Neonatal hydrocolpos presenting as a rapidly progressive abdominal mass with inferior caval vein syndrome

Abstract

A 7-week-old infant was presented at the emergency department with an abdominal mass, unilateral swelling of the groin and suspicion of an inferior caval vein syndrome with bluish discolouration and oedema of the lower extremities. Abdominal imaging showed two large cysts and profound bilateral hydronephrosis. Following laparotomy, an extreme hydrocolpos and an overdistended urinary bladder were found. These findings turned out to be secondary to a transverse vaginal septum. She was treated surgically and was hospitalised for 2 weeks. Long-term follow-up showed normalisation of previously present hypercalciuria and hydronephrosis.

A hydro(metro)colpos should be considered in the differential diagnosis of a female infant presenting with an abdominal mass, to apply the appropriate investigations and therapy.

Background

Hydro(metro)colpos due to a transverse vaginal septum is a rare condition but may be associated with severe complications. Despite its low incidence, a transverse vaginal septum should be considered and excluded in a female infant presenting with an abdominal mass. Careful perineal examination, combined with ultrasonography (US), may prevent the need for exploratory surgery.

Case presentation

A female infant, 7 weeks of age, was referred by her paediatrician to our emergency department with an abdominal mass in the left hemiabdomen. Her parents had first noticed this growing mass 1 week earlier and visited their general practitioner, who prescribed lactulose for constipation. Other symptoms were fatigue, feeding difficulties, loss of weight, watery stools for 1 day (one time mildly blood-stained), decreased micturition and fever (maximum 38.3°C). The day before admission, a bluish discolouration was noticed at her right groin, expanding to the upper legs.

On physical examination, the infant was awake and had normal vital parameters, besides tachycardia (180 bpm). Her body temperature and blood pressure were normal. The abdomen was distended and tender when palpated, with an obvious mass in the left hemiabdomen. At first sight, the external genitals appeared normal. Her right groin showed swelling with distended veins visible on the right upper leg. Also, her lower extremities showed oedema and bluish discolouration, which was considered as inferior vena cava syndrome.

A medical history included normal antenatal US at 20 weeks and 32 weeks and an uncomplicated birth after full term pregnancy.

Investigations

On an abdominal X-ray, the most prominent finding was the absence of air in the large intestine and rectum (figure 1).

Figure 1.

Abdominal X-ray showing an abdominal mass.

An abdominal ultrasound showed two large cystic lesions of unknown origin in the lower abdomen. A first cyst, located in the left lower abdomen, was filled with clear fluid whereas the more right-sided lesion seemed to contain a rather milky/blurry fluid as suggested by the increased echogenicity (figure 2). Apart from these findings, a bilateral hydronephrosis grade 3–4 was diagnosed.

Figure 2.

Abdominal ultrasound showing two large cysts with different echogenicities. LI, left; RE, right.

Laboratory investigations showed a mildly elevated serum creatinine of 50 µmol/L (normal values: 15–35 µmol/L) as the only abnormality.¹ Electrolytes, glucose, liver enzymes, haematocrit, white cell count and thrombocytes were all within their normal reference values.

Differential diagnosis

Our initial differential diagnosis included a duplication or mesenteric cyst, Wilms’ tumour, neuroblastoma, lymphoma, germ cell tumour, nephroma, sarcoma, hepatoblastoma and a vascular tumour. Preoperative imaging, showing two prominent cysts, excluded most of the hereinbefore mentioned differential diagnoses. The origin of the cysts, however, remained unclear initially.

Treatment

Because of the suspicion of inferior vena cava syndrome, the impaired venous circulation of the lower limbs and the undetermined abdominal masses, no additional imaging was performed and the infant underwent an urgent laparotomy. During surgery, both lesions were punctured. After drainage using needle aspiration (resulting in the evacuation of 125 mL clear fluid), the left cyst appeared to be a large distended urinary bladder. Puncture of the right mass yielded a milky fluid (40 mL), but only resulted in partial drainage of the cyst. As a hydrocolpos was suspected by that time, a gynaecological examination was performed using a nasal speculum. Perforation of a transverse vaginal septum was followed by drainage of the same milky fluid from the second cyst, which turned out to be a distended vaginal canal (hydrocolpos). On gynaecological examination, it also appeared that the urethral meatus was positioned slightly intravaginally, resulting in obstruction of the meatus and consequently urinary retention. Indwelling catheters were left in both the bladder and the vagina and the abdomen was closed.

