The Case of the Child with Diarrhea Jeremy, a seven year old African-American bo
ID: 217591 • Letter: T
Question
The Case of the Child with Diarrhea
Jeremy, a seven year old African-American boy, is brought into his pediatrician's office by his mother. For the past few days Jeremy has been suffering from abdominal pain and diarrhea (which is often explosive) that begins approximately 2 - 5 hours after eating. These incidences seem to occur more rapidly and with a greater degree of severity after breakfast compared to other meals. Jeremy's mother also notes that neither she nor her husband are exhibiting any of these symptoms while consuming the same foods as Jeremy. In talking with Jeremy, the pediatrician notes that the abdominal pain is associated with abdominal cramping and flatulence. Jeremy also states that he would occasionally feel "sick to his stomach" prior to the onset of some of these episodes. When examining Jeremy's medical record, his pediatrician notes that Jeremy's height and weight were slightly less than normal for his age and that he had exhibited similar symptoms approximately 6 months ago. Jeremy is current on all of his immunization and has no previous history of illness.
Physical examination indicates that Jeremy was afebrile and normotensive. His respiratory rate was 12 breaths per minute and pulse was strong and regular at 73 beats per minute. Examination of the ear, nose, and throat proved to be uneventful. Jeremy's reflexes were normal and within expected ranges. He did not present with any abdominal masses, splenomegaly or hepatomegaly. Additionally, there was no guarding when the internal organs were palpated. Clinical blood and urine screens were ordered and came back normal. The pediatrician asks Jeremy's mother to describe their diet, specifically indicating how Jeremy's diet may differ from either of the parents. With the exception of increased milk consumption by Jeremy, the diets are similar except in the quantity consumed by each individual.
Jeremy's pediatrician suspects Jeremy may be lactose intolerant and collects a stool sample. The pH of the stool sample is in the acid range. Based on the results of the stool sample, a lactose tolerance test is conducted. (Both the pediatrician and Jeremy's mother would prefer not to subject Jeremy to a small bowel biopsy.) Two tests are available, the breath test and a more traditional blood test. Jeremy's pediatrician explains that if Jeremy were lacking lactase, the enzyme that breaks down lactose, the primary sugar in milk, administration of an oral dose of lactose would cause both the symptoms that Jeremy presents with as well as some other physiological changes. If Jeremy was lacking lactase the amount of hydrogen gas (H2) in Jeremy's breath would increase. However, the pediatrician recommends a blood test that actually monitors the concentration of glucose in the blood following oral lactose. If Jeremy were lacking lactase, the rise in blood glucose following lactose administration would be less than normal. Jeremy's mother agrees to the blood test and the results indicate that Jeremy is indeed lactose intolerant.
The pediatrician explains to Jeremy and his mother that the easiest way to treat the problem is to stop drinking and eating most milk and milk containing products. If Jeremy wants to continue to drink milk it would be best to purchase milk that has added lactase which predigests the lactose. Also, he could probably consume cheeses and yogurt, however, these may also cause some degree of bloating, discomfort and diarrhea. Finally, the pediatrician recommends calcium supplements to ensure that Jeremy is receiving adequate calcium for bone development.
Questions:
Define the bold terms in the text.
Describe the normal enzymatic cycle catalyzed by lactase.
identify the environmental factors that can influence enzyme activity and briefly discuss how enzyme activity is altered by these factors .
Why would blood glucose concentrations fail to rise following an oral dose of lactose in individuals with lactase deficiency?
Why would the inability or digest lactose cause diarrhea?
Bacteria in the colon are able to anaerobically metabolize lactose; how would this result in some of the symptoms Jeremy presents with?
Explanation / Answer
diarrhea: intestinal symptom characterized by the expulsion of large amounts of fecal matter, many times in the liquid form, accompanied by abdominal pain.
flatulence: gas from the intestine that is expelled out of the body through the anus.
afebrile: that doesn´t present high temperature or fever.
normotensive: that has normal blood pressure.
splenomegaly: increased size of the spleen.
hepatomegaly: increased size of the liver.
acid: in the pH range there is a scale from 0 to 14. 7 is neutral pH, above 7 is basic pH and under 7 is acid pH. On the other hand pH is the amount of hydrogen present in a substance, the more hydrogen, the more acid the pH.
2. lactose is a type of sugar with two hexagonic rings, and it´s formula is: C12H22O11. Lactase breaks the link between the two rings having as a result Glucose and Galactose. That is why we measure the amount of glucose in blood to see if there is absense of lactose in the system (this would be the answer to the fourth question).
3. There are some factors that influence the enzyme activity. One example is the quantity of lactose ingested, the more lactose there is, the more difficult it is to digest it because the system saturates, meaning there is not enough lactasa. Another factor is the presence of microbiota that is able to produce lactase or not. In the intestine we all have bacteria as a defense mechanism and that can help us digest different types of food. The presence of bacteria that can produce lactase helps the digestion of lactose of the individual.