Abstract
Imaging plays a significant role in the diagnosis, management and monitoring of various otorhinolaryngological conditions, both in emergency and routine cases. It is important for GPs to consider the indications and relevance of radiological investigations, including some initiated in secondary care. Some of these investigations can be requested by GPs to aid diagnosis. Appropriate treatment can then be initiated earlier, sometimes avoiding the need for secondary care referral. In some cases, GPs can request the appropriate investigation at the same time as referral to the ear, nose and throat (ENT) department. The patient can then be reviewed with the results to enable diagnosis and further management at the same ENT appointment, saving time and appointments for the patient. This article aims to provide insights into imaging investigations in patients presenting with ENT problems, including indications and interpretation relevant to both GPs and trainees.
Clinical case scenario
A 35-year-old female presents with a painless midline neck lump noticed a few weeks ago. She denies dysphagia, change in voice or weight loss. Her maternal grandmother was diagnosed with thyroid cancer. You take a detailed history. Examination reveals a 3-cm firm, mobile lump on the right thyroid lobe. You request a thyroid ultrasound with fine needle aspiration and thyroid function tests. You refer the patient to ENT as an urgent suspected cancer.
Radiographs
Compared with other imaging methods, X-rays have a low radiation risk. They are comparatively simple to request and accessible to most GP surgeries. Cervical spine radiographs, sometimes referred to as neck radiographs, are useful in a variety of ENT conditions, including, for example, the diagnosis of adenoid enlargement, foreign body ingestion, retropharyngeal abscesses, epiglottitis, croup and salivary gland stones. AP (anteroposterior) and lateral views should be performed.
Adenoidal enlargement
The diagnosis of adenoidal enlargement is generally made on symptoms of mouth breathing, snoring and persistent nasal blockage with examination revealing decreased nasal airflow bilaterally. However, a radiograph of the cervical spine can be used as an adjunct to diagnosis. The adenoids are situated on the posterior wall of the nasopharynx. Generally, they decrease in size from the age of six and by late teens are expected to have disappeared. However, in some young children who suffer with recurrent upper respiratory tract infections they may become hypertrophic, and therefore, symptomatic (Grist, 2011). Enlarged adenoids may result in serous otitis media (glue ear) and the associated complications of hearing loss, impaired speech development and recurrent otitis media. Thus, referral to ENT for treatment of adenoidal enlargement (medical or surgical) may be considered necessary.
Lateral cervical spine radiographs are less often used to investigate for adenoidal enlargement, because flexible nasoendoscopy is more available in ENT clinics to visualise adenoids as a part of the assessment. However, radiographs hold value in younger children who are unable to tolerate flexible nasoendoscopy. It is important to note that a cervical radiograph can show the degree of adenoidal enlargement and the impact on the nasopharynx, but should not be used alone to make the diagnosis. It can be useful in primary care to aid diagnosis, especially when there are prolonged waiting periods for secondary care outpatient appointments. It is important when requesting radiography to make specific reference to the possibility of adenoidal hypertrophy to ensure consideration of this in the report. GPs may then be able to commence medical treatment for adenoidal enlargement in the form of topical steroid nasal sprays. If the adenoidal enlargement persists when the patient is eventually reviewed in the ENT clinic then surgical treatment is a consideration.
Foreign body ingestion
Foreign body ingestion occurs most often in children after placing objects in the mouth. Swallowed objects can obstruct the gastrointestinal tract or the pharynx. The risk factors for foreign body ingestion include extremes of age, cognitive impairment, alcohol abuse and rapid eating. People with dentures are at greater risk due to reduced palatal feedback during swallowing. It is important to be aware of red flag symptoms, such as progressive dysphagia and weight loss, especially in patients with a history of recurrent foreign body ingestion. Strictures and infections or inflammation of the oesophagus also predispose patients to food bolus obstruction.
In stable patients with a history of suspected foreign body ingestion or aspiration, cervical spine radiographs can help to confirm the presence and the site of a foreign body. Lateral views can show whether the foreign body is in the trachea or oesophagus and the number of foreign bodies. Sometimes an abdominal radiograph is requested if the foreign body has gone beyond the oesophagus. Patients with confirmed foreign bodies on radiographs or strongly suspected foreign bodies need to be referred to the emergency department (ED) and directed to either ENT or gastroenterology depending on the site of the foreign body. The level and location guide referral (Fig. 1). Foreign bodies in the pyriform fossa, cricopharynx or upper oesophagus are referred to ENT. Foreign bodies in the mid or lower oesophagus are referred to either gastroenterology or upper gastrointestinal surgeons, depending on local policies. The use of flexible endoscopes designed for retrieval of foreign bodies from the oesophagus and stomach, without the need for general anaesthesia reduces the risk of complications.
Ingested chicken bone seen on lateral cervical spine radiograph. Posterior to trachea, and therefore, clear it is in the oesophagus.
