Vulvar Hematoma

Etiology

During labor, a vulvar hematoma can result from either direct or indirect injury to the soft tissue. Examples of causes of direct injuries include episiotomy, vaginal laceration repairs, or instrumental deliveries, while indirect injury can result from extensive stretching of the birth canal during vaginal delivery.[4] Interestingly, most vulvar hematomas are formed after a normal delivery instead of complicated deliveries.[2][5] Risk factors for developing vulvar hematoma include instrumental delivery, episiotomy, primiparity, prolonged second stage of labor, macrosomia, use of anticoagulants, coagulopathy, hypertensive disorders of pregnancy, and vulvovaginal varicosity.[6][7]

Non-obstetric vulvar hematomas can arise from any form of trauma to the perineum, such as a saddle injury,[8] falling from a height,[3] insertion of a foreign body, sexual assault,[9] consensual coitus,[1] or surgery of the vulva.[10][11] If there is no associated trauma, spontaneous vessel rupture is a possible cause.[12] It is reported that post-coital injury is the most common non-obstetric cause of vulvar hematoma.[1]

Epidemiology

Vulvar hematomas are more common in the obstetric population, with an incidence ranging from 1:300 to 1:1000 deliveries.[12] Outside the obstetric population, it can make up about 0.8% of gynecological problems.[1]

Non-obstetric vulvar hematoma follows a bimodal age distribution. It is more common during childhood or early adolescence because the labia majora, which is composed of fat for its protective functionality, is less developed in young pre-pubertal females.[3] At the other end of the spectrum, hypoestrogenism in postmenopausal women results in atrophy and loss of elasticity of the vulva and vagina epithelium. The increased friability of the tissue makes the vulva more prone to injury, hence, vulvar hematoma formation.[3]

Pathophysiology

A hematoma is described as a collection of blood beneath an intact epidermis that presents as a swollen fluctuant lump. It can be extremely tender on palpation.[3] Due to its rich blood supply, the vulva is highly vulnerable and prone to hematoma formation. Although venous bleeding is possible, arterial bleeds mainly originate from one of the branches of the pudendal artery.[1] Vulvar hematoma, rarely, might be secondary to operative laparoscopy (especially adnexal surgery), spontaneous rupture of the internal iliac artery, or spontaneous rupture of a pseudoaneurysm of the pudendal artery.[12][13]

History and Physical

Pain is the most common symptom of a vulvar hematoma. Patients can describe it as perineal, abdominal, or buttock pain.[12] The intensity of the pain can be severe enough to interfere with mobility.[3] There may also be intermittent bleeding. Depending on the size and location of the vulvar hematoma, urological or neurological signs and symptoms may be present. Due to mechanical urethral obstruction, patients may present with urinary retention or micturition difficulties.[12] In severe cases, the patient can be hemodynamically unstable and will require urgent fluid resuscitation or blood transfusion. Symptoms usually develop within a few hours to days of delivery, depending on the severity of the condition.

If a vulvar hematoma is suspected, a detailed history should be taken to elicit possible causes associated with it. They include preceding coitus, accidents involving injury to their perineum, and recent deliveries or operations. It is also important to inquire about sexual assault in a sensitive manner. 

As bleeding into the vulva is largely restricted only by the Colles fascia and the urogenital diaphragm, a hematoma in this area will be visible on physical examination.[12] This is seen as a tender fluctuant lump of variable size. Since the Colles fascia exerts little resistance, vulvar hematomas can grow to become 15cm in diameter or more.[14] The observation of a lump or swelling in the groin may be offered by the patient if asked during the consultation. Although there is no anatomical explanation, it is discovered that the right side appears to be more commonly affected.[3][15]

During the examination, a thorough inspection should be performed for pelvic fractures and genital lacerations, especially if there is a history of significant trauma.[15] In addition, basic observations such as the patient’s heart rate, respiratory rate, and blood pressure should be measured and recorded to provide baseline values for monitoring. A urinary catheter may also be inserted if clinically indicated.

Evaluation

Complete blood count (CBC), type and screen, and if deemed necessary, coagulation screening should be performed. If there is a likelihood of the need for a blood transfusion, blood should also be taken for cross-matching.

Ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI) of the pelvis can be done to evaluate the size, site, and growth of the hematoma. MRI angiography of the pelvis may help in the detection of any aneurysms. Transperineal sonography is also a simple, non-invasive technique that can be useful for the follow-up and monitoring of patients undergoing expectant management of a vulvar hematoma.[8]

In addition, further investigations can be done to evaluate for causes of hematoma formation, such as the presence of connective tissue disorders or coagulopathies. In cases associated with severe trauma or sexual assault, the extent of injury to the perineum and pelvis must also be assessed adequately. Additional investigations, such as a pelvic X-ray for pelvic bone fractures in cases of pelvic trauma, should be done.[9]

Treatment / Management

The majority of vulvar hematomas are small and can be managed conservatively. However, large (>10 cm in diameter) or progressively enlarging hematomas causing intense pain and distress to the patient require surgical intervention. Urgent surgical management is also warranted if the hematoma is large enough to cause hemodynamic instability, or urological or neurological signs and symptoms.[3][13] A catheter may be inserted if the patient experiences difficulty urinating.(B3)

