Screening for sinus disease in patients with asthma: a computed tomography-controlled comparison of A-mode ultrasonography and standard radiography.

BACKGROUND: Paranasal sinus disease and bronchial asthma are frequently associated. Patients with asthma often have chronic inflammatory changes of the paranasal mucosa rather than acute bacterial sinusitis. Our aim was to compare the rankings of A-mode ultrasonography and standard radiography as routine screening procedures in the diagnostic workup of these patients. METHODS: We compared the evaluation of the maxillary sinuses by A-mode ultrasonography and standard radiographs. Computed tomography served as a gold standard in 19 patients with asthma who had no history of sinus surgery. RESULTS: Computed tomography showed at least some minimal mucosal thickening in any of the paranasal sinuses in 74% and of the maxillary sinuses in 61% of the patients. Compared with the results of computed tomography, plain-view radiography gave a specificity of 86.7% for the maxillary sinuses. Although all cases of severe mucosal thickening were detected, sensitivity for minimal mucosal hyperplasia was low, at 52.2%. In contrast, A-mode ultrasonography demonstrated a sensitivity of 70% but a specificity of only 22%. CONCLUSIONS: Even symptom-free patients with asthma show a high prevalence of at least limited mucosal thickening in the paranasal sinuses. Acute sinusitis is not a common finding. A-mode ultrasonography does not allow sufficient evaluation of this mucosal hyperplasia and is therefore not suitable for initial screening in these patients. It may prove helpful as a follow-up in selected patients with known anatomic characteristics, however, especially when antral fluid is involved. For routine screening in patients with asthma, a conventional Waters' view radiograph should be used in conjunction with direct visualization of the ostial-meatal area by fiberoptic or rigid rhinoscopy. This combination provides information about the degree of mucosal hyperplasia as well as mucosal inflammation and secretion.

Interaction of bemetizide and indomethacin in the kidney.

The effect of a single oral dose of 25 mg bemetizide on renal function without and with concomitant administration of the prostaglandin synthesis inhibitor indomethacin was investigated in ten healthy volunteers during sustained water diuresis. Bemetizide induced a significant increase in urinary sodium and chloride excretion from 196 +/- 30 and 163 +/- 28 mumol/min to 690 +/- 54 and 537 +/- 51 mumol/min (P less than 0.01). This effect occurred in the absence of changes in glomerular filtration rate, urinary excretion of phosphate or the delivery of chloride beyond the proximal nephron to the distal tubules (distal delivery) [(CH2O + CCl)/GFR . 100], but was associated with a significant decrease in distal fractional chloride absorption (DFACl) [CH2O/(CH2O + CCl)] from 0.84 +/- 0.02 to 0.63 +/- 0.02 (P less than 0.01). Bemetizide also increased urinary excretion of prostaglandin (PG) E2. Concomitant indomethacin administration significantly suppressed urinary excretion of PGE2 and markedly decreased urinary excretion of sodium and chloride during control and following bemetizide administration. Indomethacin had no effect on glomerular filtration rate, urinary excretion of phosphate, distal delivery or the urinary excretion of bemetizide but significantly increased DFACl both during control and after bemetizide administration. Our results show that bemetizide as a thiazide-diuretic acts in the diluting segments of the nephron. Indomethacin administration induces retention of sodium and chloride and blunts the renal effects of bemetizide via increased absorption in the diluting segments. The interaction of both drugs most likely represents a pharmacodynamic interaction.