A 67-Year-Old Man Comes to the Emergency Department Due to Abdominal

question 129

Multiple Choice

A 67-year-old man comes to the emergency department due to abdominal discomfort and distension.  Five days ago, he began having large-volume watery stools 6-8 times daily after eating at a new restaurant.  He also has had associated mild abdominal cramps and nausea but no fever, chills, vomiting, or bloody stools.  His wife, who had the same food, also experienced similar symptoms.  He self-treated with increased oral fluids and the stool frequency and consistency began to improve.  However, his bowel movements abruptly stopped yesterday, and the diffuse abdominal discomfort and distension worsened.  Medical history includes hypertension, coronary artery disease, and heart failure treated with diuretics.  Temperature is 37 C (98.6 F) , blood pressure is 116/72 mm Hg, and pulse is 102/min.  Physical examination shows dry mucous membranes.  The abdomen is distended, tympanic, and mildly tender to palpation with no guarding or rebound tenderness.  Bowel sounds are decreased.  Digital rectal examination reveals an empty rectal vault with no evidence of blood or melena.  Abdominal CT scan shows diffuse colonic dilation with nondilated small bowels.  Leukocyte count is normal and testing for Clostridioides (formerly Clostridium) difficile is negative.  Which of the following most likely contributed to this patient's current condition?

• A)Colonic endoluminal mass
• B)Colonic hypoperfusion
• C)Electrolyte abnormality
• D)Entamoeba infection
• E)Inflammatory bowel disease

---

Definitions:

M/Z Value

Mass-to-charge ratio, a key concept in mass spectrometry used to identify molecules by their mass and charge.

M+2 Peak

Denotes a secondary peak in mass spectrometry, two units higher than the molecular ion peak, often indicative of the presence of isotopes like sulfur-32 or the incorporation of two chlorine or bromine atoms.

MS Peak

A representation of a specific mass-to-charge ratio detected in mass spectrometry, indicating the presence of a particular ion or molecule fragment.

Major Isotopes

The most abundant isotopes of an element, which have a significant presence in nature.