Download BIOCHEMICAL CHANGES IN BODY FLUIDS

BIOCHEMICAL CHANGES IN BODY FLUIDS AFTER DEATH*
WALTER W. JETTER AND REGINA MOLEAN
From the Department of Légal Medicine, Harvard Médical School and the Office of the State
Pathologist, Massachusetts Department of Mental Health
The pathologist and médical examiner are frequently confronted with cases in
which the postmortem anatomic changes are inconclusive and in which further
elucidation of the problem dépends upon the récognition and interprétation of
chemical abnormalities of the tissues and body fluids. The interprétation of
many of the chemical changes that may be observed in postmortem material
must take into account the nature and extent to which postmortem change may
hâve contributed to the apparent abnormalities. We hâve arbitrarily elected to
discuss the followmg: Alcohol, carbon monoxide, chlorides and magnésium,
creatine, glucose, ketone bodies, non-protein nitrogenous substances, and oxygen.
ALCOHOL
What are the reasons for testing body fluids and tissues obtained at postmortem examination for alcohol?
1. Was death caused by acute alcoholism?
2. May alcoholism hâve contributed to death?
(a) Through a synergistic effect in combination with other poisons.
(b) Because of hypersusceptibility to alcohol as a resuit of disease or
chronic intoxication.
(c) By having predisposed the deceased to accidentai injury or assault.
(d) By having predisposed the deceased to self-inflicted injury (suicide)
by the induction of a temporary state of irrationality.
(e) By having predisposed the deceased to infection.
What may be the significance of the concentration of alcohol in the brain,
blood, or urine if it can be assumed that such a concentration existed at the moment of death? If the alcohol concentration of the brain, based on direct analysis
or as interpolated from an analysis of the blood or urine is 0.45 per cent or higher,
acute alcoholism, in the absence of other conditions obviously incompatible with
life, may be accepted as an adéquate explanation of death 1 . This is not to imply,
however, that a brain concentration of 0.45 per cent is necessarily fatal or that
lower concentrations are necessarily compatible with life. Alcohol poisoning
may be the primary or sole cause of death of persons whose tissues contain little
or no alcohol at the time of death. It is not necessary that a person die at the
height of his brain-alcohol concentration for death to hâve been caused by alcohol poisoning.
Irréversible and fatal damage may be sustained by the central nervous System
during the period of acute intoxication; but, before such injury actually results in
death, ail or most of the alcohol may hâve been excreted and metabolized. Thus,
* Read before the Medico-Legal Symposium, at the Twenty-First Annual Meeting of the
American Society of Clinical Pathologists, Philadelphia, June 6, 1942.
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BIOCHEMICAL CHANGES IN BODY FLUIDS AFTER DEATH
179
it is by no means uncommon to find relatively low blood or brain levels in individuals whose deaths were undoubtedly due to alcoholism.
How may the agonal concentration of alcohol in body fluids or tissues be modified as a resuit of postmortem change? Currently used methods for the estimation of alcohol in body fluids are relatively non-specific in that they are sensitive
to a variety of volatile reducing substances, of which alcohol is one. In living
persons, the methods are valid in that such a reducing substance, if présent in
significant amounts, consists almost entirely of alcohol2. In cadavers reducing
substances in addition to alcohol may be formed during putréfaction.
It is the authors' expérience that the concentration of alcohol in the tissues of
a body does not change appreciably after death until twenty-four or forty-eight
hours hâve elapsed. If, at the time of death, equilibrium had been established
between the blood and the tissues, there is not likely to be any significant change
in the blood level until some time after the first twenty-four to forty-eight hours.
Once putréfaction has begun, there may be a rapid increase in the amount of
volatile reducing substances and the authors hâve observed blood levels in excess
of 0.50 per cent in putrefied subjects who were known to be non-alcoholic at the
time of death.
The blood level may drop during the first twenty-four hours if death occurred
soon after drinking and before equilibrium had been established between the
blood and the tissues.
