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Ultrasonography to rule out renal malformations in newborns with isolated preauricular tags/pits

Three Part Question

In [newborns with isolated preauricular tags/pits] is [an ultrasonogram of the renal tract] required [to rule out urinary tract malformations]

Clinical Scenario

You join a new neonatal unit. On your routine baby check you find a newborn with an isolated preauricular tag/pit. The baby has no other malformation or dysmorphic feature on detailed examination. You know that this baby needs to have the hearing tested but you are not sure it needs an ultrasonogram as part of routine evaluation to rule out urinary tract anomalies. The unit where you worked previously had a policy of performing routine scans, but your registrar tells you that this is not the policy here. You decide to search for the evidence behind this.

Search Strategy

Secondary sources
Cochrane None
Pubmed - 65 results found and then each abstract read for relevant articles
Embase same search strategy. No additional papers
Primary sources
Pubmed ((("Kidney/abnormalities"[MeSH] OR "Kidney/ultrasonography"[MeSH]) OR ("Urinary Tract/abnormalities"[MeSH] OR "Urinary Tract/ultrasonography"[MeSH])) AND "Ear/abnormalities"[MeSH]). Field: Title/Abstract. Limits: All Infant: birth-23 months.

Search Outcome

6 relevant papers found

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Alexander K.C. Leung et al
1992
Canada
69 children preauricular sinus (2 with associated anomalies and 67 isolated) who were seen in ambulatory care paediatric clinic for problems unrelated to preauricular sinus or kidneys underwent renal ultrasonographyCase series (level 4)Urinary tract anomalies detected on ultra sonogram who subsequently underwent voiding cystouretherogramOverall 3/69 had significant abnormalities. Only 1/67 (1.5%) of children with isolated sinus had an anomalyThe study only looked at preauricular sinuses and did not include tags. Also there were no controls
Louanne Hudgins et al,
1992
USA
Retrospective analysis of all paediatric ultrasounds over 2 year period and review of their medical records. 30 were for children with isolated ear abnormalities microtia, pits, tags and minor structural abnormalitiesCase series (level 4)Urinary tract anomalies detected on ultra sonogramNone of the 30 children with isolated ear abnormalities had abnormal renal ultrasounds.Small sample size and no controls.
A Kugelman et al
1997
Israel
26 infants with preauricular tags (24) and pits (2). 24 had renal ultrasonography on day 3 of lifeCase series (level 4)Urinary tract anomalies detected on ultra sonogram)No malformations foundSmall sample size and no controls.
David Kohelet et al
2000
Israel
Study group: 70 infants with isolated preauricular tags underwent renal ultrasonography on day 3-4 of life. Control group: 69 infants without preauricular tags underwent urinary tract ultrasonography after day 5 as part of investigation for persistent regurgitation associated with cyanotic spellsCase control study (level 3b)Urinary tract anomalies detected on ultra sonogram which were further investigated by voiding cystography and radionuclide scintigraphy (where necessary)6/70(8.6% 95%CI 2.2-12.4) of study group had abnormalities. None (95% CI 0% to 3.6%) in control group had abnormalities. (p<0.02)The study included only preauricular tags. There were no cases of renal malformation in the control group which is less than that of normal population. Also the study was not of sufficient power to make a firm conclusion.
A Kugelman et al
2002
Israel
Study group: 92 infants born with isolated preauricular tags or pits underwent renal ultra sonogram at 1-3 mths of age Control group: 95 consecutive healthy infants who underwent renal ultrasonography on 2nd day of lifeCase control study (level 3b)Urinary tract anomalies detected on ultra sonogram2/92 (95% CI 0.2-7.0) of study group had renal abnormalities. 4/95 (4.2%: 95% CI 1.1% to 10%) of control group had renal abnormalities. P=1.0The age disparity at time of examination between cases and controls might be a source of bias.
D Mishra et al,
2003
India
Study group: 34 children with isolated preauricular tag. Control group: 34 children who underwent abdominal ultrasound for non-renal problemsCase control study (level 3b)Urinary tract anomalies detected on ultra sonogram3/34 (9% 95%CI 0.6-8.1)of study group had urinary tract abnormalities. None in control group had urinary tract abnormalities (95% CI 0% to 3.5%) p < 0.05The study included only preauricular tags. There were no cases of renal malformation in the control group which is less than that of normal population. The sample size was small and the study was not of sufficient power to make a firm conclusion.

Comment(s)

The association between external ear abnormalities and renal malformation has been reported previously. There is a general consensus on the need to rule out a urinary tract malformation in a child with a gross ear malformation or when the isolated preauricular tag/pit is accompanied with other dysmorphic features (Wang). Some experts have recommended that there is no need for renal ultrasound if isolated tags/pits are not associated with other malformation or dysmorphic feature. (Frias). However the studies above give mixed results. The three older studies did not find any increase in number of renal malformations in those with isolated preauricular tags/pits but they are all limited by small sample size and absence of controls. The other 3 studies have controls but are underpowered. The fact that the two largest studies which are from the same country with comparable sociodemographic population give opposite results, underlines the need for a larger sample size. This is not easy when you consider the fact that the incidence of preauricular tags and sinuses is around 5-10/1000 live births and the prevalence of mild renal pelvis dilatation in general population by postnatal screening is 4.6% as compared to a reported prevalence of renal malformations ranging from 2.2% to 8.6%. So to achieve a significant sample size, the study would have to be done over multiple centres for a considerable period of time. At this stage what seems a sensible practice is that the presence of a preauricular tag or pit should lead to a careful search for other malformations or dysmorphic features, the presence of which will tilt the balance in favour of doing a renal ultrasonogram.

Clinical Bottom Line

There is not enough evidence to derive a firm conclusion on the need for renal ultrasonogram in newborns with isolated preauricular tags/pits The presence of a preauricular tag or pit should lead to a careful search for other malformations or dysmorphic features, the presence of which will tilt the balance in favour of doing a renal ultrasonogram

References

  1. Alexander K, Leung C, Lane W, Robson M. Association of preauricular sinuses and renal anomalies. Urology 1992;40(3):259-261.
  2. Hudgins L, Tuvale MK, Stephensen L. Isolated anomalies of the external ear are not associated with renal malformations Proc Greenwood Genet Ctr 1992; 11:95
  3. Kugelman A, Hadad B, Ben-David J, Podoshin L, Borochowitz Z, Bader D. Preauricular tags and pits in the newborn: the role of hearing tests. Acta Paediatr 1997;86(2):170-172.
  4. Kohelet D, Arbel E A prospective search for urinary tract abnormalities in infants with isolated preauricular tags Paediatrics 2003; 40:796-797
  5. Kugelman A, Tubi A, Bader D, Chemo M, Dabbah H. Pre-auricular tags and pits in the newborn: the role of renal ultrasonography. J Pediatr 2002 Sep;141(3):388-91.
  6. Mishra D, Archana, Gupta VK. Are isolated preauricular tags a marker of urinary tract anomalies. Indian Pediatrics 2003;40(8):796-797.
  7. Wang RY, Earl DL, Ruder RO, Graham JM Jr. Syndromic ear anomalies and renal ultrasounds. Pediatrics 2001 Aug;108(2):E32.
  8. Frias JL, Carey JC. Mild errors of morphogenesis. Advances in paediatrics. Mosby-Year Book, Inc; 1996 p46-47.