A 68-year-old man with a history of dyslipidemia and chronic atrial fibrillation was sent for a neurologic consultation because of weakness and dysphagia. On detailed questioning, the patient described a 9-month history of slowly progressive painless difficulty standing from a seated position. For several months he had had to manually lift his left lower limb into the car, and he had experienced trouble turning the ignition of his car with his right hand. The dysphagia had been a more recent concern, which largely consisted of solid food “sticking” in his throat. He did not recall aspiration or nasal regurgitation. No family history of similar weakness was noted, and his only medications were apixaban and atorvastatin.
On examination, the patient had moderate-to-severe weakness of deep finger and thumb flexors on the right and knee extensors and hip flexors on the left. He had mild weakness in these muscle groups contralaterally and bilaterally in foot dorsiflexors and proximal upper limb muscles. No conspicuous ocular or bulbar paresis was noted, muscle power was not fatigable, and no fasciculations were observed. Muscle stretch reflexes were absent in the lower limbs and preserved in the upper limbs, and sensation was normal throughout.
For decades, the International Classification of Diseases (ICD) system has been the standardized means of recording and reporting clinical diagnoses. After a number of false starts, the United States transitioned in October 2015 from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM)1 to the current version, International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM).2 Given the recent change, Coding Table 1 includes a comprehensive list of diagnostic codes related to muscle disease with a crosswalk between the two systems. ICD-10-CM uses alphanumeric codes and comprises more than 68,000 diagnostic codes, four times as many as ICD-9-CM.
A number of diagnostic codes may be applied in this patient’s case. Progressive weakness in the absence of sensory abnormalities, fluctuation, or motor neuron signs suggests a myopathy. The pattern of clinical weakness raises the specific question of inclusion body myositis. In this case, appropriate ICD-10-CM diagnostic codes could include M62.81 (Muscle weakness [generalized]), G72.9 (Myopathy, unspecified), or G72.41 (Inclusion body myositis [IBM]), depending on the clinician’s level of diagnostic certainty. If extensive diagnostic testing is performed in a patient with an uncertain diagnosis, symptom-based (here, M62.81) or broader category (G72.9) coding is recommended.
A comprehensive history and neurologic examination were performed, resulting in a primary clinical suspicion for inclusion body myositis, but myopathies that might have responded to immune modulation, toxic myopathies, defects of neuromuscular transmission, and lower motor neuron diseases were also considered. The physician selected the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnostic code for generalized muscle weakness (M62.81) and decided to pursue further diagnostic workup including bloodwork and an electrodiagnostic evaluation in anticipation of a likely muscle biopsy.
One week after the initial consultation, the clinician met with the patient to review the results, noting that his serum creatine kinase (CK) was mildly elevated at 423 IU/L, and other blood tests were unrevealing. The electrodiagnostic evaluation of the right upper and lower limbs (discussed further in the continued case) demonstrated changes indicative of a chronic myopathy. Based on these findings, the clinician concluded the patient likely had a myopathy (G72.9 Myopathy, unspecified) and, after discussion with the patient, planned to pursue a definitive diagnosis through a muscle biopsy of the left vastus lateralis. In total, the clinician spent 50 minutes with the patient reviewing the results of the tests, discussing the diagnostic possibilities, explaining the risks of temporarily stopping his anticoagulation for the muscle biopsy, and arranging for the biopsy.
Evaluation and Management Coding in Muscle Disease
Current Procedural Terminology (CPT) codes provide a comprehensive list of procedural and E/M codes for cognitive services (Coding Table 2).3
The appropriate level of outpatient E/M coding can be determined by: (1) the level of comprehensiveness and complexity of the clinical encounter; or (2) in the outpatient setting, the length of time physically spent with the patient. Selection of time-based inpatient E/M code levels (not included in Coding Table 2) may include consideration of the time spent in team-based discussion of a patient’s care.
In the case, the initial visit included a comprehensive history and examination, consideration of a number of potentially high-morbidity diagnoses (which should be specifically documented), and ordering of extensive testing. By complexity, the visit would qualify for a level 5 (highest level) code. Since this patient was sent by a physician and had not been seen in the clinician’s practice within the last 3 years, the level 5 consultation code, 99245, could be considered. On further reflection of the patient’s insurer (Medicare), the neurologist recalled that the Centers for Medicare & Medicaid Services stopped payment for these consultation codes in 2010. Instead, a code for a level 5 new patient visit (99205) would be submitted, which is also the type of code for any self-referred patient who is new to a clinician’s practice. It is important to recall and document the elements of the visit and medical decision making required for the level of E/M code submitted.
