<unk>  can be difficult to diagnose, as the symptoms can be subtle and hard to distinguish from both normal variants and other neurological disorders. Three types of<unk>  symptoms in children can be distinguished: # Transient neonatal<unk>  occurs in 10 to 15% of babies born to mothers afflicted with the disorder, and disappears after a few weeks. # Congenital<unk> , the rarest form, occurs when genes are present from both parents. # Juvenile<unk>  is most common in females. Congenital<unk> s cause muscle weakness and fatigability similar to those of<unk> . The signs of congenital<unk>  usually are present in the