A case of peripheral neuropathy due to

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Case Report

A case of peripheral neuropathy due to hypothyroidism misdiagnosed as lumbar radiculopathy: A case report Raj Bahadur Singh, Arindam Sarkar, Mohd. Meesam Rizvi, Mohmmad A Rasheed Department of Anaesthesiology, Critical Care and Pain Medicine, Era’s Lucknow Medical College and Hospital, Lucknow, Uttar Pradesh, India

ABSTRACT Peripheral neuropathy is a group of disorders in which the peripheral nervous system gets damaged due to conditions such as diabetes, shingles, vitamin deficiency, acquired immune deficiency syndrome (AIDS), spinal cord disorder, poisoning by heavy metals, alchohol, etc. Patients with peripheral neuropathy usually present with symptoms such as numbness, tingling, paresthesia, and weakness of the involved limb. Here, we have discussed a case of a 34-year-old male who had tingling and numbness of the right leg and right foot. However, initially, he was treated as a case of lumbar radiculopathy but was finally managed with tablets oxcarbazepine and Pregabalin in due course of time to which he responded well. Key words: Hypothyroidism, nerve root block, peripheral neuropathy, prolapsed intervertebral disc (PIVD), Pregabalin, numbness, radiculopathy, tingling

neuropathy can also be categorized by the size of the nerve fibers involved, large or small.[2]

Introduction Both peripheral neuropathies and radiculopathies have some similarities in their presentations. Both manifest as tingling sensation, numbness, and paresthesia in the area of their distribution. Usually these symptoms are very annoying, leading to psychological disturbance of the patient and thus hampering his daily routine activity. Peripheral neuropathy has a variety of systemic, metabolic, and toxic causes. The most common treatable causes include diabetes mellitus, hypothyroidism, and nutritional deficiencies. The diagnosis, thus, requires careful clinical assessment, judicious laboratory testing, and electrodiagnostic studies or nerve biopsy.[1] Peripheral neuropathy can involve diﬀerent nerve types including motor, sensory, and autonomic nerves. Peripheral Access this article online Quick Response Code: Website: www.indianjpain.org

DOI: 10.4103/0970-5333.165847

© 2015 Indian Journal of Pain | Published by Wolters Kluwer - Medknow

Radiculopathy is caused by the compression or irritation of a nerve root as it exits the spinal column. Symptoms of radiculopathy include pain, numbness, tingling, or weakness in the arms or legs. Most patients with radiculopathy respond well to conservative treatment including medications, physical therapy, or chiropractic treatment.[3] Address for correspondence: Dr. Raj Bahadur Singh, Department of Anaesthesiology, Critical Care and Pain Medicine, Era’s Lucknow Medical College and Hospital, Lucknow, Uttar Pradesh, India. E-mail: [email protected] This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms. For reprints contact: [email protected] How to cite this article: Singh RB, Sarkar A, Rizvi MM, Rasheed MA. A case of peripheral neuropathy due to hypothyroidism misdiagnosed as lumbar radiculopathy: A case report. Indian J Pain 2015;29:181-4.

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Singh, et al.: Case of peripheral neuropathy due to hypothyroidism misdiagnosed as lumbar radiculopathy

Case Report A 34-year-old male patient was referred from the neurosurgery outpatient department (OPD) to our pain clinic with complaint of a burning and tingling sensation over the right leg and right foot for epidural steroid. He was under treatment of the neurosurgery department for 3 months, with a diagnosis of L4-L5 disc bulge. He was on oral gabapentin 300 mg and nortriptyline, deflazacort 6 mg, and methylcobalamin capsule once daily. His magnetic resonance imaging (MRI) revealed that he had mild L4-L5 prolapsed intervertebral disc (PIVD), more on the left side. There was no history of diabetes mellitus, hypertension, and other comorbid conditions. He had no bladder and bowel complaints [Figures 1 and 2]. On physical examination, the straight leg raise (SLR) test was negative, the deep tendon reflexes were intact, and Flexion, ABduction, and External Rotation (FABER)’s test was negative. So, on the basis of physical history and examination we labeled the case to be of right lumbar radiculopathy due to PIVD. The patient was given a trial of tablet Myospaz (chlorzoxazone, paracetamol) twice daily in addition to the above medication for 1 week and hence, we planed the L4-L5 nerve root block, along with epidural injection after 1 week when the symptoms did not get relieved. After 1 week, the patient reported with the same complaint and so, we gave him L4-L5 nerve root block with injection Depo-Medrol 40 mg mixed in injection

