Neurofibromatosis (NF) is an inherited systemic disease with an autosomal dominant pattern of transmission. It is caused by mutation of the genes that encode for the secretion of proteins that inhibit abnormal cell growth. The multisystem nature of the disease has several implications for peripartum anaesthetic and obstetric management.
The disorder is commonly classified into NF-1 or NF-2, but other forms/subtypes have been described. NF-1 is the most prevalent type and typically presents with widespread pigmented skin lesions, nerve sheath tumours (neurofibromas) in variable locations including the airway and mediastinum, and ocular manifestations. Patients may have associated cardiovascular dysfunction such as hypertension, cardiomyopathy, structural heart disease or vasculopathy. Other features may include scoliosis or kyphoscoliosis, learning difficulties, epilepsy and an association with phaeochromocytoma. NF-2 is a much less common form that predominantly affects the central nervous system and is characterised by the development of bilateral acoustic neuromas and cranial, meningeal or spinal tumours.
Problems and special considerations
Neurofibromas may show a hormone-mediated proliferation and/or an increase in number during pregnancy. Intracranial lesions may be associated with raised intracranial pressure (ICP) and an increased risk of brain herniation with dural puncture. Unintentional instrumentation of a spinal tumour during regional anaesthesia may result in dissemination of tumour cells or bleeding into the neuraxis. Regional anaesthesia may be difficult to perform in the presence of scoliosis or with extensive lesions on the lumbar spine.
Previously, it was thought that patients with NF-1 were sensitive to neuromuscular blocking drugs, but this is no longer thought to be the case. Nonetheless, caution is required because of the associated renal complications that may occur with the disease.
Tumours infrequently develop in the oral cavity, tongue, larynx or lower airways, and may complicate airway management.
Previous studies have reported an increased incidence of obstetric complications in women with NF-1, including pre-eclampsia, fetal growth restriction and preterm labour.
Management options
Pregnant women with neurofibromatosis require advance planning of their mode of delivery and anaesthetic management. The decision to administer regional anaesthesia in these patients should be guided by the severity of the disease, the distribution of the fibromas and the presence of cranial/neuraxial or airway tumours. A thorough history and clinical examination is essential, but it is important to remember that the absence of symptoms does not exclude the presence of spinal neuromas. Appropriate imaging of the spine and cranium, as guided by radiologist advice, enables the detection of tumours and is recommended before proceeding with central neuraxial blocks. Patients with raised ICP should be managed in the appropriate way (see Chapter 122, Idiopathic intracranial hypertension). Advanced airway management techniques may be required in the presence of a potential difficult airway (see Chapter 38, Failed and difficult intubation).
Key points
• Neurofibromatosis is a multisystem disease with a variable clinical presentation.
• Regional anaesthesia may have deleterious effects in these women, and antenatal neuroimaging is recommended.
• A thorough airway assessment is required.
Further reading
Fox CJ, Tomajian S, Kaye AJ, et al. Perioperative management of neurofibromatosis type 1. Ochsner J 2012; 12: 111-21.
Hirbe AC, Gutmann DH. Neurofibromatosis type 1: a multidisciplinary approach to care. Lancet Neurol 2014; 13: 834-43.
Sakai T, Vallejo MC, Shannon KT. A parturient with neurofibromatosis type 2: anesthetic and obstetric considerations for delivery. Int J Obstet Anesth 2005; 14: 332-5.