- Amoebiasis is an infection of small intestine, which is caused by an protozoan called Entamoeba histolytica. It is simply called – Amoebic dysentery. This is usually contracted by ingesting water or food contaminated by amoebic cysts. Amoebic abscesses may form in the liver , lungs , and brain and elsewhere in the body.
- Amoebae are parasites that can be very easily found in contaminated food or drink. They enter the body through the mouth when the contaminated food or drink is swallowed. The amoebae are then able to move through the digestive system and take up residence in the intestine and cause infections like amoebiasis.
Amoebiasis and Amoeba
There are several different species of amoeba, but the most dangerous, such as Entamoeba histolytica, live predominantly in tropical areas. People living in rural areas or persons traveling in such areas are at highest risk of developing this disease, which occurs when something infected with the parasite is eaten or swallowed.
There are mainly two types of amoebiasis:-
- Intestinal Amoebiasis:- It is frequently asymptomatic and varies from fulminant dysentery with fever, chills, and bloody or mucoid diarrhea to mild abdominal discomfort with diarrhea containing blood or mucus alternating with periods of constipation or remission.
- Extraintestinal Amoebiasis:- It occurs when the parasite invades other organs such as liver, lung, brain or skin. The incubation period varies from a few days to several months or years (commonly 2-4 weeks).
Causes of Amoebiasis:
The main cause of amoebiasis is- single cell parasite called entamoeba histolytica. The parasite burrows into the wall of the intestine to cause small abscesses and ulcers . From there they enter the veins of the intestine and are carried to the liver .
Even though there is constant spread of infection, (within a family) some people are resistant to amoebiasis. Even if infected, they only act as a carrier to the disease and do not develop themselves. This shows that the ultimate cause of suffering is hidden than the exposed causative factor i.e. amoeba.
Some Possible Causes of Amoebiasis includes:-
- Eating or Drinking contaminated water or food is one of the primary cause of amoebiasis.
- Touching, and bringing to your mouth, cysts (eggs) picked up from surfaces that are contaminated with entamoeba histolytica.
- Eating a food on which mosquito had sat, after sitting on the stool of a person infected with entamoeba histolytica, may lead to amoebiasis.
- Eating vegetables and fruits which have been contaminated by the harmful bacteria, may cause amoebiasis.
- Eating Non-Veg foods (meat and intestines of animals – goat, pig, beef, etc.), may lead to the condition of amoebiasis.
- Even vegetables grown in soil contaminated by faeces can transmit the disease.
- As, amoebiasis is a highly contagious disease – so, it may be transmitted from one person to other through direct contact.
- Unhygienic Conditions and Poor Sanitation areas are more susceptible to amoebiasis.
- Amoebic dysentery can also be spread by anal sex or directly from person to person contact.
- Older or younger age
- Recent travel to a tropical region
- Use of corticosteroid medication to suppress the immune system
Signs and Symptoms
The symptoms are in two forms:
1. By burrowing the intestines and making ulcers, which bleed and cause anaemia or other diseases due to added infection
2. Absorbing the food from the host or letting out toxic substances in the intestines
Some important symptoms of amoebiasis includes:-
- Passing of more number of stools is one of the main symptom in amoebiasis. In this case, patient may pass about 10-12 stools during an acute episode. The presence of mucus is common in stools.
- Stools can sometimes also be accompanied with blood
- Usually symptoms start with diarrhea and pain in right hypochondrium.
- The other most common symptom is colic or pain in abdomen.
- It could be associated with a low-grade fever too.
- Sometimes allergic reactions can occur throughout the body, due to release of toxic substances or dead parasites inside the intestines.
- Loss of Weight and Stamina is encountered with person suffering from amoebiasis.
- Around one in ten people who are infected with amoebiasis become ill from the disease.
- Tenesmus, may occur during amoebiasis.
- Foul smelling stools.
- Loss of Appetite.
- There will be pain over the liver, when pressure is applied just under the ribs on the right side.
- Stomach Cramps.
- Amoebic liver abscesses can also present as pyrexia of unknown origin. The abscess can sometimes rupture into the pleural, peritoneal or pericardial cavities.
- You will feel weakness or tiredness, if you are suffering from amoebiasis.
- Pain in the right shoulder could occur in chronic condition.
