Chiefs’ Inquiry Corner – 11/24/2021

November 24, 2021

Chief residents of the NYU Langone Internal Medicine Residency give quick-and-easy, evidence-based answers to interesting questions posed by house staff, both in their clinics and on the wards.

Click to toggle the answers!

  In September 2021, the American Academy of Orthopedic Surgeons updated its guidance on nonoperative treatment for knee osteoarthritis. Oral NSAIDs and acetaminophen are still first-line treatments for knee pain secondary to osteoarthritis. Topical NSAIDs are also a first-line treatment, and are becoming increasingly accessible now that some formulations are available over the counter rather than as costly prescription-only medications. Notably, prior guidelines made a strong recommendation for the utilization of tramadol, with an inconclusive recommendation made regarding other opiate/opioid medications, for OA-related pain. In the current guidelines, all opioids- including tramadol- are strongly recommended not to be used for arthritis, reflecting the growing evidence that oral narcotics result in a significant increase of adverse events and are not effective at improving pain or function. Physical exercise (supervised, unsupervised, and/or aquatic) also remains a strong recommendation in managing pain from knee osteoarthritis.

References: AAOS Guidelines-Knee Osteoarthritis
  Amikacin is a member of the aminoglycoside family of antibiotics. By binding to the 30s ribosomal subunit of a prokaryotic organism, amikacin inhibits protein synthesis and is therefore bactericidal. It is highly active against most gram-negative bacteria, Nocardia, and Mycobacteria, and is often used to provide additional gram-negative coverage when infection is causing critical illness. Like other aminoglycosides, amikacin has a narrow therapeutic index and measuring timed serum levels of the drug is critical in administering it both efficaciously and safely.  Peak serum levels correspond to the bactericidal effect of the drug, since efficacy of aminoglycosides is dose-dependent. Amikacin, like other aminoglycosides, is most effective when the ratio of peak level to minimum inhibitory concentration (MIC) of the organism is 10 or greater. Serum samples for peak concentrations should be collected one hour after the start of IV infusion and 60-90 mins after IM injection; in people with critical illness, the peak serum levels should be collected after the first dose. Ensuring adequate peak serum level is necessary to avoid underdosing, particularly in people with large volumes of distribution. Note that peak levels of more than 35-40mcg/mL for prolonged periods of time correlate with nephrotoxicity incidence.  Ototoxicity and nephrotoxicity are two of the most concerning adverse effects of amikacin. Serum trough levels, which should be drawn 30 minutes before the next dose (or prior to the next scheduled session in people on HD), correspond to toxicity. For once daily dosing, trough levels should be <1mcg/mL; for multiple daily dose regimen, trough levels should be 1-4mcg/mL if the infection is less severe (e.g., no sepsis, no bacteremia) or 4-8mcg/mL in severe infection. Significant nephrotoxicity and ototoxicity have been associated with amikacin trough levels >10 mcg/mL.

References: Medscape Reference: Amikacin Level
 A recent meta-analysis of approximately 5500 ICD recipients enrolled in five landmark ICD trials evaluated the association of device therapy with subsequent mortality. The authors found that a first appropriate ICD shock was associated with increased risk of subsequent mortality with or without concomitant occurrence of inappropriate shock, and that ICD therapy for ventricular tachycardia  ≥200 bpm or ventricular fibrillation was associated with increased mortality, whereas appropriate therapy for VT <200 bpm or inappropriate therapy was not. In addition, two or more appropriate shocks were not associated with incremental risk to the first appropriate ICD shock. This suggests that mortality in ICD recipients is associated with the underlying arrhythmia the shock is responding to, rather than the delivered shock itself.

References:  Survival After Implantable Cardioverter-Defibrillator Shocks