Hypothyroid myopathy with a strikingly elevated serum creatine kinase level

Neuromuscular Emergencies

OBJECTIVE

This article aims to familiarize the reader with the clinical approach, diagnostic considerations, and treatment strategies for patients presenting with abrupt-onset or acutely worsening weakness due to neuromuscular disorders.

LATEST DEVELOPMENTS

Neuromuscular weakness is often the result of an inflammatory process. In recent years, there has been growing recognition of pathologic antibodies that cause neuromuscular injury. This has allowed clinicians to make a more accurate diagnosis. Additionally, neuromuscular junction disorders and myopathies are increasingly identified as the adverse effects of novel anticancer therapies, namely immune checkpoint inhibitors. More data are being incorporated into frameworks for neuroprognostication after neuromuscular emergencies, especially for commonly encountered disorders such as Guillain-Barré syndrome.

ESSENTIAL POINTS

Care of patients with neuromuscular emergencies requires prompt attention to respiratory status. Once supportive measures are in place to protect the airway and facilitate effective ventilation, diagnostic considerations should hinge on appropriate neurologic localization. Aggressive immunosuppression is often required for immune-mediated neuromuscular disorders, and clinicians must be thoughtful in selecting a strategy that best aligns with each patient's risk factors and comorbidities.

Hypothyroidism: A Peculiar Presentation

Hypothyroidism constitutes a prevalent pathology, with up to 80% of afflicted individuals displaying associated muscular symptoms. However, these symptoms rarely appear as the first or only manifestation of hypothyroidism. We report the case of a previously healthy 21-year-old man, diagnosed with hypothyroid myopathy after experiencing intense myalgias and cramps, which were relieved by oral administration of levothyroxine. This case demonstrates the significance of considering thyroid-related conditions when patients present muscular symptoms as these can represent the only or initial indicator of hypothyroidism. Timely thyroxine supplementation leads to the gradual resolution of most neuromuscular symptoms.

Myxedema Coma Precipitated by Sepsis in a Patient With a Complex Mental Health History

Myxedema coma is a rare and life-threatening manifestation of severe hypothyroidism. Myxedema refers to altered mental status observed in these patients. Clinical characteristics observed include hypothermia, bradycardia, respiratory failure, hyponatremia, and altered mental status. We present the case of a 57-year-old female who was brought into the hospital with a history of collapse and a long lie. On initial assessment, she was hypothermic, hypotensive, bradycardic, and hypoglycemic with elevated infection markers, acute kidney injury, and electrolyte derangement. Her thyroid function tests on admission were severely impaired with a TSH (thyroid stimulating hormone) level of 144.46 mU/L and Free T4 (thyroxine) levels of 3.4 pmol/L. She was admitted to the intensive care unit and was started on intravenous antibiotics, intravenous liothyronine, oral levothyroxine, and intravenous hydrocortisone. Initially, her hypothermia and bradycardia were slow to respond to treatment measures, but following the introduction of liothyronine, she showed marked improvement. Over the next few days, her infection markers improved, her acute kidney injury resolved, and her thyroid function tests normalized. Liothyronine was stopped after 6 days, levothyroxine was continued at her regular dose of 175 micrograms, and she was safely discharged with outpatient endocrinology follow-up.

Severe Hypothyroidism Complicated by Myopathy and Neuropathy with Atypical Demyelinating Features

