Treatment of Painful Diabetic Neuropathy

Transcription

1 Treatment of Painful Diabetic Neuropathy Case Presentation: Part I A 60-year-old male with a history of diabetes mellitus type 2 is referred to the neurology clinic by his primary care office for pain in his feet. The patient was diagnosed with diabetes mellitus type 2 approximately 12 years ago. Since that time, he has adhered to his prescribed medication regimes but feels that he is not as compliant with his diabetic diet. Review of records sent by his primary care office suggests that his hemoglobin A1c tends to fall between 8% and 9%. About 5 years ago, he started to notice stabbing pains in all of his toes. There was also numbness in his feet with some gait imbalance when he walked on uneven surfaces. Since that time, the numbness has slowly migrated up to the middle of his shins. Furthermore, the pain has progressed and become quite bothersome. He states that when he walks he feels like he is stepping on broken glass. In addition, he describes burning in his feet when he lies down at night. The stabbing pains continue in his toes and also occur in his shins. He characterizes his pain at 8/10. He only mentioned these symptoms to his primary care doctor recently because he thought he could just live with them. His past medical history is significant for hypertension, diabetes mellitus type 2, and hypercholesterolemia. His medications include lisinopril, metformin, and long-acting insulin. He has no known drug allergies. He does not smoke, drink alcohol, or use illicit substances. He is a computer programmer. He has a strong family history of diabetes mellitus but no history of peripheral neuropathy or other neurologic diseases. A complete 14-topic review of systems was obtained and was positive for erectile dysfunction and a 15-lb weight gain. On physical examination, he is a well-developed and well-nourished obese male in no acute distress. He is afebrile. His blood pressure is 110/70, pulse is 75, and respiratory rate is 12. No bruits are heard over his neck. There are no murmurs or abnormal heart sounds. He has good dorsalis pedis pulses. He is alert and oriented to person, place, and date. Registration and 5-minute recall are normal. He follows commands and names and repeats without difficulty. His speech is fluent.

2 Cranial nerve testing reveals PERRLA; optic discs are sharp, visual fields are full to confrontation, and extraocular muscles are intact. Facial sensation and strength are normal. Hearing is intact bilaterally to finger rub. Palate, tongue, and uvula are midline. Shoulder shrug strength is normal. Motor strength is MRC grade 5/5 throughout with the exception of 4/5 toe dorsiflexion and plantar flexion. Tone is normal in the arms and legs. There is extensor digitorum brevis atrophy in the feet. There is decreased pinprick and temperature perception to the knees bilaterally. The patient has absent vibratory perception in the toes. Proprioception is mildly reduced in the toes. There is no point tenderness over his heels. Reflexes are 1/4 in the arms, 1/4 at the knees, and absent at the ankles. Plantar responses are flexor bilaterally. Coordination is normal on finger-nose-finger and heel-knee-shin testing bilaterally. His gait is slightly wide-based but steady. He has difficulty with tandem walking. You discuss with the patient the he has evidence of nerve dysfunction known as peripheral neuropathy. This type of sensorimotor peripheral neuropathy is commonly seen in patients with diabetes mellitus. However, you order laboratory work for B12, methylmalonic acid, thyroid-stimulating hormone (TSH), and serum protein electrophoresis (SPEP) to look for any superimposed causes. The patient is also referred for nerve conduction studies and electromyography to better characterize and grade the severity of his peripheral neuropathy. You encourage him to strive for better glycemic control to prevent further complications related to diabetes mellitus. In the meantime, you decide to start the patient on a neuropathic pain medication to help his pain. After reviewing the patient s insurance-preferred medication list, gabapentin is selected. The patient is instructed to titrate this upwards over the course of 6 weeks to a goal dose 1200 mg three times a day. You advise him about common side effects, including dizziness and somnolence. He is also counseled that this medication takes weeks to have full effect. This visit is concluded by discussing the importance of good foot hygiene to prevent complications like diabetic foot ulcers. Case Presentation: Part II The patient returns to the neurology clinic in 3 months. He feels he is doing well. He has been adhering to his diabetic diet and medication regime. In addition, he has started an exercise program and lost 10 lbs. His most recent hemoglobin A1c was 6.8%.

