Nasal Obstruction
Nasal obstruction, also referred to as nasal congestion, describes impaired airflow through the nasal cavity. It is a common symptom of nasal and sinus disorders and may also occur in certain systemic conditions. Nasal obstruction can present as intermittent, alternating, paroxysmal, progressive, or persistent, and may affect one or both sides of the nasal cavity. At times, there is a discrepancy between the patient's subjective sensation of nasal airflow and the actual nasal resistance, such as in cases where atrophic changes in the nasal mucosa reduce sensitivity, or when the nasal cavity is excessively widened, leading to a lack of airflow sensation and a subjective feeling of "nasal blockage" or fullness in the nasal cavity.
In newborns, nasal obstruction may manifest as intermittent difficulty during breastfeeding and disrupted sleep. It can be associated with congenital nasal anomalies, such as congenital choanal atresia. Nasal obstruction in infants and young children, particularly when accompanied by mouth-breathing during sleep or snoring, is often related to adenoid hypertrophy. Unilateral persistent nasal obstruction with foul-smelling, blood-tinged purulent discharge is commonly caused by a foreign body in the nasal cavity.
In adults, common causes of nasal obstruction include various forms of rhinitis, sinusitis, tumors, and nasal septal deviation. Nasal obstruction due to acute rhinitis is typically short-lived and occurs alongside systemic symptoms such as fever. In simple chronic rhinitis, nasal obstruction is intermittent, alternating, and varies in severity, often worsening on the side dependent during lying down. Hypertrophic rhinitis often produces persistent nasal obstruction that is unaffected by body position.
Nasal obstruction caused by sinusitis is often unilateral and accompanied by purulent nasal discharge. When nasal polyps develop as a complication, the obstruction becomes more pronounced and may be progressive or persistent. Nasal and sinus allergic conditions are typically associated with paroxysmal nasal obstruction, accompanied by symptoms such as nasal itchiness, sneezing, and watery nasal discharge, resembling the presentation of acute rhinitis but without systemic symptoms such as fever.
Nasal septal deviation, hypertrophy of the nasal septal mucosa, nasal septal hematoma, or abscess may also lead to nasal obstruction. In some cases of nasal septal deviation, not only is nasal obstruction experienced on the side of the deviation, but compensatory hypertrophy of the turbinates on the contralateral side can also result in obstruction. Nasal, sinus, and nasopharyngeal tumors typically cause progressive nasal obstruction that worsens with tumor growth. Benign tumors progress slowly, while malignant tumors progress more rapidly and are often accompanied by symptoms such as epistaxis and headache. For any degree of nasal obstruction, the possibility of malignancy should be considered if epistaxis occurs, even if only a small amount of blood or blood-stained nasal discharge is observed, and thorough examination is required to establish a diagnosis.
Systemic factors may also contribute significantly to nasal obstruction. Endocrine dysfunctions (such as hypothyroidism, diabetes, or hyperactivity of nasal mucosal glands during puberty), systemic vasomotor dysregulation, and medications such as antihypertensive drugs can all contribute to nasal obstruction. A detailed medical history should be taken for patients reporting nasal obstruction, including the severity, characteristics, duration, associated symptoms, and history of medication use.
Rhinorrhea
Rhinorrhea, also known as increased nasal secretion, runny nose, or nasal discharge, refers to an excessive production of nasal secretions. Under normal circumstances, the nasal cavity secretes approximately 1,000 mL of mucus daily. This mucus is a normal secretion from the nasal mucosal glands and goblet cells, typically thin, colorless, and imperceptible due to its steady clearance by cilia. Any condition that leads to an increase in the volume or alteration in the characteristics of nasal secretions is referred to as rhinorrhea. In severe cases, patients may experience continuous nasal discharge throughout the day. Depending on the location of the pathology, nasal discharge may flow outward through the nostrils, referred to as anterior rhinorrhea, or backward into the nasopharynx, termed posterior rhinorrhea or postnasal drip.
Rhinorrhea often occurs alongside nasal mucosal swelling and nasal obstruction, making it a common symptom of nasal disorders. In addition to nasal causes, certain external stimuli not directly related to the nasal cavity, such as exposure to cold temperatures or emotional fluctuations, can also trigger rhinorrhea. For patients presenting with rhinorrhea as the primary complaint, a thorough history-taking and physical examination are necessary to identify the cause and duration of the condition, evaluate the nature and volume of nasal secretions, and arrive at an accurate diagnosis. Additionally, any accompanying symptoms, such as nasal obstruction, sneezing, a burning sensation in the nose, changes in the sense of smell, or headache, should be documented.
