Developer site: The content shown here is test data.

MyEClinic
MyEClinic
Health Dictionary AI Health Chat Find an Online Doctor
A serene Zen garden with raked sand and smooth stones, symbolising clarity and calm

Health Dictionary

Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.

Back to skin conditions

Noonan syndrome management and follow-up

Introduction

Overview

Overview

A chronic, mutlidisciplinary, system-based approach is recommended in the management and follow-up of patients with Noonan syndrome with special emphasis on the cardiac complications, growth delay, and neurocognitive deficits.

Management and Follow-up

Management and Follow-up

A mutlidisciplinary team is often needed in the management of Noonan syndrome. A system-based approach is usually adopted and recommendations are based on the severity of disease manifestations.

Cardiovascular

  • Patients with Noonan syndrome require lifetime cardiac follow-up. After initial evaluation including a focused cardiac physical exam, echocardiography, and electrocardiography, follow up is based on work-up findings. If initial work-up is unremarkable, a follow up is recommended every 5 years. [1][2]
  • The most common cardiac finding is pulmonary valve stenosis. If mild, only periodic follow-up is recommended. If clinically significant, pulmonary balloon valvuloplasty is recommended in the absence of significant valve dysplasia. With significantly dysplastic valves a pulmonary valvectomy or pulmonary valve homograft during childhood is the first line management. [3]

Endocrine and Developmental

  • Up to 70% of patients with Noonan syndrome have some form of growth delay with mean delay in bone age of 2 years. Although growth hormone supplementation has only been studied in small studies, data suggests improved growth without significant side effects.
  • Most studies with long-term follow up suggest that better outcomes are associated with earlier initiation of GH and a longer duration of treatment.[3]
  • The largest study involving 65 patients with a mean age at initiation of 11.6 years showed a mean growth of 10.9 cm in boys vs. 9.2 cm in girls with a mean treatment duration of 5.6 years at a dose of 0.33 mg/kg/week.[4] In general, doses used in most studies ranged from 0.24-0.35 mg/kg/week.[3]
  • Special growth curves for Noonan syndrome have been developed and should be used in plotting growth.[5]
  • Plotting growth on curves specific for Noonan syndrome is recommended to be done 3 times yearly from birth till age 3 years than yearly after that.[1]
  • Patients with growth deceleration, signs of hypothyroidism, or delayed puberty should be referred to a pediatric endocrinologist.[3]

Renal and Genitourinary

  • 10% of patients with Noonan syndrome have associated renal abnormalities. Renal ultrasound is recommended at diagnosis.[3]
  • Prophylactic antibiotics can be used for hydronephrosis or recurrent urinary tract infection.[3]
  • Cryptorchidism can be found in up to 80% of boys with Noonan syndrome and close attention to descended testes is recommended. Surgical orchiopexy is usually required by the age of 1 year.[1][2]

Hematology

  • Bleeding disorders can be seen in up to 65% of patients with Noonan syndrome.[3] An initial work-up consisting of a complete blood cell count with differential, prothrombin time and activated partial thromboplastin time is recommended.[1]
  • A repeat evaluation is required if the patient was aged 6-12 months during first screening.[1]
  • If the patient requires any surgical procedure, a pre-operative screen with added factor IX, XI, and XII concentration assays, von Willebrand factor, and platelet aggregation testing is recommended in conjunction with a hematology consult.[1]

Neurologic and Behavioral

  • Neurologic, behavioral and cognitive abnormalities are often seen in patients with Noonan syndrome although they are poorly understood and very variable among patients.[3]
  • Yearly developmental screening is recommended especially between the ages of 5 and 18 years old with individual educational plans recommended in patients with delays.[1]
  • A complete neuropsychological examination is recommended if any deficits are detected on developmental screening.[3]

Gastrointestinal

Any patient with Noonan syndrome with recurrent vomiting or feeding difficulties requires a pediatric gastroenterology consultation for further investigation and management including antireflux medications, feeding tube insertion, and surgical consult in certain cases with malrotation. [3]

Eye and Ear

  • A complete ophthalmologic examination is recommended at diagnosis and at least every 2 years thereafter if no problems are detected.
  • A hearing test in recommended during infancy with yearly retesting in early childhood, and careful attention and management of ear infections to avoid hearing loss. [3]
References

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Roberts AE, Allanson JE, Tartaglia M, Gelb BD (2013). “Noonan syndrome”. Lancet. 381 (9863): 333–42. doi:10.1016/S0140-6736(12)61023-X. PMID 23312968.
  2. ↑ 2.0 2.1 van der Burgt I (2007). “Noonan syndrome”. Orphanet J Rare Dis. 2: 4. doi:10.1186/1750-1172-2-4. PMC 1781428. PMID 17222357.
  3. ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 Romano AA, Allanson JE, Dahlgren J, Gelb BD, Hall B, Pierpont ME; et al. (2010). “Noonan syndrome: clinical features, diagnosis, and management guidelines”. Pediatrics. 126 (4): 746–59. doi:10.1542/peds.2009-3207. PMID 20876176.
  4. ↑ Romano AA, Dana K, Bakker B, Davis DA, Hunold JJ, Jacobs J; et al. (2009). “Growth response, near-adult height, and patterns of growth and puberty in patients with noonan syndrome treated with growth hormone”. J Clin Endocrinol Metab. 94 (7): 2338–44. doi:10.1210/jc.2008-2094. PMID 19401366‎ Check |pmid= value (help).
  5. ↑ Witt DR, Keena BA, Hall JG, Allanson JE (1986). “Growth curves for height in Noonan syndrome”. Clin Genet. 30 (3): 150–3. PMID 3780030.

Template:Phakomatoses and other congenital malformations not elsewhere classified


Template:WikiDoc Sources

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Serge Korjian, Yazan Daaboul