Sunday, February 12, 2012

Going Viral

S's parents came into town last weekend along with L, Mom, and Dad. We didn't do much more than laugh and tell stories and we were all okay with that. C loved every minute of it. It blew her mind to realize she has four grandparents. You should hear her retell Dad's baby chipmunk story. 

I didn't get much studying done. I closed shop after lecture on Friday at 3:00 pm and didn't touch study materials until Monday which did not leave much time to prepare for the test on Wednesday. This test was about whatever bacteria were left over after the first two tests, antibiotic classes and modes of action, and the entire subject of viruses. Just because that description fits into one sentence doesn't mean  it was easy.

Antibiotics alone were rough. Fluoroquinolones, penicillins, macrolides, aminoglycosides, tetracyclines, cephalosporins, and the 10 or so stand-alone antibiotics each work in a different way, have different generations of drugs, and have about 10 major drugs within the category. Memorizing a mnemonic that size would be just as hard as memorizing the silly things in the first place. Additionally, there are six classes of DNA viruses and thirteen classes of RNA viruses that cause human disease and some are enveloped, some are icosahedral, some use intermediates, some are mitogenic, some confer a proclivity to cancer, some are airborne contagions, some replicate in oropharyngeal epithlium. Up until the hour before the exam I still didn't know which was which.

There is a God in heaven and He does care how well I do on my exams. With the test at 10 am, I got to campus when it opened at 7 am and went through my notes and my problem areas, but didn't make much headway until about 9:10. For a currently inexplicable reason, Heavenly Father decided I needed a jump start in a big way and I learned more in twenty minutes about viral classifications and features than I learned the entire two weeks leading up to the exam. Those questions were the easiest on the exam and I had them memorized in such a format that the answers were very obvious. Walking out of the test, Heavenly Father and I had a little conversation that went something like this:

-Me: "Wow, you know viral replication patterns, Baltimore classifications, and enveloped status too?!"

-Heavenly Father: "Yes, I invented the replication pattern and enveloped status, don't you know? The credit has to go to David Baltimore for his classifications and it is a simplistic way of looking at things, but it's okay for a first time exposure, I guess."

With immunology, infection, and therapeutics done we are moving on to studying systems. Blood and Lymph is the first one and as of right now I have mixed feelings about it. I found a groove that worked with all the memorizing of silly molecular details presented in lecture. I'm not sure how the test questions are going to be, but our assignments are more like, "how do you tell that this fever is a different disease process than this other fever." Seems to be more clinical which could be interesting, but I'll wait to see how fair the tests are before administering judgment.

In early August, a 42-year-old woman comes to the emergency department because of fever, rigors, frontal headache, and severe myalgias for four days. Episodes occur up to four times daily and last 20 to 40 minutes. She has been taking acetaminophen for the fevers and myalgias. The patient returned ten days ago from a one-week vacation on Cape Cod, Massachusetts. While there, she hiked regularly in the sand dunes and swam in the ocean. She has no past medical history. She has no known drug allergies. On physical exam, she appears ill. Temperature is 40.2 degrees C, pulse is 120 per minute, and blood pressure is 110/70 mm Hg. She has no rash and no enlargement of lymph nodes, liver, or spleen.
Initial laboratory studies:
Reticulocyte count is elevated
9.8 g/dL
Leukocyte count
4200/μL; 82% segmented neutrophils,
5% bands, 10% lymphocytes, 3% monocytes
Platelet count
Serum creatinine
1.2 mg/dL
Serum alanine aminotransferase
88 U/L
A Wright-Giemsa-stained peripheral blood smear is shown:

  1. What is the differential diagnosis?
  2. What is the pathogenesis?
  3. What is the epidemiology?
  4. How is a definitive diagnosis made?
  5. How is the patient managed?
  6. What are the potential complications?
  7. How can the infection be prevented?

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