ABSTRACT
Bronchial asthma (BA) is a chronic inflammatory condition of the airways characterised by bronchial hyper-responsiveness and narrowing of the airways, which is reversible either spontaneously or with treatment. It affects about 300 million people worldwide including 10% of the Nigerian population.1 Gastroesophageal reflux disease (GERD) however is a chronic gastrointestinal condition characterised by abnormal exposure of the mucosa of the lower oesophagus to acid due to dysfunction of the lower oesophageal sphincter. About 10-30% of adult population in the Western world are affected.2 GERD can aggravate asthma in several ways; and these include vagally mediated reflex triggered by acid in oesophagus as well as micro aspiration of gastric acid resulting in bronchoconstriction.3 Also some asthma drugs cause lower esophageal sphincter relaxation making acid escape easy. Hyperinflation of the chest in asthma with flattening of the diaphragm is thought to contribute to weakness of the crura muscles and dysfunction of the lower esophageal sphincter and amplification of the thoraco-abdominal pressure gradient during an attack helps to promote GERD.4 Reflux symptoms are reported in up to 77% of asthmatics while 32-82% of asthmatics have abnormal pH studies. Silent reflux may be as common as symptomatic reflux with reports suggesting that 25-50% asthmatics have no reflux symptoms but abnormal pH studies5. On the other hand, GERD has been known to have extra-oesophageal manifestation including hoarseness of voice, cough and wheezing.6 Endoscopic studies equally could be normal in up to 50% (non-erosive GERD). 7 There appears to be a diagnostic dilemma, which is further intrigued by cases of silent GERD. 24-hour oesophageal pH measurement and sometimes manometry has remained the cornerstone of GERD diagnosis, however, this is often not widely available in daily practice because of their cost and invasive nature. Hence, guidelines for their use8 have been published. Symptom analysis however has been documented as a practical and inexpensive method of diagnosing GERD, but this obviously may not detect cases of silent GERD or with atypical symptoms. A number of validated questionnaires including QUEST, REQUESTTM and FSSG9 exist with differing sensitivity and predictability. Reports of relationship between BA and GERD exist in Western literature with sometimes conflicting findings to improper definition of BA and/or GERD.10-12 There is limited information about this association among asthma sufferers in Nigeria. We aim to study this relationship among our patients to bridge the existing gap with objectives as: to determine the frequency of symptomatic GERD among previously diagnosed asthmatics attending an Asthma clinic by means of a validated questionnaire (frequency scale for symptoms of GERD (FSSG or Fscale) 9 as well as 24 hour nasopharyngeal DX PH detector, to compare GERD prevalence between the asthmatics and a control population matched for age and sex and to document the upper gastrointestinal tract endoscopic findings in the subgroup of subjects found to have GERD.