This question is what the doctors at Massachusetts’ Cambridge Hospital were trying to determine. According to a recent article in the New York Times, a twenty-two-year-old man was rushed to emergency with severe flu-like symptoms, but the flu test results were normal. However, his blood tests were dangerously abnormal, and he was admitted to the hospital.
Just days before he had felt feverish, his muscles were sore, and he was extremely fatigued. He was positive that he had the flu and decided to rest for a few days.
That was until he got up one night and found that his urine was deep, dark red in color. His symptoms worsened and became so severe that he dialed 911.
The ER doctors explained that there was damage to his liver, and his white-blood-cell count indicated a serious infection.
A Dangerous Creatine Level
The doctors questioned events of the past few days and learned that the patient had been to the gym just prior to becoming ill. They had a sample of his blood checked for creatine kinase (C.K.) enzyme elevation. C.K. can be affected by injury to muscle tissue from extremely aggressive workouts. When C.K. or other muscle elements seep into the bloodstream it causes a disorder called rhabdomyolysis. The normal C.K. level is between 100 to 200. The patient’s reading was over 40,000, which was the maximum reading for this test.
The Actual Reading
On admission, the patient’s C.K. that was reported at 40,000 was actually at 189,000. The next day it totaled 364,000.
Building a Diagnosis
Frances Ue, M.D., who was assigned to the patient, suggested that there may be a connection between his exercising and the pain he was experiencing. This proved not relevant as he explained that he keeps his routine at a fairly moderate pace.
The next questions involved drugs. Was he taking muscle-building supplements or drugs such as Adderall or cocaine which can lead to rhabdomyolysis?
When Dr. Ue asked if the patient had ever experienced similar symptoms, he remembered having dark urine when he was much younger. However, there was no accompanying muscle pain.
Although rhabdomyolysis seemed to be the most obvious reason for his illness, the doctors decided to administer tests that could identify infections in the kidneys and liver.
Dr. Ue was able to give the patient the good news that his muscles would get back to normal. However, she had to explain that his kidneys remained in serious condition.
She told the patient that areas of the muscle (myoglobin) that carried oxygen were accumulating in his kidneys. Therefore it was critical that the doctors flush his kidneys to remove the myoglobin and other elements deposited by the injured muscles.
Dr. Ue began to seek other reasons for what she termed as the worse rhabdo case she has seen to date. She searched medical files and found some cases of rhabdo that occurred after a moderate workout.
There is a connection between working out and the disorder but the missing link is the depletion of fuel that the body requires.
Identifying a Rare Disease
After the patient left the hospital, Dr. Ue sent him to Dr. McIlduff, a specialist in neuromuscular diseases at Beth Israel Medical Center. He had two subsequent episodes following mild exercise but neither was of the same intensity as the initial illness.
The two episodes were enough to point Dr. McIlduff towards an inherited syndrome that was previously considered by Dr. Ue. It is a rare group of inherited diseases called metabolic myopathies. Patients do not have the enzymes required to produce energy used for muscle contractions. Food is not being converted to fuel.
The patient was then sent for genetic testing and the missing enzyme, carnitine palmitoyltransferase type 2 (CPT2) was identified. Patients who are deficient in CPT2 do not have the biological mechanism to convert certain dietary fats to energy.
When the sugar produced from carbohydrates is used up, the body normally converts fat into fuel. But CPT2 patients cannot produce the requisite amount of fuel which causes injury to muscles, pain, and dark-colored urine.
It Takes Two
Two copies of the gene are needed to produce the disorder. The patient’s parents each have one copy of the gene. Hence he now has incurable CPT2 deficiency.
On a positive note, the disease can be managed through lifestyle changes and proper diet. Patients can obtain supplements that provide certain fats that their bodies can metabolize. An online site has been set up to support other CPT2 deficiency patients with tips and stories of encouragement.