PHENOL STUDIES VII. CHRONIC PHENOL POISONING, W I T H
SPECIAL REFERENCE TO T H E EFFECTS UPON EXPERIMENTAL
ANIMALS OF THE INHALATION OF PHENOL VAPOR
WM. B. DEICHMANN, P H . D . , K. V. KITZMILLER, M.D., AND S. WITHERUP, B.S.
From the Kettering Laboratory of Applied Physiology, College of Medicine, University of
Cincinnati, Cincinnati, Ohio
In Lister's day, cases of chronic or subacute phenol poisoning were not uncommon among surgeons and their assistants, who were exposed regularly to the 2or 3-per cent phenol spray; but as Kobert 1 remarks, many of the doctors must
have possessed great tolerance considering that they used, applied, and inhaled
sprays of carbolic acid for years without illness or apparent discomfort. No
doubt the intermittent character of their exposure was a factor in their favor.
Data which give us an insight into the quantities of phenol apparently tolerated
by man were reported in 1881 by Falkson,2 who stated that after inhaling these
vapors for several hours his own urine contained phenol in amounts up to 2
grams, while the urine of patients who absorbed the compound from the inspired
air as well as from the skin or from open wounds, contained up to 5 grams per day.
Chronic phenol poisoning is infrequent in its present occurrence. It usually
results from absorption of phenol by way of the respiratory tract or through the
skin. According to Zangger,3 chronic poisoning is characterized in man by
serious systemic disorders';—digestive disturbances, including vomiting, difficulty
of swallowing, ptyalism, diarrhea and anorexia; nervous disorders, with headache, fainting, vertigo, and mental disturbances; and an eruption on the skin.
The disease is usually fatal when there is extensive damage to the liver and
kidneys.
Investigation of the effects of prolonged absorption of quantities too low to
produce signs of acute poisoning, appears to have been made only in relation to
oral and subcutaneous administration. Biebl4 fed the compound to dogs and
found that individual doses up to 0.4 gram administered twice weekly for 9
months were tolerated well; somewhat .larger doses usually produced no signs
of acute poisoning but they sometimes resulted in dyspnea and sudden death.
Heller and Pursell5 added phenol to the drinking water of rats. They concluded
that concentrations lower than 10 grams per liter did not interfere with normal
digestion, absorption or other metabolic functions. Deichmann and Oesper6
gave rats phenol in their drinking water, and found that concentrations of 2
grams per liter and above retarded growth and lessened resistance to intercurrent
disease of the lungs. Bronchopneumonia was noted by Wachholz 8 who injected
the compound subcutaneously in sublethal concentrations into cats. Local
areas of inflammation were reported in rabbit lungs by Hesselbach. 9 I t appears
from these and other reports that the repeated absorption (from the gastroenteric
tract or subcutaneous tissues) of toxic but sublethal doses of phenol affects the
lungs with considerable frequency, also damaging such other organs as the heart,
liver and genito-urinary tract (Wandel,10 Zangger,3 Ellinger11).
273
274
W. B. DEICHMANN, K. V. KITZMILLEU AND S. WITHERUP
In view of the paucity of information on chronic phenol poisoning, especially
of the lack of information on the effect of inhalation, some observations along
this line were made and are recorded below.
EXPERIMENTAL
Six rabbits, 15 rats and 12 guinea pigs were exposed together, for 7 hours daily on 5 days
per week, to vapors of phenol in air ranging in concentration from 0.1 to 0.2 mg. per liter.
The inhalation chamber employed had a capacity of 600 liters and the phenol-laden air
passed through at a rate of about 170 liters per minute (fig. 1). The temperature in the
chamber ranged from 27° to 32°C. and the relative humidity varied between 46 and 70 per
cent. After testing various methods that could be employed for sampling the vaporair mixture in the chamber, the collection of spot samples by means of evacuated sampling
flasks (fig. 2) was found most satisfactory. The analytical procedure for the estimation of
LAYER OF O I L -
I
\mSS.(
ONE LITER
BOTTLE LINED
WITH PHENOL
WATER AT
25- C
t
J
AIR, 170 LITERS/MIN.
^
A
INHALATION CHAMBER
CAPACITY 6 0 0 LITERS
F I G . 1. APPARATUS USED FOR EXPOSURE TO PHENOL
phenol in air involves the following steps: Introduce 80 ml. of 1 per cent sodium hydroxide
into the flask containing the sample (volume) and shake for 15 minutes. The resultant sodium phenolate and the excess of sodium hydroxide are drained into a 100 ml. volumetric
flask, and the sampling flask is washed with about 8 ml. of water. To sample and washings
are then added 2 N hydrochloric acid, the quantity of which (about 9 ml.) must be determined by preliminary titration so as to bring the pH of the final solution between 11 and 12.
Water is then added to the 100 ml. mark. A 20 ml. aliquot is analyzed and to this are added
4 ml. of sodium acetate and 2 ml. of the diazotized p-nitroaniline reagent (for preparation
of reagents see method for blood 7 ), followed one minute later by 4 ml. of 20 per cent sodium
carbonate. The intensity of color, representing the concentration of phenol, is read in
a spectrophotometer (10 mm. cups) within 3 minutes, at wave length 500 nui. The relation
between density and concentration is obtained by reference to a calibration curve, that must
be prepared in advance 7 . The result gives the concentration of phenol in the 20 ml. aliquot and from this the concentration in the entire sample can be calculated. The final
estimation may also be carried out in a colorimeter by comparing' the unknown with suitable standard solutions brought also to pH 11.5 db 0.5 before development of color.
