Respiratory Distress Treated in Toddler With PWS, Moebius Syndromes

Rare combination of disorders affected girl's ability to clear her airways

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by Andrea Lobo |

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A child sits on the mother's lap as a doctor holds a stethoscope to the youngster's chest.

A toddler with both Prader-Willi syndrome (PWS) and Moebius syndrome was successfully treated for respiratory distress with a cystic fibrosis medication called dornase alfa and hypertonic saline delivered via the nose.

The girl displayed a rare combination of the two congenital diseases — meaning they were present at birth — that cause hypotonia, or low muscle tone, which affected her ability to clear her airways and increased secretions.

“This case underlines the importance of considering atypical [causes] in pediatric patients with respiratory distress, while also illustrating the effectiveness of the atypical use of Dornase alfa in a patient with underlying neuromuscular disorders,” the researchers wrote.

The study, “Acute respiratory distress in a pediatric patient with Prader-Willi and Moebius Syndromes,” was published in Cureus.

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Specific Gene Deletions Associated with More Severe PWS Disease Symptoms

In children, respiratory stress is commonly caused by respiratory infections or diseases, such as asthma, where the airways narrow and swell. It can also be associated with congenital syndromes that cause low muscle tone, however.

PWS is caused by the loss or defects in genes in a specific region of chromosome 15, the PWS locus. In most cases, genes of the paternal chromosome 15 are deleted, leading to a multitude of symptoms, including obesity at a young age, low muscle tone, increased appetite (hyperphagia), and developmental delay.

Moebius syndrome affects the nerves that control facial movements and expressions. It appears to occur randomly in most cases, but a genetic component has been suggested from reports in families.

Low muscle tone leads to trouble breathing

Researchers in the U.S. described the case of a 23-month-old girl admitted to a local hospital’s emergency department after two days of noisy breathing, shortness of breath, productive cough with clear sputum, nasal congestion, fever and vomiting.

She was taking at-home albuterol, a bronchodilator that relaxes the smooth muscles in the airways, and the glucocorticoid fluticasone twice a day using a nebulizer, and her vaccinations were up to date. According to her mother, the girl had been diagnosed in Chile with asthma, PWS, and Moebius syndrome, for which did not have any medical documentation.

The girl was born prematurely at 34 weeks of gestation by cesarean section and had a feeding tube placed to enable feeding. Also, the upper part of her stomach was wrapped around the lower part of the esophagus to prevent severe reflux.

She was in acute respiratory distress when she was admitted with an oxygen saturation of 95% and diffuse rhonchi, or continuous gurgling or bubbling sounds heard during breathing.

A possible viral infection was discarded and her blood and urine analyses were not abnormal. The doctors suspected an acute asthma exacerbation was causing the symptoms and she was treated with oxygen and several medications used for asthma symptoms, nausea, and fever. Her respiratory distress continued to worsen, though.

Confirming previous PWS, MBS diagnoses

After two days in the hospital without improvement, a repeat X-ray indicated atelectasis (collapse of one or more parts of the lung) or pneumonia, Bronchodilators were stopped and the doctors focused on PWS and MBS as they both increase the risk of aspiration (breathing food or liquid into the airways, instead of swallowing them) secondary to low muscle tone.

A physical exam focusing on neurology confirmed the PWS diagnosis with the patient presenting all major criteria of the disorder, including developmental delay, low muscle tone, feeding difficulties, and undersized lower jaw. Vision and speech defects were minor PWS criteria also observed.

She also presented characteristics of MBS, some of them common to PWS, including feeding difficulties caused by poor sucking, inability to completely close her eyes during sleeping, fixed gaze without visual tracking, speech delay (she did not produce any words at 23 months), low muscle tone, undersized lower jaw, and limited jaw opening.

The patient’s neuromuscular weakness and the related difficulty in clearing the airways with increased secretions were considered the cause of the symptoms. She was prescribed dornase alfa (sold as Pulmozyme, approved for people with cystic fibrosis) to enable her airways to clear. Pulmonary hygiene using hypertonic (high salt) saline was done and she immediately showed respiratory benefits.

The girl continued to improve over the following three days, and the rhonchi and fast breathing were resolved. She was discharged with the previous home medications for asthma and reflux.

“By focusing on the possibility of underlying airway hypotonia, our patient’s symptoms were successfully resolved,” the researchers said. “This case demonstrates the importance of physicians maintaining a high index of suspicion to consider uncommon etiologies of respiratory distress, especially in a patient with underlying neuromuscular conditions.”