Colitis-X
Encyclopedia
Colitis X, equine colitis X or peracute toxemic colitis is a catchall term for various fatal forms of acute or peracute colitis
found in horse
s, but particularly a fulminant colitis where clinical signs include sudden onset of severe diarrhea, abdominal pain, shock, and dehydration
. Death is common, with 90% to 100% mortality, usually in less than 24 hours. The causative factor may be Clostridium difficile
, but it also may be caused by other intestinal pathogens. Horses under stress appear to be more susceptible to developing colitis X, and like the condition pseudomembranous colitis
in humans, there also is an association with prior antibiotic use. Immediate and aggressive treatment can sometimes save the horse, but even in such cases, 75% mortality is considered a best-case scenario.
, tachypnea
, and a weak pulse. Marked depression is present. An explosive diarrhea develops, resulting in extreme dehydration. Hypovolemic and endotoxic shock are manifest by increased capillary refill time, congested or cyanotic (purplish) mucous membranes, and cold extremities. While there may initially be a fever
, temperature usually returns to normal.
Clinical signs are similar to those of other diarrheal diseases, including toxemia caused by Clostridium
, Potomac horse fever
, experimental endotoxic shock, and anaphylaxis
.
, clostridial
enterocolitis
, and endotoxemia. Of interest is that Clostridium difficile toxins isolated in the horse have a genotype that is also that of the current human "epidemic strain," which is associated with human C. difficile-associated disease of greater than historical severity. C. difficile can cause pseudomembranous colitis
in humans, and in hospitalized patients who develop it, fulminant C. difficile colitis is a significant and increasing cause of death.
Horses under stress appear to be more susceptible to developing colitis X. Disease onset is often closely associated with surgery or transport. Excess protein and lack of cellulose
content in the diet (a diet heavy on grain and lacking adequate hay
or similar roughage) is thought to be the trigger for the multiplication of clostridial
organisms. A similar condition may be seen after administration of tetracycline or lincomycin
to horses. These factors may be one reason the condition often develops in race horses
, having been responsible for the deaths of the Thoroughbred filly
Landaluce
,
the Quarter Horse stallion Lightning Bar
,
and is one theory for the sudden death of Kentucky Derby
winner Swale
.
The link to stress suggests that the condition may be brought on by changes in the microflora of the cecum
and colon that lower the number of anaerobic bacteria, increase the number of gram-negative enteric
bacteria, and decrease anaerobic fermentation of soluble carbohydrates, resulting in damage to the cecal and colonic mucosa and allowing increased absorption of endotoxins from the lumen of the gut.
The causative agent may be Clostridium perfringens
, Type A, but the bacteria are recoverable only in the preliminary stages of the disease.
The suspect toxin could also be a form of Clostridium difficile
. In a 2009 study at the University of Arizona, Clostridium difficile toxins A and B were detected, large numbers of C. difficile were isolated, and genetic characterization revealed them to be North American pulsed-field gel electrophoresis type 1, polymerase chain reaction ribotype 027, and toxinotype III. Genes for the binary toxin were present, and toxin negative-regulator tcdC contained an 18-bp deletion. The individual animal studied in this case was diagnosed as having peracute typhlocolitis, with lesions and history typical of those attributed to colitis X.
Use of antibiotics may also be associated with some forms of colitis-X. In humans, C. difficile is the most serious cause of antibiotic-associated diarrhea, often a result of eradication of the normal gut flora
by antibiotic
s. In one equine study, colitis was induced after pretreatment with clindamycin
and lincomycin
, followed by intestinal content from horses which had died from naturally-occurring idiopathic colitis. (A classic adverse effect
of clindamycin in humans is Clostridium difficile-associated diarrhea.) In the experiment, the treated horses died. After necropsy, Clostridium cadaveris
was present, and is proposed as another possible causative agent in some cases of fatal colitis.
are pronounced, and the intestinal contents are fluid and often blood-stained. Macroscopic and microscopic findings include signs of disseminated intravascular coagulation, necrosis of colonic mucosa and presence of large numbers of bacteria in the devitalized parts of the intestine. Typically, the PCV is >65% even shortly after the onset of clinical signs. The leukogram ranges from normal to neutropenia with a degenerative left shift. Metabolic acidosis and electrolyte disorders are also present. There is leucopenia, initially characterized by neutropenia, which might evolve in neutrophilia. Moreover, haemoconcentration is noted with an increase in the packed cell volume; total proteins are initially increased, but changes into a lower than normal value. The most significant laboratory finding in colitis X is the increase of total cortisol concentration in blood plasma. Histopathologically, the mucosa of the large colon is hemorrhagic, necrotic and covered with fibrohemorrhagic exudate, while the submucosa, the muscular tunic and the local lymphonodes are edematous.
winner Seattle Slew
, who survived colitis-X in 1978 and went on to race as a 4-year-old.