Postoperatively, the infant was hospitalised in the paediatric intensive care unit. The oedema of the lower extremities disappeared within 24 hours following surgery. Initially, she showed hypertension (maximum of 132/73 mm Hg),² which resolved in 2 days, and a transient polyuria (up to 12 mL/kg/h) which was interpreted as impaired urinary concentration due to a postobstructive tubular dysfunction. The latter can be described as the polyuric phase of acute kidney injury. Surprisingly, there were no signs of postrenal impaired glomerular filtration such as electrolyte disturbances and her serum creatinine returned to normal within 2 days. She was treated with antibiotics (amoxicillin/clavulanate) intravenously for 10 days to treat a possible bacterial infection. Oxybutynin was given to prevent bladder spasms. The vaginal catheter was removed after 8 days, once the fluid drainage had stopped. The urinary catheter was removed on the 10th postoperative day following a voiding cystourethrography (VCUG) and renal US. The VCUG showed a slightly distended bladder without signs of urethral obstruction or vesicoureteral reflux. Renal US showed mild hydronephrosis and mild caliectasis of the right kidney and bilateral medullary nephrocalcinosis. There were no signs of recurrence of the hydrocolpos on ultrasound. Urine investigations showed hypercalciuria (maximum 5 mmol calcium/mmol creatinine), which improved but persisted during the period of hospitalisation. Postobstructive tubular dysfunction was considered as the most probable cause of this hypercalciuria. Blood analysis did not show renal tubular acidosis, hypercalcaemia or hypophosphataemia. Following removal of the urinary catheter, a normal micturition was maintained. Contrast radiography showed a normal shaped uterus (figure 3).

Figure 3.

Vaginography showing a dilated vaginal canal due to a (treated) hydroocolpos.

Outcome and follow-up

The patient was discharged home 2 weeks after surgery and re-evaluated 3 weeks later. At this point, she was doing well and there were no abnormalities regarding feeding, growth or defecation. Parents did notice a weak urine stream, which improved after ceasing oxybutynin therapy. Follow-up US did not show any hydronephrosis and the severity of nephrocalcinosis had been decreased. The hypercalciuria had almost normalised (1 mmol calcium/mmol creatinine) and serum urea and creatinine were normal. Radioisotope renography using mercapto-acetyl-triglycine (MAG3) showed a slightly delayed excretion and an equally split function (right 54%, left 46%). Urodynamic testing to evaluate bladder (dys)function was perfomed at 1 year of age and showed no abnormalities and no suspicion of an Hinmans bladder. Routine urine investigations and renal US up to 2.5 years of age excluded recurrence of hypercalciuria or hydronephrosis. The patient will be followed up yearly and seen by a specialised gynaecologist at the age of 10 (or earlier in case of symptoms) for further evaluation regarding possible associated abnormalities of the internal genitalia.

Discussion

A hydrocolpos describes the distension of the vaginal canal caused by the accumulation of fluid and a congenital vaginal obstruction. The distending fluid originates from uterine and vaginal glands secreting mucoid substances in the vaginal lumen, triggered by maternal or endogenous oestrogens. The accumulation of a large amount of fluid in the vaginal space may eventually result in a distension of the uterus (hydrometrocolpos).

Vaginal obstruction is usually diagnosed around puberty when a girl is presented with primary amenorrhoea, (cyclic) pelvic pain and/or an abdominal mass due to a haemato(metro)colpos. Presentation antenatally (in case of abnormal findings on US), in the neonatal period or infancy may be explained by a more pronounced sensitivity and/or exposure to oestrogens, leading to the accumulation of higher amounts of vaginal fluid. This accumulation of fluid, known as hydrocolpos, is estimated to affect 1 in 16 000 births and it accounts for approximately 15% of all abdominal masses in female newborns.³

A hydrocolpos may initially remain asymptomatic. However, when a large amount of fluid is collected, the hydrocolpos can result in external compression of surrounding structures, causing intestinal and/or urological obstruction.^4–6 Hydronephrosis may occur when the hydrocolpos compresses the ureter or urethra. Urethral obstruction is usually associated with an ectopic urethral meatus (as illustrated by the vaginal meatus in our case) and may lead to an overdistension of the urinary bladder as well.⁷ Other possible symptoms are an abdominal mass, ascites and vena inferior syndrome with vulvar and/ or lower extremity oedema (also seen in our case).^{7 8}

