LETTER TO EDITOR
Year : 2014 | Volume
| Issue : 3 | Page : 440-442
Smith-Lemli-Opitz-syndrome: How different is the anesthetic technique?
Srinivasa Raghavan Govindarajan, Puneet Khanna, Amar P Bhalla, Anil Kumar
Department of Anesthesiology and Intensive Care, All India Institute of Medical Sciences, New Delhi, India
Department of Anesthesiology and Intensive Care, All India Institute of Medical Sciences, New Delh
Source of Support: None, Conflict of Interest: None
|Date of Web Publication||11-Jul-2014|
|How to cite this article:|
Govindarajan SR, Khanna P, Bhalla AP, Kumar A. Smith-Lemli-Opitz-syndrome: How different is the anesthetic technique?. Saudi J Anaesth 2014;8:440-2
|How to cite this URL:|
Govindarajan SR, Khanna P, Bhalla AP, Kumar A. Smith-Lemli-Opitz-syndrome: How different is the anesthetic technique?. Saudi J Anaesth [serial online] 2014 [cited 2022 Dec 8];8:440-2. Available from: https://www.saudija.org/text.asp?2014/8/3/440/136653
Smith-Lemli-Opitz syndrome (SLOS) is a rare autosomal recessive inborn error of cholesterol metabolism. The deficiency of the enzyme 3β-hydroxysterol Δ7 -reductase results in a wide array of anomalies affecting multiple systems with anesthetic implications.  These patients have additional risk of muscle rigidity and possible susceptibility to malignant hyperthermia syndrome. 
A 3-year-old male child weighing 10 kg was scheduled for urethroplasty and repair of hypospadias. He was diagnosed with SLOS and was on follow-up in genetics clinic. He was born out of term normal delivery and weighed 1.7 kg. He cried immediately at birth. His developmental milestones were delayed. On examination, the child was irritable and crying. He had coarse hair and strikingly abnormal flat facial features. A closer look revealed hypertelorism with telecanthus, low set ears, retrognathia, high arched palate with a partial cleft, syndactyly of second and third toes on both feet. [Figure 1] and [Figure 2] There were no murmurs and chest was clear to auscultation. Vital signs were within the normal limits and the caudal space was felt. We reviewed his records from the genetics clinic and that showed a normal 46XY karyotype. Ophthalmological records showed corneal clouding, anterior capsular cataract with an inferior iris coloboma. Echocardiogram was normal.
Pre-operative fasting orders were given. Plan was made to avoid inhalational agents and succinylcholine and to do check laryngoscopy to assess ease of intubation. The child was scheduled as the first patient on the operation room (OR) list. To completely remove all trace inhalational agents, the vaporizers were removed and the anesthesia workstation was made vapor free by flushing with oxygen. The circuit and soda lime was changed. Difficult airway cart with pediatric fiber optic bronchoscope was kept ready. Eutectic mixture of local anesthetics (EMLA) cream was applied to the dorsum of both hands and an intravenous (IV) line was secured. The child was pre-medicated with 5 mg midazolam syrup (Per Os) prepared oral and was brought to the OR. Monitors were attached and anesthesia was induced with fentanyl 5 μg and propofol titrated up to 20 mg. Ability to assist ventilation was checked and could be done with ease. A check laryngoscopy was done and it revealed a Cormack & Lehane CL grade 2. A #2 Ambu laryngeal mask airway (LMA) was inserted successfully. Ventilation was assisted until the return of spontaneous breaths. A caudal block with 10 ml of 0.25% bupivacaine was given. Anesthesia was maintained with propofol 200 μg/kg/min infusions and spontaneous ventilation. The temperature was measured with a nasopharyngeal probe and was between 35.8°C and 36.7°C. Intraoperative period was uneventful and the total duration was 65 min. At the end of surgery, the infusion was stopped and the LMA was removed when the child was fully awake.
After 6 months, the child was scheduled for chordee correction. The child was healthy and weighed 12 kg. The same plan of anesthesia was used successfully again and child made an uneventful recovery.
| Discussion|| |
SLOS is a rare genetic disorder of cholesterol metabolism resulting in the deficiency of 3β hydroxy sterol Δ7 -reductase, a key enzyme in the metabolic pathway.  This genetic aberration leads to wide repercussions in the clinical picture due to the abnormal embryonic development. The true incidence is mostly under estimated with the literature stating figures around 1 in 50,000 pregnancies. 
Although the literature is teeming with facts on SLOS, the anesthetic concerns in these patients are still under-reported. With hardly handful of reports available, none of them are from the Indian subcontinent. These patients undergo a variety of diagnostic and corrective procedures requiring anesthesia. Several issues play around in anesthetizing children with SLOS.
Muscle rigidity has been of great concern in these children. In children who received volatile agents in the past, there are two isolated reports of muscle rigidity. , And one report of a child developing hyperthermia without muscle rigidity.  Although other features of malignant hyperthermia such as myoglobinemia were not present, hypercarbia and acidosis was found in one patient. Furthermore, there are reports of volatile agents being used without evidence of muscle rigidity. , These reports must be extrapolated to our population with caution as there can be ethnic differences. We avoided inhalational agents in this patient. Preparing the workstation to be vapor free by flushing it and using total intravenous anesthesia is an easy and safe alternative to avoid the possible risks. Temperature monitoring is mandatory is these patients.
Patients with SLOS also pose difficulty in intubation with various predictors such as micrognathia (67-100%), tongue anomalies (12-63%), cleft palate (37-68%). , Our patient had retrognathia, high arched palate with a partial cleft. Although we used Ambu LMA in our patient, we did a check laryngoscopy to assess the ease of intubation should the need arise. Fiber optic bronchoscope of appropriate sizes should be kept standby.
Congenital heart disease is another factor contributing to the complexity of the syndrome. The incidence of congenital heart diseases is about 37-84% with ostium secundum atrial septal defect, ventricular septal defect, patent ductus arteriosus and hypoplastic left heart syndrome being common.  Pre-operative echocardiography is necessary to detect and quantify the defects. Our patient luckily had a normal echocardiography.
From 25% to 56% of these patients have congenital pulmonary anomalies like hypoplastic or incomplete lobulation.  Additional investigations may be required in symptomatic patients. These patients are at a high risk of aspiration from gastro esophageal reflux disease. Adequate fasting would avoid the need for rapid sequence intubation. Aspiration prophylaxis can be given in symptomatic patients. Intellectual impairment along with aggression, self-injurious behavior and hyperactivity may be seen in these patients.  Our patient was irritable and crying, but did not show aggressive behavior. EMLA cream would be useful in securing an IV access in these patients with risk of difficult airway.
In summary, we report the successful management of two anesthetics in a child with SLOS. These patients can pose a difficult intubation and mandate meticulous planning of airway. Careful planning of the anesthetic technique with possible avoidance of inhalational agents is necessary. Although the question whether these patients are at risk of malignant hyperthermia is still unanswered, all possible measures to avoid such a catastrophe should be taken.
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[Figure 1], [Figure 2]
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