What is the value of Tc-99m hydroxymethylene diphosphonate scintigraphy for the etiological diagnosis of mild rhabdomyolysis?

Hamstring Muscle Cramp Visualized on Bone Single-Photon Emission Computed Tomography/Computed Tomography Hybrid Imaging

ABSTRACT

It is well recognized that bone-seeking radiotracers localize in muscles sustaining an injury from various causes (e.g., strenuous physical activity, trauma, hereditary myopathies, inflammatory myositides, medications, electrical burns, etc.). This report presents the case of an active 50-yr-old man (body mass index = 29) that was recently referred to our nuclear medicine department for bone scintigraphy, for the skeletal staging of a newly diagnosed prostate adenocarcinoma. The scan findings were unremarkable for its oncological indication but revealed extraosseous radiotracer absorption in the medial region of the hamstrings bilaterally. Hybrid scintitomography (single-photon emission computed tomography) with computed tomography indicated that this uptake involved the semitendinosus muscle. On a more meticulous repeat history questioning, he recalled experiencing muscle cramps on both posterior thighs 5 days earlier, during intense work-related physical activity (plumbing) under warm environmental conditions. The combination of strenuous exercise with likely dehydration contributed to bilateral self-limiting heat cramps of the hamstrings, leading to an inconsequential localized minor rhabdomyolysis that was discovered coincidentally a few days later during a bone scan. Although extraskeletal absorption of bone-seeking radiotracers in muscles is widely documented as a result of exertion or injury, this is the first report of radiotracer absorption induced by cramping.

The clinical significance of technetium-99m methylene diphosphonate bone scintigraphy findings in patients with rhabdomyolysis

OBJECTIVE

This study evaluated the relationship between bone scintigraphy finding and clinical factors and assessed the prognostic value of bone scintigraphy finding in patients with rhabdomyolysis.

PATIENTS AND METHODS

We retrospectively enrolled 143 patients with rhabdomyolysis who had undergone bone scintigraphy. Bone scintigraphy was classified into three groups: no or equivocal soft tissue uptake, a localized uptake, and a diffuse uptake. The relationship of bone scintigraphy findings with clinical factors was evaluated. Multiple logistic regression analysis was performed to identify the risk factors for acute renal failure (ARF) and renal replacement therapy (RRT).

RESULTS

Of 143 patients, 52 (36.4%) experienced ARF and 12 (8.4%) required RRT. Among cases caused by exercise, 83.7% showed localized soft tissue uptake. Diffuse soft tissue uptake was only shown among the patients with rhabdomyolysis caused by drug and toxin. Patients with localized or diffuse soft tissue uptake had higher levels of serum creatine kinase, myoglobin, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase compared with patients with no or equivocal uptake (P<0.05). Multiple logistic regression analysis showed that age, female sex, and serum phosphate level were associated with a risk for ARF and only serum creatinine level was associated with a risk for RRT (P<0.05). Bone scintigraphy findings failed to show significance for predicting ARF and RRT (P>0.05).

CONCLUSION

Soft tissue uptake on bone scintigraphy in patients with rhabdomyolysis was related to etiologies and showed limited value for predicting ARF and RRT.