Cyberfriends: The help you're looking for is probably here.

Welcome to Ed's Pathology Notes, placed here originally for the convenience of medical students at my school. You need to check the accuracy of any information, from any source, against other credible sources. I cannot diagnose or treat over the web, I cannot comment on the health care you have already received, and these notes cannot substitute for your own doctor's care. I am good at helping people find resources and answers. If you need me, send me an E-mail at scalpel_blade@yahoo.com Your confidentiality is completely respected.

DoctorGeorge.com is a larger, full-time service. There is also a fee site at myphysicians.com, and another at www.afraidtoask.com.

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With one of four large boxes of "Pathguy" replies.

I'm still doing my best to answer everybody. Sometimes I get backlogged, sometimes my E-mail crashes, and sometimes my literature search software crashes. If you've not heard from me in a week, post me again. I send my most challenging questions to the medical student pathology interest group, minus the name, but with your E-mail where you can receive a reply.

Numbers in {curly braces} are from the magnificent Slice of Life videodisk. No medical student should be without access to this wonderful resource. Someday you may be able to access these pictures directly from this page.

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Especially if you're looking for information on a disease with a name that you know, here are a couple of great places for you to go right now and use Medline, which will allow you to find every relevant current scientific publication. You owe it to yourself to learn to use this invaluable internet resource. Not only will you find some information immediately, but you'll have references to journal articles which you can obtain by interlibrary loan, plus the names of the world's foremost experts and their institutions.

Clinical Queries -- PubMed from the National Institutes of Health. Take your questions here first.
HealthWorld
Yahoo! Medline lists other sites which may work well for you

Alternative (complementary) medicine has made real progress since my generally-unfavorable 1983 review linked below. If you are interested in complementary medicine, then I would urge you to visit my new Alternative Medicine page. If you are looking for something on complementary medicine, please go first to the American Association of Naturopathic Physicians. And for your enjoyment... here are some of my old pathology exams for medical school undergraduates.

I cannot examine every claim which my correspondents share with me. Sometimes the independent thinkers prove to be correct, and paradigms shift as a result. You also know that extraordinary claims require extraordinary evidence. When a discovery proves to square with the observable world, scientists make reputations by confirming it, and corporations are soon making profits from it. When a decades-old claim by a "persecuted genius" finds no acceptance from mainstream science, it probably failed some basic experimental tests designed to eliminate self-deception. If you ask me about something like this, I will simply invite you to do some tests yourself, perhaps as a high-school science project. Who knows? Perhaps it'll be you who makes the next great discovery!

Our world is full of people who have found peace, fulfillment, and friendship by suspending their own reasoning and simply accepting a single authority which seems wise and good. I've learned that they leave the movements when, and only when, they discover they have been maliciously deceived. In the meantime, nothing that I can say or do will convince such people that I am a decent human being. I no longer answer my crank mail.

This site is my hobby, and I presently have no sponsor.

This page was last updated February 6, 2006.

During the ten years my site has been online, it's proved to be one of the most popular of all internet sites for undergraduate physician and allied-health education. It is so well-known that I'm not worried about borrowers. I never refuse requests from colleagues for permission to adapt or duplicate it for their own courses... and many do. So, fellow-teachers, help yourselves. Don't sell it for a profit, don't use it for a bad purpose, and at some time in your course, mention me as author and KCUMB as my institution. Drop me a note about your successes. And special thanks to everyone who's helped and encouraged me, and especially the people at KCUMB for making it possible, and my teaching assistants over the years.

Whatever you're looking for on the web, I hope you find it, here or elsewhere. Health and friendship!

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Sublime tobacco! which from east to west
Cheers the tar's labor or the Turkman's rest;...
Divine in hookas, glorious in a pipe,...
Yet thy true lovers more admire by far
Thy naked beauties -- Give me a cigar!

--Lord Byron (1788-1824) The Island II.19

... And for the vanities committed in this filthy custom, is it not both great vanity and uncleanness, that at the table, a place of respect, of cleanliness, of modesty, men should not be ashamed, to sit tossing of tobacco pipes, and puffing of the smoke of tobacco one to another, making the filthy smoke and stink thereof, to exhale across the dishes, and infect the air, when very often men that abhor it are at their repast?... It makes a kitchen also often-times in the inward parts of men, soiling and infecting them, with an ... oily kind of soot, as has been found in some great tobacco takers, that after their death were opened.... Have you not reason then to be ashamed and to forbear this filthy novelty ... a custom loathsome to the eye, hateful to the nose, harmful to the brain, dangerous to the lungs, and in the black stinking fume thereof, nearest resembling the horrible Stygian smoke of the Pit that is bottomless....?