Pathophysiology of Amoebiasis
When cyst is swallowed, it passes through the stomach unharmed and shows no activity while in an acidic environment. When it reaches the alkaline medium of the intestine, the metacyst begins to move within the cyst wall, which rapidly weakens and tears. The quadrinucleate amoeba emerges and divides into amebulas that are swept down into the cecum. This is the first opportunity of the organism to colonize, and its success depends on one or more metacystic trophozoites making contact with the mucosa.Mature cyst in the large intestines leaves the host in great numbers (the host remains asymptomatic). The cyst can remain viable and infective in moist and cool environment for at least 12 days, and in water for 30 days. The cysts are resistant to levels of chlorine normally used for water purification. They are rapidly killed by purification, desiccation and temperatures below 5 and above 40 degrees.
The metacystic trophozoites of their progenies reach the cecum and those that come in contact with the oral mucosa penetrate or invade the epithelium by lytic digestion.
The trophozoites burrow deeper with tendency to spread laterally or continue the lysis of cells until they reach the sub-mucosa forming flash-shape ulcers. There may be several points of penetration.
From the primary site of invasion, secondary lesions maybe produced at the lower level of the large intestine.
Progenies of the initial colonies are squeezed out to the lower portion of the bowel and thus, have the opportunity to invade and produce additional ulcers. Eventually, the whole colon may be involved.
E. histolytica has been demonstrated in practically every soft organ of the body.
Trophozoites which reach the muscularis mucosa frequently erode the lymphatics or walls of the mesenteric venules in the floor of the ulcers, and are carried to the intrahepatic portal vein.
If thrombi occur in the small branches of the portal veins, the trophozoites in thrombi cause lytic necrosis on the wall of the vessels and digest a pathway into the lobules.
The colonies increase in size and develop into abscess.
- A typical liver abscess develops and consists of:
- Central zone necrosis
- Median zone of stoma only
- An outer zone of normal tissue newly invaded by amoeba. Most amoebic abscess of the liver are in the right lobe.
- Prevalent in unsanitary areas
- Common in warm climate
- Acquired by swallowing
- Cysts survives a few days outside of the body
- Cyst passes to the large intestine and hatch into trophozoites. It passes into the mesenteric veins, to the portal vein, to the liver, thereby forming amoebic liver abscess.
- Entamoeba Histolytica has two developmental stages:
- Trophozoites/vegetative form
- Trophozoites are facultative parasites that may invade the tissues or may be found in the parasitized tissues and liquid colonic contents.
- Cyst is passed out with formed or semi-formed stools and are resistant to environmental conditions.
- This is considered as the infective stage in the cycle of E. histolytica
- Trophozoites/vegetative form
Source: Human Excreta
Incubation Period: The incubation period in severe infection is three days. In subacute and chronic form it lasts for several months. In average cases the incubation period varies from three to four weeks
Period of Communicability: The microorganism is communicable for the entire duration of the illness.
Modes of Transmission:
- The disease can be passed from one person to another through fecal-oral transmission.
- The disease can be transmitted through direct contact, through sexual contact by orogenital, oroanal, and proctogenital sexual activity.
- Through indirect contact, the disease can infect humans by ingestion of food especially uncooked leafy vegetables or foods contaminated with fecal materials containing E. histolytica cysts.
Food or drinks maybe contaminated by cyst through pollution of water supplies, exposure to flies, use of night soil for fertilizing vegetables, and through unhygienic practices of food handlers.
Diagnosis of Amoebiasis / Amoebic Dysentery
- Stool examination – Microscopic examination for identifying demonstrable E.H cysts or trophozoites in stool samples is the most confirmative method for diagnosis. Trophozoites survive only for a few hours, so the diagnosis mostly goes with the presence of cysts. But fresh warm faeces always show trophozoites. The cysts are identified by their spherical nature with chromatin bars and nucleus. They are noticed as brownish eggs when stained with iodine.
- Biopsy also can point out E.H cysts or trophozoites.
- Culture of the stool also can guide us for diagnosis.
- Blood tests may suggest infection which may be indicated as leucocytosis (increased level of white blood cells), also it can indicate whether any damage to the liver has occurred or not.
- Ultrasound scan – it should be performed when a liver abscess is suspected
- Metronidazole (Flagyl) 800mg TID X 5 days
- Tetracyline 250 mg every 6 hours
- Ampicillin, quinolones sulfadiazine
- Streptomycin SO4, Chloramphenicol
- Lost fluid and electrolytes should be replaced
Several antibiotics are available to treat amoebiasis. Treatment must be prescribed by a physician. You will be treated with only one antibiotic if your E. histolytica infection has not made you sick. You probably will be treated with two antibiotics (first one and then the other) if your infection has made you sick.
- Observe isolation and enteric precaution2.Provide health education:
- Boil water for drinking or use purified water;
- Avoid washing food from open drum or pail;
- Cover leftover food;
- Wash hands after defecation or before eating; and
- Avoid ground vegetables (lettuce, carrots, and the like).
