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ACUTE AND CHRONIC DISEASES OF NOSE AND PARANASAL SINUSES

Learn the principles of diagnosis and treatment of acute and chronic nose and paranasal sinuses diseases

CLINICAL ANATOMY OF NOSE

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• The nose is the most prominent part of the human face. It has internal and external parts.
• The internal part of the nose is termed the nasal cavity.
• It is involved in respiration, olfaction, speech and taste.
• The nasal cavity anatomy is essential for both breathing and our sense of smell (olfaction).

FUNCTION OF THE NOSE

The nasal cavity has four functions:

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• Warms and humidifies the inspired air.
• Removes and traps pathogens and particulate matter from the inspired air.
• Responsible for sense of smell.
• Drains and clears the paranasal sinuses and lacrimal ducts.

EXTERNAL NOSE

• The external part of the nose consists of a root (superiorly), apex (inferiorly), dorsum, nares (nostrils) and the separating nasal septum.
• Bony component: nasal, maxillae and frontal bones.
• Cartilaginous component: alar cartilages (major, minor), lateral processes, septal cartilage.

NASAL CAVITY

• Bones: nasal, maxilla, sphenod, vomer, palatine, lacrimal, ethmoid.
• Apertures: nares, nasal conchae (superior, middle, inferior).
• Channels: inferior nasal meatus, middle nasal meatus, superior nasal meatus, sphenoethmoidal recess.
• Regions: vestibule, respiratory region, olfactory region.

NASAL CAVITY

Pharyngeal

• The nasal cavity is the most superior part of the respiratory tract. It extends from the vestibule of the nose to the nasopharynx, and has three divisions:

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• Vestibule – the area surrounding the anterior external opening to the nasal cavity.
• Respiratory region – lined by a ciliated psudeostratified epithelium, interspersed with mucus-secreting goblet cells.
• Olfactory region – located at the apex of the nasal cavity. It is lined by olfactory cells with olfactory receptors.

NASAL CAVITY

Pharyngeal

• The nasal cavity is the most superior part of the respiratory tract. It extends from the vestibule of the nose to the nasopharynx, and has three divisions:

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• Vestibule – the area surrounding the anterior external opening to the nasal cavity.
• Respiratory region – lined by a ciliated psudeostratified epithelium, interspersed with mucus-secreting goblet cells.
• Olfactory region – located at the apex of the nasal cavity. It is lined by olfactory cells with olfactory receptors.

NASAL CAVITY

Pharyngeal

Projecting out of the lateral walls of the nasal cavity are curved shelves of bone. They are called conchae (or turbinates). The are three conchae – inferior, middle and superior.

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NASAL CAVITY

Pharyngeal

They project into the nasal cavity, creating four pathways for the air to flow. These pathways are called meatuses:

• Inferior meatus – between the inferior concha and floor of the nasal cavity.
• Middle meatus – between the inferior and middle concha.
• Superior meatus – between the middle and superior concha.

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NASAL CAVITY

Pharyngeal

• The function of the conchae is to increase the surface area of the nasal cavity – this increases the amount of inspired air that can come into contact with the cavity walls.
• They also disrupt the fast, laminar flow of the air, making it slow and turbulent.
• The air spends longer in the nasal cavity, so that it can be humidified.

NASAL CAVITY

Blood supply

The nose has a very rich vascular supply – this allows it to effectively change humidity and temperature of inspired air. The nose receives blood from both the internal and external carotid arteries:

• External carotid artery and its branches: sphenopalatine, greater palatine, superior labial and lateral nasal arteries.
• Internal carotid artery and its branches: anterior and posterior ethmoidal arteries.

NASAL CAVITY

Clinical Relevance: Epistaxis

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• Epistaxis is the medical term for a nosebleed.
• Due to the rich blood supply of the nose, this is a common occurrence.
• It is most likely to occur in the anterior third of the nasal cavity – this area is known as the Kiesselbach area.
• The cause can be local (such as trauma), or systemic (such as hypertension).

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NASAL CAVITY

Nerve supply

• The innervation of the nose can be functionally divided into special and general innervation.
• Special sensory innervation refers to the ability of the nose to smell. This is carried out by the olfactory nerves.

NASAL CAVITY

Nerve supply

• The olfactory bulb, part of the brain, lies on the superior surface of the cribriform plate, above the nasal cavity.
• Branches of the olfactory nerve run through the cribriform plate to provide special sensory innervation to the nose.

