Amoebiasis
- protozoal infection of human beings initially involves the
colon, but may spread to soft tissues, most commonly to the liver or lungs, by
contiguity or hematogenous or lymphatic dissemination.
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
Ø
When the
cyst is swallowed, it passes through the stomach unharmed and shows no
activity while in an acidic environment.
Ø
In the alkaline medium of
the intestine, metacyst begins to move within the cyst wall.
Ø
The quadrinucleate amoeba
emerges and divides into amebulas that are swept down into the cecum.
Ø
Mature cyst
in the large intestines leaves the host in great numbers.
Ø
The cyst can remain viable
and infective in moist and cool environment for at least 12 days and in water
for 30 days.
Ø
The cysts are resistant to
levels of chlorine normally used for water purification.
Ø
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
1.
Stool exam (cyst, white and
yellow pus with plenty of amoeba)
2.
Blood exam ( leukocytosis)
3.
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
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