The lead (plumbum) salts are not much employed in medicine.

Preparations

(A) For External Use

The acetate and sub-acetate are antiseptic and astringent and are soothing to wounds and bruises. Liquor plumbi subacetatis (Goulard's extract) contains about 25 per cent. of lead subacetate. Liquor plumbi subacetatis dilutus (lead-water) is a 4 per cent. solution of the liquor. It is used as a wet dressing for wounds and bruises, and as a soothing application in skin diseases, sunburn, ivy poison, and eczema.

Lead and opium wash (Lotio Plumbi et Opii, N. F.) contains lead acetate, 26 grains (1.75 gm.), tincture of opium, 52 minims (3.5 c.c.), and water to make 3 1/3 ounces (100 c.c.).

Lead oleate is a sticky, insoluble mass, which is used as the mechanical basis of plasters. It is known as "lead plaster." From the prolonged application of plasters it has caused poisoning.

Lead sulphate is present as a sediment in liquor alumini aceta-tis (Burow's solution), when this is made of lead acetate and alum. It should be filtered off, as it has caused poisoning.

(b) For internal use the only salt employed is the acetate, dose, 2 grains (0.13 gm.). Its only use is to overcome intractable diarrhea, as from tuberculous enteritis or colitis, and to induce a temporary obstipation, as in operations about the anus or rectum. Pills of lead and opium, N. P., contain 1 grain (0.06 gm.) each of lead acetate and powdered opium.

Toxicology

Though lead has but little use in therapeutics, it is of importance to physicians because of the frequency of chronic lead-poisoning or plumbism. This occurs very commonly among painters and plumbers and other workers in lead (type, lead pipe, shot, pottery glazing, enamelware, etc.), and is one of the diseases often met with in clinics and hospitals. It may even result from hair-washes containing lead acetate, from water that has stood in lead pipes, from canned food with lead in the solder of the cans, from wall-paper, or from the prolonged application of plasters (with lead plaster base) to the skin. Gottheil reports a case of death from the sediment (lead sulphate) in Burow's solution made with lead acetate and alum. Stewart reports 64 cases in children from eating buns colored with chrome yellow.

The symptoms are: Anemia and wasting, foul breath, bad taste in the mouth, loss of appetite, especially in the morning, gastric and intestinal disturbances, pains in the joints and bones, and spots before the eyes. Sailer and Speese found almost complete absence of gastric juice in 10 out of 12 subjects. Chronic nephritis is very common, and the arterial pressure tends to be high. Blackfan gives the symptoms in children as change in disposition, peevishness, restlessness at night, appetite poor, breath foul, hemorrhage from gums, pain in epigastrium, constipation, and pain in legs. In children the paralysis usually affects the legs rather than the arms. Sixteen of Stewart's 64 cases had convulsions. In rabbits, Charteris found that lead carbonate produced a marked anemia, with degeneration of both the leukoblastic and the erythroblastic elements of the bone-marrow.

In addition to these symptoms there are usually certain manifestations which are characteristic of lead, and determine the type of the complaint to the physician, viz.:

1. Colic

Lead colic, painter's colic - true colic with marked constipation. The patient is relieved by pressure upon the abdomen and will often be found lying prone upon a pillow or bolster. Mosse found that the injection of lead acetate into animals caused degenerative changes in the sympathetic ganglia of the abdomen, and it has generally been believed that the constipation is due to irritation of the splanchnic inhibitory nerves of the intestine. But both the constipation and the colic are probably due to an irregular irritation of the vagus nerves, the motor nerves of the small intestines, for Oliver found that in animals dead from lead-poisoning the small intestines were contracted tightly at irregular intervals, and Hertz noted by the x-rays that the retardation occurs in the small intestine, which is unusual in constipation. It is presumably a spastic constipation. In the small intestine in rabbits and cats Hirschfelder found irregular constrictions which were checked by atropine and nicotine. The intestinal arteries were strongly contracted. Vaquez (1904) and Pal (1905) found the colic associated with a crisis of general arterial hypertension. Its severity can be lessened by atropine, nitrites, opium, or cathartics, the establishment of coordinated peristalsis apparently aiding in overcoming the spasms. Colic is the most frequently observed of the striking manifestations. It is sometimes followed by a soreness in the abdomen which persists for weeks.

