xRead - Olfactory Disorders (September 2023)

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INTERNATIONAL CONSENSUS ON OLFACTION

TABLE IX-30 Use of sodium citrate to treat OD Study Year LOE Study design

Study groups

Clinical end point SS-ID (12 odors) Reported side effects

Conclusions

Thirty patients (97%) improved by a mean of 4 points, 74% had subjective improvement lasting 3 hours Itching was the most common side effect

Unspecified (16%) Posttraumatic olfactory loss (3%) Nasal surgery (23%) PIOD(58%)

Panagiotopoulos et al 1559

2005 3

Prospective

observational (n = 31) 1 mL of sodium citrate – citrate acid (3.5 g/140 mL, pH 7.4, osmolarity 298) to both nostrils RCT with patients acting as own controls (n = 57) 1 mL of sodium citrate solution (3.5 g/140 mL, pH RCT comparing bilateral sodium citrate with placebo (n = 55) 1 mL of 9% sodium citrate solution; 0.5 mL to each side of the nose 7.4, osmolarity 298) to one side

Whitcroft et al 1555

2016 2

PIOD(12%) Posttraumatic

Monorhinal SS-ID and SS test (PEA) 20 to 30 minutes posttreatment Reported side effects

Only increase seen was inPIOD identification

olfactory loss (18%) Sinonasal disease (53%) Idiopathic olfactory loss (18%)

scores (mean 2.29 ± 1.89)

Nasal discharge was the most common side effect 32% had threshold improvement for rose, pear, or methanol Peak improvement was seen at 47 minutes; duration 54minutes Rhinorrhea and sore throat reported

Threshold improvement for PEA threshold (rose) Threshold improvement for pear, vinegar, methanol Time until best improvement Reported side effects The 4 threshold tests were used at 15-minute intervals over 2 hours to measure any fluctuations in response Monorhinal SS-ID and threshold (PEA) 20 to 30minutes posttreatment

Idiopathic (36%) Posttraumatic olfactory loss (16%) PIOD(47%)

Philpot

2017 2

et al 1556

Whitcroft et al 1557

2017 3

Prospective,

PIODonly

No difference in threshold or identification scores posttreatment. Composite score

single-blind with patients acting as own controls (n = 49) citrate solution (3.5 g/140 mL, pH 7.4, osmolarity 298) to left nostril

1 mL of sodium

statistically but not clinically significant ( + 0.9, P = 0.04) LOE = level of evidence; OD = olfactory dysfunction; PEA = phenylethyl alcohol; PIOD = postinfectious olfactory dysfunction; RCT = randomized controlled trial; SS = Sniffin’ Sticks; SS-ID = Sniffin’ Sticks identification only.

nonconductive olfactory disorders. 1552 Four interventional studies have been identified—two prospective studies and two RCTs. With the exception of the most recent study that focused on PIOD, the remainder had mixed etiology groups included. Two studies used patients as their own controls, with monorhinal application of citrate. No studies exam ined the effect of long-term therapy. In 2016, Whitcroft et al 1555 performed a prospec tive placebo-controlled trial of monorhinal treatment of

sodium citrate versus sodium chloride for patients with olfactory loss (multiple causes, n = 57) and showed improved olfactory threshold and identification only in the PIOD cohort (n = 7). In 2017, Philpott et al 1556 com pared a single application of 0.5 mL of 9% sodium citrate per nostril versus sterile water (n = 55) in an RCT and showed statistically significant improvement in OF using olfactory thresholds lasting between 30 and 120 minutes after application. 1556 In the latter study, the response rate