Hypothyroid myopathy with manifestations of Hoffman's syndrome and myasthenia gravis

Rare Co-occurrence of Ocular Myasthenia Gravis and Thyroid-Associated Orbitopathy (Ophthalmopathy) in an Individual With Hypothyroidism

Ocular myasthenia gravis (Ocular MG, OMG) shares many clinical features with thyroid-associated orbitopathy or thyroid-associated ophthalmopathy (TAO). In the rare instance of their coexistence, clinicians may fail to diagnose ocular MG when TAO is also present. Here we report the case of a patient with both TAO and ocular MG, whose "hyperthyroidism"-most likely the hashitoxicosis variant of Hashimoto's thyroiditis-rapidly transformed to hypothyroidism after radioactive iodine therapy. This is reminiscent of a previous case of a patient with MG, in whom disease onset coincided with the methimazole-induced transformation from hyper- to hypothyroidism. It is possible that the same transformation from "hyper-" to hypothyroidism, which occurred after radioactive iodine therapy and was accompanied by hypothyroidism-associated orbitopathy (ophthalmopathy), may have induced the development of myasthenia gravis in our patient. The hypothyroidism may have been caused by the radioactive iodine therapy and/or it may simply reflect the natural course of the hashitoxicosis variant of Hashimoto's thyroiditis. The co-occurrence of hypothyroidism, hypothyroidism-associated orbitopathy (ophthalmopathy) and ocular MG has never been reported. Our case highlights the need for clinicians to focus on overlapping symptoms of hyperthyroidism and the hashitoxicosis variant of Hashimoto's thyroiditis, and to carefully differentiate between them, especially when deciding on radioactive iodine therapy. In addition, our case highlights that the possible co-occurrence of TAO should be considered when a patient with thyroid disease displays both ptosis and eye movement dysfunction, and when only the ptosis is dramatically resolved after treatment with pyridostigmine bromide.

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.

Hoffmann's disease: MR imaging of hypothyroid myopathy

Hoffmann's syndrome is a hypothyroid myopathy presenting as muscle stiffness and hypertrophy. It is a rare complication of hypothyroidism. MRI features of this syndrome have seldom been described in the literature. We present a case of Hoffmann's syndrome in a 34-year-old man who underwent lower extremity contrast-enhanced MRI. MRI can demonstrate the hypertrophic configuration, T2 hyperintensity, and enhancement of the involved muscles in Hoffmann's syndrome. Along with clinical, laboratory, and electromyography findings, MRI may be helpful in distinguishing between inflammatory myopathy, myonecrosis, subacute muscle denervation, and infectious myositis.

Rheumatic and autoimmune thyroid disorders: a causal or casual relationship?

A number of dysfunctions may affect the thyroid gland leading either to hyper- or hypothyroidism which are mediated by autoimmune mechanisms. Thyroid abnormalities may represent an isolated alteration or they may be the harbinger of forthcoming disorders as is the case of well-characterized polyendocrine syndromes. Also, they may precede or follow the appearance of rheumatic manifestations in patients affected with connective tissue diseases or rheumatoid arthritis. The mechanisms by which autoimmune thyroid disorders may be linked to systemic autoimmune diseases have not been fully unraveled yet, however alterations of common pathways are suggested by shared genetic variants affecting autoantigen presentation and regulation of the immune response. On the other hand, the higher prevalence of autoimmune thyroid disorders over rheumatic diseases compels the chance of a mere causal concomitancy in the same patient. The aim of our paper is to provide an overview of available data on thyroid involvement in different rheumatic diseases and to go over the main rheumatic manifestations in the context of autoimmune thyroid diseases.

Hoffmann's syndrome with unusually long duration: Report on clinical, laboratory and muscle imaging findings in two cases

Two adult men presented with the rare Hoffmann's syndrome (HS). Case 1: A 35-year-old male patient had progressive stiffness of lower limbs of 13 years and generalized muscle hypertrophy and myalgia of 3 years duration. Had periorbital edema, dry skin, generalized muscle hypertrophy and spastic dysarthria with hoarseness. Muscle power was normal. Jaw jerk and deep tendon reflexes were exaggerated. Case 2: A 24-year-old male patient presented with muscle hypertrophy from childhood, slowness in motor activities and hearing impairment. For 6 months, he had severe muscle pains, cramps and further increase in hypertrophy. He had yellow tinged, dry skin, hoarseness of voice, gross muscle hypertrophy and minimal weakness. Both had markedly elevated serum creatine kinase (CK) levels and high thyroid stimulating hormone, low free triiodothyronine and free thyroxine levels. Levothyroxine treatment demonstrated remarkable reduction in muscle bulk at 2 months in both and no symptoms at 6 months. Magnetic resonance imaging of lower limbs in both cases revealed almost identical features with involvement of the muscles of posterior and adductor compartment of thighs and posterior and lateral compartments of the legs. Differential diagnosis of long duration muscle pseudohypertrophy and elevated CK levels should include HS.

Thyroid disease and the nervous system

Thyroid disorders are common in the general population and in hospitalized patients. Thyroid disease may present first with neurological complications or else may occur concurrently in patients suffering other neurological disorders, particularly those with an autoimmune etiology. For this reason neurologists will commonly encounter patients with thyroid disease. This chapter provides an overview of the neurological complications and associations of disorders of the thyroid gland. Particular emphasis is placed on conditions such as thyrotoxic periodic paralysis and myxedema coma in which the underlying thyroid disorder may be occult leading to a first, often emergency, presentation to a neurologist. Information about clinical features, diagnosis, pathogenesis, therapy, and prognosis is provided. Emphasis is placed on those aspects most likely to be relevant to the practicing neurologist and the interested reader is directed to references to good, recent review articles for further information.

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.

Stepwise approach to myopathy in systemic disease

Muscle diseases can constitute a large variety of both acquired and hereditary disorders. Myopathies in systemic disease results from several different disease processes including endocrine, inflammatory, paraneoplastic, infectious, drug- and toxin-induced, critical illness myopathy, metabolic, and myopathies with other systemic disorders. Patients with systemic myopathies often present acutely or sub acutely. On the other hand, familial myopathies or dystrophies generally present in a chronic fashion with exceptions of metabolic myopathies where symptoms on occasion can be precipitated acutely. Most of the inflammatory myopathies can have a chance association with malignant lesions; the incidence appears to be specifically increased only in patients with dermatomyositis. In dealing with myopathies associated with systemic illnesses, the focus will be on the acquired causes. Management is beyond the scope of this chapter. Prognosis is based upon the underlying cause and, most of the time, carries a good prognosis. In order to approach a patient with suspected myopathy from systemic disease, a stepwise approach is utilized.