Plumbum

Lead

Lead. Plomb, Fr.; Blei, Ger.

Plumbi Oxidum

Lead oxide. Litharge. In small yellowish or orange-colored scales, insoluble in water, but almost wholly soluble, with slight effervescence, in dilute nitric acid. The solution is affected by potassa, like that of carbonate of lead in the same acid.

Emplastrum Plumbi

Lead-plaster. Litharge and olive-oil.

Plumbi Acetas

Lead acetate. Sugar of lead. In colorless crystals which effloresce on exposure to the air. It is dissolved by distilled water, with a slight turbidness, which is removed by the addition of vinegar. With this solution carbonate of sodium, produces a white, iodide of potassium a yellow, and hydrosulphuric acid a black precipitate. Upon the addition of sulphuric acid, vapor is evolved, having the smell of vinegar. Dose, gr. ss—gr. v.

Liquor Plumbi Subacetatis

Solution of lead subacetate. A colorless liquid of the specific gravity of l·267. It is decomposed by exposure to the air, carbonate of lead being formed. When added to a solution of gum it occasions a dense white precipitate.

Liquor Plumbi Subacetatis Dilutus

Diluted solution of subacetate of lead. (Solution of subacetate, 30 c. c. ; distilled water to make 1,000 c. c.)

Ceratum Plumbi Subacetatis

Cerate of lead subacetate. (Solution of subacetate of lead, 200 grm.; camphor cerate, 800 grm.)

Plumbi Carbonas

Lead carbonate. A white substance in powder or pulverulent masses, insoluble in water, but soluble, with effervescence, in dilute nitric acid. Potassa added to the solution produces a white precipitate, which is wholly dissolved by an excess of the alkali. Used in the preparation of the unguent, and also applied topically.

Unguentum Plumbi Carbonatis

Ointment of carbonate of lead. (Carbonate of lead, 10 grm.; benzoinated lard, 90 grm.)

Plumbi Nitras

Lead nitrate. In white, nearly opaque, octahedral crystals, permanent in the air, and of a sweet astringent taste. It is soluble in seven and a half parts of cold water, and in alcohol. Its solution is precipitated black by hydrosulphate of ammonium, white by ferrocyanide of potassium, and yellow by iodide of potassium.

Plumbi Iodidum

Lead iodide. A bright-yellow, heavy, inodorous powder, fusible and volatilizable by heat, and soluble in 1,235 parts of cold and 194 parts of boiling water. A hot saturated solution, on cooling, deposits the salt in brilliant, golden scales.

Unguentum Plumbi Iodidi

Ointment of iodide of lead. (Iodide of lead, 10 grm.; benzoinated lard, 90 grm.)

Antagonists and Incompatibles

Natural waters containing lime, sulphates, carbonates, carbonic acid, mineral acids and mineral salts, vegetable acids, alkalies, iodide of potassium, the vegetable astringents in general, albuminous solutions, and the preparations of opium, are incompatible. In cases of poisoning by acetate of lead, the proper antidotes are the sulphates of soda or magnesia, phosphate of soda, milk, and albuminous solutions. Emetics and the stomach-pump should be used.

Synergists

Cold, digitalis, ergot, veratrum viride, and agents acting similarly, favor the influence of acetate of lead over the circulatory system. Copper, mercury, antimony, and remedies promoting waste, increase the depressing effects of lead on the nutrition of the body.

Physiological Actions

The acetate is astringent; that is, it combines with albumen to form compounds, for the most part insoluble in water and in acids. All the salts of lead are more or less toxic. As the acetate, which is most frequently the preparation taken, has a sweetish taste, mistakes not infrequently happen; but the after-taste is decidedly astringent and slightly metallic. As the combination of the salts of lead with albumen takes place on contact, this action ensues in the mouth in part, and is completed in the stomach. Any part of the lead reaching the intestinal canal must be converted into the insoluble sulphide. A very large quantity of the acetate of lead is required to produce a fatal effect; not less than an ounce. When swallowed in this quantity and retained, it produces intense gastric irritation, sometimes choleriform symptoms, numbness, paralysis, coma, collapse. Owing to the fact that so large a quantity of acetate of lead will be rejected by vomiting, cases of acute poisoning rarely terminate fatally, and are infrequent. On the other hand, chronic poisoning by lead is very common, owing to the use of cosmetics and hair-dyes containing lead, the use of food preserved in tin cans soldered with lead, and to the contamination of drinking-water. Very rarely is the acetate of lead so persistently used in medical practice as to produce toxic symptoms.

