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Firstly, to define malabsorption which is technically the defective mucosal absorption of nutrients and minerals. Now, this is contrasted with maldigestion which is the impairment of nutrient breakdown or hydrolysis. So in other words someone who has lactose intolerance because of lactase deficiency actually has maldigestion. They can’t break down the lactose but I think it’s really simplified in the medical literature because most people lump it together in malabsorption and that’s what I’ll malabsorption, malabsorbtion, celiac sprue, celeac sprue
So first of all we’ll talk about normal digestion and absorption, a brief physiology review. When we talk about malabsorption and I should mention what the definition is, that almost implies that you're going to have a steatorrhea and
The treatment. It’s important to correct nutritional deficiencies. You’ve got to restrict the dietary fat because if you just give them back the fat they’re just going to make their steatorrhea worse. You need to treat the underlying disorder and that’s why it’s important to do the workup because depending on what disease you find will guide you your therapy.
I’m going to just review some of these cases then which will emphasize this last point in regards to treatment. The pancreatic exocrine insufficiency, there’s a variety of diseases that cause this. It’s important to then supplement these patients back with lipase and you actually need to use higher levels of lipase than are available in just one or two capsules. In my handout, I’ve given you recommendations for high doses of lipase that you should use and it’s like up to eight tablets in a day.
Now, if you’re treating patients with chronic pancreatitis who are having pain, this is an aside, those patients should use the non-enteric coated prep because what you’re trying to interrupt at is the CCK feedback mechanism which occurs in the duodenum and the pancreatic enzymes turn off CCK which would hopefully help with the pain. So if patients have pain in chronic pancreatitis and steatorrhea, use the non-enteric coated preps. If it’s enteric coated, it wouldn’t break down until later on beyond the duodenum. So that’s just the important point to remember. The non-enteric coated will be present in the duodenum.
Small intestinal bacterial overgrowth, again, greater than 105 organisms, the pathogenesis may be from bile salt breakdown – bile salts can irritate the colonic mucosa and cause diarrhea – or direct toxic effect against the enterocyte. Predisposing lesions are structural disorders like diverticulum, strictures. Motor disorders such as you may see in scleroderma can cause bad bacterial overgrowth.
The diagnosis, again, can be by culture or breath test and the treatment is with antibiotics. In most instances you see three different patterns. You may find patients that just require one course of antibiotics. In most patients, if they have that underlying disorder, you know, sometimes you’ll see bacterial overgrowth just in the elderly for no reason. You can find no reason why they have it and you give them one course of antibiotics and it goes away.
But if you have a patient who is a diabetic or who may have an enteropathy with slow transit or scleroderma, those patients have that condition all the time and you find that you may have to cycle them with antibiotics. The majority of my patients fall in this category but I see a skewed patient population. I treat them typically with alternating different types of antibiotics. I usually do days 1-7 of the month. It’s easy to remember and then I’ll have them follow up the following month with metronidazole and then the following month maybe with ciprofloxacin.
Then the last type of patients are those that you repeatedly have to cycle and they have to be almost on it continuously. I use a different sort of antibiotics. Whether I’m really stopping resistance I don’t know. That’s why I do it.
Lactase deficiencies. The most common is disaccharidase deficiency. There’s primary or secondary lactase deficiency. The diagnosis. I typically do a dietary trial but you can also do lactose hydrogen breath tests. The treatment can be with LactAid and dietary restriction. Most patients can tolerate 8 ounces of milk so that’s usually not a problem.
Celiac sprue is an immunologic response to gluten. The diagnosis is based on an abnormal biopsy. This is just suggestive of the disorder. It’s confirmed by restriction of gluten in your diet. This is tough. This is one of those disorders where patients are looking at you to give them a pill but you give them a diet that’s hard to follow and they’re the only people that can help themselves. Complications are lymphoma, squamous cell carcinoma of the esophagus, ulcerations and carcinoma.
This is an example of a normal appearing small bowel with a normal villus pattern. You can see the nice glistening mucosa. When you go down there endoscopically with a patient with sprue, it’s just very atrophic appearing mucosa and when you add methyl blue you just really don’t see any villi stain at all. When you look at that histologically, you get villi that are nice, normal. In patients with sprue, completely blunted.
Tropical sprue is a similar biopsy. It’s an infectious disorder. We don’t know why people get it. Treatment is typically with tetracycline. These patients are often folate deficient so you need to give them back folic acid. They may also be B12 deficiency.
Lastly is Whipple’s disease. It’s a systemic illness. There are extraintestinal manifestations such as CNS disorders. These can be actually life threatening illness. There are characteristic findings on the biopsy of PAS positive staining macrophages with the organisms. Treatment is usually with Bactrim for an extended period of time with a good prognosis.