Caseous necrosis

Caseous necrosis is a form of cell death in which the tissue maintains a cheese-like appearance.[1] The dead tissue appears as a soft and white proteinaceous dead cell mass.

Tuberculous lymph node with caseating granuloma 40X
Micrograph showing caseous necrosis of a tuberculous lymph node. H&E stain.

Causes

Frequently, caseous necrosis is encountered in the foci of tuberculosis infections.[1] It can also be caused by syphilis and certain fungi.

A similar appearance can be associated with histoplasmosis, cryptococcosis, and coccidioidomycosis.[2]

Appearance

In caseous necrosis no histological architecture is preserved. On microscopic examination with H&E staining, it is characterized by acellular pink areas of necrosis surrounded by a granulomatous inflammatory process.

When the hilar lymph node for instance is infected with tuberculosis and leads to caseous necrosis, its gross appearance can be a cheesy tan to white, which is why this type of necrosis is often depicted as a combination of both coagulative and liquefactive necrosis.

However, in the lung, extensive caseous necrosis with confluent cheesy tan granulomas is typical. The tissue destruction is so extensive that there are areas of cavitation (also known as cystic spaces). See Ghon's complex.

Caseous necrosis in lung tissue

Caseous necrosis in the lung

Tuberculosis - Sub-pleural primary (Ghon) focus (6596011395)

Caseous necrosis in the pleura

Renal tuberculosis (6539942987)

Caseous necrosis in the kidney

References

  1. ^ a b Robbins and Cotran: Pathologic Basis of Disease, 8th Ed. 2010. Pg. 16
  2. ^ "Pulmonary Pathology". Retrieved 2008-11-21.

External links

Algor mortis

Algor mortis (Latin: algor—coldness; mortis—of death), the second stage of death, is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot desert), the change in temperature will be positive, as the (relatively) cooler body acclimates to the warmer environment. External factors can have a significant influence.

The term was first used by Dowler in 1849. The first published measurements of the intervals of temperature after death were done by Dr John Davey in 1839.

Dead on arrival

Dead on arrival (DOA), also dead in the field and brought in dead (BID), indicates that a patient was found to be already clinically dead upon the arrival of professional medical assistance, often in the form of first responders such as emergency medical technicians, paramedics, or police.

In some jurisdictions, first responders must consult verbally with a physician before officially pronouncing a patient deceased, but once cardiopulmonary resuscitation is initiated, it must be continued until a physician can pronounce the patient dead.

Death messenger

Death messengers, in former times, were those who were dispatched to spread the news that an inhabitant of their city or village had died. They were to wear unadorned black and go door to door with the message, "You are asked to attend the funeral of the departed __________ at (time, date, and place)." This was all they were allowed to say, and were to move on to the next house immediately after uttering the announcement. This tradition persisted in some areas to as late as the mid-19th century.

Death rattle

Terminal respiratory secretions (or simply terminal secretions), known colloquially as a death rattle, are sounds often produced by someone who is near death as a result of fluids such as saliva and bronchial secretions accumulating in the throat and upper chest. Those who are dying may lose their ability to swallow and may have increased production of bronchial secretions, resulting in such an accumulation. Usually, two or three days earlier, the symptoms of approaching death can be observed as saliva accumulates in the throat, making it very difficult to take even a spoonful of water. Related symptoms can include shortness of breath and rapid chest movement. While death rattle is a strong indication that someone is near death, it can also be produced by other problems that cause interference with the swallowing reflex, such as brain injuries.It is sometimes misinterpreted as the sound of the person choking to death, or alternatively, that they are gargling.

Dignified death

Dignified death is a somewhat elusive concept often related to suicide. One factor that has been cited as a core component of dignified death is maintaining a sense of control. Another view is that a truly dignified death is an extension of a dignified life. There is some concern that assisted suicide does not guarantee a dignified death, since some patients may experience complications such as nausea and vomiting. There is some concern that age discrimination denies the elderly a dignified death.

Dystrophic calcification

Dystrophic calcification (DC) is the calcification occurring in degenerated or necrotic tissue, as in hyalinized scars, degenerated foci in leiomyomas, and caseous nodules. This occurs as a reaction to tissue damage, including as a consequence of medical device implantation. Dystrophic calcification can occur even if the amount of calcium in the blood is not elevated. (A systemic mineral imbalance would elevate calcium levels in the blood and all tissues and cause metastatic calcification.) Basophilic calcium salt deposits aggregate, first in the mitochondria, and progressively throughout the cell. These calcifications are an indication of previous microscopic cell injury. It occurs in areas of cell necrosis in which activated phosphatases bind calcium ions to phospholipids in the membrane.

