Dysentery is diarrhea which contains blood. Other symptoms may include fever, abdominal
pain, and rectal tenesmus. It is caused by any kind of infection. It
is a type of gastroenteritis. The mechanism is an inflammatory disorder of the intestine,
especially of the colon.
Signs and symptoms In developed countries, the most common form
of dysentery is bacillary dysentery which is typically a mild illness, causing symptoms
normally consisting of mild stomach pains and frequent passage of stool or diarrhea.
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 large volume of liquid feces
passed, and the presence of mucus, pus and blood depends on the pathogen that is causing
the disease. Temporary lactose intolerance can occur. In some caustic occasions severe
abdominal pain, fever, shock, and delirium can all be symptoms.
In extreme cases, dysentery patients may pass over one litre of fluid per 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. On rare occasions, the
amoebic 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. Mechanism
Dysentery results from viral infections, bacterial 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, swelling due to
water leaking from capillaries of the intestine, 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 limits its definition to "diarrhea with visible blood."
Others define the term more broadly. 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.
Amoebic dysentery
Dysentery may be caused by amoebiasis, an infection by the amoeba Entamoeba histolytica,
and is then known as amoebic dysentery. 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. Entamoeba histolytica is mainly found in tropical
areas. When the amoebas inside the bowel of an infected person are ready to leave the
body, they group together and form a shell that surrounds and protects them. This group
of amoebas is known as a cyst. The cyst passes out of the person's body in the feces and
can survive outside the body. If hygiene standards are poor; for example, if the person does
not dispose of the feces hygienically, it can contaminate the surroundings, such as
nearby food and water. If another person then eats or drinks food or water that has been
contaminated with feces containing the cyst, that person will also become infected with
the amoeba. Amoebic dysentery is particularly common in parts of the world where human feces
are used as fertilizer. After entering the person's body through the mouth, the cyst
will travel down into the stomach. The amoebas inside the cyst are protected from the stomach's
digestive acid. From the stomach, the cyst will travel to the intestines where it will
break open and release the amoebas, causing the infection. The amoebas can burrow into
the walls of the intestines and cause small abscesses and ulcers to form. The cycle then
begins again. Bacillary dysentery
Dysentery may also be caused by shigellosis, an infection by bacteria of the genus Shigella,
and is then known as bacillary dysentery. Enteroinvasive Escherichia coli may also cause
a dysentery syndrome. Diagnosis
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.
Physical exam The mouth, skin, and lips may appear dry due
to dehydration. Lower abdominal tenderness may also be present.
Stool and blood tests 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.
Blood tests can be used to measure abnormalities in the levels of essential minerals and salts.
Prevention To reduce the risk of contracting dysentery
the following are suggested: Washing one's hands after using the toilet,
after contact with an infected person, and regularly throughout the day;
Washing one's hands before handling, cooking and eating food, handling babies, and feeding
young or elderly people; Keeping contact with someone known to have
dysentery to a minimum; Washing laundry on the hottest setting possible;
Avoiding sharing items such as towels and face cloths.
Treatment Dysentery is managed by maintaining fluids
by 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, letting it run its course may be reasonable — usually less than a week. If the shigella
is severe, antibiotics, such as ciprofloxacin or TMP-SMX may be useful. 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 is often treated with two antimicrobial drug such as metronidazole and
paromomycin or iodoquinol. Prognosis
With correct treatment, most cases of amoebic and bacterial dysentery subside within ten
days, and most individuals will achieve a full recovery within two to four 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.
Epidemiology The WHO estimates that there are 80 million
cases and 700,000 deaths from Shigellosis annually. Amebiasis infects over 50 million
people each year, of whom 50,000 die. Society and culture
The seed, leaves, and bark of the kapok tree have been used in traditional medicine by
indigenous peoples of the rain-forest regions in the Americas, West-Central Africa, and
South East Asia to treat this disease. Bacillus subtilis was marketed throughout America and
Europe from 1946 as an immunostimulatory aid in the treatment of gut and urinary tract
diseases such as Rotavirus and Shigella, but declined in popularity after the introduction
of cheap consumer antibiotics, despite causing less chance of allergic reaction and significantly
lower toxicity to normal gut flora. Notable cases
1216 – King John of England died of dysentery at Newark Castle on 18 October 1216.
1422 – King Henry V of England died suddenly from dysentery in 1422. He was thirty-five
years old. 1596 – Sir Francis Drake, Vice Admiral,
died of dysentery on 27 January 1596 while attacking San Juan, Puerto Rico. He was buried
at sea in a lead coffin, near Portobelo. 1605 – Akbar the Great, ruler of the Mughal
Empire of South Asia, died of dysentery. On 3 October 1605, he fell ill with an attack
of dysentery, from which he never recovered. He is believed to have died on or about 27
October 1605, after which his body was buried at a mausoleum in Sikandra, Agra.
1675 – Jacques Marquette died of dysentery on his way north from what is today Chicago,
traveling to the mission where he intended to spend the rest of his life.
19th century – As late as the nineteenth century, the 'bloody flux,' it is estimated,
killed more soldiers and sailors than did combat. Typhus and dysentery decimated Napoleon's
Grande Armée in Russia. More than 80,000 Union soldiers died of dysentery during the
American Civil War. 1896 – Phan Đình Phùng, a Vietnamese
revolutionary who led rebel armies against French colonial forces in Vietnam, died of
dysentery as the French surrounded his forces on January 21, 1896.
1930 – The French explorer and writer, Michel Vieuchange, died of dysentery in Agadir on
30 November 1930, on his return from the "forbidden city" of Smara. He was nursed by his brother,
Doctor Jean Vieuchange, who was unable to save him. The notebooks and photographs, edited
by Jean Vieuchange, went on to become bestsellers. 1942 – The Selarang Barracks Incident in
the summer of 1942 during World War II involved the forced crowding of 17,000 Anglo-Australian
prisoners-of-war by their Japanese captors in the areas around the barracks square for
nearly five days with little water and no sanitation after the Selarang Barracks POWs
refused to sign a pledge not to escape. The incident ended with the capitulation of the
Australian commanders due to the spreading of dysentery among their men.
Research Vaccines currently in development may eventually
become a critical part of the strategy to reduce the incidence and severity of diarrhea,
particularly among children in low-resource settings. For example, Shigella is a longstanding
World Health Organization target for vaccine development, and sharp declines in age-specific
diarrhea/dysentery attack rates for this pathogen indicate that natural immunity does develop
following exposure; thus, vaccination to prevent this disease should be feasible. Currently,
no licensed vaccine targeting Shigella exists. The development of vaccines against these
types of infection has been hampered by technical constraints, insufficient support for coordination,
and a lack of market forces for research and development. Most vaccine development efforts
are taking place in the public sector or as research programs within biotechnology companies.
Several vaccine candidates are currently in various phases of research and development,
including a number of ongoing clinical trials. References