Rhinosinusitis overview

# Overview
Rhinosinusitis is the inflammation of the nasal mucosa and paranasal sinuses. The terms sinusitis and rhinosinusitis are used interchangeably, although rhinosinusitis is preferred because inflammation of the paranasal sinuses rarely ever occurs without concurrent inflammation of the nasal mucosa. There are 4 pairs of sinus cavities, named for the skull bones they are located in: maxillary, ethmoid, frontal and sphenoidal. The cause of rhinosinusitis is mostly infectious, although it can be associated with other medical conditions such as allergies. The diagnosis is primarily clinical and imaging and other diagnostic studies are not necessary for diagnosis. A CT or MRI is indicated when rhinosinusitis is complicated by extension of the infection to surrounding structures, such as the orbit and brain. Rhinosinusitis is a self-limiting disease and treatment is supportive, in order to alleviate the respiratory symptoms and pain. Antibiotics may be indicated in select cases of acute bacterial and chronic rhinosinusitis.

# Historical Perspective
- Between 3700 and 1500 BC, the paranasal sinuses were first identified by the ancient Egyptians. The ancient Egyptians are considered to have been the first in discovering sinus surgery; when mummifying a human body, they would remove the brain through the nasal cavity.
- Hippocrates later described the process of producing voice as "air passing through empty cavities," which referred to the paranasal sinuses. He also documented in his writings about nasal polyps and how to remove them.
- In 1489, Leonardo Da Vinci was the first to illustrate the maxillary sinuses and their relationship with the teeth of the upper jaw. 
- In 1905, the first paper in literature was found on suppurative frontal sinusitis.

# Classification
Rhinosinusitis can be classified based on the location of sinus involved into maxillary, frontal, ethmoidal, sphenoidal or pansinusitis.. It can also be classified according to the duration of the disease or etiology.

# Pathophysiology
The pathophysiology for both acute and chronic rhinosinusitis involves blockage of the nasal sinuses and inflammation of the nasal sinuses. However, biofilms play a role in the pathogenesis of chronic rhinosinusitis. There are many associated conditions with rhinosinusitis, but most notably are those related to allergy and immunodeficiency.

# Causes
The causes of rhinosinusitis can be divided according to the infectious group that causes it into: bacterial, viral and fungal.

# Differential Diagnosis
Rhinosinusitis must be differentiated from other diseases that may present with a headache and/or respiratory symptoms.

# Epidemiology and Demographics
The incidence of acute rhinosinusitis and prevalence of chronic rhinosinusitis have a wide range, depending on the setting.

# Risk Factors
Anatomical abnormalities of the nasal cavity, immunodeficiency and other diseases are all risk factors for the development of rhinosinusitis.

# Screening
There are no recommendations for screening for rhinosinusitis.

# Natural History, Complications and Prognosis
Acute rhinosinusitis is a self-limiting disease. However, rarely acute and chronic rhinosinusitis can be complicated by extension of the infection to the surrounding structures, such as the eyes and brain.

# History and Symptoms
Rhinosinusitis can present with a wide range of constitutional and respiratory symptoms.

# Physical Examination
Examination of the nose with a speculum or otoscope may reveal mucosal edema, narrowing of the middle meatus, purulent rhinorrhea and other findings.

# Laboratory Findings
There are several lab findings that can be done when suspecting rhinosinusitis, but these findings are nonspecific.

# X-Ray
A plain x-ray of the sinuses has no role in the workup of rhinosinusitis. It may show a fluid level in the sinuses, but a plain x-ray is associated with a high negative and high positive rate for rhinosinusitis.

# CT
Although not routinely indicated for suspected cases of rhinosinusitis and findings are highly nonspecific, CT scan is the imaging modality of choice in cases of chronic or complicated rhinosinusitis. Positive CT scan findings are not essential for diagnosis, but negative CT scan findings rules out rhinosinusitis. Findings include mucosal thickening and narrowing of the osteomeatal sinuses.

# Other Imaging Findings
MRI is an excellent alternative to CT scan in detecting orbital and intracranial complications of rhinosinusitis.

# Other Diagnostic Studies
Nasal endoscopy and anterior rhinoscopy can be done in the case of rhinosinusitis to evaluate for nasal anatomy, nasal polyps and the paranasal sinuses. Endoscopy can be done as part of the functional endoscopic sinus surgery (FESS), which is used as a treatment in the case of chronic rhinosinusitis and nasal polyps.

# Medical Therapy
Supportive therapy is the mainstay of treatment for both cases of acute and chronic rhinosinusitis. Antibiotics can be added in select cases of acute, as well as chronic rhinosinusitis.

# Surgery
Functional endoscopic sinus surgery (FESS) is reserved for cases of chronic rhinosinusitis not responding to medical therapy.

# Primary Prevention
There are no clear guidelines on how to prevent the occurrence of rhinosinusitis.

# Secondary Prevention
Secondary prevention is mostly aimed at preventing the exacerbation of chronic rhinosinusitis or another episode of acute recurrent sinusitis. Methods such as abstinence from smoking, using saline nasal irrigation, and treatment of the underlying cause can be used to promote healthy sinuses.