PEDIATRICS
L7 Dr. Tariq
Enterobiasis
Etiology :
It is caused by the pinworm (Entrobius vermicularis ) which is 1 cm in
length , white thread-like worm . It inhabits the cecum , appendix and
the ascending colon . At night , the gravid female migrates to perianal
region to deposit eggs . Human infection occurs by ingestion of eggs
that carried by fingernails , clothes and host dust .
Epidemiology :
Pinworm infections occur at all ages and socioeconomic levels but it is
higher in rate at age of (5-14 yrs) . It is common in areas where children
live , play and sleep together . The human is the only host .
Pathogenesis :
Pinworm infection may cause symptoms by mechanical stimulation ,
allergic reaction and migration .
Clinical Features :
The most common symptoms include itching , restless sleeping. In rare
cases , appendicitis , chronic salpingitis , peritonitis and hepatitis which
occur due to worms migration .
Diagnosis :
By identification of eggs and worms by using of adhesive cellophane
tape pressed against perianal region in early morning . Routine stool
examination rarely demonstrates the ova .
Treatment :
To the patient and his family . One of the following options :-
A - Metronidazole (100 mg PO) single oral dose repeated after 2 wks .
B - Albendazole (400 mg PO ) single dose repeated after 2 wks .
C – Pyrantel pamoate (11 mg/kg ) single dose repeated after 2 wks .
Prevention :
The household contacts should be treated at the same time with the
patient . Good hands washing is the most effective method of
prevention .
Hookworms
Etiology :
Two major generations of hookworms which are Necator americanus
and Ancylostoma which include A. duodenalae and less common
zoonotic species such as A. ceylanicum , A.caninum and A. braziliense .
The larvae in the soil infect the human either by penetrating the skin
(N. americanus and A. duodenalae ) or by ingestion as in cases of
A.duodenalae . Larvae that penetrate the skin undergo extraintestinal
migration through the venous circulation before reaching the intestine
. When it is orally ingested , it may undergo extraintestinal migration or
remain in the intestine to develop e adult worm
.
Epidemiology :
It is common infection because it require adequate moisture , shade
and warmth of the soil . Hookworm infections are usually confined to
the rural areas especially when human feces is used as fertilizer or in
inadequate conditions of sanitation .
Pathogenesis :
The major morbidity of hookworm infection is a direct result of
intestinal blood loss.Each adult A. duodenalae causes loss of 0.2ml
blood per day while N.americanus causes less blood loss .
Clinical Features :
The most important c.f is iron deficiency anemia due to chronic blood
loss , others like ground itching when the larvae penetrate skin causing
vesiculation and edema at the site of penetration . Respiratory
symptoms like cough and laryngotracheobronchitis occur when larvae
migrate to the lung . Intestinal symptoms include pain ,anorexia
,diarrhea and melena .
Diagnosis :
By detection of the eggs by the direct stool examination .
Treatment :
Albendazole (400 mg) single dose or mebendazole (100 mg bid) for
3 days .
Prevention :
1 - improvement of sanitation .
2 - health education .
3 - avoidance of using human feces as fertilizer .
Ascariasis
Etiology :
Ascariasis is caused by the nematode or roundworm ( Ascaris
lumbricoides ) . Adult worm inhabits the intestinal lumen and have
a lifespan of 10- 24 mo .
Epidemiology :
Ascariasis is most common in the tropical areas , key factors related to
the high prevalence include poor socioeconomic state , using human
feces as fertilizer and geophagia . The highest rate of infection is in pre-
school and early school ages . Transmission is primarily hand to mouth
but may involve ingestion of contaminated raw fruit and vegetables .
Pathogenesis :
After ingestion , Ascaris ova hatch into larvae , the larvae migrate
through the venous circulation to the lung , enter the alveoli then
migrate through bronchi , swallowed and return back to the intestine
where it mature into adult worm .
Clinical Features :
They depend on the intensity of infection and the organ involved , the
most clinical problem is to pulmonary disease and intestinal or biliary
tract obstruction .
Respiratory symptoms include fever , urticarial , dyspnea , cough and
pulmonary infiltration . Abdominal symptoms are vomiting , abd.
cramp and bowel obstruction . The worm may migrate to the biliary or
pancreatic duct leading to cholecystitis or pancreatitis .
Diagnosis :
By direct microscopic stool examination .
Treatment :
-
Albendazole (400 mg po) single dose .
-
Mebendazole (100 mg po bid ) for 3 days .
-
Pyrantel pamoate (11 mg/kg po) single dose .
-
Piperazine citrate (150 mg/kg po) initially followed by 65 mg/kg
by 6 doses .
Surgery may be required in severe obstruction .
Prevention :
1 – improve sanitation .
2 – don’t use human feces as fertilizer .
3 – anti helminthics for all individuals in areas of high endemicity and
for target groups with high frequency of infection like primary schools
students .
Taeniasis
Etiology :
The beef tapeworm (Taenia saginata ) and the pork tapeworm ( Taenia
solium ) , their length may be 4-10 m . The adult stage only found in
human intestine , the adult stage consist of hundreds or thousands of
segments ( proglottids) .
Clinical Features :
The proglottids are mobile and usually cause pruritus , the adult worm
rarely cause I.O , choleangitis or appendicitis .
Diagnosis :
By identification of gravid proglottids in stool , eggs are usually absent
in stool
.
Treatment :
Praziquantel ( 5-10 mg/kg ) single dose
Or niclosamide (50 mg/kg ) single dose .