Conservative management usually involves the use of ice packs, local compressions, bed rest, and analgesics. In the event that conservative management has not been effective, surgery may be performed. In fact, conservative management of large hematomas has been found to be associated with a longer period of hospitalization, greater need for antibiotics, and blood transfusion[14]. A conservative approach is also not advisable for hematomas that are expanding acutely.[16](B2)

Surgical management includes surgical drainage of the hematoma, evacuation of any clots present, ligation of bleeding points, and the assessment for signs of pressure necrosis (a complication of vulva hematoma).[1] These can be done under local anesthesia. As further blood loss during surgery is anticipated, the necessary investigations such as cross-matching and preparations for a possible blood transfusion should be done. An intravaginal approach for incision and evacuation of hematoma produces better cosmetic results.[17](B3)

Alternatively, selective arterial embolization may be performed. This procedure was first described by Brown et al. for the treatment of postpartum hemorrhage.[18] Subsequently, this approach has been used successfully for the treatment of bleeding in several obstetric and gynecological conditions.[19] Pelvic angiography is done prior to selective embolization to investigate and locate bleeding vessels. Surgeons may choose angiographic embolization if bleeding continues post-operatively, or if the vulvar hematoma reforms after surgical management. It may also be the choice of treatment in situations where surgery is not possible, such as in patients who are hemodynamically unstable and not fit for surgical ligation procedures.[20] A case of successful transarterial embolization after a failed conservative treatment for an expanding non-obstetrical vulvar hematoma has also been reported.[21](B3)

Differential Diagnosis

There are a few more frequently diagnosed vulvar conditions that can present similarly to a vulvar hematoma. These include Bartholin’s gland cysts and abscesses, vulvar varicosities, and folliculitis.[1][22] In addition, as with any conditions presenting as a growth, vulvar cancer must also be considered on the list of differential diagnoses.

The Bartholin’s glands are two pea-sized glands located symmetrically at the vaginal opening. These glands function by lubricating the vagina through mucus production.[23] A Bartholin’s gland cyst forms as a result of a blocked duct, which leads to a collection of secretions. This can subsequently develop into a Bartholin’s gland abscess when infected. While the former can be asymptomatic, Bartholin’s gland abscesses usually present with surrounding cellulitis.[23] A non-obstetric vulvar hematoma has been reported to be misdiagnosed as a Bartholin’s gland duct abscess.[15] Such a misdiagnosis is possible as extravasated blood of a vulvar hematoma can trigger an inflammatory reaction similar to an abscess.

Vulvar varicosities can also be a differential diagnosis. However, it is important to note that there have been case reports of postoperative vulvar hematoma following surgical management for vulvar varicose veins.[10] Unlike vulvar hematomas, vulvar varicosities are much more common, especially in multigravid females. In addition, they are often asymptomatic, with only a minority of cases causing mild discomfort.[24]

Vulvar folliculitis arises due to inflammation of the hair follicles and often resembles acne in the genital region. Patients with vulvar folliculitis may present to the clinic with genital pain or itchiness. However, on examination, it is usually seen as small papules or pustules uniformly distributed over the vulva.[25]

Finally, although vulvar carcinoma can present as a fleshy lump or mass, most cases have a history of pruritus and do not usually present with pain. In addition, vulvar carcinoma can also be described as ulcerated, leukoplakic, or warty.[26] Metastatic choriocarcinoma is a highly vascularized trophoblastic tumor which should also be suspected in patients with trophoblastic disease. In a case report by Bhattacharyya SK et al., vulvovaginal metastasis of choriocarcinoma was initially misdiagnosed and managed as an old infected vulvar hematoma.[27]

Prognosis

Vulvar hematomas may cause serious morbidity but rarely leads to mortality. A complete recovery is often seen. For small vulvar hematomas, most resolve spontaneously under conservative management.[28] Management with surgical intervention or selective arterial embolization is also effective, with most patients being able to mobilize within a day or two, and discharged home without any complication.[13][21]

Complications

Necrosis is a complication that will necessitate surgical debridement. This complication arises due to the pressure applied by the large or growing hematoma on surrounding tissues.[1] Pressure necrosis can be prevented with the prompt surgical evacuation of blood clots.[12][29] In situations where there is increasing pain and necrosis on presentation, urgent surgical intervention will be necessary.

As with any condition managed operatively, the risk of infection is a potential complication, and patients should follow up shortly after discharge from the hospital to check for recurrence of hematoma or infection. Prophylactic antibiotics may be prescribed if clinically indicated.

Selective pelvic arterial embolization, although not readily available, is an effective procedure in competent hands.[30] Reported post-procedural complications include muscle pain, guidewire perforation, and vaginal fistula.[31] Low-grade fever, pelvic infection, and temporary foot drop are also possible. Pelvic arterial embolization means some degree of exposure to ionizing radiation.[32]