Case Studies (December 2017)

Case 1

JM is a 68-year-old woman who is given a diagnosis of cellulitis on her left calf by a medical resident. JM has a medical history of hypertension, chronic obstructive pulmonary disease, and heart failure, as well as a urinary tract infection (UTI) that was treated with levofloxacin 2 weeks ago. The resident asks you, the infectious diseases stewardship pharmacist, for your advice regarding empiric therapy for JM’s cellulitis, telling you that the cellulitis is associated with purulent drainage and is likely a sebaceous cyst infection. The resident drains the cyst and is considering treating JM with cephalexin 500 mg every 6 hours for 5 days.

As the pharmacist, what antibiotic course would you recommend?Case 2

TO is a 54-year-old woman who presents to your primary care clinic for continued management of her insulin regimen. TO was recently given a diagnosis of type 2 diabetes, with a glycated hemoglobin concentration of 10.2%. Her insulin regimen includes insulin lispro 2 units 3 times daily taken 5 minutes before meals and insulin NPH 5 units before breakfast and 10 units before bed. TO brings in her glucometer, and on reviewing her finger-stick results, the resident sees all her glucose readings are in the target range except her prefasting breakfast readings, which have been consistently high (198-240 mg/dL) over the past 1 to 2 weeks. TO reports strict adherence to her insulin regimen and has not made any significant changes to her diet. The resident wants to increase TO’s insulin, but is unsure by how much. The resident consults you, the pharmacist, to help manage TO’s insulin regimen.

What would you recommend regarding TO’s insulin therapy?SEE THE ANSWERS BELOW

ANSWERSCase 1:

Staphylococcus aureus is the most common agent causing purulent cellulitis. Consequently, when a diagnosis of purulent cellulitis is made, it is important to consider a patient’s risk factors for methicillin-resistant S aureus (MRSA), including nasal colonization, prior MRSA infection, recent hospitalization, and/or antibiotic use. Because JM has purulent cellulitis and has had recent exposure to an antibiotic (levofloxacin for her UTI), empiric therapy should include an antibiotic with MRSA coverage (ie, trimethoprim-sulfamethoxazole, doxycycline or minocycline, linezolid or clindamycin). As the pharmacist, you might recommend doxycycline 100 mg taken orally twice daily.

Case 2:

The pharmacist should explain to the resident that it would be best to collect more information before increasing TO’s insulin dose because there are multiple reasons why she could have morning hyperglycemia. Specifically, TO could be experiencing a “Dawn phenomenon” or a “Somogyi effect.” The Dawn phenomenon occurs due to insufficient basal insulin administration overnight, and the Somogyi effect occurs because of too much basal insulin overnight, causing hypoglycemia and rebound hyperglycemia. You explain further that the way to distinguish between the 2 would be to have your patient take early-morning (2AM-3AM) fasting blood glucose readings via finger stick. If these blood glucose values are consistently high, the patient is likely experiencing the Dawn phenomenon. If these blood glucose readings are low, the patient is probably experiencing the Somogyi effect.