Large amounts of IV fluids are needed to counter the severe dehydration, and electrolyte replacement is often necessary. Flunixin meglumine
(Banamine) may help block the effects of toxemia. Mortality rate has been theorized to fall to 75% if treatment is prompt and aggressive, including administration of not only fluids and electrolytes, but also blood plasma, anti-inflammatory and analgesic drugs and antibiotics. Preventing dehydration is extremely important. Nutrition is also important. Either parenteral
or normal feeding can be used to support the stressed metabolism of the sick horse. Finally, the use of probiotics is considered beneficial in the restoration of the normal intestinal flora. The probiotics most often used for this purpose contain Lactobacillus
and Bifidobacterium
.
Colitis
In medicine, colitis refers to an inflammation of the colon and is often used to describe an inflammation of the large intestine .Colitides may be acute and self-limited or chronic, i.e...
found in horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s, but particularly a fulminant colitis where clinical signs include sudden onset of severe diarrhea, abdominal pain, shock, and dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
. Death is common, with 90% to 100% mortality, usually in less than 24 hours. The causative factor may be Clostridium difficile
Clostridium difficile
Clostridium difficile , also known as "CDF/cdf", or "C...
, but it also may be caused by other intestinal pathogens. Horses under stress appear to be more susceptible to developing colitis X, and like the condition pseudomembranous colitis
Pseudomembranous colitis
Pseudomembranous colitis, a cause of antibiotic-associated diarrhea , is an infection of the colon. It is often, but not always, caused by the bacterium Clostridium difficile. Because of this, the informal name C. difficile colitis is also commonly used. The illness is characterized by...
in humans, there also is an association with prior antibiotic use. Immediate and aggressive treatment can sometimes save the horse, but even in such cases, 75% mortality is considered a best-case scenario.
Clinical signs
Colitis-X is a term used for colitis cases in which no definitive diagnosis can be made and the horse dies. Clinical signs include sudden, watery diarrhea that is usually accompanied by symptoms of hypovolemic shock and usually leads to death in 3 to 48 hours, usually in less than 24 hours. Other clinical signs include tachycardiaTachycardia
Tachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
, tachypnea
Tachypnea
Tachypnea means rapid breathing. Any rate between 12-20 breaths per minute is normal. Tachypnea is a respiration rate greater than 20 breaths per minute. - Distinction from other breathing terms :...
, and a weak pulse. Marked depression is present. An explosive diarrhea develops, resulting in extreme dehydration. Hypovolemic and endotoxic shock are manifest by increased capillary refill time, congested or cyanotic (purplish) mucous membranes, and cold extremities. While there may initially be a fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, temperature usually returns to normal.
Clinical signs are similar to those of other diarrheal diseases, including toxemia caused by Clostridium
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...
, Potomac horse fever
Potomac Horse Fever
Potomac Horse Fever is a potentially-fatal febrile illness affecting horses caused by the intracellular bacterium Neorickettsia risticii. PHF is also known as Shasta River Crud and Equine Monocytic Ehrlichiosis...
, experimental endotoxic shock, and anaphylaxis
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...
.
Causes
To date, the precise causative factor has not been verified, and the disease has been attributed by various sources to viruses, parasites, bacteria, use of antibiotics and sulfonamides and heavy metal poisoning. Other possible causes include peracute salmonellosisSalmonellosis
Salmonellosis is an infection with Salmonella bacteria. Most people infected with Salmonella develop diarrhea, fever, vomiting, and abdominal cramps 12 to 72 hours after infection. In most cases, the illness lasts four to seven days, and most people recover without treatment...
, clostridial
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...
enterocolitis
Enterocolitis
Enterocolitis is an inflammation of the colon and small intestine. However, most conditions are categorized as one or the other of the following:* Enteritis is the inflammation of the small intestine...
, and endotoxemia. Of interest is that Clostridium difficile toxins isolated in the horse have a genotype that is also that of the current human "epidemic strain," which is associated with human C. difficile-associated disease of greater than historical severity. C. difficile can cause pseudomembranous colitis
Pseudomembranous colitis
Pseudomembranous colitis, a cause of antibiotic-associated diarrhea , is an infection of the colon. It is often, but not always, caused by the bacterium Clostridium difficile. Because of this, the informal name C. difficile colitis is also commonly used. The illness is characterized by...
in humans, and in hospitalized patients who develop it, fulminant C. difficile colitis is a significant and increasing cause of death.
