Over the past year, much of our effort as a speciality has been directed towards crisis management and keeping services afloat. Our practice has changed in untold ways, but unprecedented numbers of patients with smell disorders will increasingly require our attention, so here’s Wahidah Wahid and Lisha McClelland with some invaluable suggestions on how to forge a smooth clinical pathway.
'COVID anosmia’- the loss of sense of smell as a result of COVID-19, is the newfound term that has gained significant spotlight since the beginning of the pandemic. Loss of smell (LOS) and taste was found to be the most prevalent symptom of COVID-19. Whilst most recover within a few weeks, 10% of patients continue to suffer with persistent anosmia.
Given the high prevalence of COVID-19 infection in the general population, it is expected that we will see a surge in patients referred with persistent smell loss when elective service resumes. We are also faced with the huge task of clearing the backlogs, whilst still ensuring safe practice in the post-COVID era. It is therefore vital that we consider effective ways of running our specialist smell clinic.
Pre-COVID: a typical day in the smell clinic
At the Queen Elizabeth Hospital Birmingham, we run a weekly smell clinic with referrals from the local catchment, out-of-area GP referrals and tertiary referrals. Eight patients are seen over a four-hour clinic session with a mixture of new and follow-up. Trained nurses carry out the Sniffin’ Sticks smell test before the patient sees the ENT consultant for history taking, examination, investigations, and treatment.
Post-COVID: factors to consider in setting up the smell clinic
Referrals should be risk-stratified and directed to either initial advice and guidance, teleconsultations or face-to-face consultations. Red flag symptoms should be considered for urgent two-week-wait clinics.
Primary care: anosmia management
Primary care physicians play an important role in the initial management of anosmia and can be signposted to the primary care British Rhinological Society (BRS) guidance published in the British Medical Journal (BMJ) . Most patients will improve spontaneously. It is recommended to offer smell training, anosmia advice and signpost to support groups e.g., Fifth Sense. For post-viral rhinosinusitis, therapies such as intranasal corticosteroids, decongestants and saline spray or rinses can be trialled . Ideally the criteria for referral are those with smell and taste symptoms persisting more than three months.
Teleconsultations and early instigation of treatment
Remote teleconsultation has been the ‘new normal’ and it remains a good place to start. Depending on the likely differential diagnosis, investigation and treatment could be instigated earlier on in the pathway. Many will still require a second appointment for formal examination, including nasendoscopy and smell test.
“It is important to remember that there is a wide-ranging differential diagnosis for LOS”
It is important to remember that there is a wide-ranging differential diagnosis for LOS. In the pre-COVID era, the majority of patients seen had a conductive olfactory problem such as chronic rhinosinusitis. Post-viral olfactory loss (PVOL) is the second most common cause, followed by post-traumatic olfactory loss (PTOL). Other less common causes include neurological disease, congenital, and a proportion of patients have an undetermined cause. A thorough history should include duration, concomitant sinonasal symptoms, possible fluctuation, distortions and events preceding the olfactory deficit.
For those with persistent symptoms (>3months) and obvious history of isolated LOS following upper respiratory tract infection (URTI) e.g., COVID infection, a trial of high dose oral steroids (+/- shielding) and/or Omega-3 supplements can be considered at the initial teleconsultation. For those with additional nasal symptoms, a trial of intranasal corticosteroids should be instigated. Vitamin A intranasal drops in addition to smell training have been trialled with good outcomes , although it comes with side-effects of local irritation. In majority of PVOL imaging is not required.
In PTOL, clinicians can consider the use of zinc in addition to oral steroids, though the evidence is weak . Qualitative smell disorders, such as phantosmia and parosmia, need to be addressed. Parosmia, which is the distortion of smell triggered by an odour source, seems to be prevalent in patients with COVID-19. Conservative management includes valsalva manoeuvre, distraction technique, and trigeminal nerve stimulants. When appropriate, imaging and blood tests can be organised prior to the consultation.
Smell clinic: face-to-face consultation
Prior teleconsultation improves clinic flow as patients are attending for a follow-up with smell or taste testing and nasendoscopy. We envisage they would have started smell training, have been offered support, received initial treatment or have had basic investigations. Patients can explore possible treatment options and be counselled on the prognosis and consequences of their disorder. The infographic outlines the suggested clinic pathway template along with suggested investigations and treatments.
Challenges and considerations in the smell clinic
There are several considerations and precautions that will need to be taken into account to ensure we provide a safe and efficient service.
Which smell test?
Several smell tests exist (Table 1). The Sniffin’ Sticks dispense odours through pen-like devices and assess threshold, identification and discrimination, and are validated for use in the UK. The Connecticut Chemosensory Clinical Research Center (CCCRC) uses bottled fragrances and assesses threshold and identification. This test is not commercially available and is usually devised by the hospital lab for clinical use, making it an inexpensive option. The reusable testing does have limitations, including its considerable testing time, the need for personnel resources and the potential risk of microbial contamination, due to the close proximity of pen tip or bottled fragrances to the nose or lips. One precautionary measure is mandatory pre-clinic COVID test and self-isolation three days prior to the clinic attendance, similar to preoperative measures. In order to avoid contact of Sniffin’Sticks, the German Society for Otolaryngology recommends using single-use cellulose paper strips, appropriate for identification and discrimination tests.
“Vitamin A intranasal drops in addition to smell training have been trialled with good outcomes, although it come with side effects of local irritation”
The UPSIT and BSIT test uses ‘scratch and sniff’ that contain microcapsule fragrances, but only assesses identification and have not been validated in the UK. These tests can be self-administered, are single-use and have high reliability. Some departments may opt to post single-use smell test to patients prior to their smell clinic, eliminating the need for outpatient smell testing and pre-clinic COVID screening.
Most patients will require nasal endoscopy to rule out contributing pathology such as mucosal congestion, infection, polyps, neoplasms, and anatomical anomalies. Nasal endoscopy should be performed with appropriate personal protective equipment. Clinic timings may be impacted by conversion to potentially aerosol-generating procedure following a sneeze, and therefore additional rooms should be considered to ensure smooth clinic flow.
Teleconsultation follow-up may help reduce the pressure on clinic room availability and travel for patients.
Financial burden and limited resources
The expected increased referral numbers, along with the costs associated with resources, such as personnel, test kit, and the extra precautions needed to make the smell clinic safe, mean the ENT department is likely to have financial constraints that will need to be addressed. The clinic flow may also take much longer than it did pre-COVID, so realistic goals about the number of consultations per session needs to be agreed.
Returning to the ‘old normal’ is likely to be a slow and difficult process. We are experiencing increasing demand whilst having reduced face-to-face clinic capacity. We should be proactive in applying the knowledge we have gained over the past 12 months regarding triaging and telephone clinics to augment the traditional pathway for patients. Specific considerations need to be made to ensure the smooth and safe running of a much-needed smell service in the post-COVID era.
1. Walker A, Pottinger G, Scott A, Hopkins C. Anosmia and loss of smell in the era of covid-19. BMJ 2020;370:m2808.
2. Fokkens WJ, Lund VJ, Hopkins C, et al. European Position Paper on Rhinosinusitis and Nasal Polyps 2020. Rhinology 2020;58(Suppl S29):1-464.
3. Hummel T, Whitcroft KL, Rueter G, Haehner A. Intranasal vitamin A is beneficial in post-infectious olfactory loss. Eur Arch Otorhinolaryngol 2017;274(7):2819-25.
4. Jiang RS, Twu CW, Liang KL. Medical treatment of traumatic anosmia. Otolaryngol Head Neck Surg 2015;152(5):954-8.