E

Echinococcosis

Synonym: Hydatid disease.

NOTE: (1) Collect all tissues that appear to be infected. (2) Usually, cultures are not required, only direct examination for parasites. (3) Request Giemsa stain for parasites (p. 172). (4) Special precautions should be exercised in removing the cysts, as the contents are highly infectious (p. 146). (5) Serologic studies are available from the Center for Disease Control and Prevention, Atlanta, GA (p. 135). (6) This is not a reportable disease.

Organs and Tissues

Procedures

Possible or Expected Findings

Liver

Lungs

Other organs

Blood and bone marrow

If the liver is the site of involvement, prepare roentgenogram. Prepare cholangiogram if Echinococcus multilocularis organisms are present (p. 56). Photograph intact cysts and cut sections. Cysts should be placed in formalin before processing.

If the lung is the site of involvement, prepare roentgenogram. Photograph cysts. For further processing, the lung should be fixed in formalin (p. 47).

Procedures depend on expected findings or grossly identified abnormalities as listed in right-hand column.

For preparation of sections and smears, see p. 96. Request Giemsa stain (p. 172).

The liver, especially the right lobe, is the most common site of involvement. Secondary infection or calcification may be present.

The lung is the second most common site of involvement. Fluid and air may be visible on the roentgenogram.

Cysts may be present in the abdominal cavity, muscles, kidneys, spleen, bones, heart, and brain. Eosinophilia.

Eclampsia (See "Toxemia of pregnancy.")

Edema, Angioneurotic Synonym: Angioedema.

NOTE: Possible causes and suggested autopsy procedures are described under "Death, anaphylactic."

Edema, Chemical Pulmonary

Related Term: Silo-filler's disease.

NOTE: This condition is caused by inhalation of toxic gases, such as oxides of nitrogen (silo-filler's disease) and phosgene (COCl2). See also "Bronchitis, acute chemical" and "Poisoning, gas."

Organs and Tissues

Procedures

Possible or Expected Findings

Upper airways and lungs

Remove lungs together with pharynx, larynx, and trachea. Open airways posteriorly. Record lung weights. Submit one lobe for microbiologic study (p. 103). Perfuse one lung with formalin (p. 47).

Acute chemical laryngotracheitis; acute pulmonary edema. Obliterating fibrous bronchiolitis and diffuse, progressive pulmonary fibrosis may be present after prolonged survival.

From: Handbook of Autopsy Practice, 3rd Ed. Edited by: J. Ludwig © Humana Press Inc., Totowa, NJ

Effusion(s) and Exudate(s), Pleural

Organs and Tissues

Procedures

Possible or Expected Findings

External examination

Chest cavities and chest organs

Other organs

Prepare chest roentgenogram.

Submit samples of pleural fluid for microbiologic study (p. 102). These samples should be obtained before the chest is opened because laceration of the subclavian veins renders clear exudates or transudates hemorrhagic. In true hemorrhagic exudates, determination of the hematocrit value may be useful. For cytologic study, spin down pleural fluid and prepare smears and histologic sections of pellet. Record volume of pleural fluid; remove fluid with vacuum suction apparatus. If the fluid is milky-white, dissect and record appearance of thoracic duct system (p. 34).

300-500 mL of fluid must be present before it becomes visible.

Myocardial infarction or other cardiac abnormalities that may have caused congestive heart failure;* pneumonia; pulmonary infarction; tumor(s); bacterial, fungal, or viral infection; immune connective tissue disease; amebiasis;* trauma to thoracic duct system; other causes.

Pancreatitis;* subphrenic empyema;* other intra-abdominal disease, with or without ascites.

Electricity (See "Injury, electrical.") Electrocution (See "Injury, electrical.") Electrolyte(s) (See "Disorder, electrolyte(s).") Elliptocytosis, Hereditary (See "Anemia, hemolytic.")

Embolism, Air

NOTE: Possible causes include: (1) blood transfusion when the bottle had emptied unnoticed (particularly when the pressure in the bottle had been artificially increased or when a pump had been used); (2) injury to large veins, particularly cranial sinuses (during neurosurgical procedures) and veins of the neck (knife wounds, surgery) or uterus (criminal abortion); (3) insufflation of fallopian tubes (particularly in pregnancy or during menstrual period); (4) malfunctioning of dialysis machine; (5) positive-pressure ventilation in newborn infants; (6) subclavian vein catheterization in the semi-Fowler position; and (7) fracture in the hub of a central venous catheter used for parenter-nal nutrition.

Autopsy Procedure and Diagnosis

If air embolism is suspected, the autopsy should be performed as soon after death as possible. Decomposition gases may be produced within a few hours. Roentgenography of the whole body may detect large quantities of air, and the roentgenograms may serve as a guide to the most advantageous way of dissection.

Air embolism can be diagnosed if one succeeds in demonstrating, with an ophthalmoscope, air bubbles in the retinal arteries. This should be done as a first step of the autopsy in all cases in which this diagnosis is entertained. The cornea must be moistened with isotonic saline so that the opaqueness of it does not interfere with this method of diagnosing air embolism (1).