Calcification can occur in dead or degenerated tissue.

Fat necrosis

Fat necrosis is a form of necrosis characterized by the action upon fat by digestive enzymes.In fat necrosis the enzyme lipase releases fatty acids from triglycerides. The fatty acids then complex with calcium to form soaps. These soaps appear as white chalky deposits.It is usually associated with trauma of the pancreas or acute pancreatitis.It can also occur in the breast, the salivary glands and neonates after a traumatic delivery.

Ghon's complex

Ghon's complex is a lesion seen in the lung that is caused by tuberculosis. The lesions consist of a Ghon focus along with pulmonary lymphadenopathy within a nearby pulmonary lymph node. A Ghons complex retains viable bacteria, making them sources of long-term infection, which may reactivate and trigger secondary tuberculosis later life.In countries where cow milk infected with Mycobacterium bovis has been eliminated (due to culling of infected cows and pasteurization), primary tuberculosis is usually caused by Mycobacterium tuberculosis and almost always begins in the lungs. Typically, the inhaled bacilli implant in the distal airspaces of the lower part of the upper lobe or the upper part of the lower lobe, usually close to the pleura. As sensitization develops, a 1- to 1.5-cm area of gray-white inflammation with consolidation emerges, known as the Ghon focus. In most cases, the center of this focus undergoes caseous necrosis. Tubercle bacilli, either free or within phagocytes, drain to the regional nodes, which also often caseate. This combination of parenchymal lung lesion and nodal involvement is referred to as the Ghon complex. During the first few weeks, there is also lymphatic and hematogenous dissemination to other parts of the body.

In approximately 95% of cases, development of cell-mediated immunity controls the infection.

Gumma (pathology)

A gumma is a soft, non-cancerous growth resulting from the tertiary stage of syphilis. It is a form of granuloma. Gummas are most commonly found in the liver (gumma hepatis), but can also be found in brain, heart, skin, bone, testis, and other tissues, leading to a variety of potential problems including neurological disorders or heart valve disease.

H37Rv

Mycobacterium tuberculosis strain H37Rv is the most studied strain of tuberculosis in research laboratories. It was first isolated by Dr. Edward R. Baldwin in 1905. The strain came from a 19 year old patient with chronic pulmonary tuberculosis at the Trudeau Sanatorium in Saranac Lake, New York. It was maintained for many years by serial passage of cultures at the Trudeau Sanatorium and initially named strain H37. Over time it was found to have variable virulence in animal models based on which medium it was grown on. Strains with different virulence were then intentionally produced, with H37R being less virulent after growing in acidic media and H37S was more virulent in guinea pigs after being grown in alkaline media (with R standing for resistant to environment, and S for sensitive to environment). The more virulent strain was later renamed H37Rv, with R standing for rough morphology and v standing for virulent. The strain was used for many laboratory studies and became the standard for tuberculosis. It was later designated as the neotype for the species. Koch first discovered mycobacterium tuberculosis as the cause of tuberculosis in 1892 but the strains he studied were not preserved and it is unclear how related H37Rv may be to those strains. H37Rv has continued to be the strain of tuberculosis most used in laboratories, and was the first to have its complete genome published in 1998. It is unclear how much H37Rv may have evolved in more than 100 years under artificial conditions in laboratories from strains in the wild, but its genome is similar to a strain isolated from a 19th century grave in Yorkshire. However it does not have some characteristics, such as causing caseous necrosis in rabbits, that are seen in modern clinical isolates. Strains in different labs that derive from H37Rv have also been shown to have evolved differences over time, with one survey of 6 strains finding from 5 to 10 polymorphisms per strain. These included independent insertions and deletions of IS6110 transposable elements which would change the strain's spoligotype. The authors of the study cautioned against considering all strains labeled as H37Rv as a reference since there may be significant differences based on the laboratory in which it is maintained.

Hans Schmaus

Hans Schmaus (22 May 1862 in Munich – 4 December 1905 in Munich) was a German pathologist.

