Seminar: Parasitic disorders: toxoplasmosis, toxocariasis, ascariasis, enterobiasis, giardiasis, and scabies.

Clinical classes: Clinical manifestations, diagnostic workup, and treatment of pediatric parasitic infections.

Additional activity: Clinical case presentation and discussion.

Time: 4 hours (8:00 AM – 12:00 PM)

Goal

To understand the epidemiology, routes of transmission, clinical manifestations, diagnostic methods, treatment, and prevention of common parasitic infections in children. Particular emphasis is placed on the appropriate use and interpretation of laboratory diagnostic tests.

Before the class

Students should revise:

• Basic classification and life cycles of common human parasites.
• Host-parasite interactions and immune responses.
• The role of eosinophils in parasitic infections.
• Basic principles of stool examination and serological diagnosis.
• Principles of antiparasitic treatment.

Topics

1. Toxoplasmosis

1.1. Etiology and transmission of Toxoplasma gondii.

1.2. Acquired and congenital toxoplasmosis.

1.3. Clinical manifestations of congenital infection.

1.4. Diagnostic methods, including serology and PCR.

1.5. Principles of treatment and prevention.

2. Toxocariasis

2.1. Etiology and routes of transmission of Toxocara canis.

2.2. Visceral larva migrans.

2.3. Ocular toxocariasis.

2.4. Laboratory and serological diagnosis.

2.5. Principles of treatment.

3. Ascariasis

3.1. Life cycle of Ascaris lumbricoides.

3.2. Intestinal and pulmonary manifestations.

3.3. Diagnosis using stool examination.

3.4. Treatment and prevention.

4. Enterobiasis (pinworm infection)

4.1. Life cycle and transmission of Enterobius vermicularis.

4.2. Clinical manifestations, particularly perianal pruritus.

4.3. Diagnosis using the adhesive tape test.

4.4. Treatment and prevention of reinfection.

5. Giardiasis

5.1. Etiology and transmission of Giardia duodenalis.

5.2. Clinical manifestations and malabsorption.

5.3. Stool antigen detection and molecular diagnostics.

5.4. Principles of antiparasitic treatment.

6. Scabies

6.1. Etiology and transmission of Sarcoptes scabiei.

6.2. Clinical manifestations and characteristic distribution of lesions.

6.3. Diagnosis and differential diagnosis.

6.4. Topical and systemic treatment options.

6.5. Household management and prevention of reinfestation.

7. Diagnostic approach to suspected parasitic infection

7.1. Importance of epidemiological history.

7.2. Interpretation of eosinophilia.

7.3. Selection of stool examinations, antigen tests, serology, and PCR.

7.4. Limitations of serological testing.

7.5. Indications for specialist consultation.

8. Additional activity: Clinical case presentation and discussion

Each six-student group is required to prepare and deliver a clinical case presentation on the final day of the course. The case will be assigned by the group's clinical instructor.

Students must prepare a slide presentation and present the assigned case to the entire class.

The primary objective is to demonstrate clinical reasoning and a structured diagnostic approach, rather than to focus on the rarity of the final diagnosis.

The presentation should include:

1. Clinical presentation: A clear and structured summary of the patient's medical history, symptoms, and physical examination findings.
2. Clinical interpretation: Identification and interpretation of the key clinical findings, including their potential diagnostic significance.
3. Differential diagnosis: Development of a prioritized list of possible diagnoses, with an explanation of the reasoning behind each.
4. Diagnostic strategy: Selection and justification of appropriate laboratory tests, imaging studies, and other diagnostic procedures.
5. Interpretation of results: Critical evaluation of diagnostic findings and their impact on subsequent clinical decisions.
6. Diagnostic reasoning: A step-by-step explanation of how the differential diagnosis was narrowed down and how the final diagnosis was established.
7. Key learning points: A summary of the generalizable diagnostic principles and clinical lessons illustrated by the case.

Important: Although the assigned cases may involve rare diseases or unusual clinical presentations, the purpose of this exercise is not to provide an extensive review of the rare condition itself. Instead, students should demonstrate how to approach a patient presenting with particular symptoms, formulate a reasonable differential diagnosis, select appropriate investigations, and interpret the results to reach a diagnosis.

Students are encouraged to present the case progressively, revealing clinical findings and diagnostic results step by step, allowing their colleagues to participate in the diagnostic reasoning process.

Each six-student group is required to prepare a clinical case presentation collaboratively. However, only one student will deliver the presentation on behalf of the entire group. The presenting student will be selected randomly on the day of the presentation. Therefore, all six students must actively participate in preparing the presentation and be fully prepared to present and discuss the assigned case.

The presentation will be followed by a group discussion moderated by the clinical instructor.

Topics' details

Students should be able to explain or discuss:

• Routes of transmission and life cycles of common pediatric parasites.
• Differences between congenital and acquired toxoplasmosis.
• Clinical manifestations and complications of congenital toxoplasmosis.
• Interpretation and limitations of Toxoplasma IgM and IgG antibodies.
• Clinical features of visceral and ocular toxocariasis.
• Diagnostic limitations of Toxocara serology.
• The significance of eosinophilia in parasitic infections.
• Clinical manifestations of intestinal and pulmonary ascariasis.
• Why the adhesive tape test is preferred for diagnosing enterobiasis.
• Mechanisms of malabsorption and diarrhea in giardiasis.
• Appropriate selection of stool microscopy, antigen detection, and molecular tests.
• Typical distribution of scabies lesions in infants and older children.
• Principles of antiparasitic treatment and prevention of reinfection.
• The importance of family and household management in selected parasitic diseases.
• Hygiene, food safety, and other preventive measures.

Clinical skills

During clinical classes, students should practice:

• Taking a focused epidemiological history relevant to parasitic infections.
• Identifying symptoms suggestive of selected parasitic diseases.
• Selecting appropriate laboratory investigations.
• Interpreting stool examination and serological findings.
• Formulating a differential diagnosis in children with eosinophilia, abdominal symptoms, or pruritus.
• Proposing initial treatment and prevention strategies.