Patients often present to ENT specialists in secondary care complaining of a foreign body sensation after eating fish, however, only around 20% are found to have a fish bone in situ. Often the foreign body sensation is caused by abrasion of the mucosa by the temporarily impacted fish bone. However, the complaint must be taken seriously, as ingested fish bones can migrate and cause serious complications. Ingested fish bones cause more problems than ingested chicken bones. The tonsillar fossa is the most common site of impaction, other areas being the base of the tongue and vallecular (Knipe and Jones, 2014).
Cervical spine radiographs (AP and lateral) are useful for detecting radio-opaque fish bones in the oropharynx. Patients so affected can be referred to ENT for removal of the fish bones. Neck radiographs have a low sensitivity (around 35%) for direct visualisation of fish bones, because the bones may be obscured by fluid or swelling of the soft tissue and because not all fish bones are radio-opaque (Goh et al., 1989). Cod, haddock, red snapper, lemon sole and monk fish have bones that are seen more easily using plain radiographs (Ell and Sprigg, 1991). Chicken bones are mostly radio-opaque. It is important to note that computed tomography (CT) is more sensitive for the detection of ingested fish bones, but plain radiographs are an important first step. CT scans are typically performed after specialist assessment.
Retropharyngeal abscess
Acute retropharyngeal abscesses can result secondary to upper respiratory tract infections or from a primary infection in the head and neck draining into the retropharyngeal lymph nodes and leading to adenitis and subsequent abscess formation. These abscesses present with a variety of possible complaints, including generalised systemic illness and reluctance to eat, and more obvious, localised features including drooling, stridor, neck swelling, restricted neck movements and dysphagia. These patients can become very unwell and if suspected should be referred urgently to secondary care for admission.
Chronic retropharyngeal abscess
Chronic infection of the retropharyngeal space leading to an abscess results secondary to tuberculosis of the cervical spine from spread of infection through the anterior longitudinal ligament into the retropharyngeal space. Other causes include external trauma to the neck, iatrogenic instrumentations, such as oesophagoscopy, and foreign body ingestion. Patients may present with systemic features of infection and subacute odynophagia, dysphagia, change in voice or drooling.
Lateral neck radiographs were used historically in the diagnosis of retropharyngeal abscesses with typical features including loss of cervical lordosis, pre-vertebral soft tissue shadow (greater than two thirds of the AP diameter of the cervical vertebral body) and air fluid levels or gas shadows. Lateral neck radiographs have now been replaced by intravenous (IV) contrast-enhanced CT imaging of the neck in patients with suspected retropharyngeal abscesses, as these provide more detailed images of the extent of the abscess, size of collection and relation to important anatomical structures. Such images help plan management, especially surgical drainage. An X-ray still holds some value and may still be requested if CT is not available. However, CT with contrast remains the current imaging modality of choice (Philpott and Hutson, 2019). Retropharyngeal abscesses are potentially life-threatening, as they can cause airway compromise and patients suspected of having this diagnosis need to be referred urgently to the ED.
Epiglottitis
Acute epiglottitis is typically caused by Haemophilus Influenzae, resulting in an infection of the supraglottic larynx (Shah, 2020). The incidence of epiglottitis or supraglottitis in children has significantly decreased, due to immunisation against H.Influenzae (Singh and Chieng, 2010). It can lead to swelling of the epiglottis and the rest of the supraglottis, thus potentially obstructing the laryngeal inlet. Epiglottitis may be suspected in an unwell patient with one or all of the following: a change in their voice, worsening dysphagia, drooling and stridor. Patients suspected of having epiglottitis should be admitted to secondary care as an emergency, because of the risk of airway obstruction.
Lateral neck radiographs are helpful in the diagnosis of epiglottitis, especially in children. Throat examination is contraindicated, as it holds a very high risk of triggering laryngospasm, and rapid compromise of the airway. The typical appearance of the swollen inflamed epiglottis on a plain radiograph has been described as the ‘thumb sign’ (Singh and Chieng, 2010). Adults with epiglottitis or supraglottitis are generally stable enough to tolerate flexible nasoendoscopy for diagnosis. Supraglottitis is another airway emergency, especially in children, requiring urgent same-day referral. CT is rarely performed, as lying flat can precipitate respiratory arrest and is typically only done where there is diagnostic uncertainty.
Croup
Croup is an upper respiratory tract infection primarily seen in young children, generally in those less than 2 years in age. It is most commonly causes by the parainfluenza virus, but other viruses, such as respiratory syncytial virus are also implicated (Gaillard and Murphy, 2022). It characteristically presents gradually with a typical barking cough, low-grade fever and inspiratory stridor due to oedema of the larynx.