-- King James I of England (1566-1625)

A Counterblast to Tobacco

The incessant, witless repetition of advertisers' moron-fodder has become so much a part of life that if we are not careful, we forget to be insulted by it.

-- The Times of London

Some years ago a model named David Goerlitz told me that while posing for a Winston ad he had asked a group of R.J. Reynolds executives if any of them smoked. He said one of them replied: "Are you kidding? We reserve that right for the poor, the young, the black, and the stupid." -- Bob Herbert, New York Times columnist, 1998

TOBACCO SMOKING: Med. Clin. N.A. 76: 355, 1992. Here are some facts you may find handy in talking with patients.

Tobacco was discovered by the American Indians, and has been described as their revenge. The addictive leaves were smoked in pipes, called tobaccos, which gave the plant its European name. Early explorers introduced tobacco to the rest of the world. No country has ever been able to rid itself of tobacco -- even when tobacco use has been a capital crime. With widespread smoking of cigarets (today's preferred spelling of "cigarettes"), previously-rare diseases such as lung cancer and emphysema became common. Even Hitler and his people recognized that smoking was highly addictive and explained the new epidemic of lung cancer, and as part of their "purity" campaign undertook a strong anti-tobacco campaign (Br. Med. J. 313: 1450, 1996); the German tobacco industry called this "unscientific". Cigaret smoking is now a major problem throughout the world. Mainland China has the world's highest cigaret consumption per capita. The role of the U.S. in all this is troubling: Thorax 46: 153, 1991. In Singapore, they're now caning anybody under 18 caught doing tobacco ("Good" says Ed; Br. Med. J. 313: 636, 1996).

Today, tobacco smoke is the most widespread of the known pollutants. In developed countries, ethanol and tobacco are the two principal causes of avoidable death. Surgeon General Koop called cigaret smoking "the chief, single, avoidable cause of death in our society and the most important public health problem of our time." (I'd have voted for alcoholism on the second point, but it's close....) Tobacco smoking kills 1000 people in the US each day. Mortality rates for young and middle-aged cigaret smokers is 1.7 x that of nonsmokers. By taking up smoking, a person cuts his or her life expectancy by 15 years (JAMA 258: 2080, 1987); the estimate of "5 minutes of life lost for every cigaret" is probably low.

Tobacco smoke is a complex mixture that contains nicotine (the addictive component) and many other harmful substances, including carbon monoxide, benzopyrene (* mutates ras codon 12 G-->T; Cancer 72: 432, 1993), nickel, polonium, and radon. "Low-tar" and "low nicotine" cigarets are not measurably less dangerous than the regular kind (Am. J. Pub. Health 77: 546 & 685, 1987). Smoking without inhaling (pipes, cigars) is less addictive and easier on the lungs, but the risk of mouth and throat cancer is high.

"Smokeless tobacco" ("spit tobacco") is as addictive as cigarets. The average age at which an American begins "chewing tobacco" is now ten (JAMA 266: 3143, 1991). Tobacco companies make "starter" (low-nicotine, nice flavors) chewing tobacco products targeted at kids, who then graduate to the more familiar products. And every school kid knows that chewing tobacco and snuff are much safer in the long-term than smoking. (If anti-tobacco education really was concerned with telling the whole truth and saving lives, rather than "teaching values", we'd encourage teens who cannot quit using tobacco to switch to smokeless tobacco. But this is politics.) Snuff produces a trademark mutation in p53 (Int. J. Cancer 81: 527, 1999), and a variety of curious benign mucosal lesions (which often appear within a few days after beginning smokeless tobacco use), and occasionally causes a mouth cancer (same genes mutated as in smokers' mouth cancer: Cancer 83: 204, 1998... one has to wonder whether this really demonstrates cause and effect). The risk of getting cancer from chewing is much less than is generally supposed (Oral Surg Oral Path 86: 697, 1998). No surprise. Apart from some nitrosamines, the noted carcinogens in tobacco smoke are products of combustion. Cardiovascular effects of snuff, at least in Sweden (Reg. Tox. Pharm. 28: 1, 1998; J. Am. Coll. Card. 34: 1784, 1999), are conspicuous by their absence: nor does Swedish snuff produce any measurable increased risk of cancer (Cancer 82: 1367, 1998). A study of baseball players, about half of whom use smokeless tobacco, showed that it was bad for their gums and teeth (gee whiz) but produced no difference in athletic performance (ooh, Abstract 98185116; no cancers either). Smokeless tobacco does not impair middle-aged men's exercise abilities (Eur. J. Clin. Inv. 27: 427, 1997). But if you are not already physically addicted to nicotine, using smokeless tobacco has nothing to recommend it.

