【Pediatric anesthesia】Duchenne muscular dystrophy

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Duchenne muscular dystrophy

Case Review:

4y8M, 15.
3kg The oblique hernia admission is intended for high ligation of the hernia sac
.
Past medical history: the child did not suffer from jaundice after birth, biochemical examination showed a significant increase in muscle enzymes, and the examination of the genes related to hereditary myopathy in the child and mother suggested that the child's DMD gene was missing mutation in exon 19-43, and the mother DMD gene did not see large mutations, and liver function
was not regularly followed.
Diagnosis: 1.
Elevated transaminases 2.
Duchenne muscular dystrophy Duchenne muscular dystrophy 3.
Left inguinal oblique hernia
.

The relevant examinations of this admission are as follows:

Please consult with a specialist: the elevated transaminases of the child are considered to be caused by myopathy, do not need hepatoprotective treatment, and specialist follow-up
.

Preoperative evaluation: no obvious abnormalities in the airway and no obvious abnormalities
in cardiac ultrasound.

Comprehensive consideration, inform the child's family of the risk of increased enzymes, weigh it, and feasible surgery
.

Anesthesia with attention to airway management and malignant hyperthermia
.
Simple medication, intravenous anesthesia
.

2022 / 9 / 23

Disease Awareness:

1.
What is the definition of Duchenne muscular dystrophy and its natural history?

DMD is a progressive, X-chromosome recessive neuromuscular disorder that affects 1 in 3,500
male births.
An estimated 8% to 10% of female children present with mild clinical manifestations, such as mild muscle weakness
.
The disorder is characterized by abnormal motor development, including inability to walk independently, run, jump, climb stairs, and pseudohypertrophy of the gastrocnemius muscles
at age 18 months.
Classic Gower syndrome is usually seen, where the feet are as far apart as possible and the need to help him get up
from the ground by holding the support with his hands.
About 30% of children with this disease have some degree of developmental delay
.
These clinical signs are a sign of a deletion or mutation in a dystrophin gene leading to muscle necrosis and replacement
by connective or adipose tissue.
Two-thirds of children with DMD had no family history, and the mean age at diagnosis was 4.
5 years
.
The disease is relentless, requiring wheelchair use by the age of 12 years, and there is progressively worsening respiratory muscle damage with dilated cardiomyopathy
.
Dilated cardiomyopathy develops in one third of patients at the age of 14 years, and almost all patients develop cardiomyopathy
by the age of 18 years.
Without treatment, the average age of death is 19 years
.
With corticosteroid therapy and close monitoring of lung function and toilet care, patients can survive to the age
of 30.

2.
Perioperative concern for patients with Duchenne muscular dystrophy

For anesthesiologists, the main concerns should be the child's cardiorespiratory function, the potential for a difficult airway, and the possibility
of malignant hyperthermia-like reactions.
We should be alert to difficult airways that are at high risk in such children, that is, children with Duchenne muscular dystrophy are known to have tongue hypertrophy, upper airway muscle weakness, limited cervical range of motion, and limited
mandibular displacement.
From a respiratory function perspective, these patients are very debilitating and many need to use NPPV
.
In addition, their cough reflex is weakened, and the risk of respiratory infections after surgery increases
.
Preoperative pulmonary function tests can guide
intraoperative and postoperative respiratory therapy.
Postoperative selective ICU admission is sensible, allowing the patient to be extubated at the right time followed by NPPV or similar noninvasive ventilatory support
.

Patients with DMD progress to dilated cardiomyopathy, which can cause hemodynamic instability, arrhythmias, and sudden heart failure
.
Depending on the degree of cardiomyopathy, children may require high-dose opioid-based anesthesia to maintain hemodynamic stability
.
If clinical circumstances permit, ketamine is an alternative anesthetic
.
Some drugs, such as propofol, can cause severe hypotension when administered intravenously and must be closely monitored
when used in some abnormally sensitive patients.
Fine fluid management and electrolyte adjustment optimization are necessary
.
DMD patients with DMD bleed more pronounced than other patients during gastrostomy catheterization, and male children often lose more blood than the average blood loss, so they should be prepared for
blood transfusion.
Even for "minor" procedures, it is wise to give inotropes as most patients require such supportive care
.

Previous studies have shown an increased
risk of hyperthermia in patients with muscular dystrophy.
However, a 2009 review of anesthesia literature from Children's Hospital of Philadelphia (CHOP) cited the claim that patients with muscular dystrophy are at increased risk of developing "malignant hyperthermia-like syndrome" when receiving inhalation anesthetic drugs (Gurnaney et al.
, 2009).

Therefore, inhalation anesthesia should be avoided unless specifically indicated
.
Since the risk of fatal hyperkalemia in these patients is associated with the use of succinylcholine (skolin), succinylcholine is contraindicated
in these patients with DMD.

3.
What are the guiding principles for the perioperative management of patients with Duchenne muscular dystrophy?

Anesthesiologists must focus on multiple organ systems
in the body of DMD patients.
It is crucial to improve the preoperative examination and adjust the patient's condition, as there is a risk
of complications during or after surgery or even when the test results are normal.
It is very wise
to prepare for the ICU and support of cardiorespiratory function during and after surgery.

Source of the case: Xiamen Children's Hospital

Article | Wu Yajun

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