OVERVIEW
- Nasal obstruction is a common presenting symptom for the entire range of pathological conditions of the nose. An approach to diagnosis starts with obtaining from the general medical history details of family, past or present history indicative of allergic disease, features of an upper respiratory tract infection and medications used, prescribed or illicit
- Anosmia or complete loss of smell is rare. Reduced or diminished sense of smell, hyposmia, is more common, and when due to a secondary conductive blockage usually responds well to surgery coupled with steroid medication
- The commonest nasal swelling is an enlargement of the proximal end of the inferior turbinate, that may be engorged by physiological and pathological disorders
- There is limited correlation between the severity of the septal deviation and the degree of nasal blockage
- The treatment of nasal polyposis can be medical, surgical or most usually a combination of both. Anti-inflammatory steroid therapy is a mainstay of treatment and best applied topically either in the form of a nasal spray or drops. Systemic steroids are prescribed in short courses to improve symptom control or as an adjunct to surgical treatment.
- Chronic rhinosinusitis is an inflammatory condition of the nose and paranasal sinuses with symptoms lasting for 12 weeks or more, affecting adult men and women equally, the diagnosis being made most commonly on symptoms
Symptoms
Nasal obstruction is a common presenting symptom for the entire range of pathological conditions of the nose. The key to arriving at a diagnosis is based as much on the associated symptoms as it is on the presentation and temporal characteristics of the nasal obstruction. An approach to diagnosis starts with obtaining from the general medical history details of family, past or present history indicative of allergic disease e.g. atopic dermatitis in childhood (allergy), features of an upper respiratory tract infection and medications used—prescribed or illicit. Many drugs can cause nasal obstruction, such as excessive use of topical vasoconstrictors in the nose.
The history should then focus on the presenting symptom of nasal obstruction and seek to determine:
- Onset of the nasal blockage—Is it sudden or gradual?
- The presence of precipitating or relieving factors—Is it triggered by exposure to perfume, suggestive of vasomotor rhinitis or following a nasal injury?
- Localisation—Is it bilateral or unilateral?
- Temporal characteristics—Is it persistent or intermittent?
Smell disorders
Anosmia—the complete loss of smell—is rare. The most common presentation of olfactory disturbance is hyposmia or a reduction in olfactory acuity. The olfactory sensory epithelium is located in the olfactory cleft in the upper reaches of the nasal cavity. The sensory cells are ciliated and contain odorant specific receptors. These cells synapse with the olfactory bulb in the forebrain by dendritic processes which traverse through the bony perforations of the cribriform plate (Figure 14.1). The binding of a specific odorant molecule with its receptor triggers depolarisation of the sensory cell and generation of an action potential that is transmitted along the olfactory pathways to the brain.
A number of conditions can impair the olfactory process and these maybe categorised into:
Treatment and likely outcome
Investigation of the patient with a disorder of smell requires a complete nasal endoscopic evaluation in all cases. Potential causes of a conductive blockage of the olfactory system will either be diagnosed or excluded based on the endoscopic findings. An MRI scan of the brain is used to identify intracranial neurosensory causes of olfactory dysfunction such as intracranial extension of the rare olfactory neuroblastoma (a tumour that originates in the neuroepithelial cells of the cribriform plate). A CT scan is a better imaging investigation for tumours that arise in the nasal mucosa and then invade the olfactory sensory epithelium or for cases of head trauma. Cases of diminished smell acuity secondary to conductive block usually respond well to surgery coupled with steroids (e.g. nasal polyps). If the olfactory epithelium has been damaged—as in tumour invasion—or the connections between the olfactory bulb and the olfactory sensory epithelium have been damaged secondary to trauma, then the prognosis for recovery is generally poor. However, up to 20% of patients show spontaneous improvement with time after head injury or postviral olfactory loss, with higher reported rates the longer the follow-up.
Signs
The approach to examining a patient with nasal obstruction is identical to that used for assessing a patient with any other nasal symptom.
Commence with inspection of the nasal appearance, looking for signs of trauma, nasal deformity such as displacement of the nasal bones or an intranasal mass distending the nasal vestibule.
Proceed to anterior rhinoscopy or examination of the nasal passages with a bright light aided by the use of a nasal speculum to gently retract or open the alar cartilage. You should be supervised by an experienced clinician when first using a nasal speculum, as it is easy to over-distend the alar cartilage and cause the patient discomfort. The use of an otoscope with a wide gauge speculum is an alternative technique for the novice that is less likely to cause the patient discomfort. An otoscope is more likely to be available to students and clinicians practising outside a specialist environment. The otoscope will provide a light source and the otoscopic speculum retracts the alar cartilage.
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