NASAL CAVITY

Nerve supply

• General sensory innervation to the septum and lateral walls is delivered by the nasopalatine nerve (branch of maxillary nerve) and the nasociliary nerve (branch of the ophthalmic nerve).
• Innervation to the external skin of the nose is supplied by the trigeminal nerve.

CLINICAL ANATOMY OF PARANASAL SINUSES

• The paranasal sinuses are air-filled extensions of the nasal cavity.
• There are four paired sinuses – named according to the bone in which they are located – maxillary, frontal, sphenoid and ethmoid.
• Each sinus is lined by a ciliated pseudostratified epithelium, interspersed with mucus-secreting goblet cells.

FUNCTION OF THE PARANASAL SINUSES

The function of the paranasal sinuses is a topic of much debate. Various roles have been suggested:

• Lightening the weight of the head
• Supporting immune defence of the nasal cavity
• Humidifying inspired air
• Increasing resonance of the voice

• The paranasal sinuses are formed during development by the nasal cavity eroding into the surrounding bones.
• All the sinuses therefore drain back into the nasal cavity – openings to the paranasal sinuses can be found on the roof and lateral nasal walls.

Frontal Sinuses

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• There are two frontal sinuses located within the frontal bone of the skull. They are the most superior of the paranasal sinuses, and are triangular in shape.

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• Drainage is via the frontonasal duct. It opens out at the hiatus semilunaris, within the middle meatus of the nasal cavity.

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• Sensation is supplied by the supraorbital nerve (a branch of the ophthalmic nerve), and arterial supply is via the anterior ethmoidal artery (a branch of the internal carotid).

Sphenoid Sinuses

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• The sphenoid sinuses are situated within the body of the sphenoid bone. They open out into the nasal cavity in an area supero-posterior to the superior cocha – known as the spheno-ethmoidal recess.

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• They are innervated by the posterior ethmoidal nerve (a branch of the ophthalmic nerve), and branches of the maxillary nerve. They recieve blood supply from pharyngeal branches of the maxillary arteries.

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Ethmoidal Sinuses

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There are three ethmoidal sinuses located within the ethmoid bone:

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• Anterior – Opens onto the hiatus semilunaris (middle meatus)
• Middle – Opens onto the lateral wall of the middle meatus
• Posterior – Opens onto the lateral wall of the superior meatus

They are innervated by the anterior and posterior ethmoidal branches of the nasociliary nerve and the maxillary nerve. The anterior and posterior ethmoidal arteries are responsible for arterial supply.

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Maxillary Sinuses

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• The maxillary sinuses are the largest of the sinuses.
• They are located laterally and slightly inferiorly to the nasal cavities.

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• They drain into the nasal cavity at the hiatus semilunaris, underneath the frontal sinus opening. This is a potential pathway for spread of infection – fluid draining from the frontal sinus can enter the maxillary sinus.

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Paranasal sinuses

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OSTIOMEATAL COMPLEX

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• The ostiomeatal complex (OMC) is the collection of structures that aids in mucus drainage and airflow between the maxillary sinus, the anterior ethmoid air cells, and the frontal sinus.
• It is located on the lateral wall of the nasal cavity and has several well defined borders.
• The OMC contains several important landmarks, such as the ethmoid bulla, hiatus semilunaris, ethmoidal infundibulum, frontonasal duct (recess) and uncinate process.

PARANASAL SINUSITIS

Paranasal sinusitis is an inflammation of the mucous membranes in the paranasal sinuses.

PARANASAL SINUSITIS

Four classifications:

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• Acute rhinosinusitis: Sudden onset, lasting less than 4 weeks with complete resolution.
• Subacute rhinosinusitis: A continuum of acute rhinosinusitis but less than 12 weeks.
• Recurrent acute rhinosinusitis: Four or more episodes of acute, lasting at least 7 days each, in any 1-year period.
• Chronic rhinosinusitis: Signs of symptoms persist 12 weeks or longer.

PARANASAL SINUSITIS

Causes of sinusitis

• Causes are a combination of environmental and host factors.
• Acute sinusitis is most commonly due to viruses and is usually self-limiting.
• Approximately 90% of patients with colds have an element of viral sinusitis.

PARANASAL SINUSITIS

Causes of sinusitis

• Those with atopy commonly get sinusitis. It can be caused by allergens, irritants, viruses, fungi, and bacteria.
• Popular irritants are animal dander, polluted air, smoke, and dust.