Although bladder urine is a less désirable test material than blood or brain,
certain significant information may be obtained by comparing the postmortem
alcohol concentrations of blood and urine 3 . Before the onset of putréfaction the
alcohol level in the urine may remain stationary, may decrease, or may increase
depending upon the state of equilibrium that existed between blood and urine at
the time of death. If, at the moment of death the urine level was disproportionately low, alcohol will diffuse through the bladder wall until equilibrium is
established or until putrefactive changes alter the composition of the body fluids.
If, at the moment of death the alcohol concentration of the bladder urine was
disproportionately high, diffusion will occur in the reverse direction.
If, in a non-putrefied body, it is found that the urine alcohol as compared to the
blood alcohol is disproportionately high, it can be assumed that at some time
within a few hours prior to death the blood level was higher than it was at the
moment of death. If, in such an instance, the alcohol content of the urine is
found to be disproportionately low, it can be assumed that the blood alcohol
curve was probably ascendant at the time of, or very shortly before, death.
CARBON MONOXIDE
Of the many problems that may be raised incident to the interprétation of
tests on postmortem samples of blood for carbon monoxide at least four deserve
spécial considération.
1. What constitutes a fatal concentration in the blood?
2. How long after death may CO persist in the blood?
3. Can a significant amount of CO be absorbed by the blood after death?
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4. Can CO be formed in the body after death?
What is the fatal concentration of CO? There is immense individual variation so far as lethal blood concentration is concerned. Death may resuit from
concentrations as low as 30 per cent saturation or life may continue until saturations of between 75-80 per cent hâve been reached4.
How long does CO persist in the blood after death? Most reports on the
duration of CO after death hâve been based on qualitative tests 6 . Controlled observations on animais sacrificed by CO asphyxia show a progressive loss of approximately 5 per cent during each twenty-four hours after death 6 over a period
of three days. Although adequately controlled quantitative observations on
human blood for long postmortem intervais are not available it is a fact that
saturations of 50 per cent or more may be encountered in putrefied bodies days or
even weeks after death.
Can a significant amount of CO be absorbed by heart blood due to postmortem
exposure of a body to an atmosphère containing CO? Carefully controlled experiments on human and animal material indicate that CO is not absorbed in
significant amounts after death 67 .
Can CO be formed in the body after death? No satisfactory évidence that
CO is formed incident to the putréfaction of animal tissue has been discovered.
There is definite évidence that the formation of carboxyhemoglobin does not take
place during putréfaction6.
CHLORIDES AND MAGNESIUM
What significance can be attached to the concentration of chlorides and magnésium in samples of blood obtained at autopsy?
(1) Do the findings indicate ante mortem abnormality or are they due to postmortem diffusion of electrolytes between cells and plasma and between the
blood and the tissues.
(2) Do the findings indicate that the concentration of thèse substances was
probably altered during the agonal and postmortem period as a resuit of
diffusion between the blood and extracorporeal fluid (drowning)?
How may postmortem change affect the distribution and concentration of the
chlorides in the blood? Beginning soon after death and before the onset of
recognizable putréfaction plasma chloride decreases to a level approximating that
in whole blood. As the postmortem interval lengthens, and increasing as putrefactive changes develop, the concentration of chlorides in the whole blood falls
due to extravascular diffusion. Within seventy-two hours the whole blood
chlorides may diminish 50 per cent or more as the resuit of such diffusion8.
How may postmortem change affect the distribution and concentration of
magnésium in the blood? Beginning soon after death and before the onset of
putréfaction there is a shift of magnésium from erythrocytes to the plasma. As
the postmortem interval lengthens, and increasing as putréfaction advances, the
magnésium content of the whole blood increases, due to extravascular diffusion.
Within seventy-two hours the magnésium in the whole blood may increase by as
much as eightfold as the resuit of such diffusion.
How much différence may be found to exist normally between the concentra-
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181
tion of chlorides and magnésium in postmortem samples of blood from the right
and left sides of the heart? If the comparison is made between plasma from the
two sides of the heart the results are influenced by the amount of local hemolysis
that may hâve occurred. The greater the hemolysis, the greater will be the
réduction of the chloride content of the plasma. However, différences in plasma
chloride between the right and the left side of the heart are sometimes greater
than can be accounted for wholly on the basis of hemolysis. The greatest différences (as high as 40 mg. per cent) are usually found twenty-four to forty-eight
hours postmortem and are associated with beginning putréfaction. Thèse différences diminish as putréfaction becomes fully established. Presumably thèse
différences occur while an active attempt is being made to establish an equilibrium between the non-chloride containing tissue cells and the blood and must be
attributed to postmortem altération in the permeability of cellular membranes.
