Endocrine myopathy

Introduction to endocrine myopathy Endocrine myopathy (endocrinemyopathy) includes thyroid myopathy, corticosteroid polymyopathy, adrenal insufficiency, parathyroid and pituitary myopathy. 1. Thyroid myopathy (thyroidmyopathy) is a muscle disease caused by thyroid function changes including chronic hyperthyroid myopathy, exophthalmia ophthalmoplegia, hyperthyroidism periodic paralysis, hyperthyroidism or hypothyroidism myasthenia gravis, hypothyroidism Myopathy and so on. 2. Corticosteroid polymyopathy is a type of muscle disease caused by the widespread use of corticosteroids, similar to Cushing syndrome with muscle changes in corticosteroid deficiency, such as Addison disease can also lead to generalized muscle weakness, but no clear Muscle lesions These myopathy include two categories: chronic corticosteroid myopathy and acute corticosteroid myopathy. 3. Adrenal cortical insufficiency myocardium (myastheniaduetoadrenocorticalinsufficiency) includes two categories: adrenal insufficiency and myasthenia caused by primary aldosteronism. 4. Myopathycaused bythedisease of parathyroidglands includes two types: hyperparathyroidism and hypoparathyroidism. 5. Pituitary myasthenia (myastheniaduetodiseasesofthepituitarygland) is a symptom of muscle weakness caused by late pituitary disease. In the past, muscle symptoms were caused by neuritis, and Mastaglia et al pointed out that it is caused by chronic polymyopathy. Epidemiology: At present, authoritative and comprehensive statistical data on morbidity have not been found in China. basic knowledge The proportion of illness: 0.015% Susceptible people: no special people Mode of infection: non-infectious Complications: myasthenia gravis osteoporosis

Etiology of endocrine myopathy

Cause:

The etiology of some types of endocrine myopathy is related to autoimmune endocrine diseases, enzyme defects or metabolic disorders caused by abnormal levels of endocrine hormones in vivo, and some types of causes are still unclear.

Pathogenesis

Different types of endocrine myopathy, the pathogenesis is also different, some types of pathogenesis is unclear, for the convenience of description, please refer to clinical manifestations.

Endocrine myopathy prevention

Mainly to prevent and treat primary endocrine diseases.

(1) Prevention-based: Some endocrine diseases can be prevented. For example, endemic goiter caused by iodine deficiency can be prevented by early iodine supplementation. Certain hereditary diseases can also be diagnosed and treated early by genetic testing.

(2) Patients with hyperendocrine function: surgery, radionuclide therapy and drug therapy can be used.

(3) For patients with decreased endocrine function: long-term replacement therapy, gland transplantation or genetic engineering treatment can be used.

Endocrine myopathy complications Complications Myasthenia gravis osteoporosis

Myopathy is a clinical manifestation based on the primary disease, and the symptoms and signs of the primary disease are different.

Symptoms of endocrine myopathy common symptoms vitamin D deficiency congestion fatigue dyspnea hardening hypotension carpal tunnel syndrome muscle tension reduction diplopia quadriplegia

Thyroid myopathy

It is a muscle disease caused by changes in thyroid function, including chronic hyperthyroid myopathy, exophthalmia of the eye, hyperthyroidism, hyperthyroidism, hypothyroidism, hypothyroidism, and hypothyroidism.

(1) Chronic thyrotoxic myopathy: first reported by Graves and Basedow in the early 19th century, characterized by progressive skeletal muscle weakness, often associated with dominant or recessive hyperthyroidism, thyroid myopathy usually In a chronic process, the goiter is nodular.

Clinical manifestations:

1 hyperthyroid myopathy is common in middle-aged patients, males are more common, usually insidious onset, muscle weakness gradually progresses, it takes weeks to months to attract attention, muscle lesions are mostly mild to moderate, but also severe, common progress Muscular atrophy, including a certain degree of bulbar muscle, pelvic muscles and thigh muscles, muscle weakness, called Basedow paraplegia, scapular muscle and hand muscle muscle atrophy, muscle contraction when tremors and convulsions, no bundle Tremor, sputum reflex is moderately active.

2 serum CK does not increase, but sometimes decreases, EMG is generally normal, no fibrillation potential, sometimes visible short-term low-amplitude action potential or multi-phase wave percentage increase, except for type I and type II muscle fiber mild atrophy and occasional degeneration, No other abnormalities were found in the muscle biopsy.

Neostigmine treatment is ineffective, such as hyperthyroidism symptoms are controlled, muscle weakness and muscle atrophy can gradually recover.

