Keywords
Sturge–Weber syndrome - epilepsy surgery - anesthetic implications
Introduction
Sturge–Weber syndrome (SWS), also called encephalotrigeminal angiomatosis, is a rare
congenital disorder that occurs sporadically. The pathognomonic manifestations of
this neurocutaneous disorder are leptomeningeal angiomas extending into the cerebral
cortex and intracranial calcification of this lesion, along with ipsilateral angiomatous
lesions involving the facial skin, typically in the ophthalmic (V1) and maxillary
(V2) distributions of the trigeminal nerve.[1] It often presents with mental retardation, hemiparesis, or refractory epilepsy.
The most recognizable clinical feature of SWS is the facial angioma or port wine stain,
which has been reported to occur in up to 70% of patients.[2] Vascular angiomas may involve the mouth and airway and can lead to difficult mask
ventilation, laryngoscopy, and intubation. Cardiac anomalies, which may be associated
with this syndrome include septal defects, valvular stenosis, great vessels transposition,
and deep arteriovenous malformation (rare), which may lead to considerable shunt and
cardiac hypertrophy and failure. In this case report, we would like to highlight the
anesthetic challenges of a child with SWS coming for epilepsy surgery.
Case Report
We report a case of a 2.3-month-old, 9-kg, child with SWS who presented with developmental
delay and left-sided refractory focal motor seizures. On examination, she had the
typical cutaneous manifestations of SWS characterized by a large capillary angiomatous
lesion involving the entire right scalp, forehead, face, neck, and upper chest till
the nipple region with an abrupt cutoff at the midline. A magnetic resonance imaging
(MRI) of the brain showed diffuse thinning and atrophy of the right cerebral hemisphere
with marked leptomeningeal enhancements. There was compensatory enlargement of the
left hemisphere ([Fig. 1]). Though a complete airway examination was not possible preoperatively to know the
extent of the lesion, we had anticipated the airway involvement because of extensive
cutaneous involvement. Airway involvement was also confirmed by her mother's history
where she revealed that the angiomatous lesions involved the posterior pharyngeal
wall, which was visible when the child cried. But, there was no history suggestive
of airway obstruction. Routine blood investigations, electrocardiogram (ECG), and
chest X-ray were within normal limits. She was scheduled for anterior temporal lobectomy
(ATL), amygdalohippocampectomy (AH), and hemispherotomy. The child was pre-medicated
with Syrup trichlorofos at 75 mg/kg 1 hour prior to induction.
Fig. 1 MRI brain (T2W image, axial cut) showing diffuse thinning and atrophy of the right
cerebral hemisphere with marked leptomeningeal enhancements (leptomeningeal angiomatosis)
and compensatory enlargement of the left hemisphere. MRI, magnetic resonance imaging;
T2W, T2-weighted.
The child was asleep while wheeling into the theater, thus a steal induction was successfully
performed with incremental rising concentrations of sevoflurane. Apart from the routine
monitors at induction, which were pulse oximetry, ECG, non-invasive blood pressure,
and an end-tidal carbon dioxide (ETCO2), other monitoring such as an invasive arterial line in the right radial artery,
minimum alveolar concentration of the inhalational agent, neuromuscular monitor with
a nerve stimulator, bispectral (BIS) monitor, temperature, and urine output all were
monitored during surgery. As soon as the IV access was established, sevoflurane was
switched off, and anesthesia was maintained with total intravenous anesthesia. Since
there was a significant lesion on the airway mucosa, and to avoid trauma associated
with a blind routine laryngoscopy and study the extent of the lesion, we opted for
a videolaryngoscopy- (C-MAC, Video Laryngoscope, KARL STORZ, Germany) guided intubation,
which revealed extensive airway involvement extending up to the vocal cords ([Fig. 2]). The airway was secured with a 5-size uncuffed endotracheal tube (ETT) fixed at
12 cm. Anesthesia was maintained with propofol infusion at 150 to 200 µg/kg/min, which
was titrated to keep the BIS of 40 to 50, injection of fentanyl infusion at 1 to 2
µg/kg/h, and an injection of atracurium infusion of 0.3 to 0.5 mg/kg/h titrated to
achieve two twitches on the train of four. Since there was capillary hemangiomatous
lesion involving the right side of neck and chest, the left internal jugular vein
was cannulated, and a 5.5-F triple lumen catheter was inserted.
Fig. 2 Videolaryngoscopic image showing extensive hemangiomatous lesions involving the oropharynx
and larynx.