bupivacaine 2 mL 0.25% and epidural block with DepoMedrol 40 mg mixed in injection bupivacaine 10 mL of 0.25% solution. After the injection, the patient’s symptoms were relieved by 75%. The patient was discharged from the post-anesthesia care unit (PACU) after 4 h after checking the power of his limbs. He was advised to take tab Pregabalin 75 mg once daily for 7 days, tablet Tryptomer 10 mg once daily, and tablet paracetamol + tramadol in combination for 1 week, and again for follow-up after 1 week. The patient was reviewed after 1 week and he complained that the symptom had reappeared after 2 days of block and presently, he has the same symptom as before. We asked him to continue this medication and come for follow-up after 1 week. Again, the patient had no relief and it was then that we thought of reinvestigating him. We asked for nerve conduction study (NCV) of the lower limb and color Doppler to rule out veno-occlusive disease. NCV study and Color Doppler were both normal. The patient was very disturbed due to his symptoms. We again took the history and reviewed his previous treatment. We asked for his thyroid profile and found that the thyroid function test (TSH) was 25.48. We referred him to medical OPD for the treatment of hypothyroidism. They advised tablet Eltroxin 125 mg daily. So, he was rediagnosed as a case of peripheral neuropathy due to hypothyroidism. He was prescribed with tablet oxcarbazepine 300 mg daily in two divided doses, along with tablet Tryptomer 10 mg once in a day (OD) for 1 month. The patient felt better after 1 month and the same medications were continued for another 2 months. The patient’s liver function test (LFT) and TSH were monitored. After 3 months of continuous medication, the patient responded well with minimal residual symptoms. After

Figure 1: MRI of spine (Axial view)

Figure 2: MRI of spine (sagital view or side view)

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that, oxycarbemazepine and Tryptomer were tapered gradually over a period of 1 month. The patient was reviewed after a period of 6 months and he was totally relieved as his thyroid profile was also within the normal range. The patient was happy and satisfied. This shows that during the treatment of a case of tingling and paresthesia of the limb, one should consider other possibilities such as the endocrine glands and should not rely only on the MRI finding. So, we should always remember that our aim is to treat the patient and not rely on MRI finding alone.

Discussion Correct diagnosis of the cause of peripheral neuropathy is crucial for patient management. In this case, both we and the neurosurgeon missed the diagnosis initially but when we worked up the patient as a whole we reached the correct diagnosis. The most common cause of peripheral neuropathy is diabetes. So, during the taking of history, we generally ask only about the history of diabetes and forget to ask about other causes such as hypothyroidism and hyperthyroidism. Peripheral nerve dysfunction is a well-documented feature of clinical hypothyroidism. Only a few studies have evaluated the functional alterations in central and peripheral nervous systems in subjects with subclinical hypothyroidism and the results obtained have been controversial.[4] In the literature, the prevalence of neuromuscular disorders in thyroid dysfunctioning varies between 20% and 80%.[5-10] In a study, it was found that 33% of hypothyroid patients had residual symptoms and signs after 1 year of therapy. This may be explained by the pathological changes found in hypothyroid muscles: type II fiber atrophy, increased numbers of internal nuclei, and “core-like” structures in type I fibers. The absence of a significant correlation between the level of weakness and the biochemical severity of hypothyroidism suggests that hypothyroid patients do have a myopathy rather than a functional muscle disease.[5]

peripheral nerves dysfunction may be the main and presenting manifestation.[4] Peripheral neuropathy may be caused by severe, long-term, untreated hypothyroidism. Although the association between hypothyroidism and peripheral neuropathy is not fully understood, it is known that hypothyroidism can cause fluid retention resulting in swollen tissues that exert pressure on peripheral nerves.[17,18] In this case, we got confused with the findings as both radiculopathy and peripheral neuropathy symptoms mimic each other. The patient’s MRI also showed mild PIVD but it was asymptomatic and the MRI findings were incidental; hence, we had misdiagnosed the condition. Therefore, from this we have learnt that if the patient presents with tingling, numbness, and paresthesia, one must be careful to rule out other rare causes of peripheral neuropathy before diagnosis of the case as radiculopathy. As pain physicians, we give more importance to radiculopathic symptoms and unknowingly missed other causes of neuropathy. So, one must be careful in the diagnosis of such patients.

Conclusion Understanding the importance of detailed history and physical examination is the key for the diagnosis of any disease condition. Though investigation is important, taking of the complete history is very important as well. If a patient gives history of radiculopathy, one should also enquire about other causes of neuropathy before reaching any conclusion. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

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