Sinusitis

Sinusitis is an inflammation of the paranasal sinuses, which may or may not be as a result of infection, from bacterial, fungal, viral, allergic or autoimmune issues. Newer classifications of sinusitis refer to it as rhinosinusitis, taking into account the thought that inflammation of the sinuses cannot occur without some inflammation of the nose as well (rhinitis).

Classification

By location
There are several paired paranasal sinuses, including the frontal, ethmoid, maxillary and sphenoid sinuses. The ethmoid sinuses can also be further broken down into anterior and posterior, the division of which is defined as the basal lamella of the middle turbinate. In addition to the acuity of disease, discussed below, sinusitis can be classified by the sinus cavity which it affects:

Maxillary sinusitis - can cause pain or pressure in the maxillary (cheek) area (e.g., toothache, headache)
Frontal sinusitis - can cause pain or pressure in the frontal sinus cavity (located behind/above eyes), headache
Ethmoid sinusitis - can cause pain or pressure pain between/behind eyes, headache
Sphenoid sinusitis - can cause pain or pressure behind the eyes, but often refers to the vertex of the head
Recent theories of sinusitis indicate that it often occurs as part of a spectrum of diseases that affect the respiratory tract (i.e., the "one airway" theory) and is often linked to asthma. All forms of sinusitis may either result in, or be a part of, a generalized inflammation of the airway so other airway symptoms such as cough may be associated with it.

Left-sided maxillar sinusitis (Absence of the air transparency of left maxillar sinus)
By duration
Sinusitis can be acute (going on less than four weeks), subacute (4-12 weeks) or chronic (going on for 12 weeks or more). All three types of sinusitis have similar symptoms, and are thus often difficult to distinguish.

Acute sinusitis
Acute sinusitis is usually precipitated by an earlier upper respiratory tract infection, generally of viral origin. Virally damaged surface tissues are then colonized by bacteria, most commonly Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. Other bacterial pathogens include other Staphylococcus aureus and other streptococci species, anaerobic bacteria and, less commonly, gram negative bacteria. Viral sinusitis typically lasts for 7 to 10 days, whereas bacterial sinusitis is more persistent. Approximately 0.5% to 2% of viral sinusitis extends into bacterial sinusitis. One hypothesis postulates that the bacterial infection begins with nose blowing.

Acute episodes of sinusitis can also result from fungal invasion. These infections are most often seen in patients with diabetes or other immune deficiencies (such as AIDS or transplant patients on anti-rejection medications) and can be life threatening. In type I diabetes, ketoacidosis causes sinusitis by Mucormycosis.

Rarely, it may be caused by a tooth infection.

Chronic sinusitis
Chronic sinusitis is a complicated spectrum of diseases that share chronic inflammation of the sinuses in common. It is divided into cases with polyps and cases without, and the former is sometimes called chronic hyperplastic sinusitis. The causes are poorly understood and may include allergy, environmental factors such as dust or pollution, bacterial infection, or fungus (either allergic, infective, or reactive). Non allergic factors such as vasomotor rhinitis can also cause chronic sinus problems. Abnormally narrow sinus passages, which can impede drainage from the sinus cavities could also be a factor. A combination of anaerobic and aerobic bacteria are observed, including Staphylococcus aureus and coagulase-negative Staphylococci. Typically antibiotics provide only a temporary benefit, although mechanisms involving hyperresponsiveness to bacteria have been proposed for sinusitis with polyps. Most

Symptoms include: nasal congestion; facial pain; headache; fever; general malaise; thick green or yellow discharge; vertigo or lightheadedness; blurred vision, feeling of facial 'fullness' or 'tightness' which worsens on bending over; aching teeth, and halitosis; and occasionally diarrhea with a mucus-like substance in it. Very rarely, chronic sinusitis can lead to Anosmia, the inability to smell or detect odors.[citation needed] In a small number of cases, chronic maxillary sinusitis can also be brought on by the spreading of bacteria from a dental infection.

Attempts have been made to provide a more consistent nomenclature 6 for subtypes of chronic sinusitis. Many patients have demonstrated the presence of eosinophils in the mucous lining of the nose and paranasal sinuses. As such the name Eosinophilic Mucin RhinoSinusitis (EMRS) has come into being. Cases of EMRS may be related to an allergic response, but allergy is often not documentable, resulting in further subcategorization of allergic and non-allergic EMRS.

A more recent, and still debated, development in chronic sinusitis is the role that fungus may play. Fungus can be found in the nasal cavities and sinuses of most patients with sinusitis, but can also be found in healthy people as well. It remains unclear if fungus is a definite factor in the development of chronic sinusitis and if it is, what the difference may be between those who develop the disease and those who do not. Trials of antifungal treatments have had mixed results.

Symptoms

Sinus headache
Headache/facial pain or pressure of a dull, constant, or aching sort over the affected sinuses can be seen with either acute or chronic stages of sinusitis. This pain is typically localized to the involved sinus and may worsen when the affected person bends over or when in the supine position.

Acute and chronic sinusitis may be accompanied by thick purulent nasal discharge (usually green in colour and with or without blood) and localized headache (toothache) are present and it is these symptoms that can differentiate sinus related (or rhinogenic) headache from other headache phenomena such as tension headache and migraine headache.