Congenital vaginal obstruction may be caused by a transverse vaginal septum, an imperforate hymen, urogenital sinus, cloaca or a (partial) vaginal atresia. These may be associated with other Müllerian duct anomalies (such as uterus didelphys), renal anomalies (such as renal agenesis), anorectal deformities (cloacal malformation) and polydactyly (as in Bardet-Biedl syndrome).4 7 9 10 A child presenting with congenital vaginal obstruction should therefore be screened for other associated malformations. In our case, the vaginal obstruction was caused by a transverse vaginal septum. This is a vertical fusion defect and classified as a class II Müllerian duct anomaly, according to the modified Rock and Adams American Fertility Society classification. The septum is a result of defective fusion of the caudal end of the Müllerian system with the urogenital sinus or a defect in vaginal canalisation. It consists of a membrane of fibrous connective tissue with vascular and muscular components and can occur at any level of the vagina, but most often at the junction of the upper and middle third.¹¹ The incidence of a transverse vaginal septum is estimated to be 1 in 80 000 women.¹²

Thorough inspection of the genitalia and perineum is needed when suspecting a hydrocolpos, which may require general anaesthesia. Investigation of the external genitalia often shows no abnormalities in case of transverse vaginal septum, but may show a bulging hymen in case of an imperforate hymen or a vaginal dimple in case of atresia.⁸ Vaginoscopy is helpful in diagnosing a transverse vaginal septum and can also determine the septum’s exact anatomical location.

Abdominal US provides information of the abdominal swelling and can show a hydrocolpos, but also demonstrates the presence of hydronephrosis and/or hydroureter and other associated renal anomalies. A transperineal ultrasound may also be helpful when suspecting a hydrocolpos. MRI is the best imaging technique in diagnosing a transverse vaginal septum or other causes of hydrocolpos, especially in complex anomalies. It can also define the location and thickness of a septum prior to surgery.^{8 11}

Immediate treatment is necessary to relieve the urinary and intestinal obstruction and to prevent further complications. Common complications are urinary tract infections, postrenal failure, pyocolpos, sepsis, failure to thrive and ruptured hydrocolpos (with peritonitis).¹³ Treatment of an imperforate hymen or septum consists of incision and leaving an indwelling catheter to prevent reaccumulation of fluid for a short term period ranging from 1 to 3 weeks. In case of complex associated urogenital abnormalities, such as cloacal malformation, a transabdominal tube vaginostomy must be considered until definite surgical repair is performed, which may take up to several years.^{4 14 15} In addition to surgical treatment, broad-spectrum antibiotics must be considered to treat or prevent a bacterial infection.

In our case, the signs of an inferior caval vein syndrome and impaired circulation in both legs prompted us to perform an urgent exploratory laparotomy. Retrospectively, this invasive procedure could have been avoided if the hydrocolpos and vaginal septum had been diagnosed immediately. Literature study also shows several cases of an unsuspected hydrocolpos in which a laparotomy was performed, with in some cases even a hysterectomy and excision of an ureter.^{4 7} This illustrates the importance of awareness of a hydrocolpos as a cause of abdominal mass and gynaecological examination should be done in a female infant.

At a later stage, surgical correction is advised to prevent complications such as stenosis and obstetric difficulties. Several techniques are described, which involve excision of the septum and suturing of the vaginal mucosa.^{4 8 16}

Long-term follow-up of patients with a (corrected) transverse vaginal septum is recommended. Late complications include recurrence of the obstruction, vaginal stenosis, endometriosis, infertility and obstetric complications.^{16 17} The aetiology is unclear, but the higher rate of infertility may be the result of an increased prevalence of endometriosis in these patients, due to retrograde blood flow through the uterus and fallopian tubes.^{16 17}

Patient’s perspective.

As her parents, we were anxious because the diagnosis was unclear at time of presentation at the emergency room. It felt like is was a close call when we were referred for surgery. Fortunately, this was done immediately and after this, our daughter recovered quickly. All care takers showed their empathy and made us feel comfortable during our stay.

Our daughter is doing well now and is regularly checked in the hospital. At the time she is 10 years old, she will be evaluated by the gynaecologist.

Learning points.

• When a female infant is presented with an abdominal mass, a hydrocolpos due to an transverse vaginal septum (or other cause of congenital vaginal obstruction) should be in the differential diagnosis and a careful examination of the perineal region, including the vaginal entrance, should be performed.

• When suspecting a hydrocolpos, an MRI should be considered to confirm the diagnosis and provide more information about the underlying cause of obstruction.

• A hydrocolpos may lead to severe intestinal and urological obstruction and infection, and prompt treatment to enable drainage is needed.

• In case of a transverse vaginal septum causing hydrocolpos, transseptal or transabdominal drainage is successful, and laparotomy is often not necessary.

• In case of a transverse vaginal septum, associated Müllerian duct and renal anomalies should be investigated and follow-up is recommended because of the increased risk of infertility and abortion.

Ethics statements

Patient consent for publication

Consent obtained from parent(s)/guardian(s).