If imaging is performed a steeple sign may be seen on a lateral neck radiograph, which in combination with the clinical history can be useful very occasionally to confirm the diagnosis of croup. The narrowed subglottis and elevated tracheal mucosa create the appearance of a church steeple.
Sialoadenitis
Sialoadenitis is the inflammation and enlargement of the salivary glands, with the parotid and submandibular glands being affected most commonly. It can be caused by bacterial (often Staphylococcus Aureus) or viral infection (consider mumps or human immunodeficiency virus), obstruction (secondary to calculi or tumours) or autoimmune disease such as Sjogren’s syndrome (van der Waal and Turner, 2022). Acute sialoadenitis is more common in older people following illnesses associated with dehydration or post-dental procedures. Bacterial infection may be present if the flow of saliva is restricted. This can be as a result of obstruction secondary to the formation of calcified stones in the salivary glands or sialolithiasis. Sialolithiasis is the most common salivary gland disease. In a classic presentation, patients complain of worsening swelling of salivary glands and pain with eating. Sialoadenitis should be considered in a patient presenting with a painful facial swelling (first presentation or recurrent) along with fever or odynophagia.
Plain radiographs can be helpful in diagnosis, and should include the parotid, mandible and upper cervical spine (AP and lateral). However, it is important to note that not all stones are radio-opaque. Plain radiographs can detect around 80–90% of submandibular stones and around 60% of parotid calculi. Sialography is useful to identify the precise location and size of a stone (Gaillard and Worsely, 2022). However, sialography is contraindicated if the gland is infected. In patients with history of recurrent sialoadenitis plain radiographs may be useful prior to ENT referral for further management.
Barium swallow
Fluoroscopy provides a continuous X-ray image in real time and is an imaging technique with a variety of indications. The primary use in ENT is for the investigation of swallowing.
Barium swallows are a quick, non-invasive and relatively accessible investigation for assessment of swallowing. GPs can request barium swallows when there is concern about swallowing symptoms and images cover the pharynx, oesophagus and proximal stomach. The study is often modified according to the history, and it is important to include detailed history and examination findings on the request form. It is a sensitive tool that detects motility issues, mucosal abnormalities (such as strictures or inflammation of the oesophagus), tumours and pharyngeal pouches (Fig. 2). Therefore, indications include high or low dysphagia. Results guide management including appropriate referrals (usually ENT or gastroenterology) for further investigation and treatment. If an oesophageal malignancy is suspected urgent suspected cancer (USC) referral for an oesophago–gastro-duodenoscopy (OGD) is recommended (National Institute for Health and Care Excellence (NICE), 2021). A barium swallow is not an adequate replacement for OGD (unless contraindicated) as direct visualisation is essential.
(a) Normal Barium swallow and (b) Barrett’s oesophagus as seen by narrowing with dilatation above on Barium swallow.
Barium swallows risk causing complications including chemical mediastinitis, pneumonitis and massive pulmonary oedema in patients with suspected perforations, leaks or aspiration due to inadequately functioning vocal cords or other laryngeal pathologies and they should be informed of this prior to referral (Jones and Chieng, 2022). In cases with a high risk of such complications, a low osmolarity agent such as Omnipaque™ (iohexol) can be used. When barium is not used, the study is called a contrast swallow.
Ultrasound
Neck ultrasound
Neck lumps present very often to GPs, in children and adults. The differential diagnoses for neck lumps are extensive, and thus, a detailed history and examination is imperative to ensure appropriate investigation and management. Causes can be infective or inflammatory.
The most common cause of a neck lump is an enlarged lymph node from either infection or malignancy, therefore assessing for red flags and associated symptoms is of utmost importance. Age is an important predictive factor when considering differential diagnoses, as the risk of malignancy increases with age. From an ENT perspective, red flags include dysphagia, hoarse voice, weight loss and risk factors for head and neck cancers, such as smoking, excess alcohol intake and previous radiotherapy (Schwetschenau and Kelley, 2002).
An ultrasound of the neck should be considered one of the first line investigations and offers significant help in diagnosis and treatment. It is a relatively quick and non-invasive modality that can show the size, site, shape and composition of the lesion. The radiologist can perform a fine needle aspiration at the same examination, thus providing histological diagnosis, if deemed appropriate. GPs can request neck ultrasound with or without fine needle aspiration (although this is at the discretion of the radiologist) for neck lumps and either see the patient back with results or refer to ENT with a provisional diagnosis. Provisional diagnosis and referral with or after ultrasound can prevent unnecessary referrals and may expedite treatment for some patients. Ultrasound features of concern with neck lesions include the presence of microcalcification, invasion of surrounding structures and/or intranodular blood flow (Morgan and Jones, 2021). Local guidelines, protocols and policies may vary and aim to assist better management of patients and efficient use of imaging.