Autoimmune hypothyroidism may result in a wide range of neuromuscular disorders. The frequently observed neurological manifestations of acquired hypothyroidism include mild to moderate myopathy and sensorimotor neuropathy, which usually resolve by clinical and electrophysiological criteria, in adults treated with thyroid hormone replacement. We report a case of a 30-year-old male with severe hypothyroidism secondary to chronic autoimmune thyroiditis who presented with a 2-year history of progressive fatigue, upper and lower limb weakness, myalgia, and intermittent paraesthesia. His neurological exam demonstrated proximal and distal muscle weakness, lower limb areflexia, and relatively intact sensory modalities. The patient's biochemistry revealed unusually and profoundly raised the thyroid stimulating hormone (TSH) level of 405.5 mIU/L (reference range (RR): 0.27–4.2 mIU/L) and creatine kinase (CK) level of 20,804 U/L (RR: 45–250 U/L), while his nerve conduction studies (NCS) demonstrated severe sensorimotor polyneuropathy with both axonal and demyelinating features. Thyroid hormone replacement therapy over the first 3 months resulted in biochemical normalization of his extremely deranged thyroid function tests (TFTs) and CK levels. At 12 months, despite maintaining euthyroidism and noticeable improvement in strength, his nerve conduction studies (NCS) demonstrated the continued absence of distal motor and sensory responses in his lower limbs with only partial improvement in sensory amplitudes and conduction velocities in his upper limbs. This report highlights the potential for severe neuromuscular consequences from advanced and chronic autoimmune hypothyroidism. The patient's myopathy has resolved over a period of three months with prompt normalization of CK levels. Concerningly, the patient achieved significant but incomplete recovery from his mixed axonal and demyelinating neuropathy with residual mild distal weakness and areflexia in his lower limbs and persistent motor and sensory impairments on his NCS. The severity and incomplete resolution of our patient's neurological manifestations emphasize the importance of early diagnosis and the need for prompt therapeutic intervention for hypothyroidism.

Spontaneous Conception, Pericardial Effusion, and Pseudohypertrophic Myopathy Mimicking Muscular Dystrophy in Delayed Presentation of Sheehan Syndrome

Sheehan syndrome, characterized by postpartum pituitary necrosis, is an important cause of hypopituitarism in developing countries. We report the case of a 50-year-old female with Sheehan syndrome, who had two spontaneous conceptions following severe postpartum hemorrhage in her first delivery and presented 27 years later with moderate pericardial effusion and features of pseudohypertrophic myopathy mimicking muscular dystrophy.

Survey analysis of exercise participation and skeletal muscle symptoms in women with hypothyroidism

This study examined the effect of exercise on skeletal muscle symptoms experienced by women with hypothyroidism. An online survey on exercise participation was completed by female participants undergoing treatment for hypothyroidism (n = 580). Basal muscle symptoms (MS) and exercise muscle symptoms were analyzed by the type of exercise performed, cardiovascular/aerobic (CV), resistance training (RT), or both (CVRT). Exercise participation affected MS (F = 7.186, p < .01) with respondents performing a combination of CVRT reporting the lowest basal MS compared to those performing CV (p = .044), RT (p = .031) alone, or those performing no exercise at all (p < .001). Associations between muscle pain (χ² = 7.963, p = .019) and muscle fatigue (χ² = 14.240, p < .001) during exercise and by exercise type were found. Muscle pain during exercise was also associated with an exercise type and frequency (χ² = 24.164, p < .019). Finally, there was an association between recovery from exercise and frequency of exercise bouts (χ² = 32.185, p < .001). Women with hypothyroidism commonly experience skeletal muscle symptoms at rest and during exercise. The results from this study indicate the type of exercise performed may have an impact on the occurrence of these symptoms.

Systemic lupus erythematosus with hypothyroidism as the initial clinical manifestation: A case report

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease and hypothyroidism is an organ-specific autoimmune disease. The two diseases may occur successively or simultaneously. The majority of previous studies observed that thyroid disease was more frequent in patients with SLE than in the general population, particularly those who had a higher incidence of anti-thyroid antibodies. However, there are no reported cases of SLE with hypothyroidism as the initial clinical manifestation, to the best of our knowledge. The present study reported on a case of SLE with this unusual initial clinical manifestation and reviewed the literature to estimate the prevalence of clinical hypothyroidism in patients with SLE (range, 3.0-21.4%). The case of the present study had no obvious facial erythema, photosensitivity or recurrent oral ulcers, and only had hypothyroidism as the initial clinical symptom, but the laboratory examination supported the diagnosis of SLE. The present study suggested that in the clinical diagnosis, attention should be paid to screening for connective tissue diseases when diagnosing hypothyroidism, and the importance of thyroid dysfunction should also be recognized in the treatment of SLE.

Severe proximal myopathy secondary to Hashimoto’s thyroiditis

Muscular symptoms in hypothyroidism are common, including myalgia, fatigue and cramps; however, a significantly raised creatine kinase and muscle weakness are rare. Differential diagnosis of patients presenting with muscle weakness and a raised creatine kinase is wide, and hypothyroidism is rarely considered. We report this case of a 30-year-old female presenting with proximal muscle weakness as her primary symptom, hypothyroid symptoms of 3-month duration and a significantly raised creatine kinase. After ruling out other causes of a raised creatine kinase, thyroxine replacement was commenced, which led to complete resolution of her proximal weakness, myalgia and normalisation of creatine kinase level. This case illustrates severe proximal myopathy can be secondary to hypothyroidism, symptoms can resolve with thyroxine replacement and emphasises the importance of measuring thyroid function in patients with proximal weakness/myalgia and a significantly raised creatine kinase.

Myopathy in a 61-year-old Hispanic man

A 61-year-old Hispanic man presented to a county hospital for subacute progressive weakness, heliotrope rash and dysphagia. There was initial suspicion for dermatomyositis (DM) given the history; however, the physical exam was not consistent. An MRI followed by a muscle biopsy revealed necrotising autoimmune myositis and anti-3-hydroxy-3-methylglutary-coenzyme A-reductase antibody titers returned positive; the patient was diagnosed with necrotising autoimmune myositis. He was treated with corticosteroids and intravenous immunoglobulin, which resulted in improvement in his weakness and functional status. This case represents a unique instance in which a cardinal feature of DM, the heliotrope rash, prompted an erroneous initial diagnosis. It highlights the necessity of developing abroad differential diagnosis and subsequent thorough investigation into patients presenting with suspected idiopathic immune-mediated myopathies.

Which nonautoimmune myopathies are most frequently misdiagnosed as myositis?

PURPOSE OF REVIEW

To discuss the spectrum of nonautoimmune myopathies that may be misdiagnosed as autoimmune myopathy.

RECENT FINDINGS

Inherited myopathies, such as dysferlinopathy, calpainopathy, and facioscapulohumeral dystrophy may be misdiagnosed as autoimmune myopathy, especially when they have inflammatory muscle biopsies. Inclusion body myositis is frequently misdiagnosed as polymyositis when rimmed vacuoles are absent on muscle biopsy, and a careful neuromuscular evaluation is not performed. Hypothyroid myopathy can be misdiagnosed as immune-mediated necrotizing myopathy if thyroid function tests, including a T4 level, are not obtained. Self-limited statin myopathy can be distinguished from statin-associated autoimmune myopathy because patients with the former do not have autoantibodies recognizing 3-hydroxy-3-methylglutaryl-coenzyme A reductase.

SUMMARY

Autoimmune myopathies can usually be distinguished from nonautoimmune myopathies based on a combination of the patient history, neuromuscular exam, laboratory findings, and/or muscle biopsy features.

MUSCULAR HYPERTROPHY AS ATYPICAL INITIAL PRESENTATION OF HYPOTHYROIDISM

Hypothyroidism is a common endocrine disease with characteristic symptoms and signs such as fatigue, weight gain, intolerance of cold, constipation, depression, mental slowdown and muscle cramps. Myopathic changes are observed in 30-80% of patients with hypothyroidism, but muscular hypertrophy with muscle stiffness has been reported in less than 10% of patients. Hoffmann's syndrome is a specific form of the hypothyroid-associated myopathy, rarely seen. Symptoms of this syndrome include proximal muscle weakness, hypertrophies in extremities, stiffness, muscle cramps, spontaneous muscle pain; and are associated with increased muscle enzymes. These findings can be seen at any time during hypothyroidism. Hofmann's syndrome has a very good prognosis. Its response to hormone replacement therapy is very good. Therefore, in patients with myopathy-like symptoms, considering in the differential diagnosis that the myopathy may be a reflection of hypothyroidism will facilitate the diagnosis and treatment. In this case, we aimed to present together Hashimoto thyroiditis and muscular hypertrophy, which is an atypical presentation of hypothyroidism and rarely seen in the literature, namely Hoffmann's syndrome.

