Day: June 2, 2008

What’s Wrong With His Belly Button?

Patient Presentation
A 1-month-old male came to clinic because his mother was concerned about discharge from his umbilicus.
At 2 weeks he was growing well and his umbilical cord stump was still attached and there were no concerns at that time.
The stump fell off 6 days prior and for the last 3 days he seemed to have some yellow discharge that appears on his clothes.
The stump is not otherwise reddened or irritated. He is not bothered by it.
The past medical history showed a full term infant without pre- or perinatal problems.
He has been gaining weight well.
The family history is negative for any genitourinary system or gastrointestinal problems.
The review of systems was negative.
The pertinent physical exam showed an alert infant with growth parameters in the 75-90%.
There was some yellowish, crusty discharge on his undershirt.
His umbilicus was not reddened generally but there was a 0.3 x 0.5 cm red, pedunculated mass extending from the center of the umbilicus.
No opening was seen in the mass and no obvious discharge was seen on the umbilicus. His abdomen was non-tender. The rest of his examination was negative.
The radiologic evaluation included an ultrasound of the abdomen which revealed an isoechoic tract extending from the umbilicus to the bladder.
There was no fluid or cyst in the tract and the bladder appeared normal. A voiding cystourethrogram also showed normal bladder anatomy and no vesicoureteral reflux.
The diagnosis of urachal remnant was made. He was referred to urology who were planning surgical resection.


Figure 60 – Midline sagittal ultrasound image demonstrates a hypoechoic tubular structure with minimal fluid within it that communicates with the umbilicus (to the left) but not with the bladder dome (to the right).


Figure 61 – Lateral view of the voiding phase of a voiding cystourethrogram that demonstrates a normal appearing bladder and urethra. No reflux of contrast through the urachus is demonstrated.

Discussion
The allantois develops in the human embryo on the 16th day of embryogenesis. It develops from the posterior portion of the yolk sac forming a small diverticulum adjacent to the forming cloaca.
The allantois is usually obliterated during embryogenesis, but a remnant may persist. This remnant connects from the umbilicus to the bladder and is called an urachal duct remnant. If the remnant is entirely open then it is called an urachal fistula and would drain urine through the umbilicus.
It is also possible only parts of the remnant are obliterated. If the remnant is obliterated near the bladder, leaving open the umbilical end, this is called a urachal sinus. If the remnant is obliterated at the bladder and umbilical end but the central portion remains, this is called an urachal cyst.
The fluid from an urachal sinus or cyst is caused by the secretory activity of the urachal duct lining.

The vitelline duct is formed by the lateral folding of the foregut and hindgut. It connects the umbilicus to the distal ileum. Usually it is also obliterated but sometimes remnants persist. Its most common remnant is the Meckel’s diverticulum.
The vitelline duct can also be patent over its entire length creating a vitelline fistula which may cause a fecal discharge at the umbilicus. A central portion of the vitelline duct may remain patent creating a vitelline cyst.
A vitelline cyst may present as intestinal obstruction as it can become entangled in the intestines.

Around the end of the 3rd month of embryogenesis, all that should remain externally of the original allantois and vitelline ducts after all the folding of the midgut/abdominal area of the embryo is the umbilical cord with 2 arteries, 1 vein and Wharton’s jelly to protect it.

Learning Point
The differential diagnosis of a mass of the umbilicus includes:

  • Umbilical granuloma – usually 0.1-1.0 cm, red, friable tissue, usually easily treated with silver nitrate cautery.
  • Urachal duct remnant – including fistula, sinus tract or cyst. May present with mucous drainage or urine.
  • Vitelline duct remnant – including polyp (usually brighter red than umbilical granuloma and does not respond to silver nitrate cautery), fistula, sinus tract or cyst. May present with fecal or mucus discharge.
  • Omphalocoele – abdominal contents pass through a periumbilical defect and the viscera are covered by a membrane. Needs surgical treatment.
  • Umbilical hernia – small defects in the periumbilical structure of the anterior abdominal wall that closes with time as the musculature develops. Usually closes by 1 year of age.

Questions for Further Discussion
1. How long after birth should the umbilical cord separate, and what causes the separation?
2. How common is a single umbilical artery and what is its clinical significance?
3. How do umbilical infections present and what organisms commonly cause these infections?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Information prescriptions for patients can be found at MedlinePlus for this topic: Infant and Newborn Care.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Sadler, TW. Langman’s Medical Embryology. 5th edit. 1985. pp. 51, 71, 239, 257.

Minkes RK,
Chen LE,
Mazziotti MV,
Kim ES, and
Bloss RS.
Disorders of the Umbilicus. eMedicine.
Available from the Internet at http://www.emedicine.com/ped/TOPIC2948.HTM (rev. 4/27/2006, cited 4/14/2008).

Pomeranz A. Anomalies, abnormalities, and care of the umbilicus. Pediatr Clin North Am. 2004 Jun;51(3):819-27, xii.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    7. All medical and invasive procedures considered essential for the area of practice are competently performed.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    12. Evidence from scientific studies related to the patients’ health problems is located, appraised and assimilated.
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Systems Based Practice
    23. Differing types of medical practice and delivery systems including methods of controlling health care costs and allocating resources are known.
    24. Cost-effective health care and resource allocation that does not compromise quality of care is practiced.

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital

    Date
    June 2, 2008