SONOGRAPHIC ASSESSMENT OF INFANTILE HYPERTROPHIC PYLORIC STENOSIS WITHOUT CLINICALLY PALPABLE PYLORIC LUMP

Abstract

Objective: To evaluate the role of ultrasound in the diagnosis of patients with suspected Infantile Hypertrophic Pyloric Stenosis (IHPS) who do not have a clinically palpable ‘pyloric lump’ or olive by taking surgery and follow-up as gold standard.
Study design: Validation study.
Setting: Radiology department at National Institute of Child Health (NICH), Karachi from January 2008 to March 2010.
Methods: Appropriate technical and ethical approval for the study was obtained. Twenty eight consecutive patients (22 males and 6 females) with clinical suspicion of IHPS without a definite palpable ‘pyloric lump’ referred to radiology department of National Institute of Child Health (NICH) were included in the study. All patients underwent ultrasonography by an experienced consultant radiologist. Patients were categorized as having or not having IHPS. The results were compared with follow up at surgery for those declared as having IHPS on ultrasound and clinical follow up for those not having IHPS on ultrasound. Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of ultrasound were calculated.
Results: Twenty four patients were diagnosed with IHPS. Four were diagnosed as not having IHPS. Out of these 4 patients 1 was subjected to barium meal examination. Patients were followed up to confirm the ultrasound findings or otherwise. Ultrasonography yielded a sensitivity of 96% and specificity of 100% in diagnosing IHPS in patients without a palpable ‘pyloric lump’ or ‘olive’. The positive predictive value of ultrasonography in these patients was 1.00 and the negative predictive value was 0.75.
Conclusion: Ultrasonography should be the initial investigation in patients with clinical suspicion of IHPS and an impalpable pyloric lump to improve early diagnosis in these babies.