Final answer:
The symptoms and test results described in the student's question suggests the patient has lactose intolerance, diagnosed with a hydrogen breath test and possibly confirmed by an intestinal biopsy. Lactose-free options and lactase supplements are available to manage symptoms.
Step-by-step explanation:
The student's question regarding a patient with symptoms of diarrhea, and a series of tests such as hydrogen breath tests, stool test for reducing substances, low stool pH, and increased stool osmotic gap suggests that the patient may be suffering from lactose intolerance. Lactose intolerance is commonly diagnosed using the hydrogen breath test which measures the amount of hydrogen exhaled after the consumption of lactose. High levels of hydrogen indicate that lactose is not being properly digested, leading to its fermentation by bacteria in the colon.
An intestinal biopsy can further confirm a diagnosis by measuring lactase enzymes or its mRNA in biopsy tissue, though this is not routine due to the need for specialized laboratory and expertise. For infants, stool acidity may be tested as other forms of testing can be risky or impractical.
For patients with lactose intolerance, there are a variety of lactose-free dairy products and dietary supplements providing lactase to help them digest lactose effectively.