What happens to tobacco smokers? You will learn about the anatomic lung pathology of uncomplicated cigaret smoking later in the course. After high serum cholesterol, cigaret smoking is the most important risk factor for coronary heart disease (heart attacks, sudden death, angina pectoris -- see Chest 94: 449, 1988) and other complications of atherosclerosis (including ruptured aortic aneurysms and strokes -- for the latter, see Lancet 2: 643, 1989). Smoking lowers HDL ("good") cholesterol; nobody knows how. Chronic bronchitis and emphysema (together, "chronic obstructive pulmonary disease") kill 150,000 people in the US each year. Lung cancer kills around 170,000 people in the US each year. Most patients who get the disease die of it. The vast majority of these cancers are caused by cigaret smoking. Mouth cancer, throat cancer, larynx cancer, and esophageal cancer are all much more common in tobacco smokers. Bladder cancer rates are roughly tripled for cigaret smokers. Pancreatic cancer and kidney cancer rates are at least doubled for cigaret smokers. Leukemia and plasma cell myeloma are also probably increased in smokers. We are now zeroing in on the molecular biology on oncogenesis on these cancers, which seem to result, at least in part, from mutations which carcinogens in tobacco cause. Smoking and cancer: Am. J. Med. 93(1A): 13S-17S, 1992. Tobacco mutates p53 (gee whiz NEJM 332: 712, 1995).

Peptic ulcer disease is especially common in cigaret smokers. Cigaret smoking accounts for an extra 15,700 cases of stroke among U.S. men each year (accelerated atherosclerosis and hypercoagulable blood: NEJM 316: 628, 1987; also Am. J. Med. 149: 2053, 1989). Buerger's disease is a (fortunately rare) disease of young male smokers, who develop gangrene of their hands and feet. Osteoporosis in women is also exacerbated by smoking, and tobacco will rob a woman of 5-10% of her total bone mass over a lifetime (NEJM 330: 387, 1994). It increases your risk for rheumatoid arthritis, probably (Arth. Rheum. 39: 732, 1996). The majority of household fires are caused by cigaret smoking. In Cuban epidemic neuropathy (1991-1993), tobacco combined with malnutrition (no thanks Fidel) to cause a grisly disease, and tobacco amblyopia (i.e., going blind from it) is probably a sporadic variant. Rear-end collisions often result from "acts of smoking" (i.e., fumbling for your tobacco, lighting, flicking, etc.: JAMA 273: 1334, 1995). And smoking causes gum disease, bad breath, and stained teeth. (An unusually candid RJR dealer once acknowledged on TV that tobacco smoking "may" cause stained teeth "in predisposed individuals".) In a study with an obvious flaw ("it's dumb to smoke, and being dumb could be hereditary"), mothers who smoked during pregnancy gave birth to kids with persistently far-lower IQ's (Pediatrics 93:221, 1994), but the "definite maybe" that this causes brain damage in the unborn child is still alarming. And we now know it greatly accelerates wrinkling of the skin (Ann. Int. Med. 114: 840 & 900, 1991). A strong statistical relationship between parents' smoking and kids' tooth decay (JAMA 289: 1258, 2003) seems harder to believe; even though this is after controlling for frequency of dental visits and all the usual socioeconomic stuff, maybe parents who blow smoke on their kids also care less about their teeth-brushing and candy consumption.

