Urology>>>>>Imaging and Principles of Uro-Radiology
Question 4#

Which of the following statements is INCORRECT?

A. Foetal death during general anaesthetic is most likely in the second trimester of pregnancy
B. Ultrasound with Doppler can be used to investigate renal colic by assessing for the presence of ureteral jets
C. A limited IVU is considered safe in pregnancy
D. Ureteroscopy and holmium laser stone fragmentation has been used safely to treat urinary tract stones during pregnancy when treatment cannot be delayed
E. Obstruction secondary to ureteric stones during pregnancy can be managed with analgesia and a nephrostomy

Correct Answer is A

Comment:

Answer A

Urolithiasis during pregnancy is uncommon. A multidisciplinary team approach must be adopted to include the urologist, obstetrician, anaesthetist and radiologist. The health of the mother and the development of the foetus are paramount. There is however an absence of prospective studies in this area. Ultrasound is the primary radiological investigation of choice, followed by either an MRI or a limited IVU. Fortunately, conservative supportive management will result in the spontaneous passage of the stone in the majority of pregnant patients. The accepted safe cumulative dose of ionizing radiation to the foetus in pregnancy is five rad (50 mGy), and no single diagnostic study should exceed this maximum. The most sensitive time period for central nervous system teratogenesis is between 10 and 17 weeks of gestation. Non-urgent radiological testing should therefore be avoided during this period. Rare consequences of excessive fetal radiation exposure include a slight increase in the incidence of some childhood cancers, such as leukaemias and, possibly, a very small change in the frequency of genetic mutations. When surgical intervention is necessary insertion of a nephrostomy to relieve the obstruction along with analgesia is an option. Ureteroscopy and holmium laser lithotripsy in pregnancy have been shown to be safe in a number of reports. However, these trials include small numbers and there exists some controversy on the possible detrimental effects of intracorporeal lithotripsy on the foetus’ hearing.

References and Further Reading:

• Srirangam B, Hickerton B, and van Cleynenbreugel B. Management of urinary calculi in pregnancy: A review. Journal of Endourology (2008) 22(5): 867–875.
• Toppenberg KS, Hill DA, and Miller DP. Safety of radiographic imaging during pregnancy. American Family Physician (1999) 1;59(7): 1813–1818.