Migraine misdiagnosis
Recent studies suggest that up to 90% of "sinus headaches" are actually migraines. The confusion occurs in part because migraine involves activation of the trigeminal nerves which innervate both the sinus region but also the meninges which surround the brain. As a result, direct determination of the site of pain origination can be confused on a cortical level. Additionally, nasal congestion is not an uncommon result of migraine headaches, due to the autonomic nervous stimulation that can also result in tearing (lacrimation) and a runny nose (rhinorrhea). A study found that patients with "sinus headache" respond to triptan migraine medications, and state dissatisfaction with their treatment when they are treated with decongestants or antibiotics.

Predisposing factors
Factors which may predispose to developing sinusitis include: allergies; structural problems such as a deviated septum or small sinus ostia; smoking; nasal polyps; carrying the cystic fibrosis gene (research is still tentative); prior bouts of sinusitis as each instance may result in increased inflammation of the nasal or sinus mucosa and potentially further narrow the openings.

Role of biofilms
Biofilms are complex aggregates of extracellular matrix and inter-dependent microorganisms from multiple species, many of which may be difficult or impossible to isolate using standard clinical laboratory techniques. Bacteria found in biofilms may show increased antibiotic resistance when compared to free-living bacteria of the same species. It has been hypothesized that biofilm-type infections may account for many cases of antibiotic-refractory chronic sinusitis. A recent study found that biofilms were present on the mucosa of 3/4 of patients undergoing surgery for chronic sinusitis.

Diagnosis

Acute sinusitis
Usually sinusitis is diagnosed clinically.

Bacterial and viral acute sinusitis are difficult to distinguish however, disease duration less than 7 days is considered as a viral whereas more than 7 days are considered as a bacterial sinusitis (usually 30% to 50% are bacterial sinusitis). Nosocomial acute sinusitis is confirmed with the help of CT scan of the sinuses.

Chronic sinusitis
For sinusitis lasting more than 12 weeks, criteria are lacking. A CT scan is recommended, but insufficient to confirm diagnosis. Nasal endoscopy, a CT scan, and clinical symptoms are used together. A tissue sample for histology and cultures can also be used. Allergic fungal sinusitis are seen in a person with asthma and nasal polyps. Multiple biopsy is informative to confirm the diagnosis.

Nasal endoscopy involves inserting a flexible fiber-optic tube with a light and camera at its tip into the nose to examine the nasal passages and sinuses. This is generally a completely painless procedure which takes between 5 to 10 minutes to complete.

Treatment

Acute sinusitis
Conservative measures
Over the counter (OTC) medication such as acetaminophen and ibuprofen can relieve some of the symptoms associated with sinusitis, such as headaches, pressure, fatigue and pain. Nasal irrigation or jala neti using a warm saline solution may also be effective.

Antibiotics
Even though antibiotics are prescribed to 60 - 90% of patients in the USA and Western Europe they have not been shown to be effective.

The vast majority of cases resolve without antibiotics, however if the symptoms are prolonged amoxicillin is a reasonable first choice with amoxicillin/clavulanate (Augmentin) being indicated for patients who fail amoxicillin alone. Fluoroquinolones, some of the newer macrolide antibiotics such as clarithromycin, and doxycycline, are used in patients who are allergic to penicillins.

Corticosteroids
Nasal corticosteroids have not been found to be better than placebo either alone or in combination with antibiotics.

Chronic sinusitis
Conservative measures
Nasal irrigation may help with symptoms of chronic sinusitis.

Medical approaches
Based on the recent theories on the role that fungus may play in the development of chronic sinusitis. Trials of antifungal treatments however have had mixed results.

Surgical treatment
For chronic or recurring sinusitis, referral to an otolaryngologist may be indicated for more specialist assessment and treatment, which may include nasal surgery. However, for most patients the surgical approach is not superior to appropriate medical treatment. Surgery should only be considered for those patients who do not experience sufficient relief from optimal medication.

A relatively recent advance in the treatment of sinusitis is a type of surgery called functional endoscopic sinus surgery (FESS), whereby normal clearance from the sinuses is restored by removing the anatomical and pathological obstructive variations that predispose to sinusitis. This replaces prior open techniques requiring facial or oral incisions and refocuses the technique to the natural openings of the sinuses instead of promoting drainage by gravity, the idea upon which the Caldwell-Luc surgery was based.

Another recently developed treatment is balloon sinuplasty. This method, similar to balloon angioplasty used to "unclog" arteries of the heart, utilizes balloons in an attempt to expand the openings of the sinuses in a less invasive manner. Its final role in the treatment of sinus disease is still under debate but appears promising.

A number of surgical approaches can be used to access the sinuses and these have generally shifted from external/extranasal approaches to intranasal endoscopic ones. The benefit of the Functional Endoscopic Sinus Surgery FESS is its ability to allow for a more targeted approach to the affected sinuses, reducing tissue disruption, and minimizing post-operative complications.

For persistent symptoms and disease in patients who have failed medical and the functional endoscopic approach, older techniques can be used to address the maxillary sinus such as the Caldwell-Luc radical antrostomy (e.g. incision in the upper gum, opening in the anterior wall of the antrum, removal of the entire diseased maxillary sinus mucosa and drainage is allowed into inferior or middle meatus by creating a large window in the lateral nasal wall.)

External links
Core Curriculum Syllabus: Nose and Paranasal Sinuses (Baylor College of Medicine)
Sinus Headache - Medterm.com
Sinus infection - MedicineNet.com.
Acute sinusitis - MayoClinic.com, from the Web site of the Mayo Clinic.
Chronic sinusitis - MayoClinic.com, from the Web site of the Mayo Clinic