Horses under stress appear to be more susceptible to developing colitis X. Disease onset is often closely associated with surgery or transport. Excess protein and lack of cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
content in the diet (a diet heavy on grain and lacking adequate hay
Hay
Hay is grass, legumes or other herbaceous plants that have been cut, dried, and stored for use as animal fodder, particularly for grazing livestock such as cattle, horses, goats, and sheep. Hay is also fed to pets such as rabbits and guinea pigs...
or similar roughage) is thought to be the trigger for the multiplication of clostridial
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...
organisms. A similar condition may be seen after administration of tetracycline or lincomycin
Lincomycin
Lincomycin is a lincosamide antibiotic that comes from the actinomyces Streptomyces lincolnensis. It has been structurally modified by thionyl chloride to its more commonly known 7-chloro-7-deoxy derivative, clindamycin...
to horses. These factors may be one reason the condition often develops in race horses
Horse racing
Horse racing is an equestrian sport that has a long history. Archaeological records indicate that horse racing occurred in ancient Babylon, Syria, and Egypt. Both chariot and mounted horse racing were events in the ancient Greek Olympics by 648 BC...
, having been responsible for the deaths of the Thoroughbred filly
Filly
A filly is a young female horse too young to be called a mare. There are several specific definitions in use.*In most cases filly is a female horse under the age of four years old....
Landaluce
Landaluce
Landaluce was, for the briefest of moments, a champion American Thoroughbred race horse. Landaluce was out of the first crop sired by the great Seattle Slew, 1977’s Horse of the Year and the 10th winner of America's Triple Crown...
,
the Quarter Horse stallion Lightning Bar
Lightning Bar
Lightning Bar was an American Quarter Horse who raced and subsequently became a breeding stallion. He was bred by his lifelong owner Art Pollard of Sonoita, Arizona, and was the offspring of Three Bars, a Thoroughbred, and Della P, a Quarter Horse mare from Louisiana, then noted for the breeding...
,
and is one theory for the sudden death of Kentucky Derby
Kentucky Derby
The Kentucky Derby is a Grade I stakes race for three-year-old Thoroughbred horses, held annually in Louisville, Kentucky, United States on the first Saturday in May, capping the two-week-long Kentucky Derby Festival. The race is one and a quarter mile at Churchill Downs. Colts and geldings carry...
winner Swale
Swale (horse)
Swale was an American thoroughbred racehorse. He is best known for winning the Kentucky Derby and the Belmont Stakes in 1984...
.
The link to stress suggests that the condition may be brought on by changes in the microflora of the cecum
Cecum
The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...
and colon that lower the number of anaerobic bacteria, increase the number of gram-negative enteric
Enteric
Enteric can refer to:* A general term describing something related to or associated with the intestines** Microorganisms that inhabit the intestines are commonly known as enteric bacteria* Enteric nervous system...
bacteria, and decrease anaerobic fermentation of soluble carbohydrates, resulting in damage to the cecal and colonic mucosa and allowing increased absorption of endotoxins from the lumen of the gut.
The causative agent may be Clostridium perfringens
Clostridium perfringens
Clostridium perfringens is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. C. perfringens is ever present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates,...
, Type A, but the bacteria are recoverable only in the preliminary stages of the disease.
The suspect toxin could also be a form of Clostridium difficile
Clostridium difficile
Clostridium difficile , also known as "CDF/cdf", or "C...
. In a 2009 study at the University of Arizona, Clostridium difficile toxins A and B were detected, large numbers of C. difficile were isolated, and genetic characterization revealed them to be North American pulsed-field gel electrophoresis type 1, polymerase chain reaction ribotype 027, and toxinotype III. Genes for the binary toxin were present, and toxin negative-regulator tcdC contained an 18-bp deletion. The individual animal studied in this case was diagnosed as having peracute typhlocolitis, with lesions and history typical of those attributed to colitis X.
Use of antibiotics may also be associated with some forms of colitis-X. In humans, C. difficile is the most serious cause of antibiotic-associated diarrhea, often a result of eradication of the normal gut flora
Gut flora
Gut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....
by antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s. In one equine study, colitis was induced after pretreatment with clindamycin
Clindamycin
Clindamycin rINN is a lincosamide antibiotic. It is usually used to treat infections with anaerobic bacteria but can also be used to treat some protozoal diseases, such as malaria...
and lincomycin
Lincomycin
Lincomycin is a lincosamide antibiotic that comes from the actinomyces Streptomyces lincolnensis. It has been structurally modified by thionyl chloride to its more commonly known 7-chloro-7-deoxy derivative, clindamycin...
