This was the resident’s third or fourth day without an answer when someone on the team suggested consulting the metabolic service. Metabolic diseases are disorders that disrupt the processes that convert food into energy at the cellular level. Most of these disorders are inherited – due to genetic mutations that alter the structure or function of one of the body’s devices to metabolize carbohydrates, fats, proteins, and other nutrients. And while most of these diseases are rare, many of them are. It is estimated that metabolic diseases affect more than one in 1,000 people. Nevertheless, most showed in infancy or childhood, not at the age of 35.
The neurology resident called Dr. a friend on the Metabolism Service Called Tyler Peix, who immediately went to see the scene. He reviewed the records, examined the patient and obtained the story from Sean and his family. It was not like any metabolic diseases he was known for. The rapid course of sister’s disease was inaccessible. He ordered tests to look for diseases that usually appear intermittently.
Neurology residents kept searching for answers. And gradually the results were tricked. It was not exposed to metal such as arsenic or mercury. It was not an autoimmune disease. It was not an infection. At the end of each day, the resident made another X on their calendar and worriedly went home. The only hope indicated was that the patient’s episodes were becoming less frequent. He was not sure but hoped that this would mean they would have enough time.
Ordering the correct test
Finally, on day 11, a test that Pex ordered came back positive. The patient had a rare form of a rare disorder called maple syrup urinary disease (MSUD). MSUD patients are born with abnormalities in certain amino acids, the machinery used to break down the building blocks of proteins. This causes the accumulation of unabolized protein components, which can harm the body. Untreated, as a result of the disease, often fatal inflammation of the brain can occur. The name comes from the smell of maple syrup in the urine and is sometimes due to the buildup of amino acids during episodes of protein overload. The patient never experienced it.
The frequency of a patient’s attacks, and the age at which they start, depends on how badly the machinery is broken. In intermittent MSUD – the patient was in this version – the body can handle low levels of amino acids, but a high protein diet or severe physical stress can affect the system and allow toxic components to form. A simple blood test provided the answer. Eventually genetic testing revealed the specific defect. A subsequent test on Andrea’s tissue revealed a similar abnormality. Patients with MSUD should maintain a low protein diet. This is the only way to prevent these crises.
It has been more than two years since Shawn received his diagnosis. He says he occasionally misses a steak or burger, but his and his sister’s memory is enough to keep him away. It was Sean’s family that brought this story to my attention. Her mother hoped that by sharing her children’s story she could help doctors and families consider the possibility of these rare metabolic diseases, when no patient present with a psychiatric or neurological disease could find out. “It’s not a difficult ordeal,” the mother said. “You have to think about it.”