After the ophthalmoscopic examination, the prosector opens the thoracic cavity, lifts the bony chest plate, and clamps the internal mammary vessels below the sternoclavicular joints. (Particular care must be taken to clamp but not lacerate the upper thoracic or neck veins.) The prosector then cuts across the sternum distal to these clamped vessels so that the sternoclavicular joint area remains intact. The pericardial sac is carefully opened. Large fatal pulmonary air embolism is readily apparent. The right atrium and ventricle are distended with fine, frothy, bright-red blood, which also may distend the pulmonary arteries and large systemic veins. The blood is fluid throughout the body, the viscera are congested, and petechiae are present in the serous surfaces and in the white matter of the brain. Microbiologic examination of blood and pericardial sac contents (p. 102) will help to rule out the presence of gas-forming bacteria that may simulate air embolism (Fig. II-1). However, the differentiation between air and decomposition gases should be done at the autopsy table with the pyrogallol test.

A 2% pyrogallol solution is prepared (it should be water-clear). Two 10-mL syringes (syringe A and syringe B) are loaded with 4 mL of the pyrogallol solution in each, without permitting any air to enter the system. Immediately before the solution is used, 4 drops of 0.5 N NaOH is aspirated through the needle of syringe A to adjust the pH to about 8 (1 drop per 1 mL of solution); the mixture will turn faint yellow. Six mL of gas is then aspirated from the heart or blood vessels. The needle is immediately sealed with a cork or replaced by a cap, and the syringe is vigorously shaken for about 1 min. In the presence of air, the pyrogallol solution will turn brown. If the solution remains clear, decomposition gases were present. In the latter instance, 4 drops of 0.5 N NaOH and 6 mL of room air should be aspirated into syringe B, which is then also sealed and shaken for 1 min. The mixture should turn brown, thus serving as a control that the pyrogallol solution had been properly prepared. Syringe B may also serve as a reserve. If only one syringe is used, the

Fig. II-1. Gas-forming bacteria simulating air embolism. The pericardial sac is opened and filled with water. The heart is kept submerged with a pair of scissors. The coronary arteries have been incised with a scalpel. Note gas bubbles and foam on the water surface. No discoloration of 2% pyrogallol was noted. Blood cultures were positive for Enterococcus organisms. Microscopically, gram-negative rods were found in most tissues.

decomposition gas can be expelled and room air can be aspirated for the control test.

If only small amounts of gas can be aspirated, the volume of the pyrogallol solution should be decreased so that the gas-fluid volume ratio is at least 3:2.

If no bacterial gas formation is present, the edges of the pericardial incision are elevated and the pericardial sac is filled with water. Clamping of the ascending aorta and venae cavae prevents the escape of gas into these vessels. The heart is held under water while the coronary arteries are incised, and the escape of bubbles is recorded. When the right coronary artery is opened, care must be taken that the right atrium is not incised. Air in the coronary arteries indicates systemic embolism. The heart chambers are then incised.

When there is gas in any of the arteries or heart chambers, gas bubbles rise to the surface of the water in the pericardial sac ("bubble test"). Sometimes the vessels have to be somewhat compressed in order to cause the gas to escape. Because large amounts of air or other gases cause the heart to float, it must be kept submerged before the vessels and chambers are incised. Basically the same procedure is used for demonstrating the presence of gas in the superior or inferior vena cava and the pelvic veins (for example, in cases of criminal abortion). In this situation, the abdominal cavity is filled with water and the inferior vena cava and its tributaries are incised.

For the diagnosis of systemic air embolism, the skull vault should be removed without puncturing the meninges, so that the meningeal vessels can be inspected for gas bubbles. The demonstration of gas bubbles in the meningeal vessels and in the circle of Willis is meaningful only when the neck vessels are still intact and the internal carotid artery and basilar artery have been clamped before the brain is removed. In acute cases, gas bubbles will be visible within the cerebral vessels. They are released under water when the clamps are removed and the vessels are slightly compressed.

For the collection of gas from blood vessels or cavities, a system of little quantitative reliability is an air-tight, water-filled glass syringe with a needle. The needle is inserted into the vessel or cavity in question and gas is carefully aspirated.

A combined qualitative and quantitative method has been described by Kulka (2) (see Fig. II-2). He devised an apparatus for gas collection and described it as shown in Fig. II-2 and caption.

The entire system is filled with mineral oil so that, when the funnel is level with the upright bottle, the oil fills only about half of the funnel. In operation, the funnel is first raised to a position 30-40 cm above the level of the upright bottle. All the cocks are opened and the position is held until every trace of gas has been driven from the system through the needle, which is thereby coated on the inside by a film of oil. After all air has been expelled, the cocks are closed and the funnel is lowered to its original position.

As a precautionary measure and control, the air-tightness of the whole system should be tested before operation. This is done by inserting the needle into musculature or skin and attempting aspiration in the manner described in the next paragraph.