2. Palsy

The usual lesion is a motor neuritis of the musculo-spiral nerve below the origin of the branch which goes to the supinator longus. This causes paralysis of the extensors of the forearm, with the exception of the supinator longus, and shows in the characteristic "wrist-drop." The first paralysis may show in the extensor indicis and the extensor minimi digiti, the extensor meta-carpi pollicis usually escaping. The intrinsic muscles of the hand undergo considerable atrophy. The paralyzed muscles show the reaction of degeneration. There is no pain. Though this is the usual lesion, the motor neuritis may show in other regions also. Indeed, it is prone to appear in the limb most used. In left-handed workers it may appear first in the left arm. In children it is usual in the legs. Starr says that colic precedes the palsy in over 90 per cent. of the paralytic cases.

There may also be a general peripheral neuritis (sensory and motor) similar to that from alcohol, with pain or great sensitiveness to pressure, ataxia, foot-drop, etc. It may be so pronounced as superficially to resemble locomotor ataxia, lateral sclerosis, or anterior poliomyelitis. And there may be an optic neuritis, causing temporary or permanent blindness, laryngeal paralysis, or involvement of any of the cranial nerves. Gowers says that a lateral tremor of the fingers is peculiar to lead. In poisoned cats, Goadby and Legg have found minute hemorrhages in the nerves.

3. Encephalopathy

This is a rare manifestation, and is said to be more frequent in negroes than in whites. It may give many different symptoms. Intense headache, vertigo, mental depression, and insomnia are the most common. But it may go on to violent delirium, with convulsions or apoplexy, or may develop into dementia paralytica. Kehrer says that lead meningitis should be distinguished from lead encephalopathy, in the latter the lesion being a degeneration of the vasa vasorum of the brain vessels. Moleen reports a lymphocytosis in the spinal fluid.

In addition to these striking results, the continued absorption of lead is believed to be a cause of arteriosclerosis, cirrhosis of the liver, chronic interstitial nephritis, and gouty attacks (by checking the elimination of uric acid). In female workers in lead it has frequently brought on abortion by causing the death of the fetus. The offspring of male workers in lead are often deficient in size and vitality, and similar results have been obtained in experiments on rabbits and fowls. Both diachylon plaster and lead acetate pills have been taken to produce abortion.

After death from lead there is a striking rapidity of decomposition with putrefactive odor. The largest amount of lead is found in the liver.

Diagnosis

In a painter, plumber, or other worker in lead, anemia, poor nutrition, backache, tremor, weakened grip, a bad taste in the mouth, and loss of appetite for breakfast are always suspicious symptoms; and it is highly advantageous for the patient if the diagnosis is made at this stage. In one not known to be working in lead, the cause may not be suspected until the characteristic colic or palsy makes its appearance. Hayhurst reports that a 5 per cent. solution of sodium sulphide applied to the skin usually shows brown or black on hands, wrists, and forearms.

In a well-marked case there are three things to be looked for, viz., lead in feces or urine, degenerated red cells, and a lead line on the gums. Lead is frequently but not always found in the feces and sometimes in the urine. Degenerative stippling or polychromatophilia in the red cells was found by Oliver in 60 per cent. of cases. It is probably a rather late manifestation, for Rambousek found it in only one of seven animals experimentally poisoned with lead acetate, and in painters Harris, of the Division of Industrial Hygiene, rarely found it in the early stages. Liebermann reports a lessened fragility of the red cells.

The lead line on the gums is usual, especially if the teeth are not in good condition. It is made by a bluish patch just within the margin of each gum, and is usually more prominent on the lower gums. Occasionally there are bluish-black patches on the insides of the cheeks and lower Up. If the teeth are absent there is no lead line.

Treatment

As prophylactic measures, lemonade containing sulphuric acid, keeping the fingers out of the mouth and washing the hands before eating, and proper ventilation to remove the dust of lead salts have proved extremely efficient in Germany and England.

Potassium iodide is the usual remedy, but in experimental animals Oliver found that it did not increase the elimination of lead. It may be that potassium iodide acts to overcome the high arterial tension, rather than to promote elimination. Gowers states that it actually increases the toxic action by increasing the solubility of the metal. Oliver recommends milk in large quantities, with the addition of sulphur to form the unabsorbable lead sulphide, and attention to the bowels. The use of sulphates to form lead sulphate in the alimentary tract has been recommended on the mistaken idea that this salt is not absorbed.

For colic, cathartics are indicated, also atropine, warm baths, heat to the abdomen, and, in some cases, opiates. For the neuritis or palsy and for the meningitis the usual treatment for such conditions is called for. For the encephalopathy, an ice-bag to the head, amyl nitrite, and lumbar puncture may be employed.