Thursday, 14 May 2009
Re-feeding syndrome and the garden in spring
I have decided that my revision is going OK - not well, but OK. Yesterday wasn't too good. I spent all day at my desk, but really only worked properly between 5pm and 7pm.
I learned about re-feeding syndrome. If you starve for more than a few days, the body switches over to a different type of metabolism, burning mostly fat and a bit of protein to keep going. If you then start eating carbohydrate again, there's a chance of a seriously adverse, potentially fatal effect. It happens because blood phosphate and stores of potassium and magnesium are seriously depleted. As insulin is secreted in response to the carbohydrate for the first time in ages, all the phosphate in your bloodstream goes into the cells with the insulin to do all the things phosphate is needed for. To a lesser degree, potassium and magnesium do the same, and this is not good for you in the short term. You can also get hallucinations and other neurological symptoms from thiamine deficiency, but I'm not sure why this happens on re-feeding rather than while you're starving. Perhaps this vitamin is also used up when carbohydrate metabolism is jump-started in this way.
This medicine and pathology exam is going to be tough. Two hours are allowed to answer three questions, so that's at least half an hour per question, which implies a fair amount of depth and detail to the answers. The questions are mostly two, maybe three sentences ("The patient reports abdominal discomfort after meals, and occasional breathlessness on exercise. What is the likely diagnosis? What further tests would you suggest?") and there is the distinct possibility that you might write for thirty minutes on the wrong medical condition. I suppose that as long as you justify your choice, the question allows for more than one diagnosis.*
Past papers cover a vast array of conditions, some of which were hardly mentioned in lectures, so it's difficult to imagine knowing enough to answer three random questions in depth. I'm probably going to concentrate on diabetes, gastrointestinal diseases, cardiovascular disease and heart failure, and hope that either anaemia or burn injury comes up (because those were the subjects of our research and presentations during the term). But I'm going to have to know a bit about obesity, eating disorders, endocrine problems, electrolyte disturbance, renal failure, liver disease, biochemical tests, cystic fibrosis, HIV/Aids malnutrition, cancer, ascites, chronic obstructive pulmonary disease and asthma as well.
I have been studying other subjects as well. I have learned that there are a large number of ways that your blood cholesterol and lipids may go awry, but none of them is very interesting. Even less thrilling is the use of Excel to solve non-linear equations, but I do marvel at some of the things we can do in seconds with a spreadsheet that would have taken days with log tables, graph paper and a ruler.
While I'm stuck inside at my desk, this is the most wonderful time of year to be walking about town, admiring the colours of Nature. In the garden the wisteria and ceanothus are in full bloom, we have bluebells and cornflowers (purple overload!) but also something I don't know the name of that flowers profusely in white. My herbs are doing quite well, although something ate one of the mint plants, leaving only the stems. Mr A is doing most of the cooking, in between his business crises. I may write an update soon on the activities of Mr A, but not at the moment.
[There's no particular reason for the Oxford photo at the top, it's just there because I haven't put up any pictures recently, and I haven't taken any pictures in the garden yet. And because of the busts of stern academics, who appearing to be doing some serious thinking.]
* For this question, I'm guessing cystic fibrosis. But I suppose it could be cancer obstructing the gut with secondary tumours in the lungs?