cyst

Infected Urachal Cyst

HEATHER KELKER, MD, and MARGARET WOLFF, MD
University of Michigan Hospital and Health Systems,
Ann Arbor

 

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A 6-month-old girl presented to the emergency department with swelling and erythema of her umbilicus. Umbilical erythema had been noted on the morning of presentation, with subsequent development of swelling and tenderness of the surrounding area. No drainage was noted. The infant had decreased oral intake but had no vomiting, diarrhea, or fever. She had no significant medical or surgical history, and her immunizations were up to date.

urachal cyst

On arrival to the hospital, the infant was fussy but consolable. She had a temperature of 36.6°C (97.9°F), a heart rate of 122 beats per minute, blood pressure of 99/46 mm Hg, and respiratory rate of 36 breaths per minute. Physical examination revealed a well-appearing infant. Her abdomen was soft, with normal bowel sounds. A tender, fluctuant, nonreducible bulge was noted at the umbilicus, with surrounding erythema and induration. The rest of the physical examination results were normal.

Laboratory testing showed a white blood cell count of 14,700/µL, with 62% neutrophils, 10% monocytes, and 27% lymphocytes. Abdominal radiography demonstrated a soft tissue bulge in the region of the umbilicus with a minimally distended distal small-bowel loop. Air was present throughout the small bowel and rectum. Abdominal ultrasonography showed a fluid-filled structure measuring 1.2 × 1.1 cm, with internal echogenic debris that extended deep to the abdominal wall musculature. There was surrounding edema and increased flow to the umbilicus. These findings were consistent with an infected urachal cyst.

Antibiotic therapy with clindamycin was begun, and erythema and tenderness improved within 24 hours. The infant completed a 14-day course of clindamycin; 2 months after presentation, she underwent excision of the urachal cyst without complication.

The urachus is an embryologic tract that connects the developing bladder to the umbilicus and involutes in utero to form a fibrous band. Failure of involution can lead to a spectrum of urachal anomalies. The most severe type is a patent urachus, which is a patent connection between the bladder and the umbilicus. A patent urachus generally presents as a persistently draining umbilicus in infancy. The other types of urachal anomalies present with a variety of symptoms such as abdominal pain, abdominal or umbilical masses, or dysuria. Urachal cysts are the most common urachal anomaly and occur when the urachus incompletely involutes, resulting in a cyst that does not connect to the bladder or umbilicus.1

Urachal anomalies can be difficult to diagnose owing to the variability of the presenting symptoms, which often mimic more common diagnoses such as appendicitis or incarcerated umbilical hernia.2 For an infant presenting with an umbilical mass, the list of differential diagnoses includes umbilical hernia, omphalitis, umbilical pyogenic granuloma, urachal remnants, and patent omphalomesenteric duct.3 Left untreated, complications of urachal cysts include malignant degeneration, calculus formation, rupture, hemorrhage, bowel obstruction, and infection.4

When a urachal cyst is suspected, ultrasonography is the preferred initial imaging modality and can be diagnostic in approximately 80% of cases. When ultrasonography is nondiagnostic, computed tomography or fistulography may be considered.5 Treatment of an infected urachal cyst traditionally consists of antibiotic therapy followed by complete excision. Nonoperative management with drainage and antibiotics also may be considered.6

REFERENCES:

1. Yiee JH, Garcia N, Baker LA, Barber R, Snodgrass WT, Wilcox DT. A diagnostic algorithm for urachal anomalies. J Pediatr Urol. 2007;3(6):500-504.

2. Ash A, Gujral R, Raio C. Infected urachal cyst initially misdiagnosed as an incarcerated umbilical hernia. J Emerg Med. 2012;42(2):171-173.

3. Hsu JW, Tom WL. Omphalomesenteric duct remnants: umbilical versus umbilical cord lesions. Pediatr Dermatol. 2011;28(4):404-407.

4. Allen JW, Song J, Velcek FT. Acute presentation of infected urachal cysts: case report and review of diagnosis and therapeutic interventions. Pediatr Emerg Care. 2004;20(2):108-111.

5. Widni EE, Höllwarth ME, Haxhija EQ. The impact of preoperative ultrasound on correct diagnosis of urachal remnants in children. J Pediatr Surg. 2010;45(7):1433-1437.

6. Lipskar AM, Glick RD, Rosen NG, et al. Nonoperative management of symptomatic urachal anomalies. J Pediatr Surg. 2010;45(5):1016-1019.