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Morquio, disease
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[MIM 252 300, 253 000, 253 010]
(Mucopolysaccharidosis type IV, Morquio-Brailsford syndrome)
Incidence: from 1/76.000 (Ireland) to 1/640.000 (Australia). Autosomal recessive transmission.
- type IV A: deficiency in N-acetylgalactosamine-6-sulfatase (chromosome 16q24.3); classic, severe form (1/250,000)
- type IV B: deficit in β-D-galactosidase (chromosome 3p21.33), (very rare) more slowly progressive form
Onset of symptoms between 1 and 3 years of age:
1) skeleton: platyspondyly, osteoporosis (tulip-shaped chest), ligament hyperlaxity, short stature, hypoplasia of the odontoid process, dorsal kyphosis with barrel-shaped chest (pectus carinatum), multi-level stenosis of the spinal canal, genu valgum
2) later: progressive deafness
3) predominant valve involvement in the left heart: most often, aortic insufficiency
4) coronary artery disease, sometimes cardiomyopathy
5) macroglossia, infiltration of the upper airways (oro- and nasopharynx), hypertrophy of the tonsils and adenoids; submucosal deposits of mucopolysaccharides.
6) hepatosplenomegaly
7) respiratory involvement: restrictive syndrome, obstructive and central sleep apnea, tracheobronchomalacia, tracheal stenosis and kinking (excessive growth in relation to the chest)
8) corneal opacities
9) normal intelligence.
Treatment of the IVA form: IV alpha elosulfase 1x/week, sometimes hematopoietic stem cell transplantation. Treatment is most effective if initiated before 2 years of age, but oropharyngeal, pulmonary and cardiac damage continues to progress.
Anesthetic implications:
1) preoperatively: echocardiography, ENT examinations (nasofibroscopy, polysomnography), spinal MRI, CT scan of the neck and tracheobronchial tree (from 7 years of age)
An airway assessment score has been developed for adolescent and adult (even treated) patients with mucopolysaccharidosis: the Salford score (table). It comprises 15 parameters graded from 0 to 3. Parameters 1-6 are based on clinical examination, 7-10 on nasal endoscopy, 11-13 on chest CT and 14-15 on respiratory function tests (if feasible).
A total score of 0-15 indicates minor, 15-30 moderate and 30-45 severe involvement of the airways. A score of ≥ 25 means that difficult airway management should be considered.
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Nr |
parameter |
measures |
score |
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1 |
mouth opening |
> 5 cm 4-5 3-4 < 3 |
0 1 2 3 |
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2 |
teeth protrusion (profile) |
none minor moderate severe |
0 1 2 3 |
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3 |
mobility /stability
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non limited 60-90° flexion 30-60° flexion < 30° or instable |
0
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4 |
tongue bulkiness |
normal light (< 1/3 of the floor) moderate (1/3 to ½ of the oral cavity) severe (> 1/2 of the oral cavity) |
0 1 2 3 |
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5 |
Mallampati score |
1 2 3
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0
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6 |
Thyromental distance |
> 6 cm 5-6 4-5 < 4 |
0 1
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7 |
larynx height - epiglottis/ soft palate |
> 4 cm 3-4 2-3 < 2 |
0
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8 |
epiglottic bulkiness |
normal (filling < 1/3 of the oropharynx) mild (1/3 to ½ of the oropharynx) moderate (1/2 of the oropharynx) severe (filling the entire oropharynx) |
0
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9 |
supra-glottis bulkiness |
normal (filling < 1/3 of the laryngopharynx) mild (1/3 to ½ ) moderate (1/2 ) severe (filling the entire laryngopharynx) |
0 1
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10 |
glottis bulkiness |
normal (filling < 1/3 of the glottis) mild (1/3 to ½ ) moderate (1/2 ) severe (filling the entire glottis) |
0
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11 |
sub-glottis or cricoid diameter |
> 7 mm 6-7 5-6 > 5 |
0
2 3 |
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12 |
tracheomalacia
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no stenosis decrease of 50-75 % decrease of 75-99 % complete obstruction |
0
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13 |
Tracheal tortuosity |
none present |
0 3 |
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14 |
Expiratory volume max 1 sec |
> 80 % 60-79 40-59 < 40 |
0 1 2 3 |
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15 |
Vital capacity |
> 80 % 60-79 40-59 < 40 |
0 1 2 3 |
2) perioperatively: difficult intubation and mask ventilation due to macroglossia, short neck and instability of C1-C2 with risk of paraplegia: the head and neck must be positioned in a neutral position (flexion aggravates the obstruction) so that the external auditory canal is aligned with the collarbone (small roller under the shoulders, no head ring). Intubation is even more difficult after performing cervical arthrodesis. Progressive laryngo- and tracheomalacia; in the older patient, the trachea has an irregular diameter and may be angulated. Restrictive syndrome. Obstructive apnea: use a nasopharyngeal tube (beware of the risk of epistaxis) rather than an oropharyngeal cannula. Aortic insufficiency. Coronary insufficiency. Positive experience with the laryngeal mask to guide fibroscopic intubation or the Glidescope®. In case of direct or indirect laryngoscopy, traction on the tongue (Magill forceps) facilitates the insertion of the blade into the oral cavity and laryngoscopy. It is necessary to provide an intubation tube the size of which is smaller (from 2 to 3 sizes!) than expected for age.
Given the risk of postoperative paralysis caused by spinal cord ischemia following patient's positioning or hypotension, monitoring of the spinal cord function (sensory and motor evoked potentials) during any surgery even if remote from the spine in case of:
- kyphoscoliosis with an angle > 60°
- surgery for > 90 min or with a risk of hemodynamic instability
- kyphoscoliosis with an angle < 60 ° and surgery for > 90 min or with a risk of hemodynamic instability.
It is important to obtain baseline values of these potentials after induction of anesthesia and before changing the patient's position.
3) Neuraxial block: the benefit-risk ratio of epidural blockade should be evaluated with caution because the spinal cord is weakened: narrow spinal canal by accumulation of glycosaminoglycans in the ligament structures and platyspondyly with a risk of mechanical compression (change of position under anesthesia), hypoperfusion in case of low blood pressure or epidural injection.
4) postoperatively: full awake extubation; respiratory, cardiac and neurological monitoring
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EXPERT CONSENSUS for MANAGEMENT:
Surgical morbi-mortality is greater than in the normal population and the risk of anesthetic complications is very high: these patients must therefore be managed in facilities where those complications can be managed. It is why : - a full neurological examination is necessary before general or locoregional anesthesia - imaging (MRI or CTscan) of the full spine is recommended - a flexion/extension MRI of the cervical spine is necessary if there is any concern about its stability - polysomnography, respiratory functional tests (restrictive or obstructive syndrome) and cardiac evaluation (echocardiography) must be considered before an anesthesia - morphological and functional anomalies of the upper airway, a decrease in mobility of the cervical spine and bronchial airway anomalies increase the morbidity and mortality of anesthesia - a sedative premedication can be administered before anesthesia - for intubation, a videolaryngoscope and a intubating fiberscope must be immediately available - tracheostomy can be extremely difficult in those patients, particularly in emergency; it is crucial to identify the position of the cricothyroid membrane (XRays, echography) before anesthesia - extubation must be preferably done in the operating room; if this may not be the case, an experienced team must be present - in patients in whom a fragility of the spinal cord is suspected (concept of spinal cord at risk : significant cyphosis, risk of hypotension, long lasting surgery, difficult surgical positioning), neurological monitoring must be done during the whole procedure, and it is better to avoid epidural anesthesia Reference:
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References :
Updated: February 2024