Do abnormalities in the distribution and concentration of chlorides in the
blood indicate the occurrence of agonal or postmortem diffusion between the
blood and extracorporeal fluid (drowning)? If prior to the'onset of putréfaction,
the chloride in the plasma from the left side of the heart is at least 60 mg. per cent
lower than that in the right, the diagnosis of death by drowning is probably justified. Again this diagnosis can be made if the absolute chloride réduction is 50
per cent below the normal ante mortem level. Even though putréfaction is
présent, if the blood chlorides on the left side of the heart are found to be 25 per
cent or more lower than those on the right side, death by drowning in fresh
water is to be suspected.
If the chlorides in both sides of the heart are increased by 25 per cent or more
above the expected normal levels in an individual who had apparently been in
good health prior to death, or if the chloride content in the left heart is 25 per
cent or more higher than that of the blood in the right heart, death by drowning
in sea water is probable, If putréfaction has occurred the absence of such
changes does not exclude the possibility of drowning in sea water.
Do abnormalities in the distribution and concentration of magnésium in the
blood indicate the occurrence of agonal or postmortem diffusion between blood
and extracorporeal fluid (drowning)? Conclusions, generally similar to those
drawn from the chloride results, may be made concerning magnésium. However, since magnésium is higher in the red blood cells than in the plasma the
effect of hemolysis is to increase the plasma magnésium. Différences of as much
as 1.0 mg. per cent magnésium between plasma of the right and left sides of the
heart are without significance. If the magnésium content of the blood from the
left heart is 2 mg. or more per 100 ce. higher than that of the right heart death by
drowning in sea water should be suspected. In persons who hâve not been taking magnésium in the form of médication the finding of significant amounts of
magnésium in the gastric contents suggests that sea water has recently been
swallowed and should lead to inquiry regarding the possibility of drowning.
CREATINE
For what purpose would a postmortem spécimen of urine be tested for creatine?
Although sniall amounts of creatine (10-20 mg./24 hrs.) are found in the urine of
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WALTER W. JETTER AND REGINA MCLEAN
children and intermittently in the urine of normal adult females its présence in
large amounts indicates unusual breakdown of body tissues (starvation, diabètes,
exopthalmic goiter, fever, muscular dystrophies, violent physical exertion, etc.) 9 .
In severe starvation unusually large amounts of creatine may appear up to 200
mg./24 hrs10.
Is creatine formed in the urine after death? Controlled expérimental observations hâve shown that creatine is not formed in the urine as a resuit of
postmprtem change.
What is the fate of the creatine présent in the urine at the time of death?
Small amounts of creatine such as may be présent in the urine of a child or a nongravid female disappear rapidly and are usually non-detectable at the end of
twenty-four hours. Creatine présent in large amounts in the urine at the time of
death remain détectable in significant quantities until at least twenty-four hours
postmortem.
GLUCOSE
What is the purpose of testing a postmortem sample of blood or urine for
glucose? The purpose is usually to obtain information as to the cause of an
otherwise obscure death or to corroborate an unverified clinical impression. No
significance can be attached to the results obtained from testing postmortem
samples of blood or urine for glucose unless due considération is given to the
extent to which agonal and postmortem change may affect its concentration.
In the event that the glucose content of the blood in the left side of the heart
was normal at the time of death how may it be altered incident to postmortem
change? There is a progressive lowering of the glucose in the blood after death.
The speed of glycolysis varies according to the température of the body and at
37.5 C progresses at the rate of about 12.8 mg. per 100 ce. of blood per hour11.
The more rapidly the body température falls the slower will be the destruction
of glucose. Thus, if it could be assumed in a given instance that the ante mortem blood glucose level werë normal, and if the postmortem température of the
body were known, it might be possible to estimate the duration of the postmortem
interval from the amount of glucose still présent in the blood in the left side of the
heart. It should be remembered that not ail of the reducing substances detected by the conventional quantitative tests are sugar and to obtain a true value
for glucose the fermentation technic of Van Slyke should be employed.
In the event that the glucose content of the blood in the right side of the heart
was normal at the time of death how may it be altered incident to postmortem
change? Although glycolysis occurs in the right as well as in the left side of the
heart, large amounts of glucose may be liberated from the liver during the early
part of the postmortem interval so as to raise the glucose level in the right side of
the heart by as much as 400 or 500 per cent above its ante mortem level. Thus
the finding of a glucose value of between 500 and 600 mg. per cent in a sample of
blood removed from the right side shortly after death does not necessarily indicate that the ante mortem level was abnormal. Obviously the amount of glucose
contributed to right heart blood by glycogenolysis in the liver will dépend on the
BIOCHEMICAL CHANGES IN BODY FLUIDS AFTER DEATH
183
ante mortem glycogen content of that organ. In cases of liver disease or starvation the liver glycogen reserve may be so depleted that there will be no significant addition of glucose as a resuit of postmortem change.
How may ante mortem hypoglycemia be recognized at postmortem examination? If the glucose value as established by the différence between the métairie
reducing substances in the blood filtrate (Folin-Wu) and the fermented filtrate
(Van Slyke), in a sample removed from either side of the heart, within the first
few hours after death, is lower than can be accounted for by a rate of glycolysis
based on the duration of the postmortem interval, and the température of the
body during that interval, ante mortem hypoglycemia can be regarded as having
been présent.
How may ante mortem hyperglycemia be recognized at postmortem examination? Except in those rare instances in which the rénal threshhold is abnormally
low the présence of a significant amount of glucose in a spécimen of urine obtained
before the onset of putréfaction is indicative of ante mortem hyperglycemia.
Sugar in the urine undergoes progressive postmortem destruction by glycolysis
and the rate of glycolysis is roughly proportional to its original concentration.
At 37 C the loss is about 50 per cent in the first twelve hours with a loss of an
additional 25 per cent during the next twelve hours.
What may be the significance of a high blood glucose at the moment of death?
As previously indicated the présence of an abnormally high concentration of sugar
in a postmortem sample of blood from the right heart does not indicate ante
mortem hyperglycemia. An élévation in the glucose content of a postmortem
sample of blood from the left heart, however, is significant and up to forty-eight
hours the significance increases as the interval between death and the time of
testing is increased.
It should be borne in mind, however, that a state of agonal hyperglycemia does
not necessarily indicate that there was any chronic or significant altération in
sugar metabolism. In addition to diabètes mellitus there are many conditions
which may resuit in an acute agonal hyperglycemia due presumably to terminal
libération of adrenalin with resulting liver glycogenolysis. Thus hyperglycemia
is found normally in persons dead of asphyxia. Among other conditions which
may resuit in a sudden increase of blood glucose to between 500 and 600 mg. per
100 ce. are shock, head injury, and coronary thrombosis.
Of what value is a comparison of the results of the postmortem blood and urine
tests for glucose? If the postmortem blood analysis indicates an ante mortem
hyperglycemia while the urinalysis is négative for glucose it may be reasonably
stated that the hyperglycemia was agonal in origin. If, however, both hyperglycemia and glycosuria are found to be présent it should be assumed that the
ante mortem altération in sugar metabolism represented more than merely an
agonal phenomenon.
KETONE BODIES
Of what value to the récognition of an ante mortem state of acidosis is the
testing of a postmortem spécimen of urine for ketone bodies? So far as the
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WALTEK W. JETTEB AND EEGINA McLEAN
medico-legal autopsy is concerned the principal reasons for seeking information aa
to the présence or absence of a terminal state of acidosis is that such évidence
may be the final deciding factor in the suggestion of diabetic coma or death due to
simple starvation. Obviously, neither condition can be recognized by ketosis
alone; but other facts may point to the probable cause of the acidosis, once its
existence has been proved.
Are ketone bodies formed in the urine after death? Urine containing no ketone
bodies by qualitative tests at the time of death, remains négative even after the
onset of putréfaction. Ketone bodies are not formed in the urine as the resuit of
putréfaction.
What is the f ate of ketone bodies présent in the urine at the time of death? By
quantitative analysis acétone and diacetic acid gradually disappear over a period
of forty-eight hours after death. However, beta-hydroxybutyric acid remains
relatively constant up to at least three days.
NONPROTEIN NITROGENOUS SUBSTANCES
What is the purpose of testing postmortem blood for nonprotein nitrogenous
substances? The purpose is usually to obtain information in which the pathologie findings suggest that the immédiate cause of death may hâve been due to
uremia.
What is the effect of postmortem changes on the nonprotein nitrogenous constituents of normal blood présent at the time of death? I t appears probable from
still incomplète data that nonprotein nitrogen, urea and creatinine are not increased within the first twelve hours by more than 40 per cent above the ante
mortem level. With putréfaction, protein breakdown is manifested by large
increases in the N.P.N.
What may be the significance of an increase in the nonprotein nitrogenous
constituents of the blood at the time of death? It is generally agreed that
severe ante mortem azotemia does not necessarily indicate the présence of true
uremia (rénal insumciency). Factors prïmarily responsible for the development
of azotemia may be extrarenal in origin. A significant élévation of blood nonprotein nitrogen may develop as a resuit of dehydration, fever and toxemia incident to such conditions as severe vomiting and diarrhea, acute and extensive
hemorrhage, posttraumatic shock, or severe sepsis. It is also important to
recognize the terminal élévation in nonprotein nitrogen if death has been accompanied by significant dehydration or toxemia. Methods for urea based
upon eventual estimation of ammonia yielded extremely high values. When
urea was. determined by estimation of the CO2 formed by urease there was
no change from the original ante mortem level. Creatinine values increased
with the development of putréfaction but the increases were irregular and their
significance is questionable. Uric acid did not increase, but on the contrary,
with the onset of putréfaction, it decreases to a constant level in the vicinity of 1
mg. per cent. The xanthoproteic index, advocated by Steen12 as useful in the
differentiation of rénal insumciency, increases sharply and its détermination is
not recommended in postmortem work.
BIOCHEMICAL CHANGES IN BODY FLTJIDS AFTEB DEATH
185
If interpolated on the basis of a 50 per cent increase, it appears possible that
significant information may be obtained from an analysis of the nonprotein
nitrogen up to twelve hours postmortem.
OXYGEN
What information of value may be expected from determining the oxygen
saturation of a postmortem sample of heart's blood? On theoretical grounds it
might be expected that following death from sudden cardiac arrest, such as may
be caused by electrical shock or in some instances by coronary occlusion, the
arterial blood might contain a significantly greater amount of oxygen than would
be expected if death were preceded by a period of circulatory failure.
That this assumption is true under expérimental conditions has been shown by
comparing the oxygen saturation of the heart's blood of animais killed by electrical shock with the blood of animal killed by chemical and by mechanical
asphyxia13. The ventricular blood at the time of death may be as high as 75 per
cent saturation in the former and should not exceed 4 per cent saturation in the
latter.
The rate of the disappearance of oxygen probably bears some relation to the
environmental température. As much as 80 per cent of the total residual oxygen
at the time of death may disappear from the blood in less than four hours.
Can oxygen be absorbed by the heart's blood after death? Control experiments and known observations indicate that oxygen is not taken up by the heart's
blood after death.
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Changes in the magnésium and chloI. Diagnosis of acute alcoholic
ride content of the blood following
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drowning in fresh and sea water.
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Arch. Path., 35: April, 1943.
Se, 196: 475, 1938.
(2) JETTER, W. W.: Chemical diagnosis of
(9) WRIGHT, SAMSON : Applied Physiology.
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(10) BENEDICT, P. G. : A study of prolonged
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Ante mortem and postmortem diffasting. Carnegie Institute of Washfusion of alcohol through the bladder
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(4) GONZALES, T. A., VANCE, M., AND
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(12) STEEN, W. B.: Value of the blood
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Abstract, J. A. M. A., 108: 770, 1937.
(6) BREYFOGLE, H. S.: Unpublished data. (13) GOGGIO, A. P.: Changes in oxygen
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