In pathological conditions, most rhinorrhea originates from secretions of the nasal mucosal glands or exudates from nasal blood vessels, collectively termed nasal mucus. In some cases, it may stem from the rupture of serous cysts in the nasal cavity or leakage of cerebrospinal fluid (CSF) through congenital or traumatic fistulas at the nasal-cranial junction. These conditions are collectively referred to as nasal discharge or nasal leakage. The characteristics of nasal secretions vary depending on the underlying cause, which can be categorized as follows:
Watery Rhinorrhea
The secretions are thin, transparent, and resemble clear water. This type of discharge typically results from a combination of mucosal vascular exudates and glandular secretions. It is commonly observed in the early stages of acute rhinitis, during episodes of allergic rhinitis, or vasomotor rhinitis. If the discharge is pale yellow and clear, intermittently leaking unilaterally, it is often caused by the rupture of a sinonasal mucosal cyst.
Mucous Rhinorrhea
Mucous discharge originates from the secretory activity of nasal mucosal glands and goblet cells within the epithelium, which helps maintain nasal mucosal hydration. In cases of chronic nasal inflammation, hypersecretion from mucosal glands and goblet cells results in mucous nasal discharge. This type of secretion is primarily composed of mucosal gland secretions, appearing translucent and viscous, and is rich in mucoproteins. It is commonly seen in conditions such as chronic rhinitis and chronic sinusitis.
Muco-Purulent Rhinorrhea
These secretions are thick, yellowish-white, and turbid, consisting of a mixture of mucus and pus. The main components include shed mucosal epithelial cells and infiltrated polymorphonuclear leukocytes, resulting from bacterial infection. This type of discharge is often noted during the recovery phase of acute rhinitis, as well as in chronic rhinitis and sinusitis. If the discharge is yellow-green, turbid, and foul-smelling, it is frequently associated with odontogenic maxillary sinusitis or foreign bodies in the nasal cavity. Purulent nasal discharge with large scabs is commonly seen in atrophic rhinitis.
Purulent Rhinorrhea
Purulent discharge is typical of more severe cases of sinusitis.
Bloody Rhinorrhea
This type of rhinorrhea contains traces of blood or is blood-streaked. It is commonly caused by acute nasal or sinus inflammation, trauma, foreign bodies, nasal calculi, fungal infections, or tumors in the nasal cavity, sinuses, or nasopharynx. In cases of bloody rhinorrhea, examinations of the nasal cavity and sinuses are necessary, and systemic evaluation may be required to determine the source and cause of the bleeding.
Cerebrospinal Fluid Rhinorrhea
Cerebrospinal fluid (CSF) leakage occurs when CSF drains through the nasal cavity, often due to congenital defects in the cribriform plate or sphenoid bone, fractures at the base of the anterior or middle cranial fossa, or surgical trauma. Damage to the bony attachment of the middle turbinate (e.g., the ethmoid roof) during nasal endoscopic surgery may lead to CSF rhinorrhea. Nasal discharge that is clear, transparent, watery, and nonviscous, and remains uncoagulated when left standing, strongly suggests CSF leakage. Quantitative glucose analysis of nasal discharge—showing a glucose level greater than 1.7 mmol/L or 30 mg/dL—can confirm the presence of cerebrospinal fluid.
Nasal Itch and Sneezing
The nasal mucosa is innervated by sensory nerves, as well as sympathetic and parasympathetic nerves. Sensory nerves transmit sensations of itch and play a role in the sneezing reflex. Nasal itch refers to an unpleasant subjective sensation triggered by mechanical, physical (e.g., temperature changes, light), or bacterial stimuli that induce the release of local chemical substances, irritating the superficial sensory nerve endings of the nasal mucosa. Itch and pain share the same neural pathways, and subthreshold or incomplete transmission of painful stimuli can result in the sensation of itching. The nasal mucosa contains a rich network of sensory nerve endings, all branches of the trigeminal nerve. External stimuli affecting the nasal region are transmitted via the trigeminal nerve to the semilunar ganglion, and the impulses are then relayed to the pons and medulla. From the medulla, preganglionic fibers pass through the pterygopalatine ganglion to stimulate the nasal mucosa, resulting in mucosal edema, increased secretion from mucus glands, and the production of watery nasal discharge accompanied by a distinct sensation often described as "fluid dripping" or "streaming." This is recognized as nasal itch. Additionally, the trigeminal nerve may transmit impulses to the postcentral gyrus of the cerebral cortex, further contributing to nasal itch. Certain chemical mediators, such as those released during allergic reactions or inflammation (e.g., histamine, bradykinin, and proteases), can also stimulate the nasal mucosa and cause itching.
The severity of nasal itch depends on the patient’s individual sensitivity, the nature of the underlying condition, and the intensity of external stimuli. For instance, in patients with pollen allergy, heightened nonspecific reactivity of the nasal mucosa leads to a significantly lowered itch threshold. Stimuli that may not provoke any response in other individuals can induce pronounced nasal itching in these patients, often accompanied by repetitive sneezing. Inflammatory conditions such as early-stage acute rhinitis also lower the nasal itch threshold, making sneezing a frequent consequence for these patients. The itch threshold can vary by age, with young children and elderly individuals generally having a higher threshold; stimuli sufficient to cause nasal itching in adults may not necessarily trigger symptoms in these groups.
