal
rotation of the right hip takes place. RLQ
pain elicited

18. Investigations
Laboratory
• Mild leukocytosis – Left shit – Indicates immature WBCs
present
• B-hCG – Rule out ectopic pregnancy
• Higher leukocyte counts seen with perforation
• Urinalysis – Rule out renal/ urological causes
Imaging
• US – 90-94%. Also assists in ruling out gynae causes
• CT scan – 94-100% accuracy. Appendix will appear thick
walled, enlarged (>6mm) with inflammatory changes.
Optimal investigation
• X-ray – Free air – Perforation or not

19. Alvarado score
10 point score system - Used for predicting
acute appendicitis
Mnemonic - MANTRELS
Score
• 5-6 = Compatible diagnosis with
appendicitis
• 7-8 = Probably acute appendicitis
• 9-10 = Very probable acute appenditis
diagnosis
If suspected, admission/ surgery required

20. Management
of
appendicitis
• Hydrate and correct electrolyte abnormalities (if
excessive vomiting)
• Appendectomy – Gold standard
• Some cases can be treated with antibiotics -
Metronidazole + cefuroxime
Laparoscopic surgery
• Wound infection is less likely
• Reduced pain and hospital stay
• Sooner return to normal activity
• Reduced costs outside hospital
• Intra-abdominal abscess is twice as likely
Open surgery
• Short duration of surgery and lower operation costs

21. Complications
• Perforation
• Appendix mass – Inflamed appendix becomes covered with omentum
• Pelvic abscess
• Sepsis

22. Q6 – Be able to describe the cardinal
symptoms of bowel obstruction
• Obstruction which inhibits movement of bowel contents
Epidemiology
• High likelihood in males (4:1)
• Children – Intussusception – Sliding of a part of the intestine into an adjacent part
• Adults – Hernia and adhesion
• Elderly – Adhesions and colorectal tumours

23. Aetiology
Location Causes
Intraluminal Gallstone ileus, ingested foreign body, faecal impaction
Mural Cancer, inflammatory strictures, intussusception,
lymphoma, Meckel’s diverticulum, diverticular strictures
Extramural Hernias, adhesions, peritoneal metastasis, volvulus

24. Cardinal symptoms of bowel
obstruction
Diagnosis of dynamic intestinal obstruction based on 4 principles (cardinal
features)
• Pain – Colicky or cramping
• Distention
• Vomiting – Early in proximal, late in distal
• Absolute constipation – Early in distal, late in proximal

25. Obstruction classification & Features
Small bowel obstruction
• High small bowel obstruction – Vomiting -> pain -> distension
• Low small bowel obstruction – Pain -> distension -> vomiting
Large bowel obstruction – Distension -> pain -> vomiting