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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PATEL et al.

Harm : Discomfort and time commitment of the ther apy as well as minimal risks of bleeding, infection, and theoretical risk of worsened smell loss, although this was not seen in pilot studies. Cost : Moderate direct costs of PRP. Time off work for appointments and treatments. Benefits-Harm assessment : Early studies suggest potential for improvements in smell loss with minimal risk of harm that warrant further investigation. Value judgments : Larger RCTs are needed to demon strate clinical benefits of PRP injection in smell loss. Policy level : No recommendation for the current use of PRP injection in treatment-refractory OD. Intervention : PRP injection in the OC is worthy of fur ther investigation for patients with OD without sinonasal disease in whom OT and topical steroid therapy have failed. A systematic review of the literature for medical man agement of long-term phantosmia published in 2018 showed that few studies have investigated medical man agement of phantosmia and even fewer parosmia. 1314 A small phone interview study of observation alone found that 57% of patients reported short-term improvement of symptoms, while only 32% of patients reported long term relief. 1313 Medical treatments have been evaluated in small cohort studies with variable success, including antipsychotic medications, 1613 antiseizure medications, 1614 topical cocaine application, 1615 or antimigraine prophy lactic medications. 910 Table IX-40 shows a summary of the medical treatment modalities studied. A small study of migrainous patients retrospectively identified a link between some patients’ headaches and phantosmia. Of the 14 patients in this cohort, nine demonstrated improve ment in their phantosmia with antimigraine prophylac tic therapy, including topiramate, nortriptyline, and vera pamil. In addition, none of the patients had headache res olution without a corresponding resolution in phantosmia symptoms. 910 Medical management of phantosmia lacks large clinical trial evidence and no consensus exists regarding optimal treatment. However, medical therapy for phantosmia may be directed to the underlying etiology, such as antiepilep tic therapy for olfactory hallucinations associated with focal epilepsy 19,1616 or prophylactic migraine medications for migraine-associated phantosmia. 19,910 There is some evidence that the distinction between peripheral phan tosmia (a dysfunction at the level of the ORs and neu G Phantosmia/Parosmia Treatment 1 Medical treatment options

rons) and central phantosmia (a dysfunction of the cor tical olfactory pathways) may help guide therapy in that medical therapy is more likely to fail in peripheral phantosmia. 1314,1613 OT in which patients sniff numerous scents representing major odor categories 1543 has been discussed as a potential therapy for phantosmia. 1543,1544,1617 A retrospective cohort study of 153 patients with PIOD undergoing OT therapy found that the presence of phantosmia failed to be asso ciated with clinically relevant improvement in OF, but this only points away from phantosmia being a positive predic tive factor and does not elucidate whether OT may be help ful for phantosmia itself in some patients. 1618 No clinical Aggregate grade of evidence : C (Level 4: six studies). Of note, this evidence grade is based on the studies listed in the above table. However, because of the high variation in treatment options, a reliable evidence grade is difficult to determine. Based on the available evidence, it appears that trialing these different medical therapies for recalci trant phantosmia, under careful follow-up and monitor ing, could be an option based on balance of benefit and harm. 2 Surgical treatment options The majority of patients with qualitative OD will symp tomatically improve or have resolution of symptoms with appropriate medical therapy or observation alone. 19,23,1313 Therefore, watchful waiting or trials of different medical therapy are the first-line treatment recommendation. Sur gical intervention is not recommended as a first-line ther apy and should only be considered if patients fail multi ple trials of medical therapy and symptoms are distressing enough to be life-threatening (unfortunately in rare cases, phantosmia and parosmia can lead to suicidal ideation). There are case reports of olfactory nerve/bulb resection for long-lasting phantosmia/parosmia. 1619–1621 These pro cedures not only result in permanent anosmia, but also come with the potential risks of a skull base defect and need for repair and are therefore not recommended unless as a last resort. An early case report by Leopold et al 1622 details findings from the first unilateral endoscopic intranasal excision of the OE in a patient with long-lasting phantosmia. Phan tosmia initially resolved after excision of the OE and her olfactory ability returned postoperatively. Late follow-up revealed some return of phantosmia. A recent systematic review by Saltagi et al 1314 looked at both medical and surgical management of long-lasting phantosmia. In the two surgical studies, all patients trials have been performed on this subject. Medical management of phantosmia.