Follow-up visits often may not include detailed histories, examinations, or complex medical decision making. In such cases, the established patient E/M code is therefore typically chosen according to the length of time spent with the patient. In this case of the patient with myopathy, the neurologist spent 50 minutes with the patient during the follow-up visit, leading to the most appropriate choice of a level 5 code (99215). Again, it is important to include documentation of the time spent with the patient, with specific mention that more than 50% of the time was dedicated to counseling or coordination of care.
The neurologist who performed the patient’s electrodiagnostic evaluation reviewed the patient’s history and examination prior to beginning the procedure and discussed with the patient the low risk of needle EMG while on anticoagulation. The neurologist performed, with the assistance of a technician, one motor and one sensory nerve conduction study, each in the upper and lower limbs, including repetitive nerve stimulation evaluating for a defect of neuromuscular transmission. After reviewing the nerve conduction study results, which were normal, she performed EMG on six right lower limb muscles and four right upper limb muscles. The EMG demonstrated widespread fibrillation potentials and rapid recruitment of low-amplitude, short-duration, complex motor unit potentials. The abnormalities were most prominent in the vastus lateralis and flexor pollicis longus, where some large, complex motor unit potentials were also seen. Her impression was of a diffuse chronic myopathy with features that could anticipate the pathologic observation of muscle fiber necrosis, splitting, or vacuolization.
Electrodiagnostic Coding in Muscle Disease
Procedures are billed using specific CPT codes. These codes are selected based on the types and numbers of procedures performed, unlike cognitive services, which are often coded based on the complexity of the case. For example, this patient’s chronic anticoagulation increases the technical difficulty of the study, but coding (and ultimately payment) is the same as it would be for a more straightforward procedure consisting of the same number of studies. Like other CPT codes, the valuation of electrodiagnostic codes includes the history and physical examination required to perform the procedure. E/M codes may be submitted with a -25 modifier if the E/M service is performed on the same day as the electrodiagnostic service as long as the E/M service is distinct from the procedural service and justification is included. Routine usage of this modifier may, however, expose the neurologist to an increased risk of payer audits.
Commonly used electrodiagnostic codes are summarized in Coding Table 3. In this patient, the electrodiagnostician would submit 95908 (for the four routine nerve conduction studies performed), 95937 x 2 (for the repetitive nerve stimulation performed on two separate motor nerves), 95886 (for the lower limb EMG, in which more than five muscles were examined), and 95887 (for the upper limb, in which fewer than five muscles were examined). In selecting the appropriate EMG code, it is important to note if nerve conduction studies have been performed on the same day. To avoid payment delays or denials, submitted CPT codes must be paired only with relevant ICD-10-CM codes (for example, this patient’s electrodiagnostic codes should be submitted with his diagnosis of weakness [M62.81], not his diagnosis of hyperlipidemia [E78.5]).
The patient returned for follow-up to obtain the results of the biopsy. Unfortunately, the tissue sample from the vastus lateralis demonstrated end-stage muscle changes without distinctive histopathologic features. The neurologist had a long discussion with the patient regarding his options, including performing a repeat muscle biopsy or simply proceeding with a clinical diagnosis of inclusion body myositis. Ultimately, the clinician and patient decided on a neuromuscular ultrasound of the patient’s thigh and arm muscles to improve the diagnostic yield of a repeat biopsy. The imaging demonstrated abnormal muscle echogenicity but visibly preserved contractile elements of the left vastus medialis. Subsequent biopsy of this muscle showed pathologic features of inclusion body myositis.
Ultrasound Coding in Muscle Disease
Neuromuscular imaging is increasingly used in patients with muscle disease as a diagnostic tool to aid in the selection of muscle biopsy sites, and in the case of ultrasound, as an assistive technique to ensure accurate needle placement in the electrodiagnostic laboratory. Given the ease of integration of ultrasound into neuromuscular clinic and electrodiagnostic lab workflows, increasing numbers of neuromuscular clinicians have sought training in its use in these settings. In general, two CPT codes are applied to the ultrasound evaluation of patients with muscle disease. In patients for whom ultrasound is used as a diagnostic tool, for example, to assess for abnormal muscle echogenicity suggestive of myopathy or to select a muscle biopsy site, the code 76882 (ultrasound, limited, anatomic specific) is appropriate. When ultrasound is used to confirm needle placement, for example, in needle EMG of the diaphragm, the code 76942 (ultrasonic guidance for needle placement [eg, biopsy, aspiration, injection, localization device], imaging supervision and interpretation) is used. In addition to the requisite training needed to effectively employ neuromuscular ultrasound, neurologists need to be aware that use of these codes requires creation of a permanently recorded image, use of clinically appropriate measurements, and creation of a written report or description of the needle localization process as appropriate.
The clinical diagnosis and management of patients with myopathy can be very complex, and the corresponding administrative codes used in this setting are extensive. Accurate and specific diagnostic and procedural coding are critically important in neurologic practice and will become more so as payment models evolve.