1. Introduction
In 1760 Dr Nicholls, physician to King George first described on necropsy an aortic dissection (1). Abdominal aortic aneurysm is a limited dilatation of the part of abdominal aorta just below the renal arteries and end above the iliac arteries. May be long up to 25 cm (2). The most common cause for degenerative process is atherosclerosis (3).Chief among risk factors is hypertension (3). Other causes include hereditary connective tissue disorders, aortic arthritis, chest trauma, bicuspid aortic valve (3). Possible other aortic disorders such as giant cell arthritis or systemic lupus also may predispose to dissection. AAA is very rare in young females. Crack cocaine users and pregnant woman are at increased risk of suffering from AAA (4).
In woman < 40 years ago, % 50 of aortic dissection occur during pregnancy (5). The cardiovascular complications related with cocaine abuse are adrenergic mediated, vasoconstriction, Include myocardial ischemia, infarction, myocarditis, thrombosis and aortic dissection (6).
Cocaine decreases uterine blood flow and induces uterine contractions. It is clear, however, that women who use cocaine during pregnancy are at significant risk for shorter gestations, preterm labor, spontaneous abortions, PROM, abruption placenta, and death (7).
Cocaine crosses the human placenta and is associated with free radical production, and fetal encephalopathy. Cocaine has teratogenic or adverse effects on developing brain (7).
In this report we present the case of a crack user pregnant woman who develops an aortic aneurysm.
The vasoconstriction and sympathomimetic effect of crack, coupled with cardiovascular changing during pregnancy, may predispose the patient to aortic aneurysm.
2. Case study
A 32 year old woman who was 40 weeks pregnant with her second pregnancy came to the labor department complaining of labor pain and rupture of membrane.
She had a previous cesarean section last year. She abused crack cocaine. She used crack every 2 hours.
She did not receive adequate prenatal care in this pregnancy.
Physical examination revealed a temperature of 36.8C, blood pressure: 120/75mmHg, pulse rate of 78/ min, and respiratory rate of 16/min.
Uterine contraction interval = 2minute, with duration = 50’’, cervical dilatation = 10cm, cervical effacement = 100%, station = -1, presentation = vertex, position = ROT with posterior Asynclitism and molding. Fetal heart rate = 144 beats per minute.
An emergency cesarean section was performed; the neonatal was born with 1 minute and 5 minute Apgar score 7 and 9. The infant was transported to the neonatal intensive care unit.
When the patient was admitted to the labor suite, hemoglobin = 10/5mg/dl and 6 hours after cesarean section, hemoglobin = 9/8mg/dl .Testing for syphilis, hepatitis B surface antigen, human immunodeficiency (HIV) are non reactive. First hours after C/S vital signs were stable. She was agitated and received 10 mg morphine and 10 mg diazepam in intensive unit. But she was restless and wanted more Illicit drugs. Suddenly blood pressure and pulse rate did not record by pulse oxymetry.
The patient was pronounced dead 13 hours after cesarean section in intensive care unit
Her physicians suspected myocardial infarction, cerebral hemorrhage, amniotic fluid embolism or massive pulmonary embolism.
Autopsy detects 2/5 liter blood in retroperitoneal space, and rapture of aortic aneurysm.
Her neonatal suffered from post natal abstinence syndrome and morphine was used as the analgesic and withdrawal drug in NICU.
3. Discussion
Abdominal aortic aneurysms represent a degenerative process in the media of the arterial wall, resulting in a slow and continuous dilatation of the lumen of the vessel (8, 9).
The aortic wall contains smooth muscle, elastin and collagen arranged in concentric layers in order to withstand arterial pressure (1, 8, 9).
Elastin is the principal load –bearing element in the aorta. Elastin degeneration and fragmentation are observed in aneurysm wall of aorta(10).
Most patient with aortic dissection are predisposed to a weakened or torn aorta to several factors (1, 3). The most common cause is atherosclerosis (1, 3, 8, 9, 11). Other causes include hereditary connective tissue disorders, such as Marfan and Ehlers-Danlos syndromes, granulomatous vasculitis of the aorta, chest trauma caused by a motor-vehicle accident, Turner syndrome (1-3, 8, 9, 12). Another risk factor for aortic dissection is the use crack cocaine in pregnant woman (3, 13).
The proposed mechanism of aortic dissection during cocaine abuse is mediated through catecholamine-induced, vasoconstriction, acute profound elevation of heart rate, BP and myocardial contractility causing a rapid rise in the derivative of pressure on the aortic wall resulting intima tear (14, 15).
Cardiovascular changes during pregnancy are: increased stroke volume, blood volume, heart rate, cardiac output and increase in the left ventricular wall mass (2). The increased production of estrogens, prostacyclins, nitric oxide contributes to a decrease in peripheral vascular resistance in aortic compliance (2). Nitric oxide is involved in the progression of AAA (16).
Rupture of the aorta in pregnancy usually occurs when blood volume and cardiac output are rising to a maximum. It has been known to occur at all stages of pregnancy and during the weeks after delivery.
Cocaine use and activities that cause sudden rise in blood pressure such as weight lifting have been implicated (4).
High blood pressure generated during weight changing, an increased ventricular ejection forces, accompanied by the Valsalva maneuver may be the cause of aortic dissection (5, 9).
Most people with AAA have no symptoms unless the aneurysm ruptures. Occasionally AAA can produce abdominal or back pain, or a tender spot in the abdomen (1, 3, 8, 9, 12). Rupture of an AAA usually causes massive internal bleeding and is often quickly fatal (17, 18).
Patients may have normal vital signs in the presence of ruptured AAA due to retroperitoneal containment of hematoma. Presence of a pulsatile abdominal mass is virtually diagnostic but is found in less than half of cases. The diagnosis may be confused with renal calculus, diverticulitis, incarcerated hernia, or lumbar spine disease (1, 3, 8, 9, 12, 19).
5. Conclusions
AAA also are less common in women than in men, and , as with coronary heart disease, there is evidence that women with AAA also have a worse prognosis. AAA in pregnancy is uncommon and occurs in the late stage of pregnancy. Complication related to cocaine abuse includes myocardial ischemia, thrombosis, aortic dissection, sudden cardiac death.