QUESTIONS

1. There are 4 main diseases that cause protein losing enteropathy. Name 'em.
    
2. In protein-losing enteropathy, albumin is low. How about globulin?
    
3. In the pathogenesis of lymphangiectasia, there is presumably an
   obstruction in the gi lymphatics.  This leads to a build up of lymph pressure and the dilated lacteals we see on biopsy.  The lacteals leak and/or rupture losing protein rich lymph into the gi lumen. This protein loss is too great to be handled by normal digestion & absorptive mechanisms.
   
   Which of the following is the usual mechanism of lymphatic obstruction?
   
   a) idiopathic
   
   b) congenital
   
   c) neoplasia
   
   d) inflammation
   
   e) thoracic duct obstruction
   
   f) increased central venous pressure in heart failure leading to an increase in lymphatic fluid that cannot be handled by the lymphatic vessels
    
4. A common dog breed predisposed to lymphangiectasia is _______________.
    
5. At laparotomy, in lymphangiectasia the milky lymph vessels are prominent in the mesentary.  Sometimes you also see lipogranulomas.  What is a lipogranuloma?
    
6. Explain why each therapeutic measure listed below is helpful in the treatment of lymphangiectasia:
   
   a) prednisone
   
   b) a high quality protein diet
   
   c) replacing long chain triglycerides with medium chain triglycerides.
    
7. Why would anyone want to measure fecal alpha-1-antitrypsin?
   
   
   
   
    

ANSWERS

1. The usual culprits of PLE are: lymphangiectasia, gi lymphosarcoma, gi histoplasmosis & inflammatory bowel disease. Lymphangiectasia is most common. .
   
   
   
   
    
2. In PLE, globulin is lost just as much as any other protein.  It is down. Note, in liver origin hypoalbuminemia, globulin is usually up.  In lymphangiectasia, other findings include lymphopenia, low cholesterol, fat soluble vitamin deficiencies, & low calcium (not known why. could just be from low albumin or could be from vitamin D deficiency) In histoplasmosis, globulin is usually high or normal from all that infection.
   
   
   
   
    
3. The most common type of lymphangiectasia is idiopathic :(
   
   
   
   
    
4. The breed predisposed is the basenji. (Note in the basenji form  of PLE, globulins are usually high.)
   
   
   
   
    
5. Lipogranulomas are fat laden macrophages all together in a granuloma. No one really  knows exactly how they form.  Their presence may contribute to lymphatic obstruction.
   
   
   
   
    
6. a) pred can reduce obstruction from an inflammatory cause. It may also reduce lipogranulomas.  Not all patients will respond to pred (in fact, not all patients will respond no matter what. Your goal is to achieve "remission" and keep the patient in remission as
   long as possible.  This wording in Ettinger suggests that most patients ultimately tend to come out of remission).
   
   b) high quality protein diet helps replace the proteins being lost into the gut. Ettinger recommends RD as it is low fat as well.
   
   c) long chain triglycerides are a stimulus to intestinal lymph flow (which you want to reduce).  Still, most patients have lost a lot of weight so you really don't want them to have fat restriction completely; they need the calories.  The medium chain triglycerides provide calories but do not have to be converted into chylomicra for absorption.  In fact, they get absorbed directly into the portal circulation and bypass the lymphatics totally.
   
   
   
   
   
    
7. Alpha-1-antitrypsin has a molecular weight similar to that of albumin. In PLE, it is lost from serum & lymph & excreted  in feces intact. It can be quantified by immunoassay and used to monitor treatment or to make the PLE diagnosis initially.