Acute abdominal pain in pregnancy

المساهمات : 19 تاريخ التسجيل : 11/02/2008

The approach to pregnant patients with severe abdominal pain is very similar to that for nonpregnant patients with acute abdomen. However, the physiologic changes associated with pregnancy must be considered when interpreting findings from the history and physical examination.

History

Obtain as detailed a history as possible regarding the time of onset, duration, intensity, and character of the pain and any associated symptoms. Establishing the gestational age early in the evaluation is essential because the likelihood of different etiologies changes with different gestational ages. Accurate knowledge of gestational age is required to make appropriate decisions regarding fetal viability and the need for fetal evaluation. Remember that nausea, vomiting, constipation, increased frequency of urination, and pelvic or abdominal discomfort are frequently experienced in normal pregnancy. Ask the patient to differentiate these normal pregnancy changes from the acute event for which she presents.
Also, ascertain the time course and acuteness of onset.

Did the pain begin suddenly or did it grow in intensity?
Is it steady or crampy, dull and aching, or sharp and stabbing?
Did it occur before or after a meal?
Did it awaken the patient from sleep?
How well is it localized, and has the location changed?
Is it associated with nausea and vomiting; and, if so, did these begin before or after the pain?
Does anything make the pain worse, or make it better?

Physical examination

Upon physical examination, findings may be less prominent compared to those of nonpregnant patients with the same disorder (Cunningham, 1975; McGee, 1989) Peritoneal signs are often absent in pregnancy because of the lifting and stretching of the anterior abdominal wall. The underlying inflammation has no direct contact with the parietal peritoneum, which precludes any muscular response or guarding that would otherwise be expected (Sivanesaratnam, 2000). The uterus can also obstruct and inhibit the movement of the omentum to an area of inflammation, distorting the clinical picture.
To help distinguish extrauterine tenderness from uterine tenderness, performing the examination with the patient in the right or left decubitus position, thus displacing the gravid uterus to one side, may prove helpful. When performing a physical examination of the gravid abdomen, it is essential to recall the changing positions of the intra-abdominal contents at different gestational ages. For example, the appendix is located at the McBurney point in patients in early pregnancy and in nonpregnant patients. After the first trimester, the appendix is progressively displaced upward and laterally, until it is closer to the gallbladder in late pregnancy (Baer, 1932). Such alterations in physical assessment can delay diagnosis, and many authorities attribute the increased morbidity and mortality of acute abdomen in gravid patients to this delay.
When evaluating the gravid patient, the clinician must evaluate 2 patients at the same time, the mother and the fetus. Before the gestational age at which independent viability (if delivery were to occur) is generally expected evaluation of the fetus can be limited to documentation of the presence or absence of fetal heart tones by Doppler or ultrasound. When the fetus is considered viable, a more thorough evaluation is required. The age of viability varies from institution to institution. Monitor the fetal heart rate and uterine tone continuously throughout the period of evaluation.
A nonreassuring tracing or evidence of fetal distress may suggest an obstetric etiology for the acute abdomen (eg, placental abruption, uterine rupture). A reassuring tracing allows the evaluation to continue at an appropriate pace. Monitoring for uterine contractions throughout the evaluation period and even after definitive treatment is important. A strong correlation is observed between intra-abdominal infectious or inflammatory processes and preterm labor and delivery.

Laboratory evaluation

When evaluating the gravid patient with acute abdominal pain, remember that some very commonly used laboratory tests have altered reference ranges in pregnancy. These changes can make the initial evaluation process somewhat more difficult. For example, an inflammatory process such as appendicitis would be expected to produce an elevated white blood cell count. Yet, pregnancy alone can produce white blood cell counts ranging from 6000-16,000/mm3 in the second and third trimesters and from 20,000-30,000/mm3 in early labor (Pritchard, 1962).

Ultrasound
Ultrasound is probably the most frequently used radiologic modality for evaluating a pregnant abdomen. Extensive experience documents the safety of ultrasound in pregnancy. The maternal gallbladder, pancreas, and kidneys can be evaluated easily. Ultrasound is also used with graded compression as a diagnostic aid for appendicitis. The size of the gravid abdomen may limit this approach in pregnancy, but some researchers have reported success (Puylaert, 1987; Lim, 1992). The use of ultrasound is essential for fetal evaluation. Ultrasound helps to establish gestational age and fetal viability, to exclude congenital anomalies, and to assess amniotic fluid volume and fetal well-being. This information may become critical later in the management of a gravid patient with an acute abdomen, when decisions regarding delivery, mode of delivery, and the use of tocolytics and steroids must be made.

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Radiographs
While ionizing radiation in the evaluation of patients who are pregnant is often a source of anxiety for the practicing clinician, radiograph exposure from a single diagnostic procedure does not result in harmful fetal effects.
Estimated Fetal Exposure From Some Common Radiologic Procedures
*Exposure depends on the number of films. (Table is from the American College of Obstetricians and Gynecologists, 1995.)
If multiple diagnostic procedures are needed, remember that exposure to less than 0.05 Gy has not been associated with an increase in fetal anomalies or pregnancy loss. During pregnancy, perform medically indicated diagnostic radiograph procedures when needed, but consider other imaging procedures not associated with ionizing radiation instead of radiographs when possible (American College of Obstetricians and Gynecologists, 1995). Due to the possible association of prenatal radiation exposure with childhood cancer (Harvey, 1985), use ionizing radiation only when medically necessary and minimize that exposure when possible, without compromising patient care.
Magnetic resonance imaging
MRI uses magnets rather than ionizing radiation to alter the energy state of hydrogen protons. This may prove useful in the evaluation of the maternal abdomen and of the fetus. Although no adverse fetal effects have been documented, the National Radiological Protection Board arbitrarily advises against the use of MRI in the first trimester (Garden, 1991). Not all MRI contrast agents are approved for use in pregnancy. In a recent series, MRI was found useful in the diagnosis of acute appendicitis when ultrasound was inconclusive (Pedrosa et al, 2006).
Differential diagnosis

