General and Colorectal
CASE 3: abDominal DiStenSion poSt hip replaCement
history
You are asked to review a 72-year-old man on the orthopaedic ward. He had a hemiarthroplasty of his right hip 6 days earlier. He was recovering well initially but has now developed significant abdominal distension. He has not opened his bowels or passed flatus for the past 4 days. His previous medical history includes treatment for a transitional cell carcinoma of the bladder and an appendicectomy. He is also known to have a hiatus hernia. He gave up smoking 6 months ago.
examination
His blood pressure is 114/88mmHg and pulse rate is 98/min. The abdomen is significantly distended with mild generalized tenderness. The abdomen is resonant to percussion and a few bowel sounds are heard. There are no hernias, and digital rectal examination reveals an empty rectum.
INVESTIGATIONS
|
|
Normal |
haemoglobin |
10.2 g/dl |
11.5–16.0 g/dl |
White cell count |
12.6 × 109/l |
4.0–11.0 × 109/l |
platelets |
422 × 109/l |
150–400 × 109/l |
Sodium |
131 mmol/l |
135–145 mmol/l |
potassium |
3.2 mmol/l |
3.5–5.0 mmol/l |
urea |
5.7 mmol/l |
2.5–6.7 mmol/l |
Creatinine |
78 μmol/l |
44–80 μmol/l |
an x-ray of the abdomen is performed and is shown in Figure 3.1.
Questions
• |
What is the diagnosis? |
• |
Are there any patients at particular |
|
risk of developing this condition? |
• |
What is the significance of the right |
|
iliac fossa pain in this setting? |
• |
What does conservative treatment |
|
consist of? |
Figure 3.1 plain x-ray of the abdomen.
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100 Cases in Surgery
ANSWER 3
The patient has large-bowel obstruction. When no mechanical cause is found for the obstruction, the condition is referred to as a pseudo-obstruction. The pathogenesis of the condition is still unclear, but abnormal autonomic colonic activity is thought to be a major factor. On the radiograph, air is seen throughout the colon down to the rectum, making a mechanical cause unlikely. If this is unclear, then a water-soluble contrast enema should be used to exclude a mechanical cause.
Pseudo-obstruction tends to occur in patients following trauma, severe infection, or orthopaedic/cardiothoracic/pelvic surgery. Systemic causes include sepsis, metabolic abnormalities and drugs. The clinical features are marked abdominal distension, nausea, vomiting, absolute constipation, abdominal pain and high-pitched bowel sounds. The presence of a fever with signs of peritonism suggests that the bowel is ischaemic and a perforation is imminent. This is most likely to occur in the caecum due to the distensibility of the bowel wall at this point. The patient should be examined carefully for tenderness in the right iliac fossa, and the caecal diameter noted on the radiograph. If the diameter increases to over 10 cm, then there is a significant risk of perforation.
Conservative treatment involves keeping the patient nil by mouth, intravenous fluids and nasogastric decompression. A flatus tube can be placed by rigid sigmoidoscopy to relieve some of the distension. Decompression is more effectively achieved by colonoscopy. Fluid and electrolyte abnormalities should be corrected and drugs affecting colonic motility discontinued, e.g. opiates.
KEY POINTS
•the overall mortality rate in pseudo-obstruction managed conservatively is approximately 15 per cent.
•this figure rises to 30 per cent in patients who require surgery, and as high as 50–90 per cent with faecal peritonitis.
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General and Colorectal
CASE 4: perianal pain
history
A 28-year-old man presents to the emergency department complaining of anal and lowerback pain for the previous 36 h. He has tried taking simple analgesics with no benefit. The pain is progressively getting worse and he is now finding it uncomfortable to walk or sit down. He is otherwise fit and well, and smokes ten cigarettes a day.
examination
Inspection of the anus reveals a 3 cm × 3 cm swelling at the anal margin. The swelling is warm, exquisitely tender and fluctuant. There is no other obvious abnormality.
Questions
•What is the diagnosis?
•What are the aetiological factors associated with this condition?
•How are these lesions anatomically classified?
•What treatment is required?
7
100 Cases in Surgery
ANSWER 4
This patient has a perianal abscess. The organisms responsible tend to be either from the gut (Bacteroides fragilis, Escherichia coli or enterococci) or from the skin (Staphylococcus aureus). Anorectal abscesses originate from infection arising in the cryptoglandular epithelium lining the anal canal. The internal anal sphincter can be breached through the crypts of Morgagni, which penetrate through the internal sphincter into the intersphincteric space. Once the infection passes into the intersphincteric space, it can spread easily into the adjacent perirectal spaces.
! Classification of anorectal abscesses
See Figure 4.1.
Supralevator
Levator ani abscess muscle
Ischioanal |
External sphincter |
(ischiorectal) |
Internal sphincter |
abscess |
Perianal abscess |
|
|
|
Intersphincteric or intramuscular |
|
abscess |
Figure 4.1 Diagram demonstrating the anatomy of anorectal abscesses.
!Aetiological factors for anorectal abscesses
• idiopathic (vast majority) |
• anal trauma/surgery |
• Crohn’s disease |
• pelvic abscesses may arise secondary |
• anorectal carcinoma |
to inflammatory bowel disease or |
• anal fissure |
diverticulitis |
The patient should have an examination under anaesthesia (EUA) with sigmoidoscopy to examine the bowel mucosa. The abscess should be treated by incision and drainage, and pus should be sent for culture. Skin organisms are less commonly associated with fistulae than gut organisms. Anorectal fistulas occur in 30–60 per cent of patients with anorectal abscesses. If a fistula is found at the time of incision and drainage, the location should be noted and the patient brought back once the sepsis has resolved.
KEY POINTS
•anorectal fistulas occur in 30–60 per cent of patients with anorectal abscesses.
•Sigmoidoscopy and proctoscopy should be done at the time of surgery to examine for underlying pathology.
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