Sturge-Weber syndrome — SAQ

Stem

A 3-week-old infant has a flat pink-red birthmark involving the left forehead and both left eyelids. It was present at birth. The infant feeds normally, has no observed seizures and has clear corneas. The parents were told it was a “strawberry mark” that would disappear.[2][5]

Questions

a) Identify the skin lesion and distinguish it from infantile haemangioma. (3 marks)[3][5]

b) Explain the SWS risk phenotype and molecular basis. (3 marks)[1][2]

c) State the appropriate assessments now, including the role and limits of MRI and EEG. (4 marks)[2][9]

d) If the infant later has a prolonged focal-to-bilateral convulsive seizure and brain involvement is confirmed, outline immediate and longer-term management. (3 marks)[4][13]

e) Counsel the parents about cutaneous treatment and inheritance. (2 marks)[1][3]

Model answer and exact marking

a) Lesion and differential — 3 marks

• 1 mark: This is a port-wine birthmark (PWB; capillary malformation), not a vascular tumour.[3][5]
• 1 mark: PWB is present at birth, persists and grows proportionately; it may darken or thicken and does not characteristically involute.[3]
• 1 mark: Infantile haemangioma usually appears after birth, proliferates and later involutes; waiting for this congenital lesion to disappear is inappropriate.[5]

b) Risk phenotype and molecular basis — 3 marks

• 1 mark: Forehead/median/hemifacial or extensive segmental PWB raises risk of SWS brain involvement; embryologic vascular territory is more accurate than a blanket “V1” rule.[2][5]
• 1 mark: Any eyelid/periocular PWB, including lower-eyelid disease, raises glaucoma concern; the stain alone does not prove SWS and the full classic triad is not required.[2]
• 1 mark: SWS is usually post-zygotic tissue mosaicism, most commonly GNAQ p.Arg183Gln; rare mosaic GNA11 variants overlap.[1][16]

c) Assessment now — 4 marks

• 1 mark: Because any eyelid/periocular PWB raises glaucoma concern, arrange prompt baseline paediatric ophthalmology with pressure, corneal/optic-nerve and dilated retinal assessment, followed by individualized periodic surveillance.[2]
• 1 mark: Because this infant's forehead distribution raises neurological SWS risk, refer to paediatric neurology for baseline and periodic clinical review; document development and teach caregivers to recognize subtle focal seizures.[2][5]
• 1 mark: Do not order automatic contrast MRI solely because the infant is asymptomatic. Consensus recommends selective specialist-led imaging for subtle symptoms, extensive/bilateral PWB or a presymptomatic-treatment discussion; early MRI can be falsely negative.[2][8][9]
• 1 mark: EEG may support risk assessment or evaluate suspected seizures, but is not diagnostic and a normal EEG does not exclude later brain involvement. After neurological symptoms, obtain optimized pre/post-contrast MRI including SWI.[2]

d) Acute and longer-term neurological care — 3 marks

• 1 mark: Treat the prolonged seizure immediately with an age-appropriate status protocol: ABC, bedside glucose, prompt rescue benzodiazepine, second-line antiseizure medication and anaesthesia/PICU escalation if refractory; do not delay treatment for imaging.[13]
• 1 mark: After stabilization, use individualized maintenance antiseizure therapy; persistent deficit or a prolonged non-resolving stroke-like episode requires urgent neurological reassessment and MRI. Drug-resistant unilateral SWS warrants specialist epilepsy-surgery evaluation.[2][4]
• 1 mark: Aspirin or presymptomatic antiseizure therapy is not routine preventive treatment. Low-dose aspirin 3–5 mg/kg/day is off-label specialist practice supported by small retrospective studies, with bruising/bleeding and local viral-illness precautions discussed.[14][15]

e) Skin treatment and inheritance — 2 marks

• 1 mark: PDL is first-line for lightening PWB, usually over multiple sessions; complete clearance is uncommon, benefit is not guaranteed, and anaesthesia is individualized. Selected infants can be treated without general anaesthesia.[3][17]
• 1 mark: Typical SWS is sporadic post-zygotic mosaic disease, not Mendelian inheritance. Sibling recurrence is expected to be extremely low rather than mathematically zero; consider genetics review for atypical or apparently familial disease.[1][16]

Total: 3 + 3 + 4 + 3 + 2 = 15 marks.[2]

[2] [14]

References

1. [1]Shirley MD, Tang H, Gallione CJ, et al. Sturge-Weber syndrome and port-wine stains caused by somatic mutation in GNAQ. N Engl J Med, 2013.PMID 23656586
2. [2]Sabeti S, Ball KL, Bhattacharya SK, et al. Consensus Statement for the Management and Treatment of Sturge-Weber Syndrome: Neurology, Neuroimaging, and Ophthalmology Recommendations. Pediatr Neurol, 2021.PMID 34153815
3. [3]Sabeti S, Ball KL, Burkhart C, et al. Consensus Statement for the Management and Treatment of Port-Wine Birthmarks in Sturge-Weber Syndrome. JAMA Dermatol, 2021.PMID 33175124
4. [4]Yeom S, Comi AM. Updates on Sturge-Weber Syndrome. Stroke, 2022.PMID 36263782
5. [5]Poliner A, Fernandez Faith E, Blieden L, et al. Port-wine Birthmarks: Update on Diagnosis, Risk Assessment for Sturge-Weber Syndrome, and Management. Pediatr Rev, 2022.PMID 36045161
6. [8]Zallmann M, Leventer RJ, Mackay MT, et al. Screening for Sturge-Weber syndrome: A state-of-the-art review. Pediatr Dermatol, 2018.PMID 29034507
7. [9]Zallmann M, Mackay MT, Leventer RJ, et al. Retrospective review of screening for Sturge-Weber syndrome with brain magnetic resonance imaging and electroencephalography in infants with high-risk port-wine stains. Pediatr Dermatol, 2018.PMID 30020536
8. [13]Glauser T, Shinnar S, Gloss D, et al. Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in Children and Adults: Report of the Guideline Committee of the American Epilepsy Society. Epilepsy Curr, 2016.PMID 26900382
9. [14]Day AM, Hammill AM, Juhász C, et al. Hypothesis: Presymptomatic treatment of Sturge-Weber Syndrome With Aspirin and Antiepileptic Drugs May Delay Seizure Onset. Pediatr Neurol, 2019.PMID 30482419
10. [15]Lance EI, Sreenivasan AK, Zabel TA, et al. Aspirin use in Sturge-Weber syndrome: side effects and clinical outcomes. J Child Neurol, 2013.PMID 23112247
11. [16]Polubothu S, Al-Olabi L, Carmen Del Boente M, et al. GNA11 Mutation as a Cause of Sturge-Weber Syndrome: Expansion of the Phenotypic Spectrum of G(α/11) Mosaicism and the Associated Clinical Diagnoses. J Invest Dermatol, 2020.PMID 31838126
12. [17]Jeon H, Bernstein LJ, Belkin DA, et al. Pulsed Dye Laser Treatment of Port-Wine Stains in Infancy Without the Need for General Anesthesia. JAMA Dermatol, 2019.PMID 30865245