Blood-Pressure.
—Several methods are available for the estimation of the blood-pressure. The pressure may be roughly estimated as too high or too low by means of the finger. The presence of thickening of the arteries may be also estimated in this way, but for determining the absolute blood-pressure it is necessary to use one or other of the instruments on the market. The estimation of blood-pressure is an important point in relation to the suspected presence of arterio-sclerosis, and should be performed wherever possible. Sphygmographic tracings may also be taken. Such a tracing in a case of typical poisoning gives a peculiar form of curve, which, however, may be present in alcoholism and heavy work, and arterio-sclerosis of many types.
Urine Examination.
—In suspected cases of lead poisoning the examination of the urine may reveal the presence of lead. In addition, albumin is frequently present, especially in the early stages of kidney inflammation. The ordinary tests for albumin should be carried out, and it is also advisable to examine the urine spectroscopically, as at times hæmoglobin, methæmoglobin, hæmatoporphyrin, may be present in small quantities, each of which can be detected by means of spectroscopic examination. Blood is not common in the urine of lead-poisoned persons, although microscopically hæmorrhages undoubtedly take place in the kidney. These hæmorrhages are interstitial, and as a rule do not cause any blood-pigment to be passed in a quantity that can be determined. It is as well, however, to centrifugalize the urine, and examine the deposit for red blood-cells.
The presence of hæmatoporphyrin, as suggested by Steinberg[10], is probably due to hæmorrhages in the intestine, and its presence in the urine should be regarded with suspicion in a lead-worker.
Where a lead-worker is suffering from continued absorption of lead, even without the manifestation of other symptoms, a change has been noted in the acidity of the blood—namely, a loss of normal alkalinity. The estimation of the alkalinity or acidity of the blood direct is an exceedingly difficult process, but much information may be obtained by careful estimation of the acidity of the urine, and of the acidity of the urine in relation particularly to the phosphates.
Joulie[11] has pointed out the extreme value which may be obtained from a knowledge of the urinary constituents by the means of estimation of the acidity with suchrate of chalk. The reagent is made by slaking lime in such a way that the resulting compound is practically dry. A quantity of this—about 25 grammes—is then thoroughly shaken up with 10 per cent. solution of cane-sugar, allowed to stand, and the solution titrated against decinormal acid until it is of one-twentieth normal. The urine is then estimated directly, the suchrate is run into the 25 c.c. of urine until a faint white flocculent precipitate appears. The number of c.c. of the solution of suchrate is then noted, and multiplied by the factor of the solution. This gives the acidity related to the phosphate and other organic acid contents, and is similar to the method used to determine the acidity of wines.
The second estimation consists of estimating the phosphates present by means of a standard solution of uranium nitrate, using either potassium ferrocyanide or cochineal as an indicator. The specific gravity of the urine is also determined. The result is then expressed in terms of this specific gravity, or, rather, in the terms of the density of the urine in relation to distilled water, and the whole answer returned per litre. By this method it is not necessary to obtain a twenty-four hours sample of the urine, the urine passed first thing in the morning being taken for examination.
By using this density figure the quantity of acid and phosphate is expressed in relation to the density, the equation being—
The observed acidity The density per litre = Acidity per litre.