Theoretically,  several possible mechanisms of both objective and subjective halitosis may be involved.A 2005 review suggested that most "sinus headaches" are migraines. The confusion occurs in part because migraine involves activation of the trigeminal nerves, which innervate both the sinus region and the meninges surrounding the brain. As a result, accurately determining the site from which the pain originates is difficult. People with migraines do not typically have the thick nasal discharge that is a common symptom of a sinus infection.Symptoms of chronic sinusitis may include nasal congestion, facial pain, headache, night-time coughing, an increase in previously minor or controlled asthma symptoms, general malaise, thick green or yellow discharge, feeling of facial fullness or tightness that may worsen when bending over, dizziness, aching teeth, and bad breath. Often, chronic sinusitis can lead to anosmia, the loss of the sense of smell. By location
The four paired paranasal sinuses are the frontal, ethmoidal, maxillary, and sphenoidal sinuses. The ethmoidal sinuses are further subdivided into anterior and posterior ethmoid sinuses, the division of which is defined as the basal lamella of the middle nasal concha.
In rare instances, these infections may involve the orbit, causing orbital cellulitis, which may in turn result in blindness, or determine central nervous system complications such as meningitis, subdural empyema, brain abscess and life-threatening cavernous sinus thrombosis.Infection of the eye socket is a rare complication of ethmoid sinusitis, which may result in the loss of sight and is accompanied by fever and severe illness. Another possible complication is the infection of the bones (osteomyelitis) of the forehead and other facial bones – Potts puffy tumor. Causes
Maxillary sinusitis may also develop from problems with the teeth, and these cases were calculated to be about 40% in one study and 50% in another. The cause of this situation is usually a periapical or periodontal infection of a maxillary posterior tooth, where the inflammatory exudate has eroded through the bone superiorly to drain into the maxillary sinus.An estimated 0.5 to 2.0% of viral rhinosinusitis (VRS) will develop into bacterial infections in adults and 5 to 10% in children. Acute
Acute sinusitis is usually precipitated by an earlier upper respiratory tract infection, generally of viral origin, mostly caused by rhinoviruses (with RVA and RVC giving more severe infection than RVB), coronaviruses, and influenza viruses, others caused by adenoviruses, human parainfluenza viruses, human respiratory syncytial virus, enteroviruses other than rhinoviruses, and metapneumovirus. If the infection is of bacterial origin, the most common three causative agents are Streptococcus pneumoniae (38%), Haemophilus influenzae (36%), and Moraxella catarrhalis (16%). Until recently, H. influenzae was the most common bacterial agent to cause sinus infections.