Laboratory Studies
See the list below:
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Allergy testing in patients who have polyps and are not clinically allergic is controversial.
Many clinicians think that the expense is not justified.
On the contrary, a thorough allergy evaluation should be considered in patients with a history of environmental allergies or a strong family history of allergies.
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Children who present with nasal polyposis should be tested for cystic fibrosis with either a sweat chloride test or with hematologic genetic testing.
Imaging Studies
See the list below:
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Coronal sinus CT scanning is the imaging study of choice in the evaluation of patients with nasal polyposis.
Coronal CT scanning of the paranasal sinuses is best for delineating the underlying pathology, the extent of disease, and possible bony destruction.
Nonenhanced CT scanning with 2- to 3-mm sections helps to delineate the location and origin of the visible polyps, evaluate the underlying condition of all of the sinuses, and assess the anatomy of the paranasal sinuses in the event of surgical intervention.
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Magnetic resonance imaging (MRI) is not an appropriate imaging modality for nasal polyposis unless intracranial extension is suspected. Bony details of the paranasal sinus anatomy are poorly visualized on MRI.
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Radiography with Waters views may show opacification of the sinuses.
Procedures
Nasal endoscopy in an office setting can sometimes be helpful in the diagnosis and evaluation of nasal polyps. This technique helps illuminate and improves visualization of the dark recesses of the nasal cavity. Endoscopy may allow the examiner to see beyond an obstructing nasal septal deviation, an enlarged turbinate, or an obstructing polyp.
Histologic Findings
Biopsy is not always required for the diagnosis of nasal polyps. Nasal masses that do not have the classic appearance of nasal polyps (translucent to gray, fleshy and pedunculated) or that do not respond to conservative medical treatment should be biopsied for confirmatory diagnosis. The histologic appearance of nasal polyps varies from edematous tissue with a few glands to an increase in glandular elements. Eosinophils may be present, indicating an allergic component.
Many factors play a role in the formation of nasal polyp. Epithelial damage has been implicated in the pathogenesis of polyps. Epithelial cells can undergo activation in response to allergens, pollutants, and infectious agents. The cells release various factors that play a role in the inflammatory response and subsequent repair. The epithelium of nasal polyps shows goblet cell hyperplasia and mucous hypersecretion that may play a role in nasal obstruction and rhinorrhea.
Mucin synthesis and goblet cell hyperplasia are thought to be under control of epidermal growth factors (EGF). Inhibitors may block mucous production and goblet cell hyperplasia. Free radicals are highly reactive molecules with an unpaired electron in the outer orbit and may also play a role in polyp formation. The body produces endogenous oxidants as a result of the leakage of electrons from electron transport chains, phagocytic cells and endogenous enzyme systems (MAO, P450, etc).
Exogenous factors include radiation, air pollutants, tobacco smoke, sun exposure, ozone, and others. A certain physiologic level of reactive oxygen species is necessary for proper regulation of cell functions. Exposure to oxidants can initiate free radical-mediated reactions and lead to oxidative stress. Free radicals can result in cellular damage or death and subsequent tissue damage.
Several inflammatory factors have been isolated and are proven to be expressed by nasal polyps. These factors include endothelial vascular cell adhesion molecule (VCAM)-1, nitric oxide synthase, granulocyte-macrophage colony–stimulating factor (GM-CSF), eosinophil survival enhancing activity (ESEA), cys-leukotrienes (Cys-LT) and many other cytokines.
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Nasal polyposis, right nasal passage.
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Nasal polyposis, right nasal passage.
