A case of anosmia and hypogeusia as a complication of propofol

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study

BACKGROUND

Decline in olfaction may occur after general anesthesia, but the exact incidence and underlying physiopathology remain scarcely investigated. Olfactory dysfunction arises with aging and is known to be linked to cognitive impairment. In this pilot study, we evaluated the incidence of immediate postoperative decline in olfaction and its association with a preoperative cognitive test, performance at Clock Drawing Test (CDT), in a group of older patients.

METHODS

This pilot study is a sub-analysis of a prospective observational study. Patients ≥ 65 years old and scheduled for elective non-cardiac surgery under sevoflurane-based anesthesia were enrolled. CDT was part of the preoperative evaluation. We assessed olfaction on the day before and the day after surgery (between 16 and 26 h postoperatively) using the Sniffin' Sticks 12-item identification test, which consists of pen-like devices displaying 12 different odors. Postoperative decline in olfaction was defined as a decrease of at least 1 standard deviation in the olfactory score.

RESULTS

We included a total of 93 patients, among whom 19 (20.4%) presented a postoperative decline in olfaction. The incidence of postoperative decline in olfaction was higher in the "CDT low-score" (score ≤ 5/8) group (11/34, 32.4%) than in the "CDT high-score" (score ≥ 6/8) group (8/58, 13.6%) (P = 0.030). Despite adjusting for confounding variables, CDT score remained independently associated with immediate postoperative decline in olfactory identification function (OR 0.67, 95% CI 0.48 to 0.94, P = 0.022).

CONCLUSIONS

Postoperative decline in olfaction occurred in 20.4% of older patients and was associated with poor preoperative performance at CDT.

TRIAL REGISTRATION

This study was retrospectively registered on https://clinicaltrials.gov/ under the NCT04700891 number (principal investigator: Victoria Van Regemorter), in December 2020.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Parosmia and dysgeusia after intravenous propofol-based general anesthesia: A case report

Various drugs, including anesthetic agents, can cause parosmia in the perioperative period. There are reported cases of patients with alterations of smell and taste due to local anesthetics, nerve damage, or as a side effect of general anesthesia. We present a case of a 58-year-old male who developed parosmia and dysgeusia in the postoperative period after radical nephrectomy and inferior vena cava thrombectomy. The anesthetics used were fentanyl and propofol for general anesthesia and ropivacaine for epidural analgesia. Clinical examination did not reveal any pathology.

Olfactory function testing before and after anesthesia

This study aimed to determine whether anesthesia would affect olfactory function. Patients who were admitted for surgical intervention that did not include the nasal cavity and paranasal sinuses were included in this prospective cohort study. Structured medical history was taken from the patients, including the following: age, sex, smoking history, alcohol intake, current medications, and sleep deficits prior to surgery. Before surgery, patients were asked for a self-rating of their olfactory function. Olfactory function was also measured using Sniffin' Sticks comprising measures of odor threshold, discrimination, and identification. The mean interval between olfactory tests was 6 days (range 3-12 days). Seventy-three patients were included in the study, 34 men and 39 women. Olfactory scores were consistent before and after surgery as indicated by correlative analyses (p < 0.05). Odor thresholds, discrimination, identification, and composite TDI scores did not change significantly, whereas odor identification scores increased (p = 0.011) after surgery. In conclusion, post-operative olfactory scores remained stable. However, identification scores exhibited a slight increase which can be attributed to a retest effect. Overall, the present results indicate that surgery outside of the nasal and paranasal sinus region performed in general anesthesia has no major effect on the sense of smell.

Isolated taste disorders in patients referred to a flavor clinic with taste and smell loss

BACKGROUND AND AIM

Approximately five percent of the general population are suffering from taste disorders. Usually, subjective loss of taste is caused by smell disorders; thus, isolated loss of the sense of taste is relatively rare. Despite the influence on quality of life, isolated taste disorders (ITD) are sparsely represented in literature and clinical research. In particular, there is need for sufficient diagnostic and treatment algorithms. Aim of study is to add further information to the sparse literature on ITD and suggest an appropriate diagnostic algorithm for ITD.

METHODS

We present a retrospective study on patients with ITD diagnosed at the Flavour clinic, ENT department, Regional Hospital West Jutland, between 2017 and 2020. All patients underwent a thorough rhinolaryngological and otoneurologic examination, including olfactory and gustatory assessment, and a wide spectrum of biochemical, microbiological, and radiological examinations.

RESULTS

In total, 522 patients referred due to smell and/or taste disorders, 423 (81%) complained of a subjective taste disorder, only 19 (3.4%) patients were diagnosed with ITD. According to etiology, the patients were categorized in following groups: medicine-related (25%), mixed (21%), iatrogenic (21%), idiopathic (11%), radiotherapy-related (11%), and autoimmune/inflammatory (11%). Based on etiology, individualized treatment was recommended with very discouraging results.

INTERPRETATION

Diagnostics of taste disorders is a delicate and expertise demanding task. The mechanisms underlying isolated loss of taste are heterogeneous. ENT and otoneurologic examination, and specific olfactory and gustatory testing are required in all patients, whereas biochemical, microbiological, and radiological examinations are only necessary on an individual basis.