In 1887 he obtained his doctorate at the University of Munich, where he spent the next several years as an assistant to Otto Bollinger at the institute of pathology. In 1889 he became habilitated for pathology, becoming an associate professor at Munich in 1899.At Munich, he performed studies involving the pathological anatomy of the spinal cord, and did research of hyaline degeneration and caseous necrosis. With pathologist Eugen Albrecht, he conducted studies of coagulative necrosis.

Lazarus sign

The Lazarus sign or Lazarus reflex is a reflex movement in brain-dead or brainstem failure patients, which causes them to briefly raise their arms and drop them crossed on their chests (in a position similar to some Egyptian mummies). The phenomenon is named after the Biblical figure Lazarus of Bethany, whom Jesus Christ raised from the dead in the Gospel of John.

Lupus miliaris disseminatus faciei

Lupus miliaris disseminatus faciei , also known as acne agminata, is a disease with a similar appearance to acne vulgaris. The cause of LMDF is unknown.

LMDF usually occurs on the face, but extrafacial presentations have been reported. Mycobacterium tuberculosis or its products may cause a caseous necrosis and thus maybe one of several possible causes. Some authors view LMDF as a variant of granulomatous rosacea or a presentation related to Demodex folliculitis. Others suggest it as a new independent entity and proposed a new term: Facial Idiopathic GranUlomas with Regressive Evolution. Misago et al. postulated LMDF as a common adult form, childhood granulomatous periorificial dermatitis as a rare childhood form, and perioral dermatitis as a peculiar form exacerbated by topical corticosteroids. There are no randomized controlled trials available for the treatment of LMDF.

The usual first-line therapy is oral tetracyclines with variable success rates. Dapsone, low-dose prednisolone, clofazimine, and isotretinoin have all been tried in some cases. The 1450-nm diode laser has been shown to improve LMDF.

Megadeath

Megadeath (or megacorpse) is one million human deaths, usually caused by a nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare.

Necronym

A necronym (from the Greek words νεκρός, nekros, "dead" and ὄνομα ónoma, "name") is a reference to, or name of, a person who has died. Many cultures have taboos and traditions associated with referring to such a person. These vary from the extreme of never again speaking the person's real name, often using some circumlocution instead, to the opposite extreme of commemorating it incessantly by naming other things or people after the deceased.

For instance, in some cultures it is common for a newborn child to receive the name (a necronym) of a relative who has recently died, while in others to reuse such a name would be considered extremely inappropriate or even forbidden. While this varies from culture to culture, the use of necronyms is quite common.

Pallor mortis

Pallor mortis (Latin: pallor "paleness", mortis "of death"), the first stage of death, is an after-death paleness that occurs in those with light/white skin.

Pott disease

Pott disease, or Pott's disease, is a form of tuberculosis that occurs outside the lungs whereby disease is seen in the vertebrae. Tuberculosis can affect several tissues outside the lungs including the spine, a kind of tuberculous arthritis of the intervertebral joints. The disease is named after Percivall Pott (1714–1788), a British surgeon. The lower thoracic and upper lumbar vertebrae are the areas of the spine most often affected. The formal name for the disease is tuberculous spondylitis.

Pott’s disease results from haematogenous spread of tuberculosis from other sites, often the lungs. The infection then spreads from two adjacent vertebrae into the adjoining intervertebral disc space. If only one vertebra is affected, the disc is normal, but if two are involved, the disc, which is avascular, cannot receive nutrients and collapses. In a process called caseous necrosis the disc tissue dies leading to vertebral narrowing and eventually to vertebral collapse and spinal damage. A dry soft tissue mass often forms and superinfection is rare.

Tubercle

In anatomy, a tubercle is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal.

Tuberculous lymphadenitis

Tuberculous lymphadenitis (or tuberculous adenitis) is the most common form of tuberculosis infections that appears outside the lungs. Tuberculous lymphadenitis is a chronic, specific granulomatous inflammation of the lymph node with caseation necrosis, caused by infection with Mycobacterium tuberculosis or related bacteria.

The characteristic morphological element is the tuberculous granuloma (caseating tubercule). This consists of giant multinucleated cells and (Langhans cells), surrounded by epithelioid cells aggregates, T cell lymphocytes and fibroblasts. Granulomatous tubercules eventually develop central caseous necrosis and tend to become confluent, replacing the lymphoid tissue.

Principles of pathology
Anatomical pathology
Clinical pathology

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.