PVOD

Q: A 44-year-old male is getting transferred from the ICU to the rehabilitation center after 6 weeks of stay, where he was admitted for severe COVID-19 infection, requiring ECMO, which was successfully decannulated after 3 weeks, and now s/p tracheostomy and is off all drips. The patient also developed a complete loss of smell. Which methodology can be implemented in the rehabilitation center to restore olfactory function?

Answer: Olfactory training

Postviral olfactory dysfunction (PVOD) or postinfectious olfactory dysfunction (PIOD) became a well-known clinical entity since the COVID pandemic. Olfactory training has shown remarkable clinical improvement.

The typical training protocol endorsed by the clinical Olfactory Working Group consists of deep sniffing of at least four distinct odors for 10 seconds, twice daily, for at least 12 weeks. The odorants used are distinct and strong. For aesthetic reasons, scents may include rose, lemon, clove, eucalyptus, cinnamon, vanilla, or orange. Supervising service can provide "smell training kits" with instructions.

Hoping that repeated olfactory stimulation will promote olfactory neuron regeneration or the creation of new synaptic connections.

Adjuvant treatment is budesonide nasal irrigations. 

#ENT

References:

1. Kattar N, Do TM, Unis GD, et al. Olfactory Training for Postviral Olfactory Dysfunction: Systematic Review and Meta-analysis. Otolaryngol Head Neck Surg 2021; 164:244.

2. Hura N, Xie DX, Choby GW, et al. Treatment of post-viral olfactory dysfunction: an evidence-based review with recommendations. Int Forum Allergy Rhinol 2020; 10:1065.

3. Fletcher ML, Chen WR. Neural correlates of olfactory learning: Critical role of centrifugal neuromodulation. Learn Mem 2010; 17:561.

4. Addison AB, Wong B, Ahmed T, et al. Clinical Olfactory Working Group consensus statement on the treatment of postinfectious olfactory dysfunction. J Allergy Clin Immunol 2021; 147:1704.