McCune–Albright syndrome is a rare chromosomal endocrine disorder characterized by
hypersecretion of hormones, polyostotic fibrous dysplasia, café au lait spots, and
sexual precocity, affecting around 1 in 100,000 to 1,000,000.[1] There is limited information about the neuro-anesthetic management of this disorder.
We describe anesthetic concerns of such a patient scheduled for embolization of jugular
arterio-venous fistula (AVF). Informed consent was obtained from the patient for publication
of this report.
An 18-year-old male weighing 30 kg diagnosed with McCune–Albright syndrome having
right jugular AVF was scheduled for embolization in the neurointerventional radiology
suite. The patient had associated hyperthyroidism, hypophosphatemia, café au lait
spots, fibrous dysplasia, and left facial lower motor neuron palsy. He gave history
of multiple times fracture of long bones. In the past, he had undergone optic nerve
decompression for sudden loss of vision. The patient had history of gradually progressive
dysphagia and nasal regurgitation (cranial nerve IX and X involvement) that improved
after a course of oral steroids. On examination, the patient was conscious, oriented
with no cardiorespiratory compromise. He had short, deformed, and swollen upper and
lower limbs and coarse facial features including frontal bossing, wide nose, flared
nostrils, thickened jaw and chin, and large tongue with café au lait spots on the
forehead. The patient's angle of mouth was deviated to the right and he was unable
to close the left eye (CN VII involvement). On airway assessment he had Modified Mallampati
grade 3, mouth opening 2.5 finger breadths, thyromental distance of 6 cm, upper lip
bite test class 1, and normal neck extension. He also had thyroid swelling in the
neck, suggestive of multinodular goiter on ultrasound. Chest X-ray was normal and
there was no tracheal compression. Hormonal profile showed normal thyroid-stimulating
hormone, growth hormone, cortisol, and insulin-like growth factor 1 levels and slightly
elevated parathyroid hormone level. The patient was on tab Neomercazole 2.5 mg once
daily (for hyperthyroidism) and phosphate solution.
In neurointerventional suite, a difficult airway cart was prepared. Standard ASA (American
Society of Anesthesiologists) monitors revealed normal baseline vitals: heart rate:
98/min, BP (blood pressure): 138/86 mm Hg, and oxygen saturation of 98% on room air.
Anesthesia was induced with fentanyl 2 µg/kg and sleep dose of propofol. Adequate
mask ventilation could be achieved with the help of oropharyngeal airway. After rocuronium
administration, videolaryngoscopy revealed a percentage of glottic opening to be 50%
and larynx anteriorly placed. Tracheal intubation was successful with the help of
a bougie, in first attempt. Anesthesia was maintained with sevoflurane and nitrous
oxide in air, along with fentanyl and rocuronium infusion, with a target partial pressure
of carbon dioxide of 40 to 43 mm Hg. A radial arterial line was placed for invasive
BP monitoring. Supine positioning was done with utmost care to avoid any fractures
and pressure points were padded properly. The patient was handed over to the neuroradiologist.
Through left femoral arterial access, diagnostic cerebral angiography was done, which
showed an osteodural fistula at the left clival region fed by bilateral ascending
pharyngeal arteries, vertebral artery draining into aneurysmally dilated left sigmoid
sinus ([Fig. 1A]). Using a microcatheter, glue was injected to obliterate the fistula and postprocedure
angiogram showed complete obliteration of the osteo-dural fistula ([Fig. 1B]). After reversal of neuromuscular blockade, trachea was extubated and patient was
shifted to neuro-intensive care unit for observation.
Fig. 1 Digital subtraction angiography showing (A) preprocedure right jugular AV fistula with multiple feeders; (B) postembolization view of obliterated fistula with dye uptake in normal vessels.
AV, arterio-venous.
The cause of McCune–Albright syndrome is a spontaneous mutation of the GNAS gene during
embryogenesis that codes for G-signaling complex found in multiple tissue types, including
bone, skin, and endocrine tissues. An increase in intracellular cAMP signaling is
responsible for the clinical manifestations of McCune–Albright syndrome.[1] These patients might present in operation room for biopsies, transsphenoidal hypophysectomy,
fixation of fractures, thyroidectomy, adrenalectomy, and excision of fibrous dysplastic
bone causing compression symptoms. Vascular fragility may make venous access difficult
in these patients and might require central venous access depending on the type of
procedure. For embolization of cerebral fistula, general anesthesia is the preferred
technique. The important preoperative considerations include complete evaluation of
endocrine abnormalities and assessment of airway.[2] Hyperthyroidism, growth hormone excess, hyperparathyroidism, hyperprolactinemia,
and/or hypercortisolism may coexist in the same patient. Recognition and control of
hyperthyroidism are of particular importance as cardiac complications and thyroid
storm hugely increase morbidity. Presence of Cushing's syndrome requires preoperative
treatment of hypertension, hyperglycemia, and/or hypokalemia. Patients who have undergone
adrenalectomy for Cushing's disease, require subsequent replacement with steroids.
Etomidate may be omitted in these patients when cortisol dysfunction is suspected.
The associated craniofacial fibrous dysplasia, coexisting Cushing's syndrome, and
acromegaly can result in a potential difficult airway that requires adequate planning
and preparation.[3] History of obstructive sleep apnea remains an important factor in deciding the perioperative
management. Upper lip bite test has been suggested as a more reliable indicator of
easy intubation in these patients.[4] At times, it might even require awake fiberoptic intubation in small children.[5] Altered airway anatomy due to craniofacial fibrous dysplasia may make airway blocks
less reliable as well as difficult to perform. These patients can have coexisting
cardiac disease secondary to hyperthyroidism or acromegaly and can develop arrhythmias
and hemodynamic instability. Increased bone fragility and nerve entrapment (secondary
to fibrous dysplasia) require adequate padding and vigilance during positioning. Fractures
are not uncommon in these patients, so careful positioning of the patient remains
a prime concern. Restrictive lung disease may be present secondary to spinal column
deformity and requires careful perioperative respiratory support. Postoperatively,
these patients should be closely monitored for vitals and particularly for any obstructive
sleep apnea, electrolyte abnormalities, thyroid storm, and peripheral nerve injuries.
To conclude, perioperative management of patients with McCune–Albright syndrome involves
optimization of endocrine abnormalities, care of difficult airway, proper positioning,
and attention to neuropathies. Out-of-operation room anesthesia in neurointerventional
suite has its own challenges and requires proper preoperative assessment and adequate
preparation, beforehand.
