Heart MRI can aid in diagnosing Pompe disease: Case report
Imaging revealed enlargement of heart's ventricles, fibrosis
Heart defects detected with cardiac MRI (CMR) may help diagnose classic infantile-onset Pompe disease in early childhood, a case report from China suggests.
An imaging exam showed a patient’s heart ventricles — the chambers that pump blood through the bloodstream and lungs — were enlarged, along with fibrosis (scarring).
CMR, together with clinical symptoms and laboratory analysis, can help diagnose classic infantile-onset Pompe disease, although a definitive diagnosis is made with genetic testing, the researchers said. “Familiarity with the radiologic findings of Pompe disease can aid in making an accurate diagnosis and determining the appropriate treatment.”
The case was reported in “Hypertrophy cardiomyopathy: A case of infantile-onset Pompe disease in cardiac magnetic resonance findings” in Heliyon.
Pompe disease is caused by mutations in the GAA gene, leading to a deficiency of the enzyme acid alpha-glucosidase (GAA), which breaks down the sugar molecule glycogen. This deficiency leads to glycogen accumulating, particularly inside muscle cells, where it can interfere with their function.
Classic infantile-onset Pompe disease typically features hypertrophic cardiomyopathy, wherein the heart becomes enlarged and isn’t able to pump blood properly, usually appearing in the first weeks of life.
Diagnosing Pompe disease with heart imaging
Diagnosing the disease can be difficult, partially because its typical symptoms appear in other diseases. When feasible, a definitive diagnosis involves measuring the activity of GAA and genetic testing to identify GAA mutations.
Checking for heart damage may include chest X-rays to determine if the heart is enlarged, an electrocardiogram to detect an abnormal heartbeat, and an echocardiogram to identify problems in the heart’s functioning.
CMR uses a magnetic field and radio waves to image the heart and nearby structures, revealing Pompe-related changes. “However, there are few reports about CMR of Pompe disease,“ wrote the researchers in China who described the case of a 9 month-old child with classic infantile-onset Pompe disease to identify characteristics that could contribute to a diagnosis.
The boy was initially diagnosed with Down syndrome at 4 months, due to growth delay and pneumonia (lung infection and inflammation).
He was admitted to the researchers’ hospital due to repeated fever up to 39.4 C (102.9 F), cough, hoarseness (changes in the pitch or quality of the voice), and rapid breathing.
In a physical exam, he could hardly hold his head up and had abnormal facial characteristics, such as small nasal bones and a greater than normal distance between the eyes. He also made breathing sounds and had poor muscle tone and an enlarged liver.
Laboratory tests revealed liver and muscle damage, as assessed by levels of several enzymes. Several abnormalities in the heart’s structure and function were seen on electrocardiogram and echocardiogram, and a chest X-ray and a CT scan suggested a larger than normal heart and pneumonia.
A CMR exam showed heart muscle enlargement in both ventricles and fibrotic tissue. These are relatively typical characteristics of Pompe disease, the researchers said.
The diagnosis was confirmed by genetic testing, which showed two mutations in the GAA gene — one resulted in the the GAA enzyme’s low activity and the other was deemed likely disease-causing.
Although the final diagnosis relied on genetic testing, typical characteristics of Pompe disease on CMR can play “an important role in differential diagnosis of cardiomyopathy of unknown reasons by combining with the clinical manifestations and laboratory tests,” the scientists wrote.