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DEAR DR. ROACH: I was recently admitted to the hospital with pneumonia in both lungs. Given the recent outbreak of Legionella where I live, I was concerned whether I might have had this instead. They did do some tests in the hospital to try to find out.
-- R.C.
ANSWER: I looked at the labs that you sent me, and several of them are consistent with Legionella. You had a very high C-reactive protein level, a relatively low procalcitonin level, pneumonia in both lungs, low blood sodium and a relatively low heart rate. All of these suggest Legionella rather than pneumococcal pneumonia (the most common type). However, your doctors did two urine tests for Legionella, and they were both negative.
The urine test for Legionella isn't perfect. It detects 70% to 80% of only one of the several serogroups of Legionella (serogroup 1 -- the most common type and the one that's implicated in the current outbreak in New York). It doesn't detect the other serogroups at all.
Physicians often need to reconcile conflicting clinical information, and sometimes there are formal mathematical models to help. In your case, you meet at least three of the four criteria for Legionella. In one study, people with three or more criteria points had a 98% to 100% likelihood of having Legionella. Busy clinicians who are taking care of sick patients usually don't have the time to read research papers and calculate point scores to help determine the likelihood of a Legionella infection versus pneumococcal pneumonia.
However, clinicians need to know that they shouldn't exclusively rely on one test result against the results of many other tests.
DEAR DR. ROACH: Last week, I had some blood work done. Some tests for my liver didn't come back well. My thinking is that it's because I no longer have a gallbladder. Is my thinking correct?
-- T.
ANSWER: Immediately after surgery, liver enzymes such as alkaline phosphatase and AST (aspartate aminotransferase) transiently increase. However, when a person is 10 or more years out from surgery, there's still an increased risk of an elevated alkaline phosphatase level (but not AST or bilirubin).
Your alkaline phosphatase level is mildly elevated, and your AST is normal. Your bilirubin level, however, is also mildly elevated. I can't tell you definitively whether this is worrisome, but I don't think that the gallbladder surgery explains everything. Some people have a benign condition called Gilbert's syndrome with elevated bilirubin levels of no clinical significance.
ToYourGoodHealth@med.cornell.edu.