3 Overall, the gabapentin has helped his pain symptoms, and his current level of pain is 2/10. He is not having any side effects from the medication. His medical history and physical examination are unchanged. His nerve conduction study and EMG were consistent with a length-dependent sensorimotor axonal polyneuropathy. You discuss with him that his laboratory work was otherwise unremarkable. You offer to start an adjunctive treatment to further help his pain. Possibilities could include oral medications and topical agents. However, the patient is content with the current level of pain control and does not want to take any more medicine. You once again stress the importance of good foot hygiene. Questions 1. According to the recent AAN evidence-based guideline Treatment of Painful Diabetic Neuropathy, 1 there was insufficient evidence to support or refute the usefulness of which of the following therapeutic interventions? A. Gabapentin B. ɑ-lipoic acid C. Venlafaxine D. Sodium valproate E. Percutaneous electrical nerve stimulation The correct answer is B. 2. Which of the following is true about painful diabetic neuropathy? A. Painful diabetic neuropathy is a chronic disease, but there are no data on the efficacy of the chronic use of any treatment. B. Painful diabetic neuropathy generally represents an asymmetric and non-length-dependent injury to the peripheral nerves. C. The therapeutic mechanism of percutaneous electrical nerve stimulation for painful diabetic neuropathy is well understood. D. There have been many head-to-head trials between different medications used to treat painful diabetic neuropathy. E. There is Level A evidence that gabapentin should be offered for the treatment of painful diabetic neuropathy. The correct answer is A. 3. Which of the following is false about sodium valproate in the treatment of painful diabetic neuropathy? A. Valproate is potentially teratogenic and should be avoided in diabetic women of childbearing age. B. Potential adverse effects of valproate include weight gain and worsening of glycemic control. C. Patients taking valproate need routine laboratory monitoring, including cell counts and liver function testing.

4 D. Valproate has been associated with pancreatitis. E. There is Class I evidence to suggest that valproate should be offered for the treatment of painful diabetic neuropathy. The correct answer is E. Diagnosis Coding 2 Discussion Though the point here is to discuss the coding of neuropathy, it is also important to discuss documentation for proper coding. In the first visit there is indeed clarification that the diagnosis is sensorimotor peripheral neuropathy. The documentation implies other etiologies are being evaluated, though this type of neuropathy is like that seen in diabetics. The highest level of specificity is then sensorimotor peripheral neuropathy. ICD-9-CM does not classify neuropathies well, and there is no entry for sensorimotor neuropathy. Thus, without a commitment to diabetic neuropathy at this visit, the code would be: Hereditary and idiopathic peripheral neuropathy, unspecified7. Had the diagnosis been stated as diabetic neuropathy, the coding becomes more difficult. All neurological complications of diabetes require that a diabetes code be listed first, and these codes have fifth digits requiring specific information: Fifth digit 0 Descriptor Type II or unspecified type, not stated as uncontrolled (Use for Type II patients even if they require insulin) 1 Type I [juvenile type], not stated as uncontrolled 2 Type II or unspecified type, uncontrolled (Use for Type II patients even if they require insulin) 3 Type I [juvenile type], uncontrolled Two codes would be used for this patient: Diabetes with neurological manifestations Polyneuropathy in diabetes The first code listed contains an instruction to Use additional code to identify the manifestation, and the second code contains the instruction to Code first the underlying disease. Both then indicate that two codes must be reported. As a reminder, the second note gives the report of a study describing the neuropathy, but does not state the final diagnosis. Even if you choose your own codes as is recommended, there must also be documentation of the diagnosis in the record.