During the 1950's (people still idealize the "family values" era), popular ads showed physicians endorsing particular brands of cigarets, and it was considered very rude to complain if somebody blew smoke in your face in public. Today, there is no longer any reasonable doubt that passive smoking (inhaling someone else's cigaret smoke) is dangerous. It is hard to know how many people die as a result of second-hand smoke, but histopathologists may examine JAMA 268: 1697. 1992). Parents' smoking and children's health: Am. Rev. Resp. Dis. 133: 959, 1986; spouses' health: Am. J. Pub. Health 77: 548, 1987; smoking and children's asthma Chest 122: 409, 2002; one problem with this kind of work is controlling for the fact that any adult who'd smoke around his/her asthmatic kid probably doesn't take good care of the kid in general. More: Arch. Ped. Adol. Med. 151: 135, 1997. In New Zealand, they're monitoring nicotine levels in kids' hair to see whether the parents smoke around them (Arch. Env. Health 56: 117, 2001). The impact of passing smoking on coronary disease (if real) is probably small: NEJM 340: 920, 1999 (the literature is full of people still trying to show an effect.) The EPA (Am. J. Med. 93(1A): 38-S, 1992) decided that second-hand smoke kills 53,000 Americans yearly (which is plain silly, as EPA pronouncements so often are). Philip Morris fought back with a campaign calling this "junk science", but ended up quietly admitting that environmental smoke could indeed cause lung cancer (Am. J. Pub. Health. 91: 1742, 2001). But the push to a smoke-free workplace is laudable. In the mid-1990's, the ethics circus included a proposed ban on smokers adopting babies.

It is very difficult to quit, and people have done so deserve our congratulations. Quitting smoking greatly and quickly improves one's chance of a long and healthy life. The risk of sudden cardiac death drops almost to baseline immediately, while the risk of heart attack and lung cancer return to baseline over the next several years (NEJM 322: 213, 1990). Only the changes of emphysema are known to be irreversible.

Defenses of tobacco smoking are ingenious but flawed, and closely resemble other forms of junk science / pseudoscience. (See, for example, "Dr. Oat Cell"'s letter, JAMA 255: 1016, 1986.) Even the scientists who get their grant money from the tobacco companies ("The Council on Tobacco Research") are pretty much unanimous in agreeing that smoking obviously causes disease (Am. J. Pub. Health. 81: 894, 1991). People don't smoke "because they like the taste" -- if they did, you could buy tobacco-flavored ice cream at "31 Flavors". People smoke because they are physically addicted to nicotine (see Chest 93(2S), 1988; the withdrawal syndrome is as severe as drugs that actually give pleasure, see JAMA 261: 898, 1989). Most addicts started smoking as teenagers, in order to assert their "independence" and as a sign of "maturity". The majority are never able to quit. Addicts cannot really exercise "freedom of choice". There is not a shred of evidence for "a gene to like cigarets" that also causes all cigaret-related diseases. There is no evidence, either, that smokers are self-medicating for a primary deficiency in certain neurotransmitters.

Our laws governing tobacco are "peculiar". The laws protecting US citizens from dangerous products all contain specific exemptions for tobacco. Before the 1997 compromise, the words addictive and death were kept off tobacco warning labels, as a compromise with dealers. We have banned heroin, cocaine, cyclamates, many useful drugs, lawn darts, and pet turtles, but we subsidize and advertise tobacco and allow smoking in public. Some (not all) conservatives shout for more and tougher penalties for the recreational drugs, while sporting "Smokers' Rights" bumper stickers. Advertising by tobacco dealers is a multi-billion dollar industry (NEJM 311: 725, 1987). The Camel mnanufacturers actually sued the physician who did a study intended to show that Joe Camel appealed primarily to children (JAMA 266: 3143, 1991); of course in 1999, the Marlboro Man rode Joe into the sunset. The Minnesota Tobacco Trial documents are a good read: JAMA 280: 1173, 1998. Today, tobacco advertisers are making a special effort to target minority youth, especially Hispanics, blacks, and gays (Am. J. Pub. Health 92: 1086, 2002), and to young people going to bars, where they are going to take up drinking and are most susceptible to taking up other "adult" habits as well (Am. J. Pub. Health 92: 75, 2002). U.S. tobacco companies presently give cigarets to minority youths in the US at sponsored "youth events" and to children in the poor nations as "gifts", i.e., to get them addicted. Perhaps there's some good news ... Mainland China was the heaviest-smoking country in the late 20th century, but if we're to believe the Red Chinese (uh, sure), only 1 in 300 of their high school students are presently smokers Am. J. Pub. Health 91: 1653, 2001. The cost to the U.S. of cigarets in terms of lost productivity is estimated at $53.7 billion per year (Onc. Times 9(9): 5, 1987). Of course, this ignores savings generated by cigarets -- specifically, in old-age care and pensions that smokers never use! (I suspect this is why tobacco is not more closely regulated!) Perhaps most disturbing of all, U.S. "fair trade" treaties with third world nations restrict their attempts to prevent their citizens from smoking (Am. J. Pub. Health 80: 659, 1990). Despite the grandstanding of the 1997-8 settlement ("Protect children!"), don't expect this to change. Follow-up on the "settlement": Am. J. Pub. Health. 94: 218, 2004.

