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

614

INTERNATIONAL CONSENSUS ON OLFACTION

X SPECIAL CONSIDERATIONS A Delay in initiating treatment may be detrimental to potential recovery In certain circumstances, such as in the case of a child pre senting with congenital anosmia associated with congeni tal hypogonatropic hypogonadism, also known as Kallman syndrome, timely diagnosis and treatment could change the course of the patient’s life. 18 In other forms of smell loss, the timing of diagnosis and treatment also matters with regard to the patient’s chance of regaining normal smelling ability. In clinical tri als evaluating intervention to help those with olfactory loss, the duration of loss was a significant factor in how well patients responded to treatment. 1522,1541,1544 Addition ally, in functional brain mapping and connectivity stud ies, chronic peripheral olfactory loss led to wide-ranging changes in functional connectivity throughout the brain, both in olfactory-specific cortices but also in recruiting other neural networks. 1077,1625 Although it appears clear that the sooner an intervention takes place the more likely the patient will be able to benefit from it, the exact answer as to how long is too long before no more improvement is possible, is not currently known. This is an important question for our field to answer, as it would lead to more accurate counseling of our patients regarding prognosis, as well as improved allocation of clinical time and resources to those that we know we can help. B Multiple-hit hypothesis In specific forms of olfactory loss, such as that associ ated with CRS, there are particular risk factors that can predispose a patient to developing more permanent or longer-lasting OD. We know that polyp status, asthma, DM, and age are all independent predictors of this. 1358 We also know that in addition to age, male patients, and patients with poor general health (including histories of asthma, cancer, cardiovascular disease, nasal disease, and obesity), less physical activity, a history of cigarette smok ing, lower family income, exposures to environmental tox icants, heavy drinking behavior, poorer education, being an ethnic minority, and those with lower cognitive func tion, are more likely to experience olfactory loss from other causes. 123,1626 These types of predisposing or predic tive factors appear to support a multiple-hit hypothesis, by which sequential inflammatory insults or insults related to decreased blood flow, and the associated decrease in oxy genation and nutrition, to the structures within the olfac tory system, may lead to OD that is more permanent and difficult to recover from. However, we are lacking any real data demonstrating the weight of each of these factors

(n = 11) underwent endoscopic intranasal excision of the OE in the involved nostrils. 18,1613 Postoperatively, phan tosmia resolved in 10 of 11 patients. Of the eight patients included in the Leopold et al 18 study, two underwent bilat eral surgery and four underwent repeat surgery for per sistent symptoms. OF was unchanged in five of the oper ated nostrils, decreased in three, and improved in two. All patients included in the Morrissey et al 1613 study (n = 3) developed anosmia postoperatively. There were no post operative CSF leaks. Of note, an indication for surgery in both studies was the ability to abort the phantom smell with anesthetization of the involved nostril. Although ini tial success rates with surgical excision of the olfactory mucosa are relatively good, follow-up is lacking. Addition ally, there are serious risks of worsening OF and CSF leak, therefore treatment should only be performed by surgeons who routinely perform CSF leak repair. A recent case report published in August 2020 by Liu et al 1623 details a novel surgical treatment in a patient with long-lasting peripheral parosmia. The OC was blocked by creating intranasal adhesions. The patient had resolution of parosmia postoperatively and no recurrence at 2-year follow-up. The patient did have resulting anosmia. The procedure has not been validated and therefore cannot be recommended at this time. Surgical intervention for parosmia/phantosmia. Aggregate grade of evidence : D (Level 4: five studies). Benefit : Given the lack of strong evidence in the liter ature, a definitive benefit of surgical intervention cannot be supported at this time except in extremely rare cases of life-threatening parosmia/phantosmia. Harm : There are risks of worsening OF and CSF leak with surgical excision of olfactory mucosa. The surgery is technically challenging and should only be performed by experts in the field. Cost : There are no studies investigating the costs of sur gical treatment of phantosmia. Benefits-harm assessment : The risks of OC surgery outweigh the benefits at this time unless in the hands of an expert. Given that most cases tend to resolve with time, watchful waiting and medical management should always be first recommended. Value judgements : Surgical intervention should only be considered in severe cases of phantosmia that are life threatening and do not respond to multiple trials of differ ent medical therapies. This technically challenging surgery should only be performed by experts in the field. Policy level : Option for rare cases. Intervention : Surgical intervention for phantosmia is not recommended at this time, except in extremely rare cases. Referral to an expert in this field can be considered in cases that do not resolve with time, have failed multiple trials of medical therapy, and are life-threatening.