How an “air-contrast barium enema” performed

 

Presentation: 65-year-old woman with a loss of appetite, abdominal cramps, constipation, and blood in her stool.
History: Delores Murphy, a 65-year-old white female, was in good health until about 6 weeks ago, when she noted occasional cramps in the left lower quadrant of the abdomen associated with constipation. The episodes of cramping last about 30 minutes each and are most severe in the hour following her meals. She has taken laxatives which have partially relieved her symptoms, but she has had a decreased appetite and 12-pound weight loss over the past four weeks. In addition, she has become increasingly fatigued over this period. When questioned about her bowel habits, she reported bright red blood in her stools and a smaller caliber (i.e., diameter) of stool over the past two weeks.
Physical Examination: She appeared fatigued and distressed. Head and neck exams were normal, as was her thorax. Palpation of the abdomen revealed a 10 x 10 cm mass and tenderness in the left lower quadrant. Percussion over this area revealed a hollow, tympanic sound. Hepatomegaly was noted, and a hard and slightly tender liver edge was felt in the right upper quadrant. Bowel sounds were noticeably reduced. A stool sample was tested with Guaiac paper and was positive for blood.
Questions: Choose one of the three sets of questions to serve as your initial response.
1. Propose an explanation for Delores’s abdominal cramps and left lower quadrant mass.
2. Propose an explanation for Delores’s reduced bowel sounds and smaller-caliber stools.
3. What is “flexible sigmoidoscopy”?
OR
1. How is an “air-contrast barium enema” performed?
2. Propose an explanation for Delores’s weight loss and decreased appetite.
3. How would the appearance of an adenoma differ from that of a carcinoma under the microscope?
OR
1. Why was it important to biopsy suspicious lesions?
2. What kinds of information can be gained by performing an air-contrast barium enema?
3. Ninety percent of all cancers are carcinomas. Propose an explanation for why such a disproportionately high number of cancers are carcinomas.
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Discussion 1- Scenario 2
Presentation: A 14-year-old girl with cystic fibrosis has complained of an increased cough productive of green sputum over the last week. She also complained of being increasingly short of breath, and she is noticeably wheezing on physical examination.
Arterial blood was drawn and sampled, revealing the following values:
pH 7.30
pCO2 50 mm Hg
pO2 55 mm Hg
Hemoglobin – O2 saturation 45 %
[HCO3-] 24 meq / liter
Normal Levels of Substances in the Arterial Blood:
pH 7.40 + 0.05
pCO2 (partial pressure of carbon dioxide) 40 mm Hg
pO2 (partial pressure of oxygen) 90 – 100 mm Hg
Hemoglobin – O2 saturation 94 – 100 %
[HCO3-] 24 meq / liter
Questions: Choose one of the two sets of questions to serve as your initial response:
1. What causes cystic fibrosis? Describe the pathophysiologic mechanisms of the disease.
2. How would you classify this girl’s acid-base status?
3. How does cystic fibrosis cause this acid-base imbalance?
OR
1. How would the kidneys try to compensate for the girl’s acid-base imbalance?
2. This girl has also had a long history of diarrhea and poor weight gain. Explain why.
3. List some other causes of this type of acid-base disturbance.

 

 

Sample Solution

Case 1: Delores Murphy

Set 1: Questions

1. Propose an explanation for Delores’s abdominal cramps and left lower quadrant mass.

  • Possible explanation: The abdominal cramps and left lower quadrant mass are highly suggestive of a colonic malignancy, specifically colorectal cancer. The location of the mass in the left lower quadrant is consistent with a tumor in the descending or sigmoid colon.

2. Propose an explanation for Delores’s reduced bowel sounds and smaller-caliber stools.

  • Possible explanation: The reduced bowel sounds indicate decreased intestinal motility, which can occur due to a partial obstruction caused by the colonic mass. The smaller-caliber stools suggest a narrowing of the colon downstream from the tumor, leading to difficulty in passing stool.

3. What is “flexible sigmoidoscopy”?

  • Flexible sigmoidoscopy is a diagnostic procedure that allows visualization of the lower part of the colon (sigmoid colon and rectum). A thin, flexible tube with a light and camera is inserted into the rectum to examine the inner lining of the colon for abnormalities such as polyps, inflammation, or tumors.

Set 2: Questions

1. How is an “air-contrast barium enema” performed?

  • Air-contrast barium enema involves introducing barium sulfate (a contrast material) into the colon followed by air. This procedure allows for better visualization of the colon’s mucosal lining and can help identify abnormalities such as polyps, tumors, or inflammatory bowel disease.

2. Propose an explanation for Delores’s weight loss and decreased appetite.

  • Possible explanation: The weight loss and decreased appetite are likely due to the underlying malignancy. As the tumor grows, it can interfere with normal digestion and absorption of nutrients. Additionally, the body’s response to cancer can lead to anorexia and cachexia.

3. How would the appearance of an adenoma differ from that of a carcinoma under the microscope?

  • Adenoma: Typically appears as glandular tissue with abnormal growth patterns but without evidence of invasion into surrounding tissues.
  • Carcinoma: Shows invasive growth with abnormal cells infiltrating the surrounding tissue. There may also be evidence of metastasis to other organs.

Set 3: Questions

1. Why was it important to biopsy suspicious lesions?

  • Biopsy is essential to confirm the diagnosis of cancer. By obtaining a tissue sample from the suspicious mass, pathologists can examine the cells under a microscope to determine if they are cancerous.

2. What kinds of information can be gained by performing an air-contrast barium enema?

  • Air-contrast barium enema can provide valuable information about the shape, size, and location of the colon, as well as any abnormalities such as polyps, tumors, or strictures. It can also help assess the overall bowel function.

3. Ninety percent of all cancers are carcinomas. Propose an explanation for why such a disproportionately high number of cancers are carcinomas.  

  • Carcinomas originate from epithelial cells, which are the lining cells of organs and tissues. The body is composed primarily of epithelial tissue, making it the most common site for cancer development. Additionally, epithelial cells are constantly exposed to environmental factors and irritants, increasing their risk of malignant transformation.

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