To make the test, the bottle is inverted and the needle is inserted into the cavity in question. When the needle is in position, all cocks are opened. The funnel is lowered about 70-90 cm, or until adequate suction is created. This aspirates the contents of the cavity, which may consist of air or other gases, either pure or mixed with blood or other liquid. Any gas or liquid entering this system may be observed through the wall of the short bent glass tubing. In a positive test, gas bubbles will collect in the bottle above the level of the oil. If desired, this gas can be saved for further examination by closing all the cocks and returning the bottle to its upright position (4).

Interpretation of Findings

The volume of intravenous air needed to cause death in adults is probably in the range of 100 mL. Very small amounts entering the systemic circulation may cause death within minutes. Delayed air embolism with fatal outcome may also occur.

References

1. Kevorkian J. The fundus oculi and the determination of death. Am J Pathol 1956;32:1253-1269.

2. Kulka W. A practical device for demonstrating air embolism. J Forens Med 1965; 12:3-7.

3. Kulka W. Laboratory methods and technical notes: a practical device for demonstrating air embolism. Arch Pathol 1949; 48:366-369.

4. Bajanowski T, West A, Brinkmann B. Proof of fatal air embolism. Int J legal Med 1998;111:208-211.

Fig. II-2. Apparatus for demonstration of air embolism. Top, Apparatus. Bottom, Position of separatory funnel during test. (A) One wide-mouth glass bottle (2-3 ounces; 60-90 mL) fitted tightly with a two-hole rubber stopper. (B) Two sections of glass tubing, approx 3 mm inside diameter, each bent at an angle of 120°. One of these sections should be longer than the other. The shorter one should reach just through and be even with the inner surface of the stopper. The longer one should reach to within 1 or 1.5 cm of the bottom of the bottle. Both tubes should fit tightly into the holes of the stopper. (C) One separatory funnel (60100 mL, pear-shaped) connected to the longer section of bent glass tubing by rubber tubing 100 cm in length (F). An amber, pure gum rubber tubing, such as is used on blood-diluting pipets, has proved satisfactory. (D) One transfusion needle, 14- or 15-gauge and 4-5 cm long, connected to the shorter glass tube by a short (<5 cm) section of rubber tubing (F). (E) Two pinchcocks, one for each length of tubing. They may be of the spring type or of the household syringe type. The latter will prove advantageous if the gas collected is to be transported for analysis. Adapted with permission from ref. (3).

Embolism, Amniotic Fluid

Organs and Tissues

Procedures

Possible or Expected Findings

External examination Blood

Lungs

Uterus and placenta Other organs Lungs of stillborn

If purpura is present, prepare photographs and record extent.

Submit sample (from right atrium) for microbiologic study (p. 102). Collect blood from right atrium and right ventricle. After the heart has been removed, allow blood in pulmonary vessels to pool in the pericardial sac.

Centrifuge this blood and submit sample of flocculent layer above buffy coat for microscopic study (1).

Submit one lobe for bacteriologic study (p. 103). Dissect pulmonary arteries (p. 45); prepare histologic sections of all lobes; request muci-carmine stain and the alcian blue and phloxine-tartrazine stain of Lendrum (p. 172). Also request Sudan stain on frozen sections (p. 172).

For dissection techniques, see p. 60.

Skin purpura.

Vernix, lanugo hairs, and meconium can be found in pericardial blood pool.

Meconium-type material in blood vessels. In histologic sections, squamous epithelium, meconium, and fat from vernix caseosa.

Complete or incomplete lower uterine tear; chorioamnionitis.

Manifestations of disseminated intravascular coagulation* and fibrinolysis. Intrauterine pneumonia.

Interpretation of Findings

Large amounts of debris in the blood vessels of all sections of the lungs may be considered to be lethal if there is no other cause of death. Small amounts in one or more blocks of pulmonary tissue are more likely incidental (1). A small uterine tear is more likely followed by a fatal amniotic fluid embolization than is a large tear, which may result in fatal hemorrhage or fibrinogen depletion. Chorioamnionitis, intrauterine pneumonia, and positive lung cultures of the mother indicate infection of the amniotic fluid.

Reference

1. Attwood HD. Amniotic fluid embolism. In: Pathology Annual 1972. Sommers SC, Rosen PP, eds. Appleton-Century-Crofts, New York, 1972, pp. 145-172.

Embolism, Arterial

Synonyms and Related Terms: Arterial thromboembolism; atheroembolism; bone marrow embolism; embolic syndrome; foreign body embolism; paradoxic embolism; tumor embolism.

NOTE: A history of urinary eosinophilia may have been obtained in patients with renal atheroembolism.

Organs and Tissues

Procedures

Possible or Expected Findings

External examination Heart

Aorta and elastic artery branches

Record patency and size of oval foramen, or presence of septal defect(s).*

If infective endocarditis is suspected, follow procedures described on p. 103. For general dissection techniques, see p. 22.

For celiac or mesenteric arteriography, see p. 55.

Gangrene of extremities. In presence of intracardiac right-to-left communication, paradoxic embolism may occur.

Infective endocarditis.*

Myocardial infarction; mural or valvular thrombi in left atrium or in left ventricle; atrial dilatation in patients who had atrial fibrillation; mitral or aortic valve prostheses. Thrombi on atheromatous ulcers; thrombi in aneurysms.

Embolism to celiac or mesenteric artery system.

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