5 E&M Coding For the initial visit, this patient would be coded as a level 4 outpatient consultation visit (99244) if the patient has a private insurance policy or a level 4 new patient (99204) if he has Medicare. Medicare no longer reimburses for consultations. This coding choice is driven by Medical Decision Making which is only moderate complexity even though a comprehensive history and examination were performed. Of the 3 keys components for Medical Decision Making, the risk of complications, morbidity, and mortality is only moderate and the amount and/or complexity of data is moderate. For this second visit, one would bill for a level 3 established patient (99213) based on low complexity Medical Decision Making. The patient is improved and only a limited amount of data was reviewed and the number of diagnoses or management issues were limited. If one spent 25 minutes with the patient and more than half of it was expended in counseling the patient and providing coordination of care, then one could code a level 4 established patient (99214) using time as the primary coding criterion. EMG and Nerve Conduction Studies Nerve Conduction Studies, Reflex and Late Response Testing The following applies to nerve conduction tests ( ): Codes describe nerve conduction tests when performed with individually placed stimulating, recording, and ground electrodes. The stimulating, recording, and ground electrode placement and the test design must be individualized to the patient s unique anatomy. Nerves tested must be limited to the specific nerves and conduction studies needed for the particular clinical question being investigated. The stimulating electrode must be placed directly over the nerve to be tested, and stimulation parameters properly adjusted to avoid stimulating other nerves or nerve branches. In most motor nerve conduction studies, and in some sensory nerve conduction studies, both proximal and distal stimulation will be used. Motor nerve conduction study recordings must be made from electrodes placed directly over the motor point of the specific muscle to be tested. Sensory nerve conduction study recordings must be made from electrodes placed directly over the specific nerve to be tested. Waveforms must be reviewed on site in real time, and the technique (stimulus site, recording site, ground site, filter settings) must be adjusted, as appropriate, as the test proceeds in order to minimize artifact, and to minimize the chances of unintended stimulation of adjacent nerves and the unintended recording from adjacent muscles or nerves. Reports must be prepared on site by the examiner, and consist of the work product of the interpretation of numerous test results, using well-established techniques to assess the amplitude, latency, and configuration of waveforms elicited by stimulation at each site of each nerve tested. This includes the calculation of nerve conduction velocities, sometimes including specialized F- wave indices, along with comparison to normal values, summarization of clinical and electrodiagnostic data, and physician or other qualified health care professional interpretation. Code describes nerve conduction tests when performed with preconfigured electrodes customized to a specific anatomic site Nerve conduction, amplitude and latency/velocity study, each nerve; motor, without F-wave study

6 95903 motor, with F-wave study sensory (Report 95900, 95903, and/or only once when multiple sites on the same nerve are stimulated or recorded) Motor and/or sensory nerve conduction, using preconfigured electrode array(s), amplitude and latency/velocity study, each limb, includes F-wave study when performed, with interpretation and report (Report only once per limb studied) (Do not report in conjunction with , ) H-reflex, amplitude and latency study; record gastrocnemius/soleus muscle (To report a bilateral study, use modifier 50) The Proper Use of Codes There have been a major ambiguity in the nerve conduction study code definitions: How to code for studies of two or more branches of a given motor or sensory nerve? This question is clarified by the current definitions of codes and supporting documentation from the AMA starting in CPT Numbers of Motor and Sensory Nerve Studies With the approval by the AMA CPT Editorial Panel, the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM, formerly American Association of Electrodiagnostic Medicine) developed a list of all motor and sensory nerve conduction studies that can be coded as separate procedures. If a procedure is on this list, it can be coded as a separate unit of 95900, or The latest version is included in Appendix J of CPT 2011, and is specifically referenced in the section on nerve conduction studies: (For listing of nerves considered for separate study, see Appendix J). The statement (Report 95900, 95903, and/or only once when multiple sites on the same nerve are stimulated or recorded) has remained in CPT 2011, however. It now serves solely as a reminder that a nerve conduction study assessing different segments of a single nerve cannot be coded as separate units. For example, study of four segments of the right ulnar motor nerve (without F-waves) (1) axilla-above elbow, (2) above-below elbow, (3) below elbow-wrist, and (4) wrist-abductor digiti minimi muscle can only be coded as one unit of Numbers of Studies That Should be Performed Appendix J of CPT 2011 includes a table outlining the recommended numbers of motor and sensory nerve conduction studies that can be used to diagnose 90% of patients with certain common conditions and symptoms. CPT Changes 2006: An Insider's View explained the rationale behind this table as follows:

