Final answer:
The best course of action would be to perform a rectal exam to identify the cause of the symptoms. A CT scan of the abdomen and prescribing a laxative may also be considered.
Step-by-step explanation:
The best course of action for a 75-year-old woman complaining of constipation and abdominal pain for two days with a moderately distended abdomen would be to perform a rectal exam. A rectal exam can help identify any signs of obstruction or impaction that could be causing the constipation and abdominal pain.
Ordering a CT scan of the abdomen may be considered if the rectal exam reveals a potential cause for concern or if there are additional symptoms that suggest further investigation.
Prescribing a laxative may help relieve the constipation, but it is important to determine the underlying cause first. Referring the patient to a gastroenterologist may also be considered if the symptoms persist or worsen.