Page 16 - Portuguese Journal - SPORL - Vol 61. Nº2

Introduction aureus , but some studies have also implicated
Definition nasal microbial community dysbiosis as an
Chronic rhinosinusitis (CRS) is a syndrome etiological factor .
2-9
characterized by symptomatic sinonasal Environmental and individual factors interact
inflammation persisting for more than 12 with each other and trigger one or more chronic
weeks. In adults, it is clinically defined by inflammation pathways (endotypes) that lead
the presence of two or more of the following to the clinical presentation (phenotype).
symptoms:
• Nasal obstruction and/or anterior/posterior Pathophysiology
rhinorrhea (at least one of these two The sinonasal mucosa serves as a barrier that
symptoms is mandatory) and limits and regulates the interaction between
• Pain/facial pressure and/or hyposmia/ environmental factors and the immune
anosmia. system .
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This is a broad definition and does not specify In healthy people, when this barrier is crossed, a
the etiology, pathogenesis, and natural history self-limited and specific (cellular and humoral)
of the disease. In a small subset of patients, immune response is generated, which targets
this syndrome occurs in association with pathogens. Type 1 immune response targets
other systemic disorders or local processes viruses, type 2 parasites, and type 3 immune
(secondary rhinosinusitis). In the vast majority response targets extracellular bacteria and
of cases the etiology is unknown (primary fungi. In the case of CRS, this mucosal invasion
rhinosinusitis), although various environmental results in a chronic inflammatory response
and genetic/epigenetic factors have been that uses type 1, 2, or 3 inflammatory pathways
proposed. Genetic and epigenetic variation alone or in combination. As mentioned above,
of the immune response is believed to play a there is no evidence of a specific dominant
key role . Most environmental etiologic factors microbiological agent and the immune
1
remain unknown, but tobacco, fungi, viruses, response is usually polyclonal, against antigens
bacteria, pollution, and allergens have been from several organisms, including the nasal
implicated. The most commonly associated microbiota 11,12 . In some cases, the body's
microbiological agent is Staphylococcus antigens are also targeted by the immune

Figure 1
Classification of primary chronic rhinosinusitis according to the the European Position Paper on
Rhinosinusitis and Nasal Polyps (EPOS) 2020.

ARFS: Allergic fungal rhinosinusitis; ADCC: Atopic disease of the central compartment; CRS: Chronic rhinosinusitis;
CRSwNP: Chronic rhinosinusitis with nasal polyps; ECRS: Eosinophilic chronic rhinosinusitis.

158 Portuguese Journal of Otorhinolaryngology - Head and Neck Surgery