Acute abdomen, as it presents with pregnancy, has many possible causes. Clearly, the case of a pregnant patient with acute abdomen is a clinical scenario that overlaps specialties. Do not hesitate to involve a surgeon, obstetrician/gynecologist, and a specialist in maternal-fetal medicine when dealing with this challenging situation. Any cause for acute abdomen can occur coincident with pregnancy. Some clinical conditions are more likely to occur in pregnancy. Other conditions are specific to pregnancy. Thus, a wide range of possible differential diagnoses should be considered.
Incidental to pregnancy

Gastrointestinal
- Acute appendicitis
- Acute pancreatitis
- Peptic ulcer
- Gastroenteritis
- Hepatitis
- Bowel obstruction
- Bowel perforation
- Herniation
- Meckel diverticulitis
- Toxic megacolon
- Pancreatic pseudocyst
- Toxic megacolon
Genitourinary
- Ovarian cyst rupture
- Adnexal torsion
- Ureteral calculus
- Rupture of renal pelvis
- Ureteral obstruction
Vascular
- Superior mesenteric artery syndrome
- Thrombosis/infarction - Specifically mesenteric venous thrombosis
- Ruptured visceral artery aneurysm
- Splenic artery aneurysm
Respiratory
- Pneumonia
- Pulmonary embolism
Other
- Intraperitoneal hemorrhage
- Splenic rupture
- Abdominal trauma
- Acute intermittent porphyria
- Diabetic ketoacidosis
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Conditions associated with pregnancy

Acute pyelonephritis
Acute cystitis
Acute cholecystitis
Acute fatty liver of pregnancy
Rupture of rectus abdominus muscle
Torsion of the pregnant uterus

Due to pregnancy

Early pregnancy
- Ruptured ectopic pregnancy
- Septic abortion with peritonitis
- Acute urinary retention due to retroverted gravid uterus
Later pregnancy
- Red degeneration of myoma
- Torsion of pedunculated myoma
- Placental abruption
- Placenta percreta
- HELLP (hemolysis, elevated liver function, and low platelets) syndrome – Spontaneous rupture of the liver
- Uterine rupture
- Chorioamnionitis
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Treatment

Treatment of acute abdomen in pregnancy depends on the specific diagnosis. Indications for emergency surgery are the same for patients who are pregnant as they are for any other patients. If surgery is required but is considered elective, waiting until after the pregnancy is completed is prudent. If surgery is deemed necessary during pregnancy, perform it in the second trimester if possible; the risk of preterm labor and delivery is lower in the second trimester compared to the third, and the risk of spontaneous loss and risks due to medications such as anesthetic agents are lower in the second trimester compared to the first.
Laparoscopy during pregnancy
Laparoscopy has become increasingly popular in the treatment and evaluation of acute abdomen. In the past, pregnancy was considered a contraindication for laparoscopy, although multiple reports of the successful use of diagnostic and therapeutic laparoscopy have been published more recently (Mazze, 1989; Gadacz, 1991).

The Hasson technique, an open approach to entering the abdomen, has been suggested to avoid potential injury to the gravid uterus with the Veress needle or trocar. Advantages of laparoscopy over laparotomy include shortened hospital stay, less need for narcotics, easier postoperative ambulation, and earlier tolerance of oral intake postoperatively. Care must be taken to minimize manipulation of the uterus. Adjust the location of trocar placement based on uterine size. Monitor fetal heart tones during the surgical procedure. The surgeon must work closely with the obstetrician to maintain fetal well-being during the surgical procedure. An experienced laparoscopist is important to keep surgical times as short as possible (Gurbuz, 1997). Although generally accepted as safe, reports of fetal demise after laparoscopy continue to occur in the literature (Carver et al, 2005).
Obstetrical concerns
Preterm labor and delivery is the most significant threat to the fetus in the management of acute maternal intra-abdominal disease. Insufficient data are available to quantitate the risk, but the severity of the disease process appears to be a major determinant of that risk (Saunders, 1973; Kammerer, 1979; Allen, 1989).
The prophylactic effect of tocolytics remains unproven in these patients. If used, tocolytics should be administered with care. Monitor the patient carefully, and bear in mind the potential for pulmonary complications. Magnesium sulfate, beta-mimetics (eg, ritodrine, terbutaline), and indomethacin (if fetus is <32 wk gestation) can be used. Whenever using tocolytic agents, make certain that no contraindications to tocolysis, such as severe placental abruption, chorioamnionitis, or lethal anomalies, are present. If preterm delivery is likely, glucocorticoids can be administered to the mother to decrease the risk of neonatal complications. Avoid glucocorticoids if the mother is at serious risk for significant infection.
Delivery
Base delivery decisions on obstetric indications. The mode of delivery used should also be decided based on obstetric indications. If continuation of the pregnancy is expected to lead to maternal morbidity or mortality, delivery is indicated. If improvement of the maternal condition cannot be expected with delivery, treat the patient with the fetus in utero

المساهمات : 93 تاريخ التسجيل : 07/09/2007

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