The association between sinusitis and asthma has long been appreciated. The incidence of sinusitis in asthmatic subjects is generally stated to range from 40% to 75%.1-7Although these studies strongly suggest that sinusitis triggers or worsens asthma, it could be argued that they merely coexist and represent different end products of the same process (inflammation) occurring in different organ systems.
Perhaps the most direct evidence of a cause-and-effect relationship has been provided by studies that show that appropriate treatment of sinusitis by medical intervention can result in significant improvement of asthma symptoms.[8-10] Additionally, sinus surgery in patients with asthma has been shown to bring about improvement in lower airway disease, although adequate controls have not been incorporated in most studies.

Hypotheses are forwarded that upper and lower airways need to be considered as different stages of unique entity influenced by common mechanisms in the inflammatory process. Sinusitis and asthma therefore, are considered as manifestations of one disease process.

The aim of the present study was to know the incidence of sinusitis in asthmatic populations, and to compare the relevant findings pertaining to sinus involvement obtained by clinical and radiological studies.

The sample of this study was conducted in the period from March 2003 to April 2005, in the Department of Medicine, royal medical services (Amman-Jordan).

After institutional ethical committee clearance and written informed consent one hundred cases of bronchial asthma patients of either sex were studied. Age of patients ranged from 18-60 years with the mean age of 33.67 years.

Asthmatic patients were selected as per the guidelines advocated by the American Thoracic Society in 1995. [11] All these asthmatic patients underwent a detailed history taking and a through general examination, systemic examination and were screened for clinical and radiological evidence of sinusitis. CT scan of paranasal sinus was performed for all patients.

The clinical criteria for diagnosing sinusitis were the presence of: [12]

1. Nasal congestion/stuffiness
2. purulent rhinorrhoea
3. postnasal drainage
   
4. Local pain and tenderness overlying the sinuses
5. Night cough
6. Unpleasant smell, or taste (Fetor oris)

CT criteria for the diagnosis of sinusitis was the presence of: [13]

1. Mucosal thickening > 6 mm in children and > 8 mm in adults,
   
2. Indistinct bony margins,
   
3. Erosion of mucoperiosteum,
   
4. Obstruction of ostiomeatal complex.

As per history and clinical examination 58 (58%) patients had symptoms and signs suggestive of sinusitis. The most common symptom was nasal congestion found in 52 (52%) patients.

CT Scan PNS showed evidence of sinusitis in 78 (78%) patients whereas 22 (22%) patients had no evidence of sinusitis. Maxillary sinusitis was found in 78 (78%) patients, and 52 (52%) patients had frontal sinusitis. Ethmoid sinusitis was seen in 22 (22%) of patients and 8 (8%) of patients had sphenoid sinusitis. Maxillary polyp was found in 22 (22%) of patients and ostiomeatal complex block in 54 (54%) patients.

Among one hundred patients of bronchial asthma, clinically 58 (58%) patients had evidence of sinusitis whereas CT scan detected sinusitis in 78 (78%) patients.

In our study, clinically 58 (58%) of patients out of 100 patients of bronchial asthma had signs and symptoms of sinusitis whereas 42 (42%) of patients were asymptomatic for sinusitis.

On CT scan of paranasal sinus, 78 (78%) patients of bronchial asthma showed evidence of sinusitis. All 58 patients, who were clinically symptomatic for sinusitis, had evidence of chronic sinusitis on CT scan PNS.

In addition, on CT scan PNS 20 (47%) more patients were detected to have sinusitis out of 42 clinically asymptomatic patients. 54 (54%) of patients showed evidence of ostiomeatal complex block. The ostiomeatal complex is the common drainage pathway for maxillary, frontal and anterior ethmoid sinuses. CT scan has given newer understanding of how the patient is affected with sinusitis.

Various mechanisms have been proposed to explain the relationship between sinusitis and asthma. The 5 most common are sinonasobronchial reflex [14-25]; inhalation of cold, dry air [26-31]; aspiration of nasal secretions[32-38]; cellular and soluble mediators [39-42], and diminished?-agonist responsiveness.

In one study Weille [43] examined 500 patients with asthma, 72% of whom had concomitant chronic sinus disease. Of 100 patients who underwent sinus surgery, 56 subsequently experienced improvements in chest symptoms; complete resolution of asthma occurred in 10. Twenty-three of 24 patients with simultaneous chronic sinusitis and asthma experienced a 75% or greater improvement in asthma symptoms after surgical drainage in another study.[44] This association is supported by other researchers, including Slavin,[45] who reported that lower airway symptoms were significantly reduced after nasal surgery in patients with severe asthma that often required daily oral corticosteroid therapy. In a follow-up of similar patients, 60% were found to have experienced improved asthma symptoms that persisted for 5 years.

In another study of sinus surgery in patients with asthma, 17 patients were treated with nasal surgery because of severe sinus disease. Fifteen of these patients experienced improved sinus symptoms, and 13 experienced significantly improved asthma symptoms, postoperatively.[46] Most of these patients underwent the Montgomery procedure, in which the mucosal lining of the sinuses is obliterated, and adipose tissue from the abdomen is implanted. This procedure promotes the formation of fibrous tissue, which helps to reduce the recurrence of infection. In one patient, severe asthma symptoms that could not be controlled with high-dose corticosteroids developed after the procedure. When the implant was removed, however, control of the asthma was regained. This phenomenon supports the idea that sinus disease and asthma exacerbations are related.

The association of sinusitis and asthma seems to be more than an epiphenomenon.
In our study out of 100 asthmatics evidence for sinusitis was found clinically in 58% cases while CT Scan PNS detected sinusitis in 78% cases. This observation assumes significant clinical importance that all asthmatics need to be examined for evidence of sinusitis preferably by CT scan.

It is very pertinent to mention that ENT specialist must look down into the chest for evidence of bronchospasm and chest physicians should examine asthmatic patients for evidence of rhinosinusitis.