Postnasal drip syndrome

Etiology

The development of postnasal drip syndrome is closely related to pathology of the nasal cavity and sinonasal region. The main causes include:

• Rhinitis: can be allergic (seasonal, perennial) and non-allergic (vasomotor rhinitis with autonomic regulation disorders).
• Medication-induced rhinitis: occurs as a "rebound" effect due to the abuse of topical vasoconstrictors (decongestants).
• Infectious conditions: acute infections (as in a common cold) or chronic bacterial rhinosinusitis.
• Anatomical factors: for example, nasal septum deviation or the presence of bone spurs.
• Ciliary disorders: impaired epithelial ciliary function (found in Kartagener syndrome).

Clinical presentation and nasal functions

The key manifestation of the syndrome is a cough. An interesting feature is the so-called "silent" cough. In more than a fifth of patients, it is the sole manifestation, without pronounced nasal congestion or abundant discharge, which greatly complicates clinical diagnosis.

Normally, the nasal cavity and paranasal sinuses perform a number of important functions, the disruption of which leads to symptoms:

• Air conditioning (warming, purification, humidification).
• Olfaction.
• Formation of the first line of immune defense thanks to antibodies in the mucosa.
• Voice resonance (which explains the nasal voice during colds).
• Ensuring nasal breathing (mouth breathing is physiological only during exertion).

Diagnostic methods

The mere fact of having a cough is not enough to make a diagnosis. An integrated approach is required:

1. Targeted examination: multislice computed tomography (MSCT) of the paranasal sinuses and an otolaryngologist consultation are mandatory.
2. Trial treatment: the diagnosis is considered definitively confirmed if the prescribed therapy brings symptom relief.

In complex cases, for example, in the differential diagnosis of inflammation and tumors or excluding other causes of anosmia (loss of smell), MRI is used.

Radiological imaging and treatment

Low-dose CT or cone-beam CT is widely used to assess nasal structures. This is possible due to the high contrast of bone structures and air. During the study, the physician assesses the presence of anatomical anomalies, the extent of inflammation (fluid levels or foamy secretion indicate an acute process), as well as the state of bone tissue and the impact of dental pathology (odontogenic sinusitis).

Treatment: Conservative drug therapy is effective in most cases. If it fails, the patient may be indicated for functional endoscopic sinus surgery (FESS). Its main goal is to widen the natural mucociliary pathways, such as the maxillary sinus ostium, to normalize mucus outflow.

What else to study on this topic

• Radiological assessment of mucociliary pathways (CT signs)
• MRI diagnostics of anosmia after traumatic brain injury
• Anatomical variants of nasal conchae structure (concha bullosa)
• Principles of functional endoscopic sinus surgery (FESS)
• Differential diagnosis of nasal polyps and mucocele

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.