Hemimegalencephaly

Classification according to ICD-10
Q04.5	Megalencephaly
ICD-10 online (WHO version 2019)

The hemimegalencephaly (from ancient Greek ἥμι hemi , German , half ' ) is a special type of Megalencephaly , in which only one side of the brain (hemisphere) is increased abnormally. It is a very rare congenital disease that belongs to the PIK3CA-related overgrowth spectrum . The main clinical symptom is therapy-resistant epilepsy

Ultrasound of hemimegalencephaly in a newborn, transfontanellar coronary section. The irregular cerebral structure, displacement of the midline and the lateral ventricle is clearly visible

Synonym : unilateral megalencephaly

distribution

The frequency is not known; this disease is found in around 0.2% of childhood epilepsy .

root cause

It is based on a disturbed brain development (disturbance of cellular differentiation and cell proliferation ) with hamartomatous enlargement of one half of the brain, mostly of the cerebrum or parts of it. In addition to the brain, other forms of hemihypertrophy can occur. Associations with neurocutaneous diseases have been described.

Classification

Hemimegalencephaly can be classified as follows:

• Isolated hemimegalencephaly with no other malformations
• Total hemimegalencephaly with enlargement of the brain stem and cerebellum
• Syndromal hemimegalencephaly in:
  • Epidermal nevus syndrome
  • Klippel-Trénaunay-Weber syndrome
  • Fibrous dysplasia
  • Proteus Syndrome
  • Hypomelanosis Ito
  • Neurofibromatosis type 1 (rare)
  • Tuberous sclerosis (rare)

Clinical manifestations

Clinical criteria are:

• Often therapy-refractory seizures in the first few months of life
• Developmental delay, also psychomotor
• progressive hemiplegia
• Often megalencephaly without increased intracranial pressure

diagnosis

The diagnosis can be made at an early stage using sonography , otherwise using magnetic resonance tomography or computed tomography . In addition to the enlargement in sections, there are signs of cortical dysplasia , pachygyria , heterotopia and gliosis .

Differential diagnosis

The following are to be distinguished:

• asymmetrical enlargements from other causes such as gliomatosis cerebri
• asymmetrical reductions in the opposite side such as brain atrophy , Rasmussen encephalitis or Dyke-Davidoff-Masson syndrome
• Sturge Weber Syndrome
• other disorders of cell migration without overgrowth such as polymicrogyria , lissencephaly , agyria or pachygyria

therapy

Treatment sometimes consists of a hemispherectomy .

literature

• M. Lettau: Total hemimegalencephaly. In: RöFo : Advances in the field of X-rays and nuclear medicine. Volume 185, Number 12, December 2013, pp. 1204-1206, doi: 10.1055 / s-0033-1350109 , PMID 23857071 .
• H. Zeumer, W. Sturm: Hemimegalencephaly. Neuroradiological and clinical findings. In: RöFo : Advances in the field of X-rays and nuclear medicine. Volume 133, Number 6, December 1980, pp. 663-664, doi: 10.1055 / s-2008-1056812 , PMID 6453799 .
• A. Poduri, GD Evrony, X. Cai, PC Elhosary, R. Beroukhim, MK Lehtinen, LB Hills, EL Heinzen, A. Hill, RS Hill, BJ Barry, BF Bourgeois, JJ Riviello, AJ Barkovich, PM Black, KL Ligon, CA Walsh: Somatic activation of AKT3 causes hemispheric developmental brain malformations. In: Neuron. Volume 74, number 1, April 2012, pp. 41-48, doi: 10.1016 / j.neuron.2012.03.010 , PMID 22500628 , PMC 3460551 (free full text).
• AJ Barkovich: Pediatric Neuroimaging. 2nd edition, Raven 1995, pp. 225ff, ISBN 0-7817-0179-1

Individual evidence

1. ↑ ^{a b} Hemimegalencephaly. In: Orphanet (Rare Disease Database).
2. ↑ Rare Diseases
3. ↑ ^{a b c} Radiopaedia
4. ↑ SD Shorvon, F. Andermann, R. Guerrini: The Causes of Epilepsy, Common and Uncommon Causes in Adults and Children. Cambridge Univ. Pr., 2011, ISBN 0-521-11447-0 .
5. ↑ Olav Jansen, Ulrich Stephani et al.: Malformations and early childhood damage to the CNS . Thieme, Stuttgart 2007, ISBN 978-3-13-156671-3 , p. 24.
6. ↑ DD Broumandi, UM Hayward, JM Benzian, I. Gonzalez, MD Nelson: Best cases from the AFIP: hemimegalencephaly. In: Radiographics: a review publication of the Radiological Society of North America, Inc. Volume 24, Number 3, 2004 May-Jun, pp. 843-848, doi: 10.1148 / rg.243035135 , PMID 15143232 .
7. ↑ ^{a b} Peter Reimer, PM Parizel, F.-A. Stichnoth (Ed.): Clinical MR Imaging. A practical approach. 2nd Edition. Springer, Berlin / Heidelberg et al. 2006, ISBN 3-540-31530-6 .
8. ↑ K.-H. Deeg, V. Hofmann, PF Hoyer (Ed.): Ultrasound diagnostics in paediatrics and pediatric surgery. Textbook and atlas . 4th, completely revised and expanded edition. Thieme, Stuttgart 2013, doi: 10.1055 / b-003-106490
9. ^ AA Abdel Razek, AY Kandell, LG Elsorogy, A. Elmongy, AA Basett: Disorders of cortical formation: MR imaging features. In: AJNR. American journal of neuroradiology. Volume 30, Number 1, January 2009, pp. 4-11, doi: 10.3174 / ajnr.A1223 , PMID 18687750 (review).
10. ↑ W. Koelfen, M. Freund, H. Rohr, C. Schultze, H. Holthausen: hemimegalencephaly. Treatment with hemispherectomy. In: Monthly Pediatric Medicine Volume 141, Number 4, April 1993, pp. 300-302, PMID 8487791 .

Web links

• Rare Diseases
• Speech development in hemimegalencephaly

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !