Summary about Disease
Extraintestinal amebiasis is a parasitic infection caused by the protozoan Entamoeba histolytica, where the parasite spreads beyond the intestines to other organs of the body. The most common site of extraintestinal infection is the liver, resulting in amebic liver abscess. Other less common sites include the lungs, brain, and skin. It is a serious condition that can be fatal if left untreated.
Symptoms
Symptoms vary depending on the organ affected, but common symptoms include:
Amebic Liver Abscess: Right upper quadrant abdominal pain, fever, chills, sweating, weight loss, fatigue, nausea, vomiting, and an enlarged, tender liver.
Amebic Lung Abscess: Cough, chest pain, shortness of breath, fever, and possibly bloody sputum.
Amebic Brain Abscess: Headache, seizures, altered mental status, and neurological deficits.
Amebic Skin Infection: Painful ulcers or lesions.
Causes
Extraintestinal amebiasis occurs when Entamoeba histolytica parasites, initially causing intestinal infection (amebiasis), invade the intestinal wall and enter the bloodstream. They are then carried to other organs, most commonly the liver, where they can form abscesses. Infection occurs through ingestion of *E. histolytica* cysts, typically via contaminated food or water.
Medicine Used
Treatment typically involves a combination of medications:
Metronidazole: This is usually the first-line treatment to kill the Entamoeba histolytica parasites in the tissues.
Tinidazole: An alternative to metronidazole with a shorter course of treatment.
Luminal Amebicides (e.g., Diloxanide Furoate, Iodoquinol, Paromomycin): These are used after metronidazole or tinidazole to eliminate any remaining parasites in the intestines and prevent recurrence. These kill the cyst form of the parasite.
Is Communicable
Extraintestinal amebiasis itself is not directly communicable from person to person. However, the intestinal infection (amebiasis) that precedes it is communicable. People infected with *E. histolytica* can shed cysts in their feces, which can contaminate food or water and infect others if sanitation and hygiene are poor.
Precautions
Practice good hygiene: Wash hands thoroughly with soap and water after using the toilet and before preparing or eating food.
Safe water: Drink safe water, either boiled or treated with iodine or chlorine.
Safe food: Avoid eating raw fruits and vegetables unless you can peel them yourself. Ensure food is properly cooked, especially in areas where amebiasis is common.
Avoid fecal-oral contact: Be cautious in areas with poor sanitation.
Traveler's precautions: When traveling to areas with high rates of amebiasis, be especially careful about food and water safety.
How long does an outbreak last?
An outbreak's duration depends on the source and effectiveness of control measures. Localized outbreaks can be controlled relatively quickly (weeks) if the source of contamination is identified and eliminated, and if proper sanitation and hygiene practices are implemented. Larger outbreaks affecting communities can last longer (months) until widespread interventions reduce transmission.
How is it diagnosed?
Diagnosis involves a combination of:
Medical History and Physical Examination: Assessing symptoms and risk factors.
Stool Tests: While extraintestinal amebiasis involves infection outside the intestines, stool tests may still be performed to look for evidence of intestinal amebiasis, as it often precedes extraintestinal infection.
Blood Tests: Serologic tests (e.g., ELISA) can detect antibodies against E. histolytica, indicating past or present infection.
Imaging Studies: Ultrasound, CT scans, or MRI can identify abscesses in the liver, lungs, or brain.
Aspiration and Examination: In some cases, fluid from a liver abscess may be aspirated and examined microscopically to confirm the presence of E. histolytica.
Timeline of Symptoms
The timeline of symptoms can vary:
Incubation period (Intestinal Amebiasis): 2-4 weeks between ingestion of cysts and the onset of intestinal symptoms.
Extraintestinal Symptoms: Can develop weeks, months, or even years after the initial intestinal infection. The onset of symptoms is often gradual, but can be acute depending on the size and location of the abscess.
Important Considerations
Early Diagnosis and Treatment: Prompt diagnosis and treatment are crucial to prevent serious complications and death.
Differential Diagnosis: Consider other possible causes of liver abscess, lung abscess, or neurological symptoms.
Follow-up: Monitor patients closely after treatment to ensure resolution of the infection and prevent recurrence.
Public Health Implications: Extraintestinal amebiasis is a significant public health concern in areas with poor sanitation and hygiene. Public health measures to improve sanitation and hygiene are essential for prevention.
Drainage of Abscesses: Large liver abscesses may require drainage via percutaneous aspiration or surgery in addition to medication.