Common causes of nasal itching include exposure to irritating dust or chemical gases, stimulation from nasal crusts or secretions, early stages of viral or bacterial infections, inhalation of allergenic substances, and responses to cold exposure. Specifically, cooling of the body, especially the surface and lower extremities, may reflexively cause vasoconstriction of nasal mucosal vessels, initially resulting in pallor of the nasal mucosa, followed by turbinate swelling, increased secretions, and sneezing. Mild cases may present with an itchy sensation inside the nose, while more severe cases may involve dull pain in the nasal region, throat itchiness, or a sensation of dryness.
Sneezing is a protective reflex characterized by a sequential event where stimulation of the nasal mucosa triggers a sudden and deep involuntary inspiration, followed by a forceful expulsion of air through the mouth and nose accompanied by sound. Sneezing may also involve facial muscle movements, eye closure, tearing, transient increased nasal secretions, and nasal mucosal congestion. Its primary function is to expel foreign particles, microorganisms, and antigens that have entered the nasal cavity. However, frequent and repetitive sneezing is indicative of an underlying pathological condition and represents a significant symptom of certain nasal disorders. In rare cases, sneezing may occur as a symptom of central nervous system disorders.
The neural pathways involved in sneezing are complex and consist of two interconnected mechanisms: the nasal phase and the respiratory phase. The nasal phase mirrors the mechanism of nasal itching, where clear, watery nasal secretions and the "dripping" sensation stimulate the trigeminal nerve. The impulses travel via the trigeminal nerve to the pons and medulla, where they reach the respiratory center located in the floor of the fourth ventricle. From there, the diaphragm is activated via the phrenic nerve, and the intercostal and abdominal muscles are engaged via the anterior spinal nerve roots, initiating inspiratory movements. The respiratory phase then transitions to exhalation, during which the soft palate elevates, the pharyngeal constrictor muscles contract (closing off the nasal cavity), and the diaphragm, intercostal muscles, and abdominal muscles contract. This sequence increases thoracic pressure and forces the nasopharynx to open, resulting in an explosive expulsion of air from the nose and mouth, producing the sneezing action.
Patients with allergic rhinitis experience frequent episodes of sneezing as a result of heightened nasal mucosal reactivity and increased sensitivity of peripheral nerves. Common triggers include dust, pollutants, irritating odors, nasal inflammation, infections, and allergens. Additionally, sudden exposure to bright light or psychological factors can provoke sneezing. Occasional sneezing is considered physiological, while persistent and repetitive sneezing warrants attention. Diseases commonly associated with sneezing include infectious rhinitis, allergic rhinitis, and idiopathic rhinitis (e.g., vasomotor rhinitis and non-allergic rhinitis with eosinophilia syndrome). Key mediators involved in the sneezing reflex include substances such as histamine and bradykinin.
Olfactory Disorders
Olfaction is the sensory function by which odorant particles (odorants) carried by inhaled air enter the nasal cavity, come into contact with the olfactory mucosa, dissolve in the secretions of Bowman’s glands, and stimulate olfactory cells to generate nerve impulses. These impulses are transmitted via the olfactory nerve, olfactory bulb, and olfactory tract to the cortical centers, resulting in the perception of smell. Clinically, olfactory disorders (dysosmia) generally fall into three categories:
- Reduced Olfactory Sensitivity: Also referred to as hyposmia or diminished sense of smell, this condition is usually reversible. Patients are unable to detect weak odorant stimuli but can still perceive strong ones.
- Anosmia: This refers to the loss of the ability to detect certain odorants or all odorants, known as partial or complete anosmia. Recovery is usually difficult.
- Olfactory Abnormalities: These include hyperosmia (increased olfactory sensitivity), paraosmia (misperception of one odorant as another), phantosmia (perception of a foul odor instead of a pleasant one), and olfactory hallucinations (perceiving smells in the absence of odorants).
Olfactory disorders can be categorized based on their causes into the following two types:
Respiratory Hyposmia and Anosmia
Also known as mechanical or obstructive hyposmia or anosmia, this type arises from nasal conditions that obstruct airflow, preventing odorants from reaching the olfactory mucosal area. The olfactory mucosa, olfactory nerve, and olfactory center are generally unaffected, making hyposmia the more common presentation in such cases. When the underlying cause is resolved, normal olfaction often returns. However, prolonged obstruction may lead to degeneration of nerve endings, making recovery difficult even after the obstruction is removed. Common conditions associated with respiratory hyposmia and anosmia include anterior and posterior nasal choanal atresia, acute and chronic rhinitis, allergic rhinitis, acute and chronic sinusitis, specific nasal infections (e.g., tuberculosis, syphilis, rhinoscleroma), nasal polyps, nasal septal disorders (e.g., deviation, hematoma, abscess), nasal cavity narrowing or atresia following trauma, and benign or malignant tumors of the nasal cavity or sinuses.