7 The maximum number of studies table summarizes the recommended maximum number of studies per diagnostic category necessary for a physician to arrive at a diagnosis in 90% of patients with that final diagnosis, when performing needle electromyography (EMG) tests ( and ); nerve conduction studies (95900, 95903, and 95904); and other EMG studies (95934, 95936, and 95937). The numbers in the table are to be used as a tool to detect outliers to assist in appropriate reporting. Each number in the table represents one study or unit. The maximum numbers are designed to apply to a diverse range of practice styles as well as practice types, including those at referral centers where more complex testing is frequently necessary. In simple, straightforward cases, fewer tests will be necessary. This is particularly true when results of the most critical tests are normal. In complex tests, the maximum numbers in the table will be insufficient for the physician to arrive at a complete diagnosis. In cases where there are borderline findings, additional tests may be required to determine if the findings are significant. The appropriate number of studies to be performed should be left to the judgment of the physician performing the electrodiagnostic (EDX) evaluation; however, in the small number of cases that require testing in excess of the numbers listed in the table, the physician should be able to provide supplementary documentation to justify the additional testing. Such documentation should explain what other differential diagnostic problems needed to be ruled out in that particular situation. In some patients, multiple diagnoses will be established by EDX testing, and the recommendations listed in the table for a single diagnostic category will not apply. It should be noted that in some situations it is necessary to test an asymptomatic contralateral limb to establish normative values for an individual patient. Normal values based on the general population alone are less sensitive than this approach; therefore, restrictions on contralateral asymptomatic limb testing will reduce the sensitivity of electrodiagnostic tests. Electromyography Needle electromyography procedures include the interpretation of electrical waveforms measured by equipment that produces both visible and audible components of electrical signals recorded from the muscle(s) studied by the needle electrode Needle electromyography; one extremity with or without related paraspinal areas two extremities with or without related paraspinal areas three extremities with or without related paraspinal areas four extremities with or without related paraspinal areas limited study of muscles in one extremity or non-limb (axial) muscles (unilateral or bilateral), other than thoracic paraspinal, cranial nerve supplied muscles, or sphincters Proper Use of Needle EMG CPT Codes CPT codes 95860, 95861, 95863, and (Needle electromyography of 1, 2, 3, or 4 limbs with or without related paraspinal areas).

8 To bill these codes, extremity muscles innervated by three nerves (for example, radial, ulnar, median, tibial, peroneal, femoral, not sub-branches) or four spinal levels must be evaluated, with a minimum of five muscles studied per limb. One cannot bill paraspinals separately with these codes - unless studying paraspinals between T3-T11, in which case code is to be used. CPT code (Needle electromyography; other than paraspinal (eg, abdomen, thorax)). This CPT code can be billed at one unit per extremity. The code can also be used for muscles on the thorax or abdomen (unilateral or bilateral). One unit may be billed for studying cervical or lumbar paraspinal muscles (unilateral or bilateral), regardless of the number of levels tested. This code should not be billed when the paraspinal muscles corresponding to an extremity are tested and when the extremity codes 95860, 95861, 95863, or are also billed. Principles of CPT Coding, Sixth Edition states: That code may be used more than once. For example, if three muscles are tested in each upper extremity, use code with two units of service, rather than code (page 453) CPT 2011 American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association. 1. Bril V, England J, Franklin GM, et al. Evidence-based guideline: Treatment of painful diabetic neuropathy: Report of the American Academy of Neurology, the American Association of Neuromuscular and Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation. Neurology 2011;76: Epub 2011 April Centers for Disease Control and Prevention. International classification of diseases, ninth revision, clinical modification (ICD-9-CM). The AAN develops these clinical case examples as educational tools for neurologists and other health care practitioners. You may download and retain a single copy for your personal use. Please contact guidelines@aan.com to learn about options for sharing this content beyond your personal use. Disclaimer This statement is provided as an educational service of the American Academy of Neurology. It is based on an assessment of current scientific and clinical information. It is not intended to include all possible proper methods of care for a particular neurologic problem or all legitimate criteria for choosing to use a specific procedure. Neither is it intended to exclude any reasonable alternative methodologies. The AAN recognizes that specific patient care decisions are the prerogative of the patient and the physician caring for the patient, based on all of the circumstances involved American Academy of Neurology