(2) exophthalmic ophthalmoplegia (exophthalmic ophthalmoplegia): or invasive exophthalmos, eye muscle biopsy can be found in extraocular muscle edema, with the progression of the disease gradually fibrosis, muscle fiber degeneration and lymphocytes, monocytes and fat Cell infiltration, called invasive exophthalatosis, histological features suggest that the disease is an autoimmune disease, Kodama et al found antibodies to the eye muscle tissue extract in serum, supporting autoimmune mechanisms.

Clinical features: this disease is hyperthyroidism (Graves disease) complicated by extraocular muscle paralysis and exophthalmos, the pupil sphincter and ciliary muscle are usually not damaged, the degree of exophthalmos is different, the patient's eye symptoms may appear earlier than hyperthyroidism symptoms, or appear After effective treatment of hyperthyroidism, it is often accompanied by eyelid pain. The sudden eye is occasionally unilateral. Especially when the disease starts, all the extraocular muscles can be affected. Usually, the extraocular muscles are heavier, leading to strabismus and diplopia. The rectus muscle and the medial rectus muscle are most often involved, the eyeball is often restricted, the eye contracture causes the patient to have a blinking appearance, and Graves' disease can lead to congestive eyelid disease, which is characterized by conjunctival edema, vascular congestion of the medial rectus and lateral rectus muscle. In the extreme outreach of the eyeball, it can be found that the extraocular muscle swelling can be found by orbital ultrasound and MRI.

(3) thyrotoxic periodic paralysis: unlike typical hypokalemic periodic paralysis, it is not a familial disease, often occurring in early adulthood.

Clinical features: The clinical manifestations of this disease are similar to those of familial periodic paralysis. For example, the muscles of the trunk and limbs are mild to severe muscle weakness, the head and face muscles are usually unaffected, and the muscle weakness is peaked in minutes to hours. For half a day or longer, most patients with hyperthyroidism have a low blood potassium level during the onset of muscle weakness.

Oral treatment with potassium chloride can terminate the seizure, and propranolol (160 mg/d) can prevent seizures in divided doses. 90% of cases can effectively eliminate hyperthyroidism after treatment of hyperthyroidism.

(4) Myasthenia gravis with hyperthyroidism or hypothyroidism: is a typical autoimmune disease. Patients with myasthenia gravis (MG) who are treated with anticholinesterase can With hyperthyroidism or hypothyroidism, hyperthyroidism is also considered to be an autoimmune disease. About 5% of MG patients may be associated with hyperthyroidism. The incidence of MG in hyperthyroidism patients is 20 to 30 times that of the general population.

Clinical features:

1 Both hyperthyroidism and MG can occur first or simultaneously. The muscle weakness and muscle atrophy of chronic thyroid toxic myopathy are present at the same time as MG, and generally do not affect the reactivity and dosage of neostigmine.

2 hypothyroidism combined with MG will increase the muscle weakness, even if the degree is light, need to significantly increase the dose of bromide, sometimes can induce muscle weakness, hypothyroidism patients with thyroxine treatment is beneficial, can make The patient's myasthenia symptoms returned to the level before the onset of hypothyroidism.

It should be noted that MG is an autoimmune disease that is independent of thyroid myopathy and must be treated separately.

(5) hypothyroidism myopathy: hypothyroidism (hypothyroid myopathy) is a hypothyroidism combined with muscle lesions, which can be manifested as mucinous edema or cretinism.

Clinical features:

1 Mucinous edema or cretinism often manifests as diffuse myalgia, increased muscle volume, stiffness and slow muscle relaxation. Patients may have enlarged tongue, dysarthria, and sometimes muscles can be hard, such as It is found that the patient's muscle tremor with muscle edema and prolonged test sputum reflex time is beneficial to clinical diagnosis.

2 cretinosis combined with the aforementioned muscle abnormalities called Kocher-Debre-Semelaigne syndrome, childhood or adult mucinous edema with muscle hypertrophy called Hoffmann syndrome, the latter similar to congenital myotonia.

3 Mucinous edema or electromyography of patients with cretinism showed myogenic changes, generally no evidence of myogenic tonic discharge, serum CK is often significantly elevated, transaminase is normal, serum globulin can be elevated, muscle biopsy muscle fiber size Different, visible vacuolar degeneration, focal necrosis and regeneration, mild expansion of the sarcoplasmic reticulum, mild increase in glycoprotein under the muscle fiber membrane.

2. Corticosteroid poly myopathies are a type of muscle lesion caused by the widespread use of corticosteroids, similar to Cushing syndrome with muscle changes, and corticosteroid deficiency such as Addison disease can also cause generalized muscle weakness, but There are no clear muscle lesions, and these types of myopathy include two types: chronic corticosteroid myopathy and acute corticosteroid myopathy.

