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At the Emergency Dept

abdominal pain

Score: 0 / 75

You are a third year medical student doing an attachment in the emergency department of a busy general hospital. You are asked by your consultant, Dr Boey Thng Choo, to talk to a patient in the extended diagnostic treatment unit. The patient is a 67 year old man, Mr Pak Tor Tia, who complains of abdominal pain and vomiting.

Question: Based on the history, which system would you like to focus your physical examination on?

Based on the presenting symptoms of colicky abdominal pain, vomiting, nausea and constipation, the problem is likely to fall within the gastrointestinal system. Thus, it would be prudent to focus on the gastrointestinal system in our subsequent physical examination. Before moving on to PE, you do a quick search for any previous medical records.

You find that Mr Pak was admitted 6 years ago for an operation. Before the operation, a diagnostic procedure was performed. Some images from the procedure are shown below.


Question: What is the procedure shown on the LEFT and what is the diagnosis?

Hint: Look at the normal histology picture. Which part of the gut does it show?
Hint: Look at the normal histology picture. Which part of the gut does it show?
Hint: Look carefully at the bottom histology picture. Evaluate the architecture of the glands and carefully look at the nuclei of the cells.

The histology of the tumour shows irregularly shaped glands infiltrating into the stroma. There is loss of crypt architecture (use the top picture as a reference for normal architecture). The abnormal glands are lined by cells showing nuclear pleomorphism, enlargement and loss of polarity. The stroma surrounding the infiltrative glands is disturbed and more cellular than usual – this is stromal desmoplasia. Thus, the features are those of a malignant gland forming tumour – adenocarcinoma.

The colonoscopy and biopsy performed showed the presence of an adenocarcinoma in the transverse colon. The baseline serum CEA (Carcinoembryonic antigen) was 41 µg/L (normal: <2.5 µg/L). The tumour was resected in a right hemicolectomy.

The pathology report from the biopsy is shown below.

Click on the relevant text that indicates the tumour GRADE.

The correct answer(s) will be highlighted in green.

(A, B) Transverse colon tumour, extended right hemicolectomy:
  • Adenocarcinoma, moderately differentiated
  • Tumour invades through the muscularis propria into pericolic fat (pT3)
  • Resection margins free of tumour
  • No lymphovascular or extramural venous invasion
  • 1 of 15 regional lymph nodes involved by metastatic carcinoma (pN1a)


Here is an explanation of the significance of various prognostic factors in the report.



Question: Regarding tumour prognosis, which of the following statements is correct?

Diagnostic imaging looks at the gross features of the tumour, such as local extent and distant spread.

Tumour grade reflects the degree of malignancy and is determined by evaluating the tumour cells microscopically e.g. the nuclear features, mitotic rate etc.

Tumour stage reflects the local extent and distant spread of tumours. On the other hand, how rapidly tumour cells grow is more related to tumour grade.

Tumour stage reflects the local extent and distant spread of tumours. Prediction of response to therapy is usually accomplished by evaluating the expression of specific target proteins by the tumour or its mutation profile.

You now feel that you have enough information to move on to the physical examination.

Question: What is likely to be the main problem?

Mr Pak is wheeled away for further investigations. In the meantime, your consultant Dr Boey asks you to read up on the causes of intestinal obstruction and give a short presentation later. You work hard to come up wth a good way to remember the causes.

Attempt to classify the causes in the box below:


A while later, a supine abdominal X-ray is performed:

Picture source: Dr Ahmed Abd Rabou, Radiopaedia.org. From the case rID: 27265
Question: Where is the likely site of intestinal obstruction?

Click on a part in the diagram below to select it as your answer.

Just before you leave for the night, you learn that Mr Pak has been admitted. Dr Boey asks you to follow him up in the ward. The next day, you visit the ward and meet the duty consultant, Dr Chang Wei Bing. He tells you that Dr Boey has asked him to check up on you. Dutifully, you look up Mr Pak's notes and see that the results from some further investigations are now ready.

The serum CEA is 2.2 µg/L (normal: <2.5 µg/L).

CT Abdomen showed no intrabdominal masses or thickening at the anastomotic site.

