Differentiating testis torsion from orchitis
Q - How can you distinguish the less obvious torsion of the testis from orchitis?
A - This is a fairly easy question to answer you can't. In children there are two sorts of torsion, an intravaginal torsion of the whole testis and a torsion of one of its appendages (typically the Hydatid of Morgagni).
The former tends to occur in adolescents with pubertal testes; the latter at 10-11 years of age, on the cusp of puberty when gonadotrophins are surging, causing an increase in size of only the hydatid.
Clinically both are a cause of an acute scrotum, although a hydatid torsion is less tender and its history more protracted, often over a few days rather than hours.
Orchitis (due to mumps and so on) or epididymo-orchitis (due to an ascending urinary tract infection) may occur in children. The former occurs usually in the postpubertal testis and is not usually a diagnostic problem.
The latter occurs during early childhood and may be related to an underlying congenital anomaly causing the infection. There is no satisfactory discriminatory test (clinical, radionuclide or ultrasonographic), but a previous history or positive urine microscopy may indicate a non-interventional approach. But the safest, and the only defensible, option is a referral for urgent scrotal exploration to exclude torsion of the testis.
Mr Mark Davenport is consultant paediatric surgeon, King's College Hospital, London