The sense of smell originates with olfactory sensory neurons located in the top of the nasal cavity.
- These neurons are connected through nerve fibers that act as chemoreceptors.
- Chemoreceptors respond to stimuli from ions or molecules dissolved in moisture from mucus membranes.
- Nerve fibers run through tiny holes in the skull bone above the nasal cavity to the olfactory center in the brain.
The Olfactory System
The olfactory sensory neurons detect odors only after they are dissolved in mucous secretions.
- This process is crucial for the perception of smell as the odor molecules must interact with the mucosal surface.
Diseases and Disorders of the Nose
Epistaxis (Nosebleed)
Definition: Epistaxis is defined as bleeding from the nose.
- Evidence of epistaxis includes visible blood coming from the nose.
Sources of blood:
- Blood may also originate from the mouth (expectorated) or swallowed into the throat.
Symptoms
Symptoms accompanying epistaxis may include:
- Lightheadedness
- A drop in blood pressure
- Rapid pulse
- Dyspnea (difficulty breathing)
- Pallor
- Other signs of shock
Causes
Common causes of epistaxis:
- Injury (external or internal), such as:
- Blow to the nose
- Nose picking
- Insertion of foreign bodies
Less frequent causes include chronic conditions such as:
- Nasal or sinus infections, leading to capillary congestion and bleeding.
- Inhalation of irritating substances.
Predisposing Factors
Systemic factors contributing to epistaxis:
- High blood pressure
- Anticoagulation drugs
- Chronic aspirin use
- Blood diseases like anemia, hemophilia, and leukemia.
Treatment of Epistaxis
Treatment varies based on:
- Cause
- Location
- Severity of bleeding
First Aid Treatment
Initial first aid measures include:
- Elevating the head to reduce blood flow to the area.
- Compressing the nostrils against the septum continuously for 5–10 minutes.
- Applying ice or cold compresses to the nose.
- Preventing swallowing of blood to assess lost amount.
- Avoiding talking or blowing the nose to minimize agitation and bleeding.
- Observing the amount of blood loss and signs of shock.
Advanced Treatments
Depends on the location of bleeding:
- Anterior Bleeding:
- Pack the area with a cotton ball or gauze pad to apply direct pressure to the source of the bleed.
- For chronic anterior bleeding, cauterization techniques may be used:
- Electric cautery
- Laser treatments
- Silver nitrate
- Posterior Bleeding:
- May require the insertion of a nasal balloon for 48–72 hours to compress the bleeding vessels.
- Small catheters with balloons passed through the bleeding site into the nasopharynx are inflated to create pressure.
- If necessary, anterior packing can also be conducted for 24–48 hours.
- Other treatments may include:
- Supplemental vitamin K
- Blood transfusions
- Surgical ligation (tying off the bleeding artery)
- Embolization of blood vessels using X-ray guided catheters.
Nasal Polyps
Nasal polyps are usually benign growths often found in multiples on both sides of the nose.
- May become large enough to obstruct the airway.
Symptoms include:
- Nasal obstruction
- Sensation of something in the nose
- Trouble breathing
- Loss of smell.
Diagnosis
Diagnosis can be made through:
- Visual observation using a nasal speculum
- Radiographs of the nasal passages and sinuses.
Pathophysiology
Nasal polyps are thought to be related to:
- Prolonged mucous membrane edema associated with:
- Allergies
- Chronic sinusitis
- Rhinitis
- Recurrent nasal infections.
Treatment
If infected, treatment may include:
- Steroids and antibiotics to temporarily reduce the size of polyps.
Surgical removal is generally considered the treatment of choice and often necessary.
Rhinitis
Allergic Rhinitis
Definition: A reaction to airborne allergens.
Symptoms include:
- Sneezing
- Profuse watery discharge
- Itching of the eyes and nose
- Conjunctivitis
- Tearing.
Mechanism
Many symptoms are a result of the body's attempt to dilute or remove irritants affecting the mucous membranes.
- Any environmental antigen can trigger allergic rhinitis, some common ones include:
- Dust
- Ragweed pollen
- Cat and dog dander.
Treatment
Treatment strategies include:
- Eliminating environmental antigens when possible.
- Use of antihistamines and topical corticosteroids.
Long-term management may involve:
- Desensitization injections of the offending allergens
- Use of air conditioning to filter air
- Relocation to a safe environment if symptoms are severe and persistent.