Pyloric stenosis--do males and females present differently?

In infants with pyloric stenosis we explored (a) if males develop symptoms and present to hospital earlier than females and (b) does any delay in presentation influence the severity of metabolic derangement.

A retrospective casenote review of 99 infants who underwent pyloromyotomy (with confirmation of pyloric stenosis) over a two year period (Jan 2006-Dec 2007) in our hospital. The data collected included: sex, age at onset of symptoms, age at presentation to hospital and initial blood results.

The group comprised 84 males and 15 females. Symptoms developed at 26 (0-70) days in males and 35 (0-77) in females. (Mann-Whitney U=428, p=0.04 two tailed). Males presented to hospital at 34 (13-91) days, females at 45 (13-98) days (Mann-Whitney U=391, p=0.01 two tailed). The differences between males and females for (1) age at onset of symptoms and (2) age at presentation to hospital became more significant when weighted averages were calculated using SPSS (Statistical Package for Social Sciences). The lower weighted averages for male infants can be seen in the final table. Increasing duration of symptoms showed a positive correlation with fall in Chloride level. (Spearman's rho: rs= -0.2, p=0.049 two tailed). There was a positive correlation between duration of symptoms and bicarbonate level but this was not significant. (rs=0.06, p>0.05 two tailed). There was a positive correlation between duration of symptoms and pH, but this was not significant (rs=0.12, p>0.05 two tailed).

In our hospital, females with pyloric stenosis develop symptoms and present significantly later than males. This should be considered when assessing a female with vomiting outside the usual 20-40 day range.