Clinical Assessment of Olfactory Disorders
Just as is the case with all medical disorders, it is knowledge of the anatomy and the systematic evaluation of the patient by physical examination (including the ENT region) that gives us the vital clues to establish the nature of an olfactory problem. At first presentation, it is vital to ascertain what kind of olfactory impairment is present: total loss of smell, partial loss, altered sensation (increased or decreased acuity) or additional unpleasant olfactory sensations. The pathological mechanisms resulting in olfactory disturbance are varied, including head injury, URTI, tumours within the anterior cranial fossa, exposure to noxious substances and infections, amongst others. Olfactory disturbance is a key feature of a number of clinical syndromes, such as Kallmann syndrome, in which hypogonadism is accompanied by anosmia, and Foster-Kennedy syndrome, in which a meningioma arising within the olfactory groove typically results in papilloedema, one-sided loss of smell plus atrophy of the optic nerve. If the cribriform plate is fractured in a head injury, there is a potential for CSF leakage from the nose and the risk of meningitis infections. Paranasal sinus endoscopy may occasion damage to the cribriform plate, which opens the way to cerebral infection. Both surgical craniotomy of the anterior base of the skull and a subarachnoid haemorrhage have the associated risk of damage to the olfactory nerves. In this chapter, the clinical assessment of olfactory disorders is discussed.
KeywordsOlfactory disorders Total loss of smell Partial loss Kallmann syndrome Foster-Kennedy syndrome
- 1.Vokshoor A. Olfactory system anatomy. In: Meyers AD, editor. Medscape. http://emedicine.medscape.com/article/835585-overview#showall. Accessed online at 12 Dec 2015.
- 6.Barkovitch AJ, Raybaud C. Congenital malformations of brain and skull. In: Barkovitch AJ, Raybaud C, editors. Pediatric neuroimaging. 5th ed. Philadelphia: Lippincott Williams and Wilkins; 2012. p. 450–62.Google Scholar
- 11.Damm M, Leung RM, Kern RC. Sinonasal olfactory disorders. In: Welge-Luessen A, Hummel T, editors. Management of smell and taste disorders. Stuttgart: Thieme; 2014. p. 76–90.Google Scholar
- 14.Duus P. Le nerf olfactif. In: Von Hassler R, editor. Diagnostic neurologique les bases anatomiques. 6th ed. Paris-Bruxelles: DeBoeck Université; 1998. p. 109–11.Google Scholar
- 15.Yasuda M, Higuchi O, Takano S, Matsumara A. Olfactory ensheathing cell tumor: a case report. J Neurol. 2006;76(2):111–3.Google Scholar
- 26.Olfactory System Wikibooks. https://en.wikibooks.org/wiki/Human_Physiology/Senses. Accessed online at 12 Dec 2015.
- 30.Kobal G. Electrophysiological measurement of olfactory function. In: Doty RL, editor. Handbook of olfaction and gustation. 2nd ed. New York: Marcel Dekker; 2003. p. 229–49.Google Scholar
- 32.Hummel T, Kobal G. Olfactory event-related potentials. In: Simon SA, Nicolelis MAL, editors. Methods and frontiers in chemosensory research. Boca Raton: CRC Press; 2001. p. 429–64.Google Scholar