Intraoperatively from the commencement of skin incision to the exposure of dura, there
was a continuous, persistent blood loss due to extensive skin and bone involvement.
Anticipating the risk of hemorrhage, we gave a loading dose of tranexamic acid at
20 mg/kg before the skin incision, followed by an infusion at 1 mg/kg/h till skin
closure. Even before hemispherotomy was initiated, the hemoglobin had dropped from
11.4 to 8.5 g%, which was replaced with crystalloids and packed red cells. The dural,
as well as the intracranial anomalous brain tissue, was strewn with thin abnormal
capillary malformations, which resulted in a total loss of 650 mL, which was almost
his total blood volume despite immaculate dissection and resection by the senior surgeon.
This blood loss was replaced with 60 mL of cryoprecipitate, 150 mL of fresh frozen
plasma, and 300 mL of packed red cells. The child remained warm and hemodynamically
stable throughout the surgery, and the arterial blood gas that was done at skin closure
was within normal limits. Since it was a long duration surgery (6 hours) associated
with massive transfusion and the airway involvement by the lesion, we had decided
to electively ventilate the child overnight. The child was sedated and ventilated
with midazolam and fentanyl infusion overnight and got extubated the next day. She
was discharged seizure free on the 10th postoperative day.
Discussion
The Sturge-Weber syndrome, also known as encephalotrigeminal angiomatosis, is characterized
by congenital angiomas and involves the skin over the trigeminal distribution. Sometimes,
these vascular changes can also be found in the dura, leptomeninges, brain tissue,
and pituitary gland. No pattern of inheritance is generally noted. Angiomas are frequently
unilateral with faciotrigeminal distribution; sometimes these can be bilateral. In
some cases, angiomas are found over the truncal and extremities areas and in deeper
structures such as the thymus, lung, spleen, and lymph nodes.[3]
[4] SWS may involve the mucosa of the nose, palate, gingiva, tongue, larynx, and trachea
posing a challenge to laryngoscopy and intubation.[5] This involvement can be diagnosed in the preoperative MRI, if slices involved the
airway as well. Anesthesia-induced vasodilation increases the size of the lesion can
lead to worsening of airway obstruction, and even a mild injury to these lesions during
airway manipulation may result in uncontrolled hemorrhage. Therefore, intubation should
be done using a soft, well-lubricated, non-stylet cuffed ETT, and careful oropharyngeal
and tracheobronchial suction are crucial in avoiding trauma to these lesions.[6]
[7]
In our case, one of the major anesthetic concern was an anticipated difficult airway
because of lesions involving the oral cavity and pharynx. We performed a gentle laryngoscopy
using a C-MAC video laryngoscope, which enabled us to gauge the extent of airway involvement
and ensured that the intubation was atraumatic. Furthermore, raised intracranial pressures
due to the cerebral edema associated with the refractory seizures and raised intraocular
pressure are commonly seen in patients with SWS attributed to pre-existing glaucoma
to require a smooth induction and intubation to limit the rise in both, which was
achieved with video laryngoscope intubation. A fiberoptic bronchoscopic intubation
could have also been an acceptable option to secure the airway with the advantage
of being able to quantify the airway involvement below the level of the vocal cords.
The second major concern was massive blood loss and its associated complication. Since
we had anticipated massive blood loss and adequate blood was arranged pre-operatively,
blood and blood products were transfused appropriately at the correct time without
making the child going into the phase of dilutional coagulopathy as well as fluid
overload.
Since the child was having refractory epilepsy, factors that can precipitate perioperative
seizures, such as hypoglycemia, hypotension, hypoxemia, and hyperthermia, were monitored
for and avoided. Additionally, since the child had been on four antiepileptic agents,
the enzyme induction caused by the anticonvulsants would definitely influence the
metabolism of the muscle relaxants and the anesthetic requirements as well. To prevent
an overdosage and to prevent awareness, we used a BIS monitor to titrate the anesthetic
and a neuromuscular monitor to titrate the relaxant infusion.
Conclusion
We conclude that patients with SWS should be carefully evaluated for associated anomalies
involving the airway, cardiovascular system, and ophthalmic involvement as well. The
perioperative anesthetic management should be planned in a way to avoid trauma to
the hemangiomatous lesions involving the airway, preventing any rise in intraocular
and intracranial pressure, prevention and management of massive blood loss, as well
avoidance of factors that may trigger a seizure. A careful plan must be made regarding
a smooth induction and intubation and a diligent extubation.