Question: What is the most likely cause of intestinal obstruction in Mr Pak's case?

Adhesions are a common cause of small bowel obstruction. Mr Pak's history of previous colorectal surgery predisposes him to adhesions.

One needs to exclude a recurrence of Mr Pak's colon cancer, however, the normal curent CEA level and CT findings render this unlikely. There are also no constitutional symptoms of weight loss.

Mr Pak has had previous abdominal surgery and is thus predisposed to incisional hernias. However, there was no incisional or inguinal hernia noted on the physical examination. Thus, an incarcerated hernia is less likely to be the cause.

Small intestinal tumours might be a possible cause, given the level of obstruction is at the small intestine. But Mr Pak has no known family history of early age cancer or familial adenomatous polyposis, and small intestinal tumours are generally rare. There are also no constitutional symptoms of cancer, but this is a weaker justification.

Intussusception might also cause small bowel obstruction. Yet intussusception is seen more in young children, so Mr Pak's age is a factor against intussusception. There was also no sausage-like mass palpated in the right hypochondrium on physical examination. He also does not have the classical presentation of red currant jelly stools, although this may not be seen in some patients with intussusception.

A basic metabolic panel and full blood count have also been performed. The results are shown below.

Na+ 140 mEq/L (135 - 145 mEq/L)
K+ 4.0 mEq/L (3.5 - 5.0 mEq/L)
Cl- 99 mEq/L (95 - 105 mEq/L)
HCO3- 28 mEq/L (22 - 26 mEq/L)
pCO2 42 mmHg (35 - 45 mmHg)
pH 7.45 (7.35 - 7.45 mEq/L)
Creatinine 90 µmol/L (60 - 110 µmol/L)
Urea 7.1 mmol/L (2.5 - 6.7 mmol/L)
Haemoglobin 14.2 g/dL (13 - 17 g/dL)
Total WBC 13×109/L (4 - 11×109/L)
Platelets 240×109/L (150 - 400×109/L)
Question: What is the main acid-base abnormality in Mr Pak's case?

The pH is 7.45, which is high. The HCO3- is elevated, and pCO2 is also somewhat high. This indicates that the primary derangement is a metabolic alkalosis (as indicated by the high HCO3-), with some respiratory compensation (as indicated by the somewhat high pCO2).

The decision is made for conservative management. Mr Pak is kept nil by mouth, and a nasogastric tube is inserted for gastric decompression. IV fluids are given to replace lost electrolytes.

Now Dr Chang asks you to look up the complications of intestinal obstruction.

Attempt to list them in the box below:



Complication Pathophysiology
Bowel ischaemia
  • Accumulation of contents in obstructed gut lumen and gut distension causes rise in intraluminal pressure
  • Veins are compressed, reducing venous outflow and causing ischaemia
  • Arterial supply may eventually be impeded
  • Bowel wall becomes oedematous, congested and dusky
Perforation
(surgical emergency)
  • Necrosis of intestinal tissue due to ischaemia or pressure
  • Integrity of intestinal wall compromised
  • Spillage of gut contents into peritoneal cavity
Peritonitis
(potentially life-threatening)
  • Bacterial translocation into peritoneal cavity due to tissue necrosis or perforation
  • Board-like rigidity, guarding, rebound tenderness

Dr Chang is happy with your answer. Eventually, your long day in the hospital comes to an end and you go home.

The next day, Mr Pak complains of increasing abdominal discomfort. He is not looking too good. An erect chest X-ray is performed.

Picture source: Dr Varun Babu, Radiopaedia.org. From the case rID: 19474
Question: Which of the four labels shows a finding that indicates a potential surgical emergency?

Label A: The chest X-ray shows free air under the diaphragm. This indicates bowel perforation, which is a surgical emergency.

Mr Pak proceeds for an emergency laparatomy. A segmental resection of the perforated bowel loop is performed, as well as adhesiolysis.

Mr Pak's recovery is uneventful, and his symptoms resolve. He is discharged well.

Final score: 0 / 75

It looks like you may need to spend more time both in the wards and hitting the books. Better luck next time!

—— End of Case ——
To recap Gastrointestinal Pathology, click HERE