(1) chronic corticosteroid myopathy: is a long-term use of corticosteroids caused by muscle lesions, patients often have a history of high-dose corticosteroids for months or years, the application dose is usually with muscle weakness The degree is not significantly related. Some people think that fluorine hormone is more likely to cause the disease than other hormones. In fact, all corticosteroids can cause disease. The mechanism of corticosteroid-induced disease is unknown, but amino acid intake is found in corticosteroid-treated animals. The level of protein synthesis is significantly reduced.

Clinical features:

1 The muscles of the proximal muscles and limbs of the limbs are weak, generally symmetrically distributed, first invading the proximal end of the lower limbs, gradually progressing to the scapular muscles, and finally affecting the distal muscles of the limbs.

2 serum CK and aldolase are generally normal, EMG is normal or slightly myogenic damage, no self-generated position, muscle biopsy only found a slight change in muscle fiber size, may be associated with type II fiber atrophy, few muscle fiber necrosis and inflammatory cell infiltration, Electron microscopy revealed mitochondrial accumulation and glycogen, lipid deposition, and mild atrophy of mild muscle fibers. These lesions are exactly the same as those of Cushing disease, suggesting a diagnosis.

(2) acute corticosteroid myopathy: is a critical illness myopathy caused by corticosteroids or acute quadri plegic myopathy.

Patients are often treated with high-dose corticosteroids for severe refractory asthma or various systemic diseases, as well as critically ill patients such as sepsis, sometimes with neuromuscular blocking agents such as muscle relaxant Pankuronin. (pancuronium bromide) can promote the onset, and can also be caused by the combination of aminoglycoside antibiotics, often with severe muscle weakness when the systemic disease improves.

Animals with a large amount of corticosteroids after muscle denervation may have a selective myosin deficiency, which is a characteristic manifestation of this disease. Restoration of myosin depends on nerve regeneration instead of stopping steroids, but multiple Patients with sclerosing have not found corticosteroid myopathy with high-dose corticosteroids. Panegyres et al observed a patient with myasthenia gravis who developed severe myosin-deficient myopathy after treatment with high-dose methylprednisolone.

Clinical features:

1 rapid onset, extensive involvement of limb muscles and respiratory muscles, manifested as severe systemic muscle weakness and dyspnea, tendon reflexes normal or weakened, or even disappeared, do not involve the sensory system, most patients improved several weeks after stopping the drug, A small number of patients with muscle weakness can last for 1 year.

2 serum CK increased frequently in the early stage of the disease, severe muscle necrosis may be associated with significantly increased CK levels, myoglobinuria and renal failure, EMG can be found in myopathy, common muscle fiber tremor, muscle biopsy shows varying degrees of muscle fiber necrosis and vacuoles Degeneration, mainly involving type II fibers, often has significant loss of thick myofilament.

3. Adrenal cortical insufficiency insufficiency (myasthenia due to adrenocortical insufficiency) includes two categories: adrenal insufficiency and myasthenia caused by primary aldosteronism.

(1) Adrenocortical insufficiency: including primary and secondary, primary adrenal insufficiency caused by Addison disease, may be caused by adrenal infection, tumor, autoimmune disorder and adrenal hemorrhage; Secondary adrenal insufficiency is caused by insufficient pituitary adrenocortical hormone.

Primary or secondary adrenal insufficiency can have typical manifestations of generalized muscle weakness, fatigue, etc., sputum reflexes, associated with water, electrolyte imbalance and hypotension, EMG examination is normal, no abnormalities in muscle biopsy.

Addison's disease is associated with muscle weakness and hyperkalemia, and it responds well to the treatment of glucocorticoids and mineralocorticoids.

(2) primary aldosteronism (primary aldosteronism): about 3/4 of patients may have muscle weakness, nearly half of patients may have hypokalemic periodic paralysis or hand and foot convulsions, chronic potassium deficiency may have periodic weakness or chronic muscle The disease is weak, and the associated alkalosis can produce tetany.

4. Myopathy caused by the disease of parathyroid glands includes two types: hyperparathyroidism and hypoparathyroidism.

(1) hyperparathyroid myopathy: secondary to parathyroidism, can be divided into primary, secondary, sporadic and pseudogenic, the first two are more common.

Primary hyperparathyroidism is caused by excessive secretion of parathyroid hormone (PTH) caused by parathyroid adenoma, adenocarcinoma, primary progenitor cell proliferation or water-like clear cell hyperplasia. Secondary hyperparathyroidism is caused by parathyroid hormone (PTH). Vitamin D deficiency, chronic renal failure and other causes of parathyroid gland hyperplasia and excessive secretion of PTH, myopathy is one of the manifestations of hyperparathyroidism, the incidence of various reports.