PARANASAL SINUSITIS

Causes of sinusitis

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Histopathology

• Fifteen percent of aspirates contain viruses
• Streptococcus pneumoniae 3%, Haemophilus influenzae 21%, anaerobes 6%, Staphylococcus aureus 4%, Streptococcus pyogenes 2%, Moraxella 2%
• Chronic: S. aureus 20%, anaerobes 3%, S. pneumoniae 4%, multiple organisms 16%
• Fungal incidence is 2% to 7%, most commonly Aspergillus and most commonly seen in immunocompromised patients.

PARANASAL SINUSITIS

Pathophysiology

• Most commonly a viral upper respiratory infection causes rhinosinusitis secondary to edema and inflammation of the nasal lining and production of thick mucus that obstructs the paranasal sinuses and allows a secondary bacterial overgrowth.
• There are frontal, maxillary, sphenoid, and ethmoid sinuses.

PARANASAL SINUSITIS

Pathophysiology

• Ciliary immobility can lead to increased mucus viscosity, further blocking drainage.
• Bacteria are introduced into the sinuses by coughing and nose blowing.
• Bacterial sinusitis usually occurs after a viral upper respiratory infection and worsening symptoms after 5 days, or persistent symptoms after 10 days.

PATHOGENESIS

WAYS OF THE

INFLAMMATORY PROGRESS

RHINOGENOUS_90%

ODONTOGENOUS 5%

HEMATOGENOUS LYMPHOGENOUS

TRAUMATOGENOUS

NOSOCOMIAL

Clinical Relevance: Sinusitis

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• As the paranasal sinuses are continuous with the nasal cavity, an upper respiratory tract infection can spread to the sinuses.
• Infection of the sinuses causes inflammation (particularly pain and swelling) of the mucosa, and is known as sinusitis. If more than one sinus is affected, it is called pansinusitis.
• The maxillary nerve supplies both the maxillary sinus and maxillary teeth, and so inflammation of that sinus can present with toothache.

LOCALISATION

FRONTITIS 4-15%

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Symptoms of sinusitis

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• nasal discharge, which may be green or yellow,
• a postnasal drip, where mucus runs down the back of the throat,
• blocked or runny nose,
• a reduced sense of smell and taste,
• a feeling of pressure or pain in the area of the forehead, cheeks and eyes,
• fever,
• headaches,
• toothache.

ACUTE PURULENT MAXILLARY SINUSITIS

Endorynoscopy

CHRONIC POLYPOSIS

MAXILLARY SINUSITIS

^:> Endoscopic polypoethmoidoantrostomy

1 day after operation 30 days after operation

CHRONIC POLYPOSIS

SINUSITIS

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Evaluation

• No laboratory tests are indicated in the emergency department for acute uncomplicated sinusitis because the diagnosis is usually clinical.

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• A plain sinus x-ray is most accurate for the maxillary, frontal, or sphenoid disease but is not useful for evaluating the anterior ethmoid cells or the ostiomeatal complex from which most sinus disease originates.

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Evaluation

• The CT is findings sinus opacification, air-fluid levels, sinus wall displacement and greater mucosal thickening.

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• Culture and biopsy are indicated for chronic bacterial and fungal sinusitis.

MEDICAL ALGORITHM OF THE SINUSITISES TREATMENT

SINUSITIS

Differential Diagnosis

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• The most common malady mistaken for sinusitis is rhinitis or an upper respiratory infection.
• A maxillary toothache can also mimic the pain caused by maxillary sinusitis.
• Tension headaches, vascular headaches, foreign bodies, brain abscesses, epidural abscesses, meningitis, and subdural empyema can also be mistaken for sinusitis.

COMPLICATION

1. REACTIV EDEMA OF THE CONNECTIVE TISSUE OF THE ORBIT AND EYELIDS

2. PERIOSTITIS OF THE ORBIT (purulent and nonpurulent)

3. EYELID ABSCESS

4. RETROBULBAR ABSCESS

5. ORBITE PHLEGMON

INTRACRANIAL COMPLICATIONS

1.EXTRADURAL ABSCES.

2.SUBDURAL ABSCES.

3. BRAIN ABSCES.

4. MENINGITIS.

5. THROMBOSIS OF THE CAVERNOUS AND SUPERIOR SAGITAL SINUSES.

6. RHINOGENOUS SEPSIS.