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Basics of an Autopsy

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"Basics of an Autopsy"
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In decades past, autopsies were routinely performed on people who died in U.S. hospitals. Today, autopsies are largely restricted to forensics cases as well as those performed at the behest of the next of kin. Medical experts are not in complete agreement on the reasons for the decline in the number of autopsies today compared to 50 years ago. A few key factors are often cited: a lack of reimbursement by insurance companies, a heightened fear of malpractice suits, and improved diagnostic tools. At any rate, the general procedure of an autopsy is largely the same regardless of the reason for its performance.

The first step of an autopsy is to positively identify the deceased and note the time of death. This information is readily available for almost all hospital patients. (Unidentified bodies recovered outside of a hospital are stored separately in the morgue or in a decomposition room. Forensics teams usually handle these cases, which are considered homicides until proven otherwise). The next step is to visually inspect the patient's body for signs of blunt force or penetrating trauma, burns, needle marks, and other skin lesions. The presence of any tattoos or large scars is also noted. If any trauma or gross lesions are present, especially on the head or neck, these areas are photographed. The oral cavity is visualized and the patient's dentition is noted. With the advent of PCR (polymerase chain reaction) and DNA identification, there is seldom a need to take dental impressions, and the autopsy continues with a thoracotomy.

Chest Cavity

A bone saw is used to cut through the ribs and expose the thoracic cavity. The pathologist purposely avoids bisecting the sternum, mainly to avoid incidental damage to the heart and mediastinal structures. The lungs are examined for the presence of primary or metastatic cancer as well as signs of other pulmonary diseases, for example tuberculosis. Collapsed lung tissue tends to be friable, disintegrating readily unless transferred to formaldehyde. The diaphragm muscle is examined along with the contents of the mediastinum, namely the esophagus and great vessels, i.e. the aorta, pulmonary artery, superior vena cava, and inferior vena cava.

After severing the great vessels, the heart is removed from the pericardial sac and weighed. Even in the absence of overt cardiac disease, other factors must be considered when examining the heart, for example, the patient's ideal vs. actual body weight, comorbid illnesses, and general state of health at the time of death. An abnormally enlarged heart, known as cardiomegaly, is encountered frequently on postmortem examination. Major disease states resulting in cardiomegaly include chronic hypertension, congestive heart failure (CHF), valvular disease (especially aortic stenosis), rheumatic fever, and severe COPD, resulting in right sided heart enlargement, also called cor pulmonale. Any evidence of past myocardial infarcts (heart attacks) or open heart surgery is noted as well. Samples of cardiac muscle, and occasionally pericardial tissue, are sent to pathology.

Abdominal cavity

The examination of the abdominal cavity and its contents is often the highlight of the autopsy. After incising the membranous covering of the abdomen called the omentum, the organs of the gastrointestinal tract are examined and weighed, including the stomach, liver, gallbladder, and pancreas. Cirrhotic livers appear yellow and abnormally small. At the other extreme, patients with CHF may exhibit hepatomegaly, or an enlarged liver, due to congestion of the hepatic sinusoids with blood. The spleen is then removed and weighed, followed by both kidneys. At this point, the pathologist usually examines the small and large bowels, noting any structural anomalies, tumors, or the presence of foreign bodies in the intestinal lumen. Once the intestines have been removed, the abdominal aorta, now clearly visible, can be inspected for aneurysms or evidence of dissection. Of all the abdominal organs, samples of the liver and kidneys are most often sent to pathology for further examination.

Pelvis and Extremities

Unless there are signs of trauma or pathology involving the urinary bladder or reproductive tract, this part of the body receives little attention. The same holds true of the upper and lower extremities.

Postmortem blood work

In cases of a suspected drug overdose, an examination of gastric contents often reveals the lethal agents. Blood samples are sent for a toxicology screen, which detects levels of blood alcohol in addition to metabolites of opiates, cocaine, amphetamines, barbiturates, hallucinogens, marijuana, and over the counter drugs like aspirin and acetaminophen. The levels of certain prescription drugs, e.g. digoxin, lithium or benzodiazepines (tranquilizers), can also be measured.

In a full autopsy, the skull is sawed open and the brain (or its remnants) are removed. The brain is preserved for 10-14 days in formaldehyde. After preservation, sections of brain are cut and frozen for histological examination. Brains obtained from autopsies are also donated to medical schools for dissections conducted in gross anatomy or neuroanatomy courses.

Post-Autopsy Protocol

After the autopsy is completed, the patient's internal organs are returned to their appropriate locations. The thoracic and abdominal incisions are sutured, and the body is returned to the hospital morgue. Except for cases of suspected homicide, the patient's body is released to the next of kin for burial or cremation. All states in the U.S. mandate the donation of unclaimed cadavers to medical schools for anatomic dissections. Cadavers unfit for scientific use are cremated or buried depending on the law of that particular state. In most states, the time limit applied to unclaimed bodies is 72 hours. One exception is Oregon, which waits 10 days before disposing of an unclaimed body. The federal government seldom interferes with a state's laws regarding unclaimed bodies unless there is reason to believe the deceased individual is a U.S. military veteran.

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