achilles
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C-forearm exercise test, its the first step in evaluation of glycogen storage disease.
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| achilles
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if the forearm stress test is abnormal then next step would be muscle biopsy to identify specific enzyme defect.
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| drk1980
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for those like me who had no clue about forearm exercise test...
Insert an indwelling catheter in a superficial antecubital vein.
Draw blood for lactate and ammonia as baseline samples.
Apply a sphygmomanometer on the arm to be tested and raise its pressure slightly above the systolic blood pressure.
Ask the patient to exercise repetitively for 1 minute by using an ergometer or by making a hard fist around a rolled-up sphygmomanometer cuff.
Assess the power generated by the patient by checking the ergometer or noting the rise in the mercury column.
Stop exercise, deflate the sphygmomanometer, and draw blood samples at 1, 3, 6, and 10 minutes after 1 minute of exercise for lactate and ammonia.
heres the fulltext
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| ARJ
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Seems to be
McArdle's disease
McArdle's disease is caused by muscle phosphorylase deficiency; patients present with muscle fatigue, cramping, and high serum CK levels; vitamin B6 (pyridoxine) supplementation reduces muscle cramp...
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| AAAAA
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McArdle's disease
Also known as:
Cori's syndrome
McArdle’s syndrome
Maladie de McArdle-Schmid-Pearson
Cori’s type V glycogenosis
McArdle-Schmid-Pearson syndrome
Synonyms:
Glycogen storage disease type 5, glycogenosis type 5, glycogen disease V, glycolysis myopathy syndrome, glycometabolic myopathy syndrome, muscle phosphorylase deficiency, myophosphorylase deficiency syndrome, myophosphorylase deficiency glycogenosis.
Associated persons:
Gerty Theresa Radnitz Cori
Brian McArdle
Carl M. Pearson
Rudi Schmid
Description:
A condition caused by an inborn abnormal accumulation of glycogen in muscle tissue due to a phosphorylase B deficiency. Symptoms are muscular pain, fatigability, and muscle cramping following exercise. Rest makes symptoms disappear. Size and initial power tone of muscle normal at outset of exercise. Onset usually in childhood, although diagnosis may be made later. The affected children appear normal early in life, but late in childhood and adolescence they tire easily. During the later stages of adolescence and adulthood, they suffer from severe cramps and myoglobinuria after exercise. Unlike other types of glycogenosis the disease is not fatal and the missing enzyme does not impair the functioning of other body systems. Inheritance is autosomal recessive. Dominant form also reported.
McArdle in 1951 first described the condition in a male patient, 30 years of age, who experienced pain followed by weakness and stiffness after exercise as having been present "all his life", but doctors had dismissed his symptoms as hysterical.
On examination McArdle noted that, unlike ordinary cramps, those experienced by the patient were electrically silent, and that his venous lactate level failed to increase after ischaemic exercise. He realised that this was the same phenomenon that occurs when muscle is poisoned by iodoacetate, a substance that blocks the breakdown of glycogen into glucose and prevents the formation of lactic acid.
The enzyme deficiency was discovered in 1959 by W. F. H. M. Mommaerts et al.
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| nida
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The answer is C.
Glycogen storage diseases and glycolytic defects may be suspected in patients who present with painful rhabdomyolysis and myoglobinuria without a compelling history for dehydration, trauma, or excessive exertion. Five glycolytic defects are associated with recurrent myoglobinuria. These defects are characterized clinically by symptoms of pain and muscle stiffness that occur during brief bursts of high-intensity exercise. The symptoms often begin in adolescence. Myoglobinuria and even renal failure may occur. By far the most common of these glycolytic defects is myophosphorylase deficiency, which is known as McArdle's disease. CK levels may vary widely, depending on the clinical scenario. All patients suspected of having glycolytic defects should undergo a forearm exercise test. In this test patients are asked to perform grip exercises repeatedly. Meanwhile, venous lactate and ammonia are measured. In normal individuals both levels rise, indicating metabolic activity. An impaired rise in lactate with a normal rise in ammonia is highly suggestive of a glycolytic defect. A lack of rise in either level indicates insufficient exercise. Aldolase is not helpful as there already is evidence of muscle damage in this patient. Electrodiagnostic studies may be suggestive of muscle defect but would not specifically aid in the diagnosis. Muscle biopsy would help in the definitive diagnosis but is premature at this point because of the level of evidence. Dystrophin gene analysis is useful in the diagnosis of Duchenne's muscular dystrophy or Becker's muscular dystrophy but has no role in this patient.
(From Harrison Self-Assessment test)
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| MAZI
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good question
thank you
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