Towards a biological perspective on disease

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  • Acute-on-Chronic Cholecystitis (Inflammation of the Gallbladder) Appearance of Disease: This specimen removed at autopsy consists of a thickened, fibrotic gallbladder (indicative of chronic inflammation), with a gallstone (calculus) impacted in the outlet of the gallbladder (cystic duct). This obstruction to the outflow of bile has resulted in acute inflammation of the gallbladder (cholecystitis), with secondary bacterial infection causing the organ to fill with pus (empyema). Peritoneal fat (omentum) has become adherent to the gallbladder, and is also acutely inflamed. This specimen shows a gallbladder with a thickened, fibrotic wall (indicative of chronic inflammation), with a gallstone obstructing the gallbladder outlet (cystic duct). This has resulted in acute inflammation of the gallbladder (cholecystitis), with pus filling the organ (empyema). Comment: Gallstones are extremely common in Western society. By far the commonest type of gallstones are the so-called mixed stones. These stones are multiple, 1-3 cm in diameter. They may be round, or have faceted surfaces. They are composed largely of cholesterol. Risk factors include increased cholesterol in bile, which is associated with increasing age; female gender; obesity; racial and genetic factors; high fat diet; diseases associated with elevated circulating levels of cholesterol, including diabetes mellitus and some forms of hyperlipidaemia. Complications of gallstones include: 1) Recurrent pain in the right upper quadrant of the abdomen (as in this case), known as "biliary colic". This is caused by passage of stones along the gallbladder outlet (cystic duct) and the common bile duct. 2) Obstruction of: a) The cystic duct or neck of the gallbladder to cause acute and chronic cholecystitis (as in this case); b) The common bile duct, causing obstructive jaundice; c) The Ampulla of Vater (where the common bile duct and pancreatic duct empty into the duodenum), resulting in pancreatitis. 3) Secondary bacterial infection, leading to: a) Empyema of the gallbladder (as in this case); b) Gangrene of the gallbladder wall; c) Perforation (rupture) leading to peritonitis; d) Inflammation of the bile ducts caused by obstruction of the common bile duct - ascending cholangitis; e) Septicaemia (as in this case) 4) Carcinoma of gallbladder. This is a rare cancer, with most cases occurring in patients with gallstones
  • Lobar Pneumonia - Appearances of Disease: <<<<< $ Not their term The specimen is a slice of the left lung. The upper lobe is relatively normal, except for an old scar near the apex of the lung caused by tuberculosis. The major abnormality is that the lower lobe is uniformly consolidated (airless and solid) due to lobar pneumonia, with inflammatory cells and exuded plasma filling the airspaces. The shaggy material on the pleural surface is fibrin, a protein derived from fibrinogen in exuded plasma. This specimen shows a slice of the left lung affected by pneumonia, caused by a virulent form of bacteria. The acute inflammation caused by the infection resulted in the solidification of the lower lobe, which became filled with inflammatory cells and exuded plasma rather than air. Relatively normal upper lobe of the lung Airless, solidified ("consolidated") lower lobe of the lung - the airspaces are filled by inflammatory cells and exuded plasma proteins Comment: Pneumonia is an acute inflammation of the airspaces of the lung, usually caused by bacterial infection. This woman died of pneumonia affecting an entire lobe of the lung, before the advent of antibiotics. Nowadays, it is uncommon to die in the acute stages of lobar pneumonia because Streptococcus pneumoniae ("the pneumococcus"), which is the bacterium that typically causes a lobar distribution of pneumonia, is sensitive to various antibiotics. However, there is an increasing incidence of pneumococcal resistance to Penicillin - usually the most effective antibiotic in this situation.
  • Towards a biological perspective on disease