- Proper collection of stool specimen
- Never give paraffin or any oil preparation for at least 48 hours prior to collectionof specimen.
- Instruct patient to avoid mixing urine with stools.
- If whole stool cannot be sent to laboratory, select as much portion as possiblecontaining blood and mucus.
- Send specimen immediately to the laboratory; stool that is not fresh is nearlyuseless for examination
- Label specimen properly.
- Skin care
- Cleanliness, freedom from wrinkles on the sheet will be helpful with all the usual precautionary measures against pressure sores.
- Mouth care
- Provide optimum comfort.
- Patient should be kept warm. Dysenteric patient should never be allowed to feel,even for a moment.
- During the acute stage, fluids should be forced.
- In the beginning of an attack, cereal and strained meat broths without fat should be given.
- Chicken and fish maybe added when convalescence is established.
- Bland diet without cellulose or bulk-producing food should be maintained for along time.
Common Nursing Diagnosis
- Altered nutrition: Less than body requirement
- Alteration in bowel elimination
- High risk for infection
- Altered body temperature
Methods of Prevention
- Health education
- Sanitary disposal of feces
- Protect, chlorinate, and purify drinking water
- Observe scrupulous cleanliness in food preparation and food handling
- Detection and treatment of carriersf.Fly control (they can serve as vector)
Nursing Care Plan
Common nursing diagnosis
- Acute pain
- Deficient fluid volume
- Imbalanced nutrition: Less than body requirements
- Impaired skin integrity
- Risk for infection
- The patient will express feelings of comfort and relief from pain.
- The patient’s electrolyte levels will stay within normal range.
- The patient’s elimination pattern will return to normal.
- The patient will report an increased energy level.
- The patient will remain afebrile.
- The patient will experience no further weight loss.
- The patient will avoid skin breakdown or infection.
- The patient will experience no further signs or symptoms of infection.
- Pain Management:
- Rationale: Alleviation of pain or a reduction in pain to a level of comfort that is acceptable to the patient
- Analgesic Administration:
- Rationale: Use of pharmacologic agents to reduce or eliminate pain
- Environmental Management:
- Rationale: Comfort: Manipulation of the patient’s surroundings for promotion of optimal comfort
- Fluid Management:
- Rationale: Promotion of fluid balance and prevention of complications resulting from abnormal or undesired fluid levels
- Hypovolemia Management:
- Rationale: Reduction in extracellular and/or intracellular fluid volume and prevention of complications in a patient who is fluid overloaded
- Shock Management: Volume:
- Rationale: Promotion of adequate tissue perfusion for a patient with severely compromised intravascular volume.
- Diarrhea Management:
- Rationale: Management and alleviation of diarrhea
- Fluid Monitoring:
- Rationale: Collection and analysis of patient data to regulate fluid balance
- Perineal Care:
- Rationale: Maintenance of perineal skin integrity and relief of perineal discomfort
- Energy Management:
- Rationale: Regulating energy use to treat or prevent fatigue and optimize function
- Exercise Promotion:
- Rationale: Facilitation of regular physical exercise to maintain or advance to a higher level of fitness and health
- Temperature Regulation:
- Rationale: Attaining and/or maintaining body temperature within a normal range.
- Fever Treatment:
- Rationale: Management of a patient with hyperpyrexia caused by nonenvironmental factors.
- Nutrition Management:
- Rationale: Assisting with or providing a balanced dietary intake of foods and fluids
- Weight Gain Assistance:
- Rationale: Facilitating gain of body weight
- Eating Disorders Management:
- Rationale: Prevention and treatment of severe diet restrictions and over exercising or binging and purging of foods and fluids
- Pressure Ulcer Care:
- Rationale: Facilitation of healing in pressure ulcers
- Infection Protection:
- Rationale: Prevention and early detection of infection in a patient at risk
- Infection Control:
- Rationale: Minimizing the acquisition and transmission of infectious agents
- Rationale: Purposeful and ongoing acquisition, interpretation, and synthesis of patient data for clinical decision making
Patient Teaching discharge and Home Health Guidance for Patient with Amoebiasis
- Teach the patient about amebicide therapy, including precautions he should take and adverse effects of the medication
- Encourage the patient to return for follow-up appointments at scheduled intervals.
- Teach the patient and his family how to handle infectious material and about the need for careful hand washing.
- Advise travelers to endemic areas and campers to boil untreated or contaminated water to prevent the disease.
Handbook of Common Communicable and infectious Disease by Dionesia Monjejar-Navales, RN, MAEd
Lippincott Review Series Medical Surgical Nursing 4th Ed
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