Sensory Hyposmia and Anosmia
This type of olfactory impairment results from pathological changes in the olfactory mucosa and the peripheral olfactory nerves. Proper olfactory functioning requires healthy, moist olfactory mucosa and intact olfactory nerve endings. Causes of sensory-related olfactory dysfunction include congenital hypoplasia or aplasia of the olfactory mucosa or olfactory nerve, rhinitis, sinusitis, atrophic rhinitis, allergic rhinitis, viral infections, chemical damage (e.g., corrosive agents, surface anesthetics, formaldehyde, smoking), toxic olfactory neuritis, trauma to the nasal roof, tumors, and age-related degenerative changes.
Rhinogenic Headache
Rhinogenic headache refers to headache caused by anatomical or pathological abnormalities of the nasal cavity or sinuses. The sensory nerves of the nasal cavity and sinuses are derived from the first (ophthalmic nerve) and second (maxillary nerve) branches of the trigeminal nerve. Nasal pathology can directly stimulate the trigeminal nerve endings in the nasal mucosa, causing headache, which may radiate via nerve branches to other areas supplied by the corresponding nerves. Common causes include acute and chronic sinusitis, anatomical abnormalities, barotrauma-induced sinusitis, nasal septal deviation, sinus cysts, and nasal or sinonasal tumors.
The characteristics of rhinogenic headache include the following:
- It is typically accompanied by nasal symptoms such as nasal obstruction and purulent nasal discharge, and often alleviates after the drainage of purulent material from the sinuses.
- It tends to worsen during acute inflammation.
- The pain is usually deep, dull, and vague, more severe during the daytime, relieved by rest, and exacerbated by activity.
- Nasal mucosal vasoconstriction or the use of surface anesthetics may reduce or temporarily relieve the headache.
- Actions such as coughing, bending forward, or straining may increase venous pressure in the head and intensify the headache.
- Headache location and timing are somewhat specific to the underlying issue.
Furthermore, the sensitivity of nasal mucosa to pain-inducing stimuli varies by location. The most sensitive areas include the mucosa near the natural ostium of the maxillary sinus and the frontal recess, followed by the turbinates and the nasal roof, and then the nasal septum and sinus mucosa.
Epistaxis
Epistaxis, or nosebleed, is one of the most common emergencies encountered in otorhinolaryngology and head and neck surgery. In most cases, blood first flows out from the anterior nostril on the affected side. When bleeding is significant or originates from an area near the posterior nasal cavity, blood may flow back into the nasopharynx or emerge from the other nostril. It may also pass through the nasopharynx into the oral cavity, where it is either expelled or swallowed.
The causes of epistaxis are classified into local and systemic factors. Local factors include trauma, surgical procedures, nasal and sinus inflammation, nasal septal lesions, nasal tumors, anatomical variations, and vascular malformations. Systemic factors include coagulation disorders (e.g., blood disorders, liver and kidney dysfunction, use of nonsteroidal anti-inflammatory drugs, excessive alcohol consumption), cardiovascular diseases, acute infectious diseases, endocrine disorders, and hereditary hemorrhagic telangiectasia. In children, common causes of epistaxis include nasal dryness, allergies, nasal foreign bodies, blood disorders, kidney diseases, and unbalanced diets.
The severity of epistaxis depends on the underlying cause. Mild cases may manifest as intermittent blood-streaked mucus (e.g., in conditions such as atrophic rhinitis or early-stage nasopharyngeal carcinoma) or minor dripping of blood. More severe cases involve active bleeding, with some cases presenting as profuse hemorrhage. In the most severe cases, bleeding may be arterial and spurting, potentially leading to hypovolemic shock or life-threatening conditions (e.g., as in ruptures of the internal carotid artery forming aneurysms or carotid-cavernous fistulas, or late-stage nasopharyngeal carcinoma).
A thorough history should be obtained for patients with epistaxis, including the initial side of bleeding, the volume and duration of bleeding, associated symptoms, history of nasal diseases, lifestyle habits, and any systemic conditions. Regardless of the cause, careful inspection of the nasal cavity under nasal endoscopy is recommended whenever possible to identify the bleeding site. In cases where routine treatment fails, bleeding from the posterior or hidden areas of the nasal cavity should be assessed, with special attention to areas such as the olfactory cleft, the posterior-superior region of the middle meatus, and the posterior vault beneath the sphenoethmoidal recess.