Dysosmia and dysgeusia presenting as depression

Systemic modulation of serotonergic synapses via reuptake blockade or 5HT1A receptor antagonism does not alter perithreshold taste sensitivity in rats

Systemic blockade of serotonin (5HT) reuptake with paroxetine has been shown to increase sensitivity to sucrose and quinine in humans. Here, using a 2-response operant taste detection task, we measured the effect of paroxetine and the 5HT1A receptor antagonist WAY100635 on the ability of rats to discriminate sucrose, NaCl, and citric acid from water. After establishing individual psychometric functions, 5 concentrations of each taste stimulus were chosen to represent the dynamic portion of the concentration-response curve, and the performance of the rats to these stimuli was assessed after vehicle, paroxetine (7mg/kg intraperitoneally), and WAY100635 (0.3mg/kg subcutaneously; 1mg/kg intravenously) administration. Although, at times, overall performance across concentrations dropped, at most, 5% from vehicle to drug conditions, no differences relative to vehicle were seen on the parameters of the psychometric function (asymptote, slope, or EC50) after drug administration. In contrast to findings in humans, our results suggest that modulation of 5HT activity has little impact on sucrose detectability at perithreshold concentrations in rats, at least at the doses used in this task. In the rat model, the purported paracrine/neurocrine action of serotonin in the taste bud may work in a manner that does not impact overt taste detection behavior.

Post-tonsillectomy dysgeusia with weight loss: possible involvement of soft palate

Objective:

To demonstrate the importance of detailed, multidisciplinary examination of patients with post-tonsillectomy taste distortions, and to show that post-tonsillectomy dysgeusia may originate in the caudal part of the soft palate.

Case report:

We describe a 29-year-old man who suffered from severe post-tonsillectomy dysgeusia and phantogeusia with secondary weight loss and depression-like symptomatology. The patient had normal electrogustometric thresholds and sensitivity to touch on the posterior tongue. In contrast, elevated taste threshold and reduced sensitivity to touch was found on the caudal part of the soft palate (the palatoglossal arches). More marked elevation of electrogustometric threshold and insensitivity to touch on the right palatoglossal arch correlated with post-operative haemorrhage from the right tonsillar fossa. Psychiatric examination excluded major depression, eating disorders and drug abuse.

Conclusions:

Dysgeusia constitutes a rare but significant complication of tonsillectomy. Damage to the lingual branch of the glossopharyngeal nerve innervating the posterior tongue is thought to be a major cause of this complication. However, damage to the tonsillar branches of the glossopharyngeal nerve and the soft palate should also be considered as a cause of post-tonsillectomy dysgeusia. Further studies are needed to assess whether post-operative haemorrhage could indicate heightened risk of dysgeusia.

Clinical and biological features associated with taste loss in internal medicine patients. A cross-sectional study of 100 cases

Which are the main features associated with taste loss in patients exposed to a wide range of drugs and diseases? In 100 consecutive patients admitted to a ward of internal medicine, we assessed taste complaints, performance status, alcohol and tobacco consumptions, diseases, drugs and laboratory data, measuring the electrical taste threshold as primary outcome. After adjusting for age, taste thresholds were not associated with sex, body mass index, tobacco, thrush, drugs, aliageusia and phantogeusia. Features associated with threshold increase included alcohol intake>or=10 gd-1, impaired performance status, complaint of taste loss, atrophic glossitis, cerebral disease, and an erythrocyte mean corpuscular volume. A multivariate analysis identified age, alcohol intake, complaint of loss or altered taste, mean corpuscular volume, and performance status as independent factors associated with taste loss. Inpatients may be screened for taste loss by a few features, to identify those for whom a nutritional intervention should be focused.

[Olfactory disorders due to medications: analysis and review of the literature]

INTRODUCTION

Olfactory disorders caused by medicinal drug intake are an uncommon occurrence. However, such an etiology should be systematically taken into account and investigated, as olfactory loss may be reversible once the particular treatment has been stopped.

CURRENT KNOWLEDGE AND KEY POINTS

An analysis of the literature shows that of the large number of drugs that are apparently responsible for olfactory disorders, this adverse side effect has in fact only been observed in animal study populations, and no clinical case report has been made on the subject. The real toxicity to man is therefore only hypothetical. Of the 150,000 cases recorded in the pharmacovigilance centers in France, only 68 have reported olfactory complications (0.05% of cases), and only 22% of the medical files on this disorder reach a satisfactory level of plausibility. Cardiovascular drugs are mainly implicated in the development of olfactory disorders. Of these, certain drugs in particular should be mentioned: conversion enzyme (ACE) inhibitors which are responsible for taste disorders, some betablockers, and a calcium antagonist (a dihydropyridine derivative). Olfactory disorders have also been reported following administration of drugs used in anesthesia, in cancerology, endocrinology (carbimazole), in immunology (interferon), in the treatment of infectious diseases (ciprofloxacine, dioxycycline, terbinafine), and in rheumatology (D-penicillamine).

FUTURE PROSPECTS AND PROJECTS

It is frequently difficult to establish a direct relationship between drug exposure and an olfactory disorder, and it is often not easy to determine with any certainty the causative role of the drug in the development of this disorder.

Paroxysmal bilateral dysosmia treated by resection of the olfactory bulbs

Dysosmia, or the distortion of olfaction, is most commonly preceded by viral illness or head trauma, but has a variety of etiologies. The precise nature of the disease process remains obscure. Medical management is largely empiric, and has been aimed at treating underlying illnesses, restricting triggering medications, as well as various pharmacologic interventions. Successful eradication of a severe case of persistent unilateral paroxysmal dysosmia with resection of the ipsilateral olfactory bulb has been reported. We report here a case of bilateral paroxysmal dysosmia, refractory to medical therapy, successfully treated with bilateral olfactory bulb resection.