Schistosomiasis (schistosoma)

· Children are infected through contact with water contaminated with cercariae.

· Cercaria emerge from the infected snails and are capable to penetrate intact human skin.

· Cercaria they migrate to the lungs and finally to the liver.

· The adult worms migrate to specific anatomic sites characteristic of each species.

· Schistosoma haematobium adults are found in the perivesical and periureteral venous   plexus, while Schistosoma mansoni adults are found in the inferior mesenteric veins.

Treatment

The drug of choice is praziquantel (40 mg/kg/day divided into two doses for one day).

Prevention

· Transmission of infection may be decreased by reducing the parasite load in the population. This goal may be achieved by the availability of oral, single- dose, effective chemotherapeutic agents.

· Improved sanitation and focal application of molluscicides, may be useful.

· Control of schistosomiasis is closely linked to economic and social development.

Hookworms (Ancylostoma)

· Larvae which are the infective form are found in warm damp soil and infect the human by penetrating the skin or by drinking contaminated water or by soil pica.

· Larvae migrate from the dermis or intestinal wall to the venous circulation and are carried to the lungs where they break into the alveolar spaces, migrate upwards and are then swallowed  to reach the upper small intestine.

Treatment

· In severe anemia (hemoglobin concentration less than 5 gm/dL), iron therapy should be given before anthelmintic drugs in a dose of 6 mg/kg /day until anemia is corrected.

· In cases of anemia with heart failure, diuretics and slow transfusion of packed red cells are indicated.

· Albendazole: 400mg orally once for all ages, or

· Mebendazole:  100mg orally twice daily for 3 days or 500 mg as a single dose, or

· Pyrantel pamoate in a dose of 11mg/kg up to 1gm as a single dose.

Enterobiasis(pinworm;Enterobius vermicularis)

Etiology

· Humans are infected by ingestion of embryonated eggs that are usually carried by fingernails, clothing, bedding or house dust.

· Eggs hatch in the stomach and larvae migrate to the cecal region where they mature into adult worms.

Clinical manifestations

  Nocturnal anal pruritus and sleeplessness.

Diagnosis

 Detection of eggs by adhesive cellophane tape pressed against the perianal region early in the morning. Repeated examination may be needed and worms may be seen in the stools.

Treatment

- Mebendazole 100mg as one dose and also repeated after 2 weeks for all ages, or

- Single oral dose of albendazole (400mg PO for all ages) repeated after 2 weeks, or

- Pyrantel pamoate 11mg/kg as one dose and repeated after 2 weeks.

Helminthic diseases Ascariasis: (Ascaris lumbricoides )

Etiology

 The infective stage is the mature larva-containing egg. Eggs are passed in the feces of infected individuals and mature in 5-10 days under favorable environmental conditions to become infective.

Pathogenesis

   After ingestion by the human host, larvae are released from the eggs and penetrate the    intestinal wall before migrating to the lung via the venous circulation. They break through the pulmonary tissues into the alveolar spaces, ascend to the bronchial tree and trachea and are reswallowed. Upon their arrival in the small intestine, the larvae develop into mature adult worms.
Clinical manifestations

1- Pulmonary ascariasis

2- Abdominal ascariasis

Diagnosis

Treatment

- Albendazolel (400 mg PO once for all ages), or

- Mebendazole 100mg twice daily for 3 days or 500mg once.

Giardiasis Clinical manifestations

· Infection occurs through ingestion of the cysts. When the cysts reach the upper small intestine, each cyst liberates four trophozoites. The trophozoites colonize the lumen of the duodenum and proximal jeujenum where they attach to the brush border of the intestinal epithelial cells.

Clinical manifestations

· The majority of the infected individuals are asymptomatic.

· Symptoms develop 1-3 weeks after exposure to the parasites.

· The most common presentations are diarrhea, weight loss, cramp abdominal pain, distension and failure to thrive.

· Malabsorption occurs in most of the patients
.Diagnosis

Treatment

One of the following drugs is used:

· Tinidazole: single oral dose of 50 mg/kg in children >3yr.

Nitazoxanide    

                    1-3 yr :100mg (5ml)bid for 3 days

                   4-11 yr :200mg (10ml)bid for 3 days

                    >12 yr :500mg bid for 3 days

 · Metronidazole: 15mg/kg/ day divided into 3 doses for 5 days.

 · Albendazole: 400 mg PO once a day for 5 days among children >6 years of age .

 · Furazolidone: 6mg/kg in 4 divided doses for 10 days.

Amebiasis Pathogenesis and pathology

Etiology

· Infection is established by ingestion of Entamoeba histolytica cysts that release trophozoites.

· The amebic cysts are resistant to low temperature and chlorine that are commonly used in water purification.

· Trophozoites are actively motile organisms and colonize the lumen of large intestine and may invade its mucosal lining.

Pathogenesis and pathology

Once the trophozoites invade the intestinal mucosa, they produce tissue destruction      (ulcers) with little local inflammatory response.

· The organisms multiply and spread through the wall underneath the intestinal epithelium to produce flask shaped ulcers.

