ملخص

SCHISTOSOMIASIS (BILHARIZIASIS)

1. Schistosoma haematobium
2. Schistosoma mansoni
3. Schistosoma japonicum

The spread continues because of

A. Water resource contamination in developing countries
B. The migration of infected populations.

PATHOLOGY

Most of the disease is due to the passage of eggs through mucosa and to the granulomatous reaction to eggs deposited in tissues.
The eggs of S. haematobium pass mainly through the wall of the bladder, but may also involve rectum, seminal vesicles, vagina, cervix and uterine tubes.
S. mansoni and S. japonicum eggs pass mainly through the wall of the lower bowel or are carried to the liver.
The most serious, although rare, consequences of the ectopic deposition of eggs are transverse myelitis and paraplegia.
Later there is fibrosis and eggs calcify
Eggs of S. haematobium, and of the other two species after the development of portal hypertension, may reach the lungs.

CLINICAL MANIFESTATION

A. Acute schistosomiasis (Katayama fever)
itching at site of cercarial penetration. After a symptom-free period , acute schistosomiasis may present with allergic manifestations , abdominal pain, headaches, cough and sweating.
On examination: Hepatomegaly, splenomegaly, lymphadenopathy and pneumonia may be present. There is eosinophilia
These allergic phenomena severe in infections with S. mansoni and S. japonicum but are rare with S. haematobium.
The features subside after 1-2 weeks.
B. Chronic schistosomiasis
The manifestation is due to egg deposition and occurs months to years after infection. The symptoms depend upon the intensity of infection



S. haematobium

Humans are the only natural hosts of S. haematobium
Painless terminal haematuria is the first and most common symptom.
Frequency of micturition
complicated by frequent urinary tract infections, bladder or ureteric stone formation,
and ultimately renal failure with a contracted calcified bladder.
association of S. haematobium infection with squamous cell carcinoma of the bladder.
Ectopic worms cause skin or cord lesions.
light infection are asymptomatic.


LIVER AND GIT INVOLVEMENT (Mainly S. Mansoni and Japanicum)

Bloody diarrhea

Abdominal pain: RUQ pain, cramping
Hematemesis (with portal hypertension)
Ascites (with portal hypertension)
Vulvar or perianal lesions
On examination: Hepatosplenomegaly
Abdominal tenderness

OTHER SITES AFFECTED BY SCHISTOSOMIASIS

Pulmonary hypertension
Dyspnea on exertion .
Cough .
Palpitations .Central nervous system (CNS)
Seizures and/or mental status changes Paralysis (with spinal cord involvement)

Diagnosis :

Clinically
Hematological and biochemically
Confirmation by Detection of ova in urine or from stool,
biopsy or snip from rectum and bladder wall.
Serological tests ELISA for screening
Radiological and scope examination
The aim is to stop egg-laying and reduce adult worm load
Praziquantel for all types and as a single dose.
Surgery in special circumstances and for some complications like ureteric stricture, and small fibrotic urinary bladder.



COMPLICATIONS OF SCHISTOSOMAISIS IN GENERAL:

1. Pulmonary hypertension

2. Cor pulmonale
3. Portal hypertension.
4. Obstructive uropathy.
5. Squamous cell carcinoma of the bladder.
6. Gastrointestinal bleeding
7. Carrier for salmonella
8. Neurological complications

Prognosis

Almost all patients improve with treatment.
patients with hepatic and urinary disease, even with fibrosis, may improve significantly over months or years following treatment.
Treatment is indicated for patients with end-stage complications of portal hypertension and severe pulmonary hypertension,
Co-infection worsens the prognosis.
PREVENTION
No accepted prophylactic regimens.
No vaccines are currently available
Early treatment after high-risk exposures should minimize morbidity.










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