Cystic fibrosis (CF) is one of the most common inherited diseases and is caused by mutations in the CFTR gene. Although the pulmonary and gastrointestinal manifestations of the disease remain in the focus of treatment, recent studies have shown expression of the CFTR gene product in skeletal muscle cells and observed altered intramuscular Ca2+ release dynamics in CFTR-deficient animal models. Physical exercise is beneficial for maintaining fitness and well-being in CF patients and constitutes one aspect of modern multimodal treatment, which has considerably increased life span and reduced morbidity. We report on a case of acute muscle trauma resulting from excessive dumbbell exercise in a young adult with cystic fibrosis and describe clinical, laboratory and imaging characteristics of acute exercise-induced muscle injury.
Life expectancy of patients with cystic fibrosis (CF) continues to improve. As randomized controlled trails demonstrate beneficial effects of exercise programs in CF patient, therapy increasingly focuses on building up and maintaining physical fitness and health [
Our patient, a 22-year-old male with cystic fibrosis, was admitted as an inpatient for scheduled intravenous antibiotic therapy of chronic pseudomonas airway infection. He was in good general health with 66 kg body weight, 184 cm height (BMI 19.5 kg/m2), and a constant Chrispin-Norman score (CN score = 7). Patient history included well-managed lung and gastrointestinal manifestations of CF, exocrine pancreatic insufficiency, impaired glucose tolerance, allergic rhinopathy, and nasal polyps. Occasional spare time sports activities were reported, although recurring air-way infections frequently prevented exercise. The treatment plan during the hospital stay included physiotherapy and supervised physical exercise.
On day 6 in hospital, the patient suddenly complained about bilateral pain and swelling of upper arm muscles. Laboratory analysis revealed a marked elevation of previously normal CK, LDH, and CK-MB levels (Table
Laboratory findings. Course of LDH (reference range < 250 U/l), CK (reference range < 190 U/l), and CK-MB serum levels. The traumatic exercise occurred on March 30th. Ultrasonography was performed on April 2nd, MRI on April 3rd.
LDH | CK | CK-MB | |
U/l | U/l | U/l | |
09.05.2005 | 192 | ||
13.05.2005 | 170 | ||
30.09.2005 | 189 | ||
28.01.2007 | 155 | ||
23.08.2007 | 148 | 84 | |
29.09.2008 | 231 | ||
27.03.2009 | 191 | ||
31.03.2009 | 1954 | 44600 | 327,9 |
01.04.2009 | 1874 | 58372 | 378,6 |
02.04.2009 (US) | 1302 | 41017 | |
03.04.2009 (MRI) | 484 | 18507 | |
04.04.2009 | 314 | 7296 | |
05.04.2009 | 185 | 2783 | |
07.04.2009 | 322 | 26,4 | |
08.04.2009 | 179 | 461 | |
17.04.2009 | 162 | ||
20.08.2009 | 234 | 149 |
As clinical symptoms persisted, an ultrasound examination was performed which revealed a diffuse bilateral increase in echogenicity limited to the biceps brachii, brachialis, and brachioradialis muscles (Figure
Ultrasound compound image (a) and corresponding sagittal MRI T2w TSE (b) of the right-hand elbow and forearm showing markedly increased echogenicity and corresponding signal increase of the brachioradial muscle (marked as *).
MRI of the right elbow (transversal T2w TSE) shows homogenous signal increase in the brachioradial (marked as *) and the brachial muscle (marked as +).
Upon interrogation, the patient admitted nonsupervised dumbbell training for more than four hours in his room one day prior to the onset of clinical symptoms, particularly exercising his “biceps” bilaterally. With immobilization and rest, clinical symptoms and laboratory findings normalized within days, so that no further imaging studies were performed. After completion of antibiotic infusion therapy, the patient was discharged in good health. Normal LDH and CK serum levels were seen on followup 4 months later (Table
Physical workout beyond the lactate threshold induces transient physiologic muscle edema during, and briefly following, exercise in healthy individuals [
In our case, excessive exertion triggered the clinical onset of muscle soreness within 24 hours. Ultrasound and MRI, performed on the second and third day of clinical manifestation, both showed signal alterations suggestive of acute muscular edema. Differential diagnosis of diffuse muscular signal increase on T2-weighted images includes autoimmune conditions, such as polymyositis or dermatomyositis, infectious myositis, radiation therapy, subacute denervation and compartment syndrome, among others [
Recently, Divangahi et al. located CFTR protein in human and murine skeletal muscle cells and demonstrated altered contractile function with force loss, dysregulated calcium homeostasis, and proinflammatory response in diaphragm cells of CFTR-deficient mice with pseudomonas lung infection [
A review of literature provides evidence that CF children benefit from exercise programs in terms of improved fitness, strength, and pulmonary function [
The authors declare no conflict of interests.