1 Mainly manifested as muscle weakness and fatigue, the proximal muscles of the lower extremities are often involved first, and the ducks are walking when walking. Then the muscle weakness gradually expands to the trunk and upper limbs. Generally, the lower limbs are heavier, the proximal end is heavier than the distal end, and the muscle strength is Examination can be found that the muscle strength is gradually reduced after each contraction of the muscles, the muscle tension is reduced, and the tendon reflex is hyperthyroidism. In severe cases, the small muscles of the hands, the neck flexors and the facial muscles are weak, and even the medullary muscle paralysis, the tongue muscle atrophy and the muscles Bundling, etc., often accompanied by extensive bone pain, mainly in the lower back, hips, ribs and limbs, local tenderness.

2 serum calcium, alkaline phosphatase and urinary calcium, urinary phosphorus, etc. can be increased, serum phosphorus is generally reduced, bone and joint X-ray film can be seen in general osteoporosis decalcification, subperiosteal cortex absorption and other signs, EMG is short Time-limited low-wavelength multi-phase electrical activity, no self-generating position, muscle biopsy showed muscle fiber atrophy, mainly type II muscle fiber involvement, electron microscopically showed sarcoplasmic vacuole expansion, apparent accumulation of lipofuscin particles and mitochondrial abnormalities, interstitial capillary The vascular basement membrane is thickened.

This disease must be distinguished from the identification of motor neuron diseases.

(2) hypoparathyroid myopathy: secondary to hypoparathyroidism, hypoparathyroidism secretion or loss of activity can lead to calcium, phosphorus metabolism disorders, manifested as hypocalcemia and high phosphorus Hemorrhagic, a series of neuropsychiatric symptoms, clinically referred to this group of diseases called hypoparathyroidism, common in thyroid surgery inadvertently injured or resected the parathyroid gland, called secondary hypoparathyroidism, there are still reasons Unexplained idiopathic parathyroidism and pseudohypothyroidism, etc., hypothyroidism with myopathy is clinically rare.

Clinical features:

1 parathyroid myopathy is mostly mild, mainly characterized by fatigue, decreased muscle strength, calf, foot and hand stiffness, often with hand and foot spasm, more panic before the attack, the performance is double The thumb is strongly adducted, the metacarpophalangeal joint is flexed, the interphalangeal joint is stretched, the wrist and elbow joint are flexed, and the talons are formed. Sometimes the feet are stiff and straight, the knee, hip flexion, facial muscles, masticatory muscles, etc. often appear. Freaking and inconvenient movements, some patients with mild or chronic illness do not necessarily have hand and foot spasms, and the increase in neuromuscular excitability is mainly caused by Chvostek sign and Trousseau sign.

2 serum calcium decreased, phosphorus increased, CK was normal, severe cases were elevated, EMG was normal or had multipotential potential and fibrillation potential, no obvious lesions were seen in muscle biopsy, and some small vacuoles or central nuclei were seen in the muscle mass. Increased or ring-shaped fibers, under the electron microscope, the structure of myofibril is destroyed, and occasionally the sarcoplasmic mass.

5. Myasthenia due to diseases of the pituitary gland (myasthenia due to diseases of the pituitary gland) is caused by muscle weakness in the late stage of pituitary disease. In the past, muscle symptoms were caused by neuritis, and Mastaglia pointed out that it is caused by chronic polymyopathy.

Clinical features:

(1) Acromegalia may have increased muscle hypertrophy and muscle strength in the early stage, and muscle atrophy and muscle weakness gradually occur as the disease progresses, especially in the proximal muscle. A few patients may have mild sensory peripheral neuropathy, but more than the carpal tunnel. Carpal tunnel syndrome is rare.

(2) In some patients, serum CK was slightly elevated, EMG showed changes in myopathy potential, and muscle biopsy showed type II muscle fiber atrophy, the number decreased, and only a few muscle fibers were necrotic.

Endocrine myopathy examination

1. Qualitative and quantitative detection of related endocrine hormones, essential for the diagnosis of primary endocrine diseases.

2. Serum electrolyte examination, muscle-related enzymatic examination is conducive to the diagnosis of myopathy.

3. Electromyography examination.

4. Muscle biopsy of the lesion.

5. Brain and spinal cord CT, MRI examination, is useful for identifying the nature of myopathy.

Diagnosis and identification of endocrine myopathy

diagnosis

1. Comply with myopathy, such as muscle weakness, muscle atrophy, enzymology and pathological changes in muscle biopsy.

2. There is a primary endocrine disease (endocrine disease should be diagnosed).

3. Meet the characteristics of different endocrine myopathy, and exclude other causes of myopathy.

Differential diagnosis

1. It should be differentiated from signs and symptoms such as muscle weakness and muscle atrophy caused by brain and spinal cord lesions, especially in the case of endocrine disorders after brain diseases (such as cerebrovascular disease), detailed medical history, combined with CT, MRI, etc. Identification is not difficult.

2. Pay attention to distinguishing from other types of skeletal muscle diseases.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.