xRead - Olfactory Disorders (September 2023)

20426984, 2022, 4, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/alr.22929, Wiley Online Library on [04/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

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improvement (as evaluated by the SS olfactory test) was observed 5 months after the initial test. 456 A prospective study with 38 patients with PTOD was performed to investigate the effect of OT. 1346 The train ing group underwent OT for 5 minutes twice daily using the following four odorants: phenylethyl alcohol (rose), eucalyptol (eucalyptus), citronellal (lemon), and eugenol (cloves). Compared with the control group, the training group had significantly higher OF scores, as measured by the SS test at 16 weeks. The improvement rates of both groups were 33% and 13%, respectively. In another study 16 of 52 patients responded to OT. The authors found factors including the absence of a cribriform plate frac ture, absence of OB encephalomalacia or siderosis, deep olfactory fossa ( > 4.9 mm), and larger OBVs ( > 27.1 mm 3 ) were related to a better prognosis. 1354 OT has also been reported to be more effective in improving olfactory thresh old scores in anosmic patients and in improving identifica tion scores in hyposmic patients. 1355 No RCTs have been performed evaluating any of these interventions on only a posttraumatic olfactory loss group. In order to fully investigate the efficacy of a medication or other intervention, it is necessary to conduct RCTs and evaluate therapeutic interventions at an early stage after injury. With the existing data, OT could potentially be help ful for these patients, with more data needed before defini tive conclusions can be made regarding use of steroids, oral zinc, or Kampo medicine. In addition, because of the lim ited efficacy of treatment options for PTOD, patient coun seling about hazardous events and safety issues is helpful since persistent OD results in a higher level of disability and lower QOL. 62 Treatment of PTOD. Aggregate grade of evidence : C (Level 1: one study; Level 2: two studies; Level 3: one study; Level 4: nine stud ies). Benefit : OT may be effective in limited patients with posttraumatic dysfunction. Oral steroids, Kampo, and oral zinc medications may also benefit these patients, although the data are not as robust to support this. Harm : High-dose steroids may induce systemic adverse effects. Some Kampo medications can elevate liver func tion levels. Cost : Expense for comparatively prolonged use of med ication to restore OT. OT is very inexpensive. Benefits-harm assessment : Beneficial to less than half of patients with PTOD with few side effects. Value judgments : It is worth trying treatment for PTOD at an early stage after injury. Policy level : Use of OT is recommended in patients withPTOD. Use of oral steroids, Kampo, and zinc medications are options in patients with PTOD.

Intervention : OT should be considered in patients with PTOD.

C Treatment of underlying sinonasal inflammatory etiologies 1 Medical treatment for CRS or AR-related olfactory loss OD affects a significant portion of the general popula tion, with some reports estimating it to be as high as 24%. 112 Inflammatory nasal pathologies such as CRS and AR are the most common forms of acquired OD, partic ularly in younger populations worldwide. 1356 Smell loss in CRS is likely caused by a combination of factors that either inhibits odorant transport to the OC and/or odor ant transduction at the level of the olfactory neuroepithe lium. These inflammatory changes may also lead to degen eration of the OE, further causing a reduction in smell. 1357 Similar inflammatory pathophysiology is thought to con tribute to OD in AR, but the degree of OD in AR is less severe and specific mechanisms are likely to differ. 225 Ther apies for OD in CRS/AR aim to decrease the regional sinonasal inflammatory burden and therefore mimic those used to treat CRS and AR in general. It is important to keep in mind that the focus of this section is to review evidence associated with medical treatment of OD specif ically; therefore, evidence and recommendations will be provided specific to olfaction and agnostic to any possible nonolfactory benefits that these medications may confer in patients with CRS or AR. The majority of clinical studies investigating olfactory outcomes include subjective assessments and/or olfactory psychophysical tests. Subjective assessments include mea sures such as olfaction specific VAS, subjective symp tom scores, and QOL questionnaires (eg, QOD). Objec tive olfactory psychophysical tests may include forced choice identification, smell discrimination, and olfac tory thresholds. Commonly employed psychophysical tests include, but are not limited to, the UPSIT R , SS test, Barcelona Smell Test (BAST), and Butanol Threshold Test (BTT). 147 As evident in the accompanying tables, the treat ment of OD in patients with CRSwNP has been stud ied to a greater degree compared to that in patients with CRSsNP or AR. This is likely secondary to the greater severity and higher prevalence of OD in patients with CRSwNP. 1358 In CRSwNP, there is grade A evidence composed of RCTs demonstrating that oral steroids and some bio logics improve subjective and psychophysical metrics of OD. 1360,184,218–220 Topical steroids also appear to improve OF based on grade A evidence, but most studies demon strate a benefit in subjective metrics only and more studies