Muscle Atrophy and Hypertrophy

Author(s):  
Aziz Shaibani

Muscle atrophy is usually caused by interruption of axonal flow [axonal neuropathies, motor neuron diseases (MNDs), etc.]. If weakness is out of proportion to atrophy, demyelinating neuropathy should be suspected. Chronic myopathies and immobility also may cause atrophy, but no electromyography (EMG) evidence of denervation or myopathy is found. The pattern of atrophy is often helpful to localize the lesions. Atrophy of the interossi and preservation of the bulk of the thenar muscles suggest ulnar neuropathy, but atrophy of both would suggest a C8 or plexus pathology. Muscle enlargement may be due to fatty replacement, which can be confirmed by EMG and magnetic resonance imaging (MRI), or due to real muscle hypertrophy from excessive discharges (neuromyotonia).

Author(s):  
Aziz Shaibani

Muscle atrophy is usually caused by interruption of axonal flow (axonal neuropathies, motor neuron diseases, etc.). If weakness is out of proportion to atrophy, conduction block due to demyelinating neuropathy should be suspected. Chronic myopathies and immobility may also cause atrophy, but no EMG evidence of denervation or myopathy is respectively found. The pattern of atrophy is often helpful to localize the lesion. Atrophy of the interossi and preservation of the bulk of the thenar muscles suggest ulnar neuropathy, but atrophy of both would suggest a C8 or plexus pathology. Muscle enlargement may be due to tissue replacement (fatt, amyloid), which can be confirmed by EMG and MRI, or may be due to real muscle hypertrophy from excessive discharges (neuromyotonia).


Cephalalgia ◽  
2001 ◽  
Vol 21 (2) ◽  
pp. 84-89 ◽  
Author(s):  
JW Lance ◽  
AS Zagami

The demonstration by magnetic resonance imaging (MRI) scanning of thickening and enhancement of the cisternal part of the oculomotor nerve in patients diagnosed as ‘ophthalmoplegic migraine’ prompts reconsideration of this uncommon disorder. The case histories of five patients, three male and two female, varying in age from 6 to 30 years, are presented here. Recurrent painful ophthalmoplegia started in infancy in two cases, childhood in two instances and adult life in one. One child had his first attacks at 3, 5 and 12 months of age, on each occasion 10 days after an injection of triple vaccine. The possibility of this condition being a recurrent demyelinating neuropathy is considered and its possible relationship to migraine explored.


2019 ◽  
Vol 23 (04) ◽  
pp. 405-418 ◽  
Author(s):  
James F. Griffith ◽  
Radhesh Krishna Lalam

AbstractWhen it comes to examining the brachial plexus, ultrasound (US) and magnetic resonance imaging (MRI) are complementary investigations. US is well placed for screening most extraforaminal pathologies, whereas MRI is more sensitive and accurate for specific clinical indications. For example, MRI is probably the preferred technique for assessment of trauma because it enables a thorough evaluation of both the intraspinal and extraspinal elements, although US can depict extraforaminal neural injury with a high level of accuracy. Conversely, US is probably the preferred technique for examination of neurologic amyotrophy because a more extensive involvement beyond the brachial plexus is the norm, although MRI is more sensitive than US for evaluating muscle denervation associated with this entity. With this synergy in mind, this review highlights the tips for examining the brachial plexus with US and MRI.


Endoscopy ◽  
2004 ◽  
Vol 36 (10) ◽  
Author(s):  
BP McMahon ◽  
JB Frøkjær ◽  
A Bergmann ◽  
DH Liao ◽  
E Steffensen ◽  
...  

2019 ◽  
pp. 10-23
Author(s):  
T. A. Akhadov ◽  
S. Yu. Guryakov ◽  
M. V. Ublinsky

For a long time, there was a need to apply magnetic resonance imaging (MRI) technique for lung visualization in clinical practice. The development of this method is stimulated by necessity of the emergence of an alternative to computed tomography, especially when radiation and injection of iodine-containing contrast agents are contraindicated or undesirable, for example, in pregnant women and children, people with intolerance to iodinated contrast. One of the reasons why lung MRI is still rarely used is lack of elaborated standardized protocols that would be adapted to clinical needs of medical society. This publication is a current literature review on the use of MRI in lung studies.


2007 ◽  
Vol 30 (4) ◽  
pp. 41
Author(s):  
A. Dechant

On the morning of October 10, 2003, the residents of New York awoke to find that an entire page of their beloved paper, The Times, had been usurped for the sole purpose of flagrant self-promotion and protestation. On his own behalf, Dr. Raymand Damadian had purchased a one page spread bemoaning his exclusion in the Nobel Prize for Medicine that year which had previously been awarded to Paul Laterbur and Peter Mansfield for their contributions to the development of Magnetic Resonance Imaging (MRI). Over the course of the next few months, the public was to witness a series of such articles proclaiming that a shameful wrong had been committed, and that the truth would eventually prove Dr. Damadian’s accusations. That truth lay in the early theoretical and technical foundations that led to the discovery of MRI. Described just after the Second World War, nuclear magnetic resonance (NMR) was hailed as a breakthrough in physical chemistry for which Felix Bloch and Edward Purcell were awarded the Nobel Prize in Physics in 1952. Two decades later, in 1971, Dr. Damadian discovered that differences between the NMR signals of cancerous and normal tissue might provide a rapid means of cancer detection. However, Laterbur and Mansfield were the first to actually demonstrate images of live tissue using the application of magnetic gradients – the key to modern MRI. Though speculation exists that Dr. Damadian may have been excluded from the prize due to his religious beliefs or political rivalry, only time will reveal the whole truth when the Nobel files are opened 50 years hence. Bradley W. The Nobel Prize: Three Investigators Allowed but Two Were Chosen. Journal of Magnetic Resonance Imaging 2004; 19:520. Laterbur P. Image formation by induced local interactions: examples of employing nuclear magnetic resonance. Nature 1973; 242:190-191. Mansfield P, Grannell P. “NMR diffraction in solids?” Journal of Physics C: Solid State Physics 1973; 63:L433-L426.


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