Hypothyroid myopathy: A peculiar clinical presentation of thyroid failure. Review of the literature

Abnormalities in thyroid function are common endocrine disorders that affect 5-10 % of the general population, with hypothyroidism occurring more frequently than hyperthyroidism. Clinical symptoms and signs are often nonspecific, particularly in hypothyroidism. Muscular symptoms (stiffness, myalgias, cramps, easy fatigability) are mentioned by the majority of patients with frank hypothyroidism. Often underestimated is the fact that muscle symptoms may represent the predominant or the only clinical manifestation of hypothyroidism, raising the issue of a differential diagnosis with other causes of myopathy, which sometimes can be difficult. Elevated serum creatine kinase, which not necessarily correlates with the severity of the myopathic symptoms, is certainly suggestive of muscle impairment, though it does not explain the cause. Rare muscular manifestations, associated with hypothyroidism, are rhabdomyolysis, acute compartment syndrome, Hoffman's syndrome and Kocher-Debré-Sémélaigne syndrome. Though the pathogenesis of hypothyroid myopathy is not entirely known, proposed mechanisms include altered glycogenolytic and oxidative metabolism, altered expression of contractile proteins, and neuro-mediated damage. Correlation studies of haplotype, muscle gene expression and protein characterization, could help understanding the pathophysiological mechanisms of this myopathic presentation of hypothyroidism.

Elevation of serum creatine kinase during methimazole treatment of Graves disease in a 13-year-old girl and a literature review of similar cases

We report a 13-year-old girl with Graves disease, who showed an increased level of serum creatine kinase (CK) accompanied by myalgia after methimazole (MMI) treatment. This patient developed muscular pain two weeks after MMI administration, along with increased CK levels. The level of thyroid hormone was within the normal range when she showed increased CK levels. After the MMI dose was decreased and levo-thyroxine was added, serum CK levels decreased to normal and the myalgia improved. The pathophysiologic mechanism of this effect has not yet been elucidated. An acute relatively hypothyroid state occurs secondary to antithyroid drug (ATD) administration in chronic hyperthyroidism, which may cause changes in the CK levels. In this report, we present a rare pediatric case, along with a literature review of similar cases. In the initial state of MMI treatment, myalgia should be detected and when it occurs, CK levels should be measured. The clinical strategy of monitoring CK levels with the aim of normalizing thyroid hormones is helpful in case of the development of adverse reactions, such as myalgia, during ATD treatment for Graves disease in children.

An unusual case of "renal failure"

Myopathy is common in hypothyroidism, but a very high creatinine kinase (CK) level in the range commonly seen with inflammatory myopathy is rare. Reversible elevation of creatinine is known to occur in hypothyroidism due to a decrease in the glomerular filtration rate, but it can also occur rarely due to enhanced creatinine production. We present a case of severe hypothyroidism with massively elevated CK levels and high creatinine levels, both of which reversed on treatment of hypothyroidism.

Hypothyroid myopathy mimicking postpolio syndrome

Hypothyroidism can have diverse neurological manifestations. Myopathy may rarely be the sole manifestation of autoimmune thyroiditis. We hereby report an atypical manifestation of severe hypothyroidism in a middle-aged woman with childhood onset of paralytic polio involving her right leg presenting with a recent onset of increased weakness in the right leg mimicking postpolio syndrome.

Hypothyroidism: etiology, diagnosis, and management

Hypothyroidism is the result of inadequate production of thyroid hormone or inadequate action of thyroid hormone in target tissues. Primary hypothyroidism is the principal manifestation of hypothyroidism, but other causes include central deficiency of thyrotropin-releasing hormone or thyroid-stimulating hormone (TSH), or consumptive hypothyroidism from excessive inactivation of thyroid hormone. Subclinical hypothyroidism is present when there is elevated TSH but a normal free thyroxine level. Treatment involves oral administration of exogenous synthetic thyroid hormone. This review presents an update on the etiology and types of hypothyroidism, including subclinical disease; drugs and thyroid function; and diagnosis and treatment of hypothyroidism.