In spite of all this, however, most adults today know that tobacco is highly addictive and lethal. U.S. men are smoking less, and the incidence of lung cancer in men is finally starting to go down. Cigaret smoking, once macho, is now a teenaged girl's vice. The most successful stop-smoking campaigns are run by industry. Each smoking worker costs industry several hundred dollars extra per year.

The most effective anti-smoking ads directed for young people are the ones which remind them "The tobacco companies are playing you for a fool" (JAMA 279: 772, 1998).

Health care professionals are natural leaders in the fight against tobacco. Today only around 20% of physicians and 20% of nurses are tobacco smokers -- way down from previous decades. There are many packages to help your patients quit. The skin patch is now over-the-counter, and nicotine (though of course "evil") itself does not seem to be a problem for heart patients, who can use the patch safely (NEJM 337: 1230, 1997). Doxepin and clonidine both ease withdrawal, and "Zyban" became a sensation in 1998. There's also "Nicotrol" nicotine nasal spray (Mayo Clin. Proc. 73: 118, 1998; "the patch for 5 months and the spray for a year" BMJ 318: 285, 1999). Bupropion and/or patch: NEJM 340: 685, 1999.

If you believe that a physician's job is to improve the health of his or her patients, you will want to talk to them about smoking. If you take two minutes to urge a patient to stop smoking, he or she is around 50% likely to eventually quit. (See also Am. J. Pub. Health 77: 313 & 782, 1987; JAMA 259: 2882 & 2883, 1988). Comparisons of three stop-smoking clinics: Am. J. Pub. Health. 80: 554, 1990. To quantitate tobacco smoke exposure in your research, measure urinary cotinine (Thorax 45: 356, 1990). To measure oxidative damage to a person, measure serum F₂-isoprostane: yes, cigarets greatly increase it (NEJM 332, 1995).

THE PNEUMOCONIOSES: A group of diseases, ancient and modern, resulting from dust inhalation. (* Conios means "dust" in Greek.) Occupational lung disease: Disease-A-Month 44: 41, 1998.

Pneumoconiosis I From Chile In Spanish

Pneumoconiosis II From Chile In Spanish

Occupational Lung Disease Bryan Lee

Dust elimination by the respiratory tree:

Particles over 5 microns are caught in the upper airways and eliminated on the mucociliary elevator

Particles under 1 micron either are not deposited or are deposited diffusely on the alveolar surfaces

Particles 1-3 microns in size tend to be deposited at the level of the respiratory bronchioles because of the sudden decrease in air velocity at this level. (These particles are the most dangerous.)

The pneumoconioses tend to involve the upper lobes more than the lower lobes, because more air goes to the upper lobes (why?)

Exception: long, thin fibers (i.e., asbestos) end up carried by the wind to alveolar duct bifurcations, where they penetrate the tissue and work their way through the lung parenchyma.

Mechanisms of dust removal from the respiratory bronchioles and alveoli include transport on surfactant and in lymphatics and/or phagocytosis by wandering macrophages.

Inorganic pneumoconioses:

Chronic diseases, typically with pulmonary fibrosis.

Silicosis, asbestosis, berylliosis, and complicated forms of coal workers' pneumoconiosis have caused widespread morbidity and mortality. They often appear and progress long after exposure to the dusts.

Except for trouble breathing, patients with the inorganic pneumoconioses usually have few or no physical signs.

* Patients with alveolar fibrosis from asbestos may have "dry velcro" rales audible best in the mid-axillary lines. The others will probably have a normal physical exam.

Respiratory failure and/or cor pulmonale (right-sided heart failure from pulmonary hypertension) eventually kill the patients.

Most inorganic dust exposures are much less dangerous.

Traditionally included among the inorganic pneumoconioses are harmless accumulations of inert dusts -- iron oxide, barium, tin, welding fumes (NEJM 316: 631, 1987), etc.

*Exotic dusts (such as produced in grinding of "hard metal" -- a tungsten alloy used in the tool and die industry) can occasionally cause disease (Eur. J. Resp. Dis. 69: 83, 1986). The chief culprit is probably cobalt (Chest 95: 2 & 29, 1989) with a contribution from nickel (Thorax 45: 267, 1990). αTNF is implicated as culprit in the pathophysiology: Am. Rev. Resp. Dis. 146: 1600, 1992.

