出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/10/02 15:25:26」(JST)
| Vaginal bleeding | |
|---|---|
| Classification and external resources | |
| ICD-10 | N92-N93, N93.8 |
| MedlinePlus | 007496 |
Vaginal bleeding is any bleeding through the vagina, including bleeding from the vaginal wall itself, as well as (and more commonly) bleeding from another location of the female reproductive system. Generally, it is either a physiologic response during the non-conceptional menstrual cycle or caused by hormonal or organic problems of the reproductive system. Vaginal bleeding may occur at any age, but always needs investigation when encountered in female children or postmenopausal women. Vaginal bleeding during pregnancy may indicate a possible pregnancy complication that needs to be medically addressed.
Blood loss per vaginam (Latin: through the vagina) (PV) typically arises from the lining of the uterus (endometrium), but may arise from uterine or cervical lesions, the vagina, and rarely from the Fallopian tube. During pregnancy it is usually but not always related to the pregnancy itself. Rarely, the blood may actually arise from the urinary tract (hematuria), although the vast majority of females can identify the difference. It can also be a sign of vaginal cancer.
There are many potential causes for abnormal vaginal bleeding.
Bleeding before the expected time of menarche could be a sign of precocious puberty. Other possible causes include the presence of a foreign body in the vagina, molestation, vaginal infection (vaginitis), and rarely, a tumor.
Most unusual bleeding or irregular bleeding (metrorrhagia) in premenopausal women is caused by changes in the hormonal balance of the body. These changes are not pathological. Exceptionally heavy bleeding during menstruation is termed menorrhagia or hypermenorrhea, while light bleeding is called hypomenorrhea. Women on hormonal contraceptives can experience breakthrough bleeding and/or withdrawal bleeding. Withdrawal bleeding occurs when a hormonal contraceptive or other hormonal intake is discontinued.[1]
There are pathological causes of unusual vaginal bleeding as well. Dysfunctional uterine bleeding is a common cause of menorrhagia and irregular bleeding. It is due to a hormonal imbalance, and symptoms can be managed by use of hormonal contraception (although hormonal contraception does not treat the underlying cause of the imbalance). If it is due to polycystic ovary syndrome, weight loss may help, and infertility may respond to clomifene citrate.[citation needed] Uterine fibroids (leiomyoma) are benign tumors of the uterus that cause bleeding and pelvic pain in approximately 30% of affected women. Adenomyosis, a condition in which the endometrial glands grow into the uterine muscle, can cause dysmenorrhea and menorrhagia.[2] Cervical cancer may occur at premenopausal age, and often presents with "contact bleeding" (e.g. after sexual intercourse). Uterine cancer leads to irregular and often prolonged bleeding. In recently pregnant women who have delivered or who have had a miscarriage, vaginal bleeding may be a sign of endometritis or retained products of conception.
Vaginal bleeding occurs during 15-25% of first trimester pregnancies. Of these, half go on to miscarry and half bring the fetus to term.[3] There are a number of causes including rupture of a small vein on the outer rim of the placenta. It can also herald a miscarriage or ectopic pregnancy, which is why urgent ultrasound is required to separate the two causes. Bleeding in early pregnancy may be a sign of a threatened or incomplete miscarriage.
In the second or third trimester a placenta previa (a placenta partially or completely overlying the cervix) may bleed quite severely. Placental abruption is often associated with uterine bleeding as well as uterine pain.
Endometrial atrophy, uterine fibroids, and endometrial cancer are common causes of postmenopausal vaginal bleeding.
The cause of the bleeding can often be discerned on the basis of the bleeding history, physical examination, and other medical tests as appropriate. The physical examination for evaluating vaginal bleeding typically includes visualization of the cervix with a speculum, a bimanual exam, and a rectovaginal exam. These are focused on finding the source of the bleeding and looking for any abnormalities that could cause bleeding. In addition, the abdomen is examined and palpated to ascertain if the bleeding is abdominal in origin. Typically a pregnancy test is performed as well.[2] If bleeding was excessive or prolonged, a CBC may be useful to check for anemia. Abnormal endometrium may have to be investigated by a hysteroscopy with a biopsy or a dilation and curettage.
In an emergency or acute setting, vaginal bleeding can lead to hypovolemia.[2]
The treatment will be directed at the cause. Hormonal bleeding problems during the reproductive years, if bothersome to the woman, are frequently managed by use of combined oral contraceptive pills.
In postmenopausal bleeding, guidelines from the United States consider transvaginal ultrasonography to be an appropriate first-line procedure to identify which women are at higher risk of endometrial cancer. A cut-off threshold of 3 mm or less of endometrial thickness should be used for in women with postmenopausal bleeding in the following cases:
A cut-off threshold of 5 mm or less should be used for women on sequential hormone replacement therapy consisting both of an estrogen and a progestagen.[4]
It the endometrial thickness equals the cut-off threshold or is thinner, and the ultrasonography is otherwise reassuring, no further action need be taken. Further investigations should be carried out if symptoms recur.[4]
If the ultrasonography is not reassuring, hysteroscopy and endometrial biopsy should be performed. The biopsy may be obtained either by curettage at the same time as inpatient or outpatient hysteroscopy, or by using an endometrium sampling device such as a pipelle which can practically be done directly after the ultrasonography.[4]
Severe acute bleeding, such as caused by ectopic pregnancy and post-partum hemorrhage, leads to hypovolemia (the depletion of blood from the circulation), progressing to shock. This is a medical emergency and requires hospital attendance and intravenous fluids, usually followed by blood transfusion. Once the circulating volume has been restored, investigations are performed to identify the source of bleeding and address it.[2] Uncontrolled life-threatening bleeding may require uterine artery embolization (occlusion of the blood vessels supplying the uterus), laparotomy (surgical opening of the abdomen), occasionally leading to hysterectomy (removal of the uterus) as a last resort.
A possible complication from protracted vaginal blood loss is iron deficiency anemia, which can develop insidiously. Eliminating the cause will resolve the anemia, although some women require iron supplements or blood transfusions to improve the anemia.
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| リンク元 | 「閉経後出血」「postmenopausal hemorrhage」 |
| 関連記事 | 「postmenopausal」 |