Thyroid ultrasound
A goitre is a term used to describe any enlargement of the thyroid and does not necessarily correlate with thyroid malfunction. Thyroid disease includes both thyroid dysfunction and enlargement. Enlargement of the thyroid may be due to benign nodules, goitres or malignancy (NICE, 2019). Ultrasound of the thyroid is useful to differentiate between solid or cystic changes (Fig. 3). In conjunction with thyroid function tests, ultrasound can aid diagnosis and treatment of thyroid swellings.
Thyroid nodule on ultrasound of the neck.
Parotid ultrasound
Parotid ultrasound for patients presenting with parotid enlargement or lumps helps in the diagnosis of acute and chronic sialoadenitis, parotid stones and parotid tumours (Morgan and Jones, 2021). If there are any red flags leading to a suspicion of cancer ENT referral should be on a USC basis.
Computed tomography
CT scans are generally requested by ENT after clinical review. CT of the temporal bones, paranasal sinuses and neck are done for various conditions and knowledge of these conditions and the relevant imaging can be helpful in primary care for discussion and patient understanding.
Cholesteatomas are skin or keratinising squamous epithelium growing in the middle ear. Recognition and early diagnosis is important to improve patient outcomes. Local expansion may result in damage to other structures including the dura, lateral sinus, facial nerve and the semi-circular canals. The main features are offensive chronic otorrhoea that is unresponsive to treatment and hearing loss. Depending on the extent of local invasion the patient may also complain of headaches, vertigo and facial nerve palsy. Examination may reveal foul-smelling scanty discharge, keratin debris in the attic or postero-superior quadrant of the tympanic membrane. CT imaging of the temporal bones is routinely performed for cholesteatoma to establish the extent of the disease, and involvement of vital anatomical structures such as facial canal, ossicles and semi-circular canals. It is also done to check for recurrence of cholesteatoma.
In cases of head injury, a standard non-contrast CT head is typically performed to assess for temporal bone fractures, which may present with hearing loss, facial palsy, cerebrospinal fluid leak or just bleeding from the ear. The standard imaging can be adjusted by the radiologist to answer the specific concerns. CT is performed as an emergency when there is suspicion of intra-temporal complications in patients with cholesteatoma and for malignant otitis externa.
Malignant or necrotising otitis externa is otitis externa that has spread to cause osteomyelitis of the skull base. It is commonly due to pseudomonas aeruginosa and anaerobes. It is important to consider this as a complication of otitis externa in the elderly, immunocompromised patients, patients with diabetes, patients presenting with otitis externa not responding to treatment and patients with facial palsy secondary to otitis externa. Patients complain of deep severe otalgia, purulent otorrhoea and evidence of granulation or necrotic tissue in the external auditory canal. This condition can be life-threatening if not treated and needs same-day urgent ENT referral. Patients require admission for observation and investigation, including CT of the temporal bones and IV treatment. It is important to put all relevant clinical history and examination on the request form, as image findings can be misinterpreted as malignancy (Hsu and Knipe, 2022).
CT of the paranasal sinuses is performed for recurrent sinusitis, sino-nasal polyposis, and suspected tumours. In the emergency setting it is usually requested along with a CT of the orbits for patients presenting with periorbital or orbital cellulitis.
CT neck (typically with IV contrast) is performed for conditions ranging from deep neck infections and abscesses to head and neck cancers, neck trauma and benign neck masses. They are sometimes used to monitor response to treatment after radiotherapy and chemotherapy.
Magnetic resonance imaging
Similar to CT scans, magnetic resonance imaging (MRI) is not usually requested at the primary care level. MRI IAM (internal acoustic meatus) is performed for asymmetric sensorineural hearing loss and for suspected tumours of seventh and eighth nerve. MRI paranasal sinus is done for sino-nasal tumours. MRI neck is performed for head and neck tumours to assess soft tissue co-relations.
Conclusion
Radiological imaging plays a significant role in the diagnosis, treatment and management of a large number of otorhinolaryngologic conditions (Table 1). Knowledge of these can help GPs in planning investigation and speeding up diagnosis, in promotion of better patient understanding of treatment and follow up plans. Direct access to imaging may vary between different localities. In some patients, particularly acutely unwell patients, it is better to refer urgently to secondary care for initiation of emergency investigation and treatment, rather than risk delay by arranging investigations.
Radiological investigations for common ENT conditions.
Key points
Imaging has a role in the diagnosis and management of a variety of ENT conditions Appropriate imaging in primary care can speed up and improve patient management Relevant clinical details and differential diagnoses should be included on request forms to help the radiologist in their interpretation of relevant radiological findings Investigations in stable patients can help direct referrals to the appropriate speciality; for example, barium swallows for referral to ENT or Gastroenterology It is beneficial for GPs and their patients to understand the role of CT and MRI in ENT conditions when making referrals Not all imaging modalities are available to GPs and use of some will vary according to the development of local policies and protocols
