Which Sibling Donates Marrow - Immunology clinical simulation case. The parents bring their 5-month-old son Yousef to the immunology clinic. He has had...
Age: 45 • Setting: Outpatient Consultation
Clinical Presentation & History
The parents bring their 5-month-old son Yousef to the immunology clinic. He has had recurrent oral thrush since 2 months of age, three episodes of otitis media, chronic watery diarrhea, and weighs only 6.8 kg. Initial lymphocyte phenotyping showed CD3 <300/µL, CD19 absent, and NK cells absent. TREC screening was zero. The parents ask about hematopoietic stem cell transplantation (HSCT) from his two HLA-identical siblings.
Differential Diagnoses to Consider
Primary differential diagnoses evaluated in this clinical scenario:
Severe Combined Immunodeficiency (SCID), T-B-NK- phenotype, most likely X-linked or JAK3-deficient
Maintain a systematic approach from history taking to definitive intervention.
Diagnostic stewardship minimizes patient harm and diagnostic delay.
Diagnostic Pitfalls & Cognitive Error Warnings
Key reasoning traps and premature closure risks associated with this presentation:
Premature closure without complete investigation carries high diagnostic error risk.
Test Your Clinical Reasoning in Real Time
Step into the active clinician role for this case. Order diagnostic tests, analyze live laboratory panels, and navigate branching clinical decisions with real-time feedback.