Biochemical markers of muscular damage

Muscle tissue may be damaged following intense prolonged training as a consequence of both metabolic and mechanical factors. Serum levels of skeletal muscle enzymes or proteins are markers of the functional status of muscle tissue, and vary widely in both pathological and physiological conditions. Creatine kinase, lactate dehydrogenase, aldolase, myoglobin, troponin, aspartate aminotransferase, and carbonic anhydrase CAIII are the most useful serum markers of muscle injury, but apoptosis in muscle tissues subsequent to strenuous exercise may be also triggered by increased oxidative stress. Therefore, total antioxidant status can be used to evaluate the level of stress in muscle by other markers, such as thiobarbituric acid-reactive substances, malondialdehyde, sulfhydril groups, reduced glutathione, oxidized glutathione, superoxide dismutase, catalase and others. As the various markers provide a composite picture of muscle status, we recommend using more than one to provide a better estimation of muscle stress.

Polymyositis-like syndrome caused by hypothyroidism, presenting as camptocormia

Polymyositis-like syndrome characterized by proximal muscle weakness and elevation of muscle enzymes may be a presenting manifestation of hypothyroidism. Camptocormia, which can be caused by myopathy of the paraspinal muscles, is an involuntary truncal flexion of the thoracolumbar spine while standing or walking. Among various neuromuscular disorders, hypothyroidism has not been reported in the literature as a cause of camptocormia. This is the first report of polymyositis-like syndrome with camptocormia caused by hypothyroidism.

Onset of acquired autoimmune hypothyroidism in infancy: a presentation of delayed gross-motor development and rhabdomyolysis

We report the case of a 23-month-old girl who presented with poor growth and delayed attainment of gross-motor milestones. Elevated creatine phosphokinase (CPK) indicated rhabdomyolysis, ultimately attributed to severe, acquired autoimmune hypothyroidism. Growth data and bone-age suggest the onset of hypothyroidism occurred at or before 12 months of age. Acquired hypothyroidism is rare before age 3 years, and rhabdomyolysis due to hypothyroidism has not previously been reported as a cause of delayed gross-motor development in toddlerhood. Despite the early onset of hypothyroidism, cognitive function appeared to be unaffected. Adequate thyroid hormone replacement quickly normalized the CPK in our patient, and gross motor development rapidly improved. Although rare, rhabdomyolysis secondary to hypothyroidism should be in the differential diagnosis of delayed gross-motor development in infancy and toddlerhood.

Simvastatin-fluconazole causing rhabdomyolysis

OBJECTIVE

To report a case of rhabdomyolysis after concomitant use of simvastatin, a commonly used hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and fluconazole, an azole antifungal agent.

CASE SUMMARY

An 83-year-old white man with a history of congestive heart failure and hyperlipidemia presented to the hospital 1 week following the addition of fluconazole to a medication regimen that included simvastatin 40 mg once daily. The patient had severe muscle weakness and a markedly elevated serum creatine kinase activity, which resolved following discontinuation of simvastatin and fluconazole.

DISCUSSION

Rhabdomyolysis is a recognized adverse effect of HMG-CoA reductase inhibitors (statins), commonly caused by their interaction with other drugs, such as azole antifungals, that inhibit the cytochrome P450 isoenzyme family. An objective causality assessment revealed that the adverse drug event was probable. Although drug interactions have been described for combinations of other HMG-CoA reductase inhibitors and azole antifungals, rhabdomyolysis likely caused by the interaction between simvastatin and fluconazole has not yet been reported. This case reinforces the importance of being vigilant for drug interactions, particularly in connection with commonly prescribed medications such as statins.

CONCLUSIONS

Patients receiving statins who have cancer may receive azole antifungals and other drugs that inhibit CYP3A4 during treatment, predisposing them to toxicity. These patients should therefore be monitored closely for drug interactions.