When lead is slowly introduced into the organism in small doses, the first symptoms usually observed are loss of appetite, failure of strength, more or less wasting, paleness of the face and of the integument generally, and constipation. The joints become the seat of rheumatoid pain; there is dry colic, the pain of which is assuaged by pressure; and the muscles of the abdominal parietes are also seized with neuralgia. At the same time the liver diminishes in size, the abdominal fat disappears, the intestines are contracted, the belly is drawn in toward the spinal column. Coincidently with the contraotion of the liver, the skin assumes an icteroid hue, the conjunctivae become yellow, and the urine is tinged with the biliary coloring matters. At this time may be observed the so-called "blue line" along the margin of the incisor teeth — a slate-colored line, probably due to a deposition of the sulphide of lead, and found only, according to the author's experience, in those not accustomed to the use of a toothbrush. The mucous membrane of the lips and mouth has often a bluish or slate-colored tint, and sometimes brownish pigment-deposits are seen on the lips near the teeth, and on the gums. Albuminuria may exist at this time, but it is commonly present further on in the history of these cases. Lead may cause that condition of hyperalbuminosis which eventuates in albuminous urine, but probably it in most cases hastens the development of changes in the kidneys already impending. As Garrod has conclusively shown, the use of lead, or its slow introduction through unknown channels, hinders the conversion of uric acid into urea, and favors the deposition of urate of soda about the joints: hence the arthritic pains which accompany the other symptoms of chronic lead-poisoning, and the intimate relation of the presence of lead in the organism and gouty attacks.

The symptoms thus far sketched are chiefly those due to the influence of the agent over the oxidation processes of the body in general. It is necessary now to consider the action of lead on the nervous system. Lead gastralgia is an early symptom, in part due to the fact that the metal acts directly on the nerves of the stomach, but it is also a symptom of the action of the poison on the central nervous system. Lead arthralgia, already referred to, is frequently an affection of the intra-muscular nerves, and has its seat more especially in the flexor muscles. The swelling of the joints and the joint-pains are doubtless due, as already explained, to the deposition of the urates in the joints themselves, but the term arthralgia is used to describe that form of pain about the joints produced by lead. Impaired sensibility to touch is also one of the phenomena of lead-poisoning. This lead-anaesthesia is found about the neck, chest, the forearms (their palmar face), hands, and fingers, and is symmetrically distributed on the two sides. Anaesthesia of the optic (amaurosis) is also a result of the direct action of lead, but dimness of vision and a sluggish pupil may also be due to the albuminuria which is so frequently present. Paralysis of the common extensors of the fingers and of the supinators, while the power of the flexors and pronators is much less diminished, constitutes that very striking symptom of lead-poisoning, "the drop-wrist." When the arms are raised the hands drop forward and to the palmar face of the forearm, from an inability of the extensors to hold them up. Paralysis may invade the laryngeal muscles, producing aphonia. Sometimes the paralysis has the hemiplegic form, and, still more rarely, the paraplegic. At the beginning of the paralysis, the muscular irritability is preserved, but it soon lessens, and is lost finally, so that the muscles cease to respond to the faradic current. For some time after the induction current fails to excite contraction, muscular movements may be obtained by a slowly-interrupted galvanic current.

Death may result from the saturnine cachexia, by the gradual failure of nutrition, and by the extension, finally, of the muscular paralysis to the muscles of respiration. Death may occur much earlier, by the development of those symptoms to which has been applied the term lead-encephalopathy—a form of disease characterized by delirium and convulsions, ending in fatal coma.

Lead is very fatal to the life of the foetus, and women the subjects of the saturnine cachexia abort early, or produce stillborn children.

After death, lead is found in various organs of the body, and relatively in large amount in the brain. It is also largely deposited in the substance of the affected muscles and nerves, and the destruction of the Hallerian irritability, the disappearance of the striation and the granular condition of the nerves, are probably due to the direct action of the metal. Lead, also, like the other minerals, tends to accumulate in the liver; much of it is probably eliminated by the intestinal glands and skin, and some passes out by the kidneys.

The treatment of lead-poisoning is prophylactic and curative. Among the former are, personal cleanliness, frequent bathing, the use of sulphuric-acid lemonade, the habitual employment of milk in large quantity as a food, and the avoidance of all sources of contamination. Among the curative measures must be placed first, large doses of the iodide of potassium, purgative doses of Epsom salts, and sulphur-baths. The affected muscles should be early faradized to prevent atrophic changes. When they fail to respond to a faradic current, a slowly-interrupted galvanic current should be used, and after a time the faradic irritability may be recovered.