Acute Lead Poisoning

As when applied externally, so when taken internally, the lead salts, if concentrated, are powerful irritants. Cases of acute poisoning are rare. The Acetate is most frequently taken. There is a burning, sweetish taste in the mouth, thirst, vomiting of whitish fluid due to lead chloride, abdominal colic, and usually constipation, but if the bowels are open the feces are black due to lead sulphide: the skin is cold, and there is collapse. If the patient live long enough, cramps in the legs, giddiness, torpor, coma, and convulsions are present. Post-mortem. - The stomach and intestines show signs of irritant poisoning.

Treatment

Give emetics (see p. 139), or wash out the stomach. Give Sodium or Magnesium Sulphate to form an insoluble sulphate, and to open the bowels. If collapse is present, stimulants and warmth should be used.

Chronic Lead Poisoning

This is so common that the sources of accidental poisoning should be borne in mind. The most important are: soft water, carbonated waters and alcoholic drinks (beer) which have passed through lead pipes or been stored in receptacles lined with lead. Occupations as painters (colica pictonum), plumbers, type-setters, gold-miners, white lead workers, potters, glaziers (Devonshire colic) because they will not wash their hands before meals nor use ordinary care; lead hair dyes and face powders, biting leaded white thread, eating certain canned fruits (lead solder), sheet-lead (tin-foil) about tobacco, filling holes in mill-stones with lead, giving of tin (lead) soldiers to children, use of lead carbonate ointment on burns, lead bullets in flesh, white or red lead used for preparing rubber for Vulcanizing, lead plates in dentistry (Osier), the use of lead chromate to color buns yellowish, have all been followed by chronic plumbism.

Symptoms

The earliest are constipation and intestinal colic. Lead is certainly absorbed, for it circulates in the blood and is excreted, chiefly, by the kidneys. It is supposed to be taken up as an albuminate, but it cannot exist in the blood as such, for it would be precipitated by the alkali of that fluid. After absorption it diminishes the amount of haemoglobin and the number of red blood-corpuscles, and produces a sallow anaemia; it checks the separation of urates from the blood and their excretion by the kidneys, hence gout is very common in those poisoned by lead. As it circulates in the gums, and the lead-impregnated plasma bathes the epithelium, through which some of the sulphur in the food and in the tartar of the teeth has diffused, a Lead Sulphide is precipitated in the gums, and forms the well-known very dark-blue line known as Burton's line, at the base of the teeth. For the same reason a blue line may occasionally be seen round the anus, and, after death, deposits of pigment in the intestines. Circulating in the nervous system, lead very often produces chronic inflammation of the peripheral nerves, especially those supplying the extensors of the hand, and hence wrist-drop is a very common symptom; but any muscle, and sometimes almost all the muscles of the body, may be paralyzed from neuritis it is a clinical observation that such muscles are very refractory to electricity. It is noteworthy that the supinator longus usually escapes, the reason apparently being that the supinator is not an extensor muscle. The sensory fibres of the nerves are not often affected, hence pain and anaesthesia are rare; but pains, especially round the joints, may occur. In exceptional cases the anterior comua of the spinal cord waste, and lead often affects the brain, causing saturnine lunacy, and also convulsions, known as saturnine epilepsy. Inflammation of the optic nerve or optic neuritis, sometimes occurs, leading to blindness, which, however, may be present without any change in the nerve. The kidneys are often the seat of chronic inflammation; whether this is due to the passage of the lead through them, or to the gout caused by the lead, is an open question.

Treatment

The treatment consists chiefly in avoidance of the source of poisoning, the use of Sulphuric Acid lemonade, and in the administration of Potassium Iodide which is often given, as it is supposed to increase the excretion of lead in the urine. This is probably incorrect as very little lead passes out by the urine; most leaves the body by the faeces. It is said also to be excreted in the bile, sweat, and milk. For a clinical account of the symptoms and treatment a text-book of medicine must be consulted.

The following method may be employed to determine the presence of lead in the urine. Administer potassium iodide for four days, collecting the urine. Evaporate to a pint; 500 c.c., and filter. Pass hydrogen sulphide gas through the urine thus concentrated, when a black precipitate will form if lead is present. Other substances give a black precipitate with hydrogen sulphide, but none are likely to be present in the urine. A simple test is to paint a small area of skin with a six per cent. solution of sodium sulphite. If lead is present the painted area will darken after a few days, (Cicconardi). Patients using face enamels containing lead will find the skin blackened on taking baths in water containing hydrogen sulphide (Richfield Springs).