    1. 1. Towards A Biological Perspective On Disease For a full transcript of the presentation, for which these slides were an accompaniment, please visit: https://sites.google.com/site/sjlewis55/presentations/brownbag2005
    2. 2. Which is, and which is not, a ‘disease’? And why?
    3. 3. ‘ My research is concerned with exploring the biological and philosophical aspects of the concepts of disease and health and considering the uses and applications of these findings.’
    4. 4. Towards a Biological Perspective on Disease <ul><li>Stephen Lewis </li></ul>
    5. 5. ‘ The point of philosophy is to start with something so simple as not to seem worth stating, and to end with something so paradoxical that no one will believe it.’ Bertrand Russell
    6. 6. ‘ [P]hilosophy is often a matter of finding a suitable context in which to say the obvious.’ Iris Murdoch (1970)
    7. 7. ‘ [I]f we want to learn anything really deep, we have to study it not in its 'normal', regular form, but in its critical state, in fever, in passion. If you want to know the normal healthy body, study it when it is abnormal, when it is ill.’ Imre Lakatos (Proofs and Refutations, 1976)
    8. 8. 'Central to the enterprises of both philosophy and medicine are the images and ideas held about what man is and what his existence signifies for himself and the world … … medicine and biology are two powerful instruments of scrutiny of the image of man. Together with philosophy, they can help contemporary man to understand a little more about what he is …’ (Editorial. (Edward Pellegrino) J. Med. Phil. 1976)
    9. 9. Which is, and which is not, a ‘disease’? And why?
    10. 10. Gall stones (Acute-on-Chronic Cholecystitis)
    11. 11. (Lobar) Pneumonia
    12. 13. Illness Disease Pathology
    13. 14. ‘ Sickness ... is the external and public mode of unhealth. Sickness is a social role, a status, a negotiated position in the world, a bargain struck between the person henceforward called 'sick', and a society which is prepared to recognise and sustain him.’ Marshall Marinker, 1975
    14. 15. Illness Disease Pathology
    15. 16. ‘ Illness ... is a feeling, an experience of unhealth which is entirely personal, interior to the person of the patient. Often [illness] accompanies disease, but the disease may be undeclared, as in the early stages of cancer or tuberculosis or diabetes. Sometimes illness exists where no disease can be found.' Marshall Marinker, 1975
    16. 17. ‘ Disease ... is a pathological process, most often physical as in throat infection, or cancer of the bronchus, sometimes undetermined in origin, as in schizophrenia … There is an objectivity about disease which doctors are able to see, touch, measure, smell.’ Marshall Marinker, 1975
    17. 18. Giovanni Battista Morgagni (1682-1771) <ul><li>De Sedibus et Causis Morborum per Anatomen Indagatis – 1761 </li></ul><ul><li>[ On the Seats and Causes of Disease Investigated by Anatomy ] </li></ul>NOT sites
    18. 20. <ul><li>Effects of the presence of the ‘seat’ </li></ul>- ‘Seat’ of disease
    19. 21. Self- Awareness Anatomy & Physiology Overall Biological State
    20. 22. Orange R – 240 G – 40 B – 10
    21. 23. Disturbance Overall Biological State Anatomy & Physiology Self- Awareness Disease Illness Pathological
    22. 24. No illness No Pathology Health
    23. 25. R - 245 B - 45 G - 5 R - 240 B - 35 G - 5 R - 235 B - 35 G - 5 R - 245 B - 45 G - 10 R - 240 B - 40 G - 10 R - 235 B - 35 G - 10 R - 245 B - 45 G - 15 R - 240 B - 45 G - 15 R - 235 B - 35 G - 15
    24. 26. Which is, and which is not, a ‘disease’? And why?
    25. 28. <ul><li>Why these particular responses? </li></ul><ul><li>Why the differences? </li></ul><ul><li>Why the similarities? </li></ul><ul><li>What are the consequences for the organism? </li></ul>Response to stimulus ‘X’ Response to stimulus ‘Y’
    26. 29. ‘ Darwinian medicine is the enterprise of trying to find evolutionary explanations for vulnerabilities to disease … Disease, [is] not … a product of [natural] selection.’ Randolph Nesse
    27. 30. ‘ The meaning of a word is its use.’ Ludwig Wittgenstein
    28. 32. Towards A Biological Perspective On Disease For a full transcript of the presentation, for which these slides were an accompaniment, please visit: https://sites.google.com/site/sjlewis55/presentations/brownbag2005

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