· These lesions are commonly seen in the caecum, transverse colon, and sigmoid colon.

· Amebae may produce similar lytic lesions if they reach the liver.

· Rarely the infection may extend extraintestinally to lungs and brain.

Clinical manifestations

1- Intestinal amebiasis

2- Hepatic amebiasis

Diagnosis

· Patients with invasive colitis show occult blood in stools.

· Detection of the parasite or cysts in the stools.

· When stool samples are negative for 3 days, segmoidoscopy is done and biopsy is taken.

· Indirect hemagglutination test may be helpful in the diagnosis of invasive intestinal amebiasis and amebic liver abscess.

Treatment

Drug	Dose (oral)
Metrnidazole	Colitis or liver abscess: 50mg/kg/day in 3 divided doses for 7-10 days
Or Tinidazole	Colitis : 50mg/kg/day once daily for 3 days
	Liver abscess : 50mg/kg/day once daily for 5 days
Followed by
Paromomycin (preferred)	30mg/kg/day in 3 divided doses for 7 days
Or
Diloxanide furoate in children >2 yrs	20mg/kg/day in 3 divided doses for 7 days
Or
Iodoquinol	30mg/kg/day in 3 dividsd doses for 20 days

Acute bacterial meningitis

Clinical manifestations

Meningococcemia

Meningial irritation signs

Nuchal rigidity,

Brudzinski sign: Involuntary flexion of the knees and hips follows flexion of the neck in the supine child.

Increased intracranial pressure

Bulging anterior fontanel is a sign of Increased intracranial pressure

Seizures due to:

- Cerebritis 

- Infarction

-          Electrolyte disturbances

-           may be associated with poor prognosis

-          Diagnosis

-          Lumbar puncture: should be performed when bacterial meningitis is suspected.

-          - The microorganisms on gram stain and culture is positive in 70-90% of the cases.

-          - Neurtophilic pleocytosis (>1000/mm3) is present.

-          - Elevated CSF proteins

-          - Reduced glucose concentrations.

-          Treatment

-          Antibiotics

-          Initial antibiotic therapy

-          Cefotaxime 200-300 mg/kg/24hr for 10-14 days IV or ceftriaxone100mg/kg/24 hr is usually used. Vancomycin (60 mg/kg/24 hr, given every 6 hr) may be added in suspected resistant strain infection.

-          Chloramphenicol: 100mg/kg/24 hr in 4 divided doses IV is used in patients allergic to          β-lactam antibiotics.

-          · Penicillin 300,000 U/kg/24hr, IV in 4-6 divided doses is used for penicillin sensitive N. meningitides infection.

see the pictures

Nuchal rigidity

Brudzinski sign

Dialated pupil

Increased intracranial pressure (

Lumbar puncture

The child is seen in convulsion

Enteric fever-Typhoid fever

Typhoid fever is caused by Salmonella typhi (S. typhi) and paratyphoid fever is caused by S. paratyphi.

Clinical picture

A- In school-age children and adolescents

B- In infants and young children

A macular or maculopapular rash (rose spots) appears on the      seventh day on the lower chest and abdomen.

Diagnosis

Widal test: measures antibodies against O and H antigens of S. typhi.

The minimal Widal   titer diagnostic for enteric fever is combined “O” agglutinin titer of 1/80 and above, with one of H agglutinin titer of 1/160 and above, provided that the other H agglutinins are at a lower titer.

Complications

Treatment

 Antimicrobial therapy
Fully sensitive

Chloramphenicol

Amoxicillin

Mulitidrug-resistant

Fluoroquinolone

 Cefixime

Quinolone-resistant

Azithromycin

Ceftriaxone

See the pictures

^{Salmonella organism}

rose spots

Widal test

Diphtheria ( Clinical manifestations ,Complications ,Treatment)

Clinical manifestations

Tonsillar and pharyngeal

A white membrane extends from tonsils to palate as a spider web, then this adherent membrane covers the tonsils, pharynx, larynx and trachea.

Cervical adenitis and bull neck from brawny pitting edema of soft tissue which is warm and tender.

Complications

1- Laryngeal affection leads to respiratory obstruction.

2- In the second week of the disease toxic myocarditis occurs.

3- Neurologic complications:  soft palate paralysis occurs in the first week, with nasal tone of voice and nasal regurgitation. Ocular paralysis and phrenic nerve paralysis occur in the third   week and peripheral nerve limb paralysis occurs in the fifth week.

Treatment

1- Antitoxin

· In mild cases is 40,000 U.

· In moderate severity is 80,000 U.

· In cases with severe pharyngeal or laryngeal or brawny edema is 120,000 U.

2- Antibiotic therapy: with one of the following drugs for 14 days: 

· Aqueous crystalline penicillin G. IM or IV (100,000-150,000U/kg/24hr divided in 4 doses).

· Procaine penicillin (25,000-50,000U/kg/24hr divided in 2 doses) IM.

· Erythromycin orally or IV (40-50 mg/kg/24hr, maximum, 2gm/24hr).

see the pictures

A white membrane of diphtheria

Bull neck

Bull neck