🩻 TOACS FCPS Station · Skull X‑ray: Mucopolysaccharidoses (MPS)
📷 Skull X‑ray (Lateral view)
🔍 Key radiographic features:
- ✓ Dolichocephaly – elongated, narrow skull shape
- ✓ Thickened calvarium – increased skull vault thickness
- ✓ J‑shaped sella turcica – elongated, shallow sella
- ✓ Large skull (macrocephaly) – with prominent frontal bossing
- ✓ Delayed suture closure – wide fontanels and sutures
📋 Clinical scenario (examiner prompt)
A 3‑year‑old child presents with coarse facial features, macrocephaly, and developmental delay. The child has hepatosplenomegaly, joint stiffness, and corneal clouding. A skull X‑ray (lateral view) is shown.
🧑⚕️ Examiner tasks · TOACS
1. Identify the diagnosis from the skull X‑ray and clinical context.
2. Describe the X‑ray findings (J‑shaped sella, thickened calvarium, dolichocephaly).
3. Explain the pathophysiology (lysosomal storage of GAGs, skeletal dysplasia).
4. Discuss differential diagnosis and management (MPS types, ERT, HSCT).
🎯 Expected answers (for examiners)
- • Diagnosis: Mucopolysaccharidosis (likely MPS I-H, Hurler syndrome)
- • X‑ray findings: J‑shaped sella turcica, thickened calvarium, dolichocephaly, macrocephaly
- • Pathophysiology: Deficiency of lysosomal enzyme → accumulation of GAGs → skeletal dysplasia (dysostosis multiplex)
- • Management: Enzyme assay (α‑L‑iduronidase), urine GAGs, ERT (laronidase), HSCT for MPS I-H
⚡ Quick FCPS‑style MCQ
A J‑shaped sella turcica on skull X‑ray in a child with coarse facies and hepatosplenomegaly is most consistent with:
A. Mucopolysaccharidosis (MPS) B. Mucolipidosis C. Osteogenesis imperfecta D. Achondroplasia📌 Topic summary ·
MPS I, II, VI
Dysostosis multiplex
Elongated skull shape
Absent in MPS II (Hunter)
MPS II (Hunter)
ERT, HSCT (MPS I)
| MPS Type | Key Skull Finding |
|---|---|
| MPS I (Hurler) | J‑shaped sella, thickened calvarium |
| MPS II (Hunter) | J‑shaped sella, dolichocephaly |
| MPS IV (Morquio) | Odontoid hypoplasia (cervical spine) |
| MPS VI (Maroteaux‑Lamy) | J‑shaped sella, macrocephaly |