| ICD-10 | A03.9, A06.0, A07.9 |
|---|---|
| ICD-9 | 004, 007.9, 009.0 |
| MeSH | D004403 |
Dysentery (formerly known as flux or the bloody flux) is an inflammatory disorder of the intestine, especially of the colon, that results in severe diarrhea containing mucus and/or blood in the faeces[1] with fever, abdominal pain[2], and rectal tenesmus. If left untreated, dysentery can be fatal.
There are differences between dysentery and normal bloody diarrhea. While diarrhea caused by dysentery is typically of small volume, very bloody, and containing many PMNs and RBCs; normal bloody diarrhea is more watery and may not contain any PMNs or mucus.
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In developed countries, dysentery is, in general, a mild illness, causing mild symptoms normally consisting of mild stomach pains and frequent passage of feces. Symptoms normally present themselves after one to three days and are usually no longer present after a week. The frequency of urges to defecate, the volume of feces passed, and the presence of mucus and/or blood depend on the pathogen that is causing the disease. Temporary lactose intolerance can occur, which, in the most severe cases, can last for years. In some caustic occasions, vomiting of blood, severe abdominal pain, fever, shock, and delirium can all be symptoms.[3][4][5][6]
Dysentery results from viral, bacterial, or protozoan infections or parasitic infestations. These pathogens typically reach the large intestine after entering orally, through ingestion of contaminated food or water, oral contact with contaminated objects or hands, and so on.
Each specific pathogen has its own mechanism or pathogenesis, but in general the result is damage to the intestinal lining, leading to the inflammatory immune response. This can cause elevated temperature, painful spasms of the intestinal muscles (cramping), swelling due to water leaking from capillaries of the intestine (edema), and further tissue damage by the body's immune cells and the chemicals, called cytokines, they release to fight the infection. The result can be impaired nutrient absorption, excessive water and mineral loss through the stools due to breakdown of the control mechanisms in the intestinal tissue that normally remove water from the stools, and in severe cases the entry of pathogenic organisms into the bloodstream.
Some microorganisms – for example, bacteria of the genus Shigella – secrete substances known as cytotoxins, which kill and damage intestinal tissue on contact. Viruses directly attack the intestinal cells, taking over their metabolic machinery to make copies of themselves, which leads to cell death.
Definitions of dysentery can vary by region and by medical specialty. The U. S. Centers for Disease Control and Prevention (CDC) limits its definition to "diarrhea with visible blood."[7] Others define the term more broadly.[8] These differences in definition must be taken into account when defining mechanisms. For example, using the CDC definition requires that intestinal tissue be so severely damaged that blood vessels have ruptured, allowing visible quantities of blood to be lost with defecation. Other definitions require less specific damage.
Dysentery may be caused by amoebiasis, an infection by the amoeba Entamoeba histolytica,[9] and is then known as amoebic dysentery.[10] Proper treatment of the underlying infection of amoebic dysentery is important; insufficiently treated amoebiasis can lie dormant for years and then lead to severe, potentially fatal, complications.
Severe dysentery may also be caused by shigellosis, an infection by bacteria of the genus Shigella,[11] and is then known as bacillary disentery (or Marlow Syndrome).
A clinical diagnosis may be made by taking a history and doing a brief examination. Treatment is usually started without or before confirmation by laboratory analysis.
Exposed individuals may experience either mild, severe, or even no symptoms at all. In extreme cases dysentery patients may pass over a litre of fluid an hour. More often, individuals will complain of nausea, abdominal pain, and frequent watery and usually foul-smelling diarrhea accompanied by mucus and blood, rectal pain, and fever. Vomiting, rapid weight loss, and generalized muscle aches sometimes also accompany dysentery. In rare occasions, the amebic parasite will invade the body through the bloodstream and spread beyond the intestines. In such cases, it may more seriously infect other organs such as the brain, lungs, and the liver.[12]
The mouth, skin, and lips may appear dry due to dehydration. Lower abdominal tenderness may also be present.[12]
Cultures of stool samples are examined in order to identify the organism causing dysentery. Usually, several samples must be obtained due to the changing number of amoeba, which changes daily.[12]
Blood tests can be used to measure abnormalities in the levels of essential minerals and salts.[12]
To reduce the risk of contracting dysentery the following precautions are suggested:[13]
Dysentery is initially managed by maintaining fluid intake using oral rehydration therapy. If this treatment cannot be adequately maintained due to vomiting or the profuseness of diarrhea, hospital admission may be required for intravenous fluid replacement. In ideal situations, no antimicrobial therapy should be administered until microbiological microscopy and culture studies have established the specific infection involved. When laboratory services are not available, it may be necessary to administer a combination of drugs, including an amoebicidal drug to kill the parasite and an antibiotic to treat any associated bacterial infection.
If shigella is suspected and it is not too severe, the doctor may recommend letting it run its course — usually less than a week. The patient will be advised to replace fluids lost through diarrhea. If the shigella is severe, the doctor may prescribe antibiotics, such as ciprofloxacin or TMP-SMX (Bactrim). However, many strains of shigella are becoming resistant to common antibiotics, and effective medications are often in short supply in developing countries. If necessary, a doctor may have to reserve antibiotics for those at highest risk for death, including young children, people over 50, and anyone suffering from dehydration or malnutrition.
Amoebic dysentery usually calls for a two-pronged attack. Treatment should start with a 10-day course of the antimicrobial drug metronidazole (Flagyl). To finish off the parasite, the doctor will sometimes prescribe a course of diloxanide furoate (available only through the Centers for Disease Control and Prevention), paromomycin (Humatin), or iodoquinol (Yodoxin).
The bark of the kapok tree has been used in the traditional medicine of the Mayan culture to cure this disease.
With correct treatment, most cases of amoebic and bacterial dysentery subside within 10 days, and most individuals will achieve a full recovery within 2 to 4 weeks after beginning proper treatment. If the disease is left untreated, the prognosis varies with the immune status of the individual patient and the severity of disease. Extreme dehydration can prolong recovery and significantly raises the risk for serious complications.[14]
The World Health Organization (WHO) has estimated that 80 million cases of Shigellosis are contracted annually, with 700,000 of these resulting in death. Amebiasis is infecting over 50 million people each year, killing about 50,000.[15]
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