Pregnancy-related death: Hepatic System

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The chapter in Autopsy Performance & Reporting titled “Pregnancy-Related Death and the Autopsy Examination” is written by Cynthia Schandl, MD, PhD, of Medical University of South Carolina. Here from that chapter is an excerpt (published without references) on the hepatic system. Dr. Schandl’s chapter also covers the cardiovascular, respiratory, hematopoietic, urogenital, and endocrine systems, as well as the gastrointestinal tract and skin and connective tissue.

The position of the liver is shifted in a superior posterior direction because of the enlarging uterus. The liver histology and mass do not normally change with pregnancy; however, a hepatic production of circulating proteins is altered in quantity. Specifically, factors VII, VIII, IX, and X and fibrinogen are significantly elevated. Along with these alterations, the placental tissues contain thromboplastin, which activates factor VII and can produce fibrin in approximately 12 seconds. This is extremely useful to the woman at delivery, who must be able to deliver the infant and the placenta without excessive blood loss. Measured alkaline phosphatase is also elevated by as much as 200%. Most of this elevation is due to the placental alkaline phosphatase isoenzyme. Other changes include a decrease in serum albumin, total protein, and g-globulin, and an increase in serum cholesterol (200%) and a-globulin and b-globulin (slight). Levels of antithrombin III (inactivator of factors II, IX, X, XI, and XII) and protein C (inactivator of factors X and XIII) and its cofactors, protein S and thrombomodulin, do not appear to be increased in tandem, thus contributing to a hypercoagulable state.

Fig. 1. Pulmonary saddle thromboembolism 1 day status post caesarian section. A. (above) Gross. B. (below) Microscopic. Other risk factors included morbid obesity. (Hematoxylin-eosin, low power.)

Embolic events account for the majority of deaths in the puerperium. Because the majority of embolic events involve thrombosis, the entity will be described here. Air and amniotic fluid embolism have been discussed (see “Cardiovascular System”). Thromboemboli must always be considered in the peripartum autopsy because of the aforementioned hypercoagulable state. Other risk factors during the pregnancy and postpregnancy state include caesarian section, maternal age of 35 years or older, obesity, and additional chronic conditions. Heyl et al recently reviewed all available cases in the states of Florida and Virginia between 1999 and 2007. They identified 46 deaths associated with pulmonary thromboembolic disease, which equated to a mortality ratio of 1.6 per 100,000 live births. Only about one-fifth of the women demonstrated symptoms in the preceding days before death; these symptoms included shortness of breath, leg or chest pain, leg weakness, and/or tachycardia.

Fig. 1, B

If pulmonary thromboembolism is suspected, the heart and lungs may be removed en bloc in order to follow the circulation through the heart into the pulmonary arteries, allowing better exposure of any pathology. With the bloc anterior surface facing the prosector, the direction of the blood flow can inform the dissection—first into the right atrium, then along the lateral wall of the right ventricle to its apex and up the anterior-medial aspect of the right ventricle into the pulmonary arterial circulation. The prosector should remain alert while cutting through any coronary arteries in order to identify dissection. If an embolus is not seen at the bifurcation (“saddle”; Fig. 1, A) of the main pulmonary trunk or proximal pulmonary arteries, the pulmonary arterial system should be dissected both lengthwise and by cross-section in order to assess for thromboembolism to the mid and peripheral pulmonary circulation. Multiple sections should be submitted for histologic examination. Grossly, if a thromboembolus is identified, a section taken through a region attached to the pulmonary intimal wall (if present) is ideal. A thromboembolus should demonstrate the microscopic features of a thrombus, with lines of Zahn appreciated (Fig. 1, B); however, prominence of this feature varies with coagulation status. If pulmonary thromboembolism is considered the cause of death and no significant comorbidities are present, at least 50% occlusion of the total pulmonary arterial vasculature should be apparent. In addition, dissection of the deep veins of the legs and the pelvic veins may be pursued in order to support the origin of the thrombosis.