Etiologic Agent
Entamoeba histolytica
- prevalent in unsanitary areas
- common in warm climate
- acquired by swallowing
- cyst 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”.
Pathology
When the cyst is swallowed, it passes through the stomach unharmed and shows no activity while in an acidic environment.
In the alkaline medium of the intestine, metacyst begins to move within the cyst wall.
The quadrinucleate amoeba emerges and divides into amebulas that are swept down into the cecum.
Mature cyst in the large intestines leaves the host in great numbers.
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 putrifaction, desiccation, and temperatures below 5 and above 40 degrees.
Source: human excreta
Incubation Period
3 days – severe infection
Several months – subacute & chronic form
3-4 weeks – average
* The microorganism is communicable for the entire duration of the illness.
Mode of Transmission
Fecal-oral transmission
Direct contact – sexual contact (orogenital, oroanal & proctogenital sexual activity)
Indirect contact – uncooked leafy vegetables or foods contaminated with E. histolytica cysts.
Clinical Manifestations
Acute amoebic dysentery
a. slight attack of diarrhea, altered with periods of constipation
b. diarrhea, watery and foul-smelling stool often containing blood-streaked mucus
c. colic and gaseous distention of the lower abdomen
d. nausea, flatulence, abdominal distention and tenderness in the right iliac region over the colon.
Chronic amoebic dysentery
a. attack of dysentery that lasts for several days, usually followed by constipation.
b. tenesmus accompanied by the desire to defecate
c. anorexia, weight loss, and weakness
d. liver may be enlarged
e. watery stool, bloody and mucoid
f. vague abdominal distress, flatulence, constipation or irregularity of bowel
g. mild toxemia, constant fatigue & lassitude
h. abdomen losses its elasticity when picked-up between fingers
I. On sigmoidoscopy, scattered ulceration with yellowish and erythematous border
j. The gangrenous type (fatal cases) is characterized by the appearance of large sloughs of intestinal tissues in the stool accompanied by hemorrhage.
Extraintestinal forms
Hepatic
a. Pain at the upper right quadrant with tenderness of the liver
b. jaundice
c. intermittent fever
d. loss of weight or anorexia
e. abscess may break through the lungs, patient coughs anchovy-sauce sputum.
Diagnostic Exam
Stool exam (cyst, white and yellow pus with plenty of amoeba)
Blood exam ( leukocytosis)
Proctoscopy/Sigmoidoscopy
Treatment Modalities
Metronidazole (Flagyl)
Tetracycline
Ampicillin, quinolones, sulfadiazine
Streptomycin SO4, Chloramphenicol
Lost fluid and electrolytes should be replaced.
Nursing Management
Observe isolation and enteric precaution.
Provide health education and instruct patient to:
- 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
- avoid ground vegetables
Posts
