Septic shock is a severe and systemic infection-that is, it affects the entire body. It is usually caused by bacteria and occurs after trauma or surgery. When pregnant women develop septic shock, it is usually a complication of one of four specific conditions:
- septic abortion;
- acute pyelonephritis (kidney infection);
- severe chorioamnionitis (infection of the amniotic sac); or
- post-cesarean endometritis (uterine infection).
Fortunately, fewer than 4% of patients with any of these infections develop septic shock.
The most common organisms responsible for septic shock are aerobic gram-negative bacilli (rod-shaped bacteria), principally Escherichia coli ( E. coli), Klebsiella pneumoniae, and Proteus species. Gram-negative bacteria, unlike other types of bacteria, have a double membrane, which makes them tougher to kill and more resistant to antibiotics. However, the most virulent and drug-resistant gram-negative bacilli, such as Pseudomonas, Enterobacter , and Serratia species, are usually not involved in septic shock-except for in patients with weakened immune systems.
Aerobic gram-negative bacilli have a complex lipopolysaccharide (fat and carbohydrate compound) in their cell wall called an endotoxin. When the bacterial cell is destroyed, the endotoxin is released into the body's blood circulation. This can affect many systems of the body in addition to blood circulation, including the immune system, central nervous system, and endocrine system and can ultimately lead to dysfunction in virtually every major organ in the body.
Septic shock causes a variety of systemic signs and symptoms, including:
- restlessness and disorientation;
- rapid heart rate (tachycardia) and low blood pressure (hypotension);
- high fever (103 to 104° F)-although some experience low body temperature (hypothermia);
- skin that is warm and flushed due to dilation of the blood vessels (vasodilation);
- extensive narrowing of the blood vessels (vasoconstriction), causing skin to become cool and clammy;
- irregular heart rhythms;
- jaundice (yellowing of the skin);
- decrease in urinary output or acute renal (kidney) failure; and
- spontaneous bleeding from the genitourinary (genital or urinary) tract or punctured veins.
In addition to these systemic signs and symptoms, affected patients may also have symptoms related to their primary site of infection-such as discolored uterine discharge, uterine tenderness, and pain and tenderness in the abdomen and flank.
Adult respiratory distress syndrome (ARDS) is another common complication of severe sepsis (infection of the blood stream). Shortness of breath, rapid and labored respirations, coughing, and lung congestion mark ARDS. ARDS is one of the major causes of death in cases of severe sepsis.
If you are pregnant and have symptoms such as those just described, your doctor must determine whether you have septic shock or shock from another condition. Other possible causes of shock include hemorrhage, heart attack, diabetic ketoacidosis, anaphylactic reaction (severe allergic reaction), a reaction to anesthesia, or a massive blood clot in the lung. Your doctor can distinguish between these disorders on the basis of a thorough history and physical examination and a limited number of laboratory studies.
A number of laboratory findings are indicative of septic shock. Your white blood cell count may be decreased initially, but likely elevated later. If blood loss has occurred, your red blood cell count may be decreased. Tests of how well your blood is clotting and your liver and kidney function may reveal further abnormalities.
A chest x-ray is taken to determine whether you have ARDS or pneumonia. In addition, various imaging tests-including CT scan, MRI, and ultrasound-may help identify the primary infection site. You may also require electrocardiographic monitoring to detect irregular heart rhythms and signs of injury to your heart.
There are three major goals in the treatment of septic shock:
- The first objective is to correct the problems in blood circulation caused by endotoxin. Your doctor uses a large intravenous catheter to administer fluids intravenously. Your pulse, blood pressure, and urine output are monitored to ensure that you receive the proper amounts of these fluids. If the initial fluid infusion does not restore proper blood circulation, your doctor inserts a right heart catheter as a further monitoring device. You may also receive dopamine. In appropriate doses, this drug improves the function of the heart and increases blood flow to major organs.
- The second objective of treatment is to administer antibiotics targeted against the most likely bacteria.
- For genital tract infections, the combination of penicillin (PenVK) or ampicillin (Principen) plus clindamycin (Cleocin) or metronidazole (Flagyl), plus gentamicin (Garamycin) or aztreonam (Azactam) is a highly effective treatment.
- Alternatively, imipenem-cilastatin (Primaxin) or meropenem (Merrem) can be administered as single drugs.
In addition, you may require surgery-perhaps to drain a pelvic abscess (collection of pus) or to remove infected pelvic organs. Even if your condition is unstable, surgery should not be delayed since the operation may reverse the circulatory problems caused by septic shock.
Other measures may help treat a severe infection. For patients with suppressed immune systems, an infusion of granulocytes (white blood cells) is often prescribed. Another approach is to administer antisera (anti-toxin) directed against the usual bacteria that cause septic shock. This therapy has appeared promising in some investigations, but remains experimental.
- The third major objective of treatment is to provide comprehensive supportive care. Your temperature is maintained as close to normal as possible by use of antipyretics (medications that reduce fever) and a cooling blanket. Coagulation (clotting) abnormalities should be identified promptly and treated by an infusion of blood platelets and coagulation factors.
Finally, you are given supplemental oxygen and observed closely for evidence of ARDS. Your oxygen status is closely monitored with one of two devices-a pulse oximeter or a radial artery catheter. If respiratory failure becomes evident, you are put on an oxygen support system.
The prognosis for patients with septic shock clearly depends on the severity of a patient's underlying illness. In patients who have other life-threatening illnesses, such as cancer, mortality may approach 80%. But in otherwise healthy patients, mortality rarely exceeds 15%. Fortunately, most obstetric patients are in the latter category. Therefore, provided that you receive timely, competent treatment, your prognosis for complete recovery is excellent.