, followed by intestinal content from horses which had died from naturally-occurring idiopathic colitis. (A classic adverse effect
Adverse drug reaction
An adverse drug reaction is an expression that describes harm associated with the use of given medications at a normal dosage. ADRs may occur following a single dose or prolonged administration of a drug or result from the combination of two or more drugs...
of clindamycin in humans is Clostridium difficile-associated diarrhea.) In the experiment, the treated horses died. After necropsy, Clostridium cadaveris
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...
was present, and is proposed as another possible causative agent in some cases of fatal colitis.
Diagnosis
At necropsy, edema and hemorrhage in the wall of the large colon and cecumCecum
The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...
are pronounced, and the intestinal contents are fluid and often blood-stained. Macroscopic and microscopic findings include signs of disseminated intravascular coagulation, necrosis of colonic mucosa and presence of large numbers of bacteria in the devitalized parts of the intestine. Typically, the PCV is >65% even shortly after the onset of clinical signs. The leukogram ranges from normal to neutropenia with a degenerative left shift. Metabolic acidosis and electrolyte disorders are also present. There is leucopenia, initially characterized by neutropenia, which might evolve in neutrophilia. Moreover, haemoconcentration is noted with an increase in the packed cell volume; total proteins are initially increased, but changes into a lower than normal value. The most significant laboratory finding in colitis X is the increase of total cortisol concentration in blood plasma. Histopathologically, the mucosa of the large colon is hemorrhagic, necrotic and covered with fibrohemorrhagic exudate, while the submucosa, the muscular tunic and the local lymphonodes are edematous.
Treatment
Treatment for colitis-X usually does not save the horse. The prognosis is average to poor and mortality is 90% to 100%. However, there are ways to treat the condition, and one famous horse that survived Colitix-X was U.S. Triple CrownUnited States Triple Crown of Thoroughbred Racing
In the United States, the "Triple Crown" is usually the Triple Crown of Thoroughbred Racing, a series of three Thoroughbred horse races for three-year-old horses run in May and early June of each year consisting of the Kentucky Derby, Preakness Stakes, and Belmont Stakes.While Daily Racing Form...
winner Seattle Slew
Seattle Slew
Seattle Slew was an American Thoroughbred race horse who won the United States Triple Crown of Thoroughbred Racing in 1977, the tenth of eleven horses to accomplish the feat. He remains the only horse to win the Triple Crown while undefeated. In the Blood-Horse magazine List of the Top 100 U.S...
, who survived colitis-X in 1978 and went on to race as a 4-year-old.
Large amounts of IV fluids are needed to counter the severe dehydration, and electrolyte replacement is often necessary. Flunixin meglumine
Flunixin Meglumine
Flunixin is a non-steroidal anti-inflammatory drug , analgesic, and antipyretic used in horses. It is often formulated as the meglumine salt. In the United States, it is regulated by the U.S...
(Banamine) may help block the effects of toxemia. Mortality rate has been theorized to fall to 75% if treatment is prompt and aggressive, including administration of not only fluids and electrolytes, but also blood plasma, anti-inflammatory and analgesic drugs and antibiotics. Preventing dehydration is extremely important. Nutrition is also important. Either parenteral
Parenteral
Parenteral is a route of administration that involves piercing the skin or mucous membrane. Parenteral nutrition refers to providing nutrition via the veins.-Etymology:...
or normal feeding can be used to support the stressed metabolism of the sick horse. Finally, the use of probiotics is considered beneficial in the restoration of the normal intestinal flora. The probiotics most often used for this purpose contain Lactobacillus
Lactobacillus
Lactobacillus is a genus of Gram-positive facultative anaerobic or microaerophilic rod-shaped bacteria. They are a major part of the lactic acid bacteria group, named as such because most of its members convert lactose and other sugars to lactic acid. They are common and usually benign...
and Bifidobacterium
Bifidobacterium
Bifidobacterium is a genus of Gram-positive, non-motile, often branched anaerobic bacteria. They are ubiquitous, endosymbiotic inhabitants of the gastrointestinal tract, vagina and mouth of mammals and other animals. Bifidobacteria are one of the major genera of bacteria that make up the colon...
.