A variety of "dust diseases" -- including simple coal-worker's pneumoconiosis -- are caused by dust accumulation plus small amounts of fibrosis around the terminal (* "membranous") and respiratory bronchioles. These compromise respiration far less than do the fibrogenic dusts.

The inorganic pneumoconioses are often "mixed", depending on type of exposure and complications.

*For example, "dental technician's pneumoconiosis" is due to inhalation of a mixture of silica, asbestos, vitallium, and other curious substances.

"Black lung" changes its meaning as the laws change.

Like most diseases, the inorganic pneumoconioses are incurable.

Some of the coal dust may be lavaged from the lungs.

Organic pneumoconioses:

Allergic diseases caused by spores, fibers, etc. They are more important than their omission from Baby Robbins would indicate.

Type I (IgE-mediated, asthma) and/or Type III (immune complexes, vasculitis) & IV (cell-mediated, granulomatous) reactions are the mechanisms of tissue injury. This is bad.

Usually patients recover, usually with little or no fibrosis, but repeated exposure causes the disease to recur. Treatment is directed against the hypersensitivity reaction.

{27639} bowling ball manufacture; rumors of dust disease {27623} taxidermy; a bad career choice for the person allergic to animals

COAL WORKER'S PNEUMOCONIOSIS (CSP, "black lung"): Path standards: Arch. Path. Lab. Med. 103(8), 375-432, 1979 (still the best)

{27458} coal miner
{27514} coal workers

A complex pneumoconiosis:

Lesions attributed to coal dust itself ("simple CWP", i.e., the coal macule)

Lesions of silicosis (anthracite coal contains more silica, but bituminous coal workers get silicosis too)

Lesions possibly due to air pollution (miner's wives also suffer severe respiratory symptoms)

Lesions of cigaret smoking (Most disabling "black lung" really results from cigaret smoking!)

Lesions of co-existing tuberculosis

Lesions typical of autoimmune lung disease ("Caplan's syndrome" when the patient has an inorganic pneumoconiosis)

Lesions not easily accounted for by any of the above -- notably progressive massive fibrosis ("genuine black lung").

Simple CWP: the coal macule (macule means "spot")

Focal accumulations of coal dust in the lung. Coal macules are considered practically harmless.

Patients with simple CWP rarely have serious respiratory problems unless there is additional pathology (silicosis, TB, Caplan's, progressive massive fibrosis, cigaret damage).

Coal macules do not grow after coal dust exposure ceases, though patients will cough up black dust for years afterwards. This will impress the miner (and the politicians), who may believe this indicates serious disease.

*Symptomatic graphite pneumoconiosis is now believed to be due to silica in graphite.

Gross pathology:

You can feel the coal macules as 1 mm, hard black bumps. These are located at the centers of pulmonary lobules (i.e., around respiratory bronchioles).

Microscopic pathology:

Aggregates of carbon-laden macrophages within a reticulin network. There is no dense fibrosis. There is mild focal stretching of air-spaces ("emphysema") around the bronchiole, but (in non-smokers!) this is not believed to impair respiratory function.

Hut lung
From indoor air pollution
Dr. Warnock's Collection

Silicosis
Lung pathology series
Dr. Warnock's Collection

{08762} anthracosilicosis

In our polluted times, carbon pigment is present in the lungs of every adult. This is ordinarily called anthracosis.

Progressive massive fibrosis

PMF is variously defined to be many large nodules and/or one or more circumscribed areas of dense black scar-like tissue, usually in an upper lobe.

It is uncommon, affecting less than 1% of those exposed to coal dust

"Fibrosis" is a misnomer, as there is not nearly so much collagen in these lesions as you'd find in a scar or a silicotic nodule

Collagen: 20-30%

*Calcium phosphate: 1-30%

*Glycosaminoglycans: 10-20%

*IgA and IgG: several % (but no IgM)

Coal: up to 20%

*All the rest is "amorphous protein" including fibronectin

The etiology of PMF is still obscure, but is probably immune-mediated and caused by the carbon itself.

*Thinking about etiology focuses on rupture of carbon-filled hilar lymph nodes, with discharge of their contents into the air spaces. This makes the most sense.

*A PMF-like lesion can be induced in immunologically altered animals by giving coal dust, and PMF occurs in graphite and carbon electrode workers.

PMF is progressive and lethal. Death usually occurs within a few years. There is no treatment.