CHRONIC P H E N O L
POISONING
275
RESULTS
The rabbits were exposed on 63 days over a period of 88 days. At no time did
they exhibit any signs of illness or discomfort, but the fact that phenol was
actually absorbed was evidenced by analyses of blood drawn by heart puncture
at the end of the period of exposure from time to time. After 27 exposures,
carried out over a period of 37 days, the blood averaged 0.5 mg. "free" phenol,
0.7 mg. "conjugated," or 1.2 mg. as total phenol per 100 ml. Following the last
of the 63 exposures, the analyses were repeated. The concentration of phenol
F I G . 2. F L A S K E M P L O Y E D FOR THE COLLECTION OF S P O T S A M P L E S O F A I R C O N T A I N I N G
PHENOL
in the two forms was essentially unchanged. The animals were killed by air
embolism.
Examination of the lungs showed widespread confluent lobular pneumonia.
Much of the alveolar exudate was undergoing organization and in places resembled granulation tissue. Histiocytes and fibroblasts were numerous in the thickened septums. Lesions of chronic purulent bronchitis occurred with considerable
frequency and the peribronchial tissue was often hyperplastic and inflamed.
Degenerative changes with medial fibrosis and endothelial hyperplasia occurred
in the pulmonary vessels.
There were also changes in other organs. Myocardial degeneration and some
276
W. B. DEICHMANN, K. V. KITZMILLER AND S. WITHERUP
necrosis of muscle bundles, interstitial fibrosis and fibrous replacement were
found, together with variable histiocytic changes and lymphocytic infiltration.
The liver exhibited well defined centro-lobular degeneration and necrosis with
relatively little exudative inflammatory response and no significant increase in
interstitial tissue or change in the Kupffer cells. The hepatic cells were large,
pale, coarsely granular; the nuclei were swollen, fragmented and pyknotic. In
the kidney, there was generalized cloudy swelling and edema of the convoluted
tubules. The lumens of some of them were occluded by swollen epithelial cells,
while others contained granular casts. There were also scattered focal cortical
lesions characterized by tubular degeneration, atrophy, and dilatation, varying
degrees of glomerular degeneration, and sclerosis and proliferation of the interstitial tissue together with well marked lymphocytic infiltration. The glomeruli
not involved in these focal lesions had undergone chronic degenerative changes
with hyalin thickening of tuft and capillaries and some lymphocytic infiltration.
The guinea pigs were found to be more susceptible than rabbits to poisoning
by vapors of phenol. After the first 3 to 5 exposures they began to show a
decreased activity which was particularly apparent during the exposure periods.
Their weight either decreased or remained stationary. After about 20 exposures
over a period of 28 days some of them began to display respiratory difficulties
and signs of paralysis affecting primarily the hind quarters. Five died at this
time, and the others were killed after 29 exposures. Analytical results on the
blood of the latter were as follows: "free" blood phenol, about 1.0 mg., "conjugated" phenol about 0.4 mg. and total phenol 1.4 mg., all for 100 ml. of whole
blood.
The injurious effects of the exposure were greater than those noted in the case
of rabbits although the duration of their exposure was shorter. There was extensive coagulation necrosis of the myocardium with extensive reactive inflammation; a more acute type of lobular pneumonia with occasional abscesses and a
more striking type of vascular damage including frequent fibrinocellular thrombosis of the capillaries. Hepatic lesions were similar to those seen in rabbits
but in addition there were well defined fatty changes such as are commonly seen
in the livers of guinea pigs after exposure to a variety of toxic compounds. The
renal lesions were very similar to those noted in the rabbits except that there were
more pronounced degenerative lesions in the cortex and the focal lesions were not
so advanced.
The rats were exposed on 53 days over a period of 74 days; at no time did they
show signs of illness, nor did the inhalation of these phenol vapors produce gross
or microscopic evidences of injury. After the last exposure some of the animals
were killed, and their carcasses were ground up and analyzed for phenol. The
average quantity of "free" phenol found was about 0.2 mg., of "conjugated"
phenol about 0.35 mg., and of total phenol about 0.6 mg. per 100 grams of tissue.
These figures represent normal values for tissue phenol.
SUMMARY
Chronic phenol poisoning caused in man by absorption of the compound
through the skin or by way of the respiratory tract is characterized by digestive
277
CHRONIC PHENOL POISONING
disturbances, nervous disorders and an eruption on the skin. The disease is
usually fatal when there is extensive damage to the liver and kidneys. The
first signs of illness noted in experimental animals exposed to phenol vapor or
treated orally or subcutaneously with toxic but sublethal doses, are respiratory
difficulties and pulmonary injury; this may be followed by damage to other
organs as the heart, liver and genito-urinary tract. The inhalation of phenol
vapor in concentrations ranging from 0.1 to 0.2 mg. per liter, by guinea pigs,
caused obvious distress and illness, with respiratory difficulties, loss of weight and
paralysis after 20 successive periods of exposure (7 hours per day) accompanied
by post-mortem evidence of acute toxic injury to the lung, heart, liver and kidney.
Rabbits showed no signs of illness after 63 such periods of exposure, but suffered
extensive and progressive pulmonary inflammation and injury. Rats failed to
show signs of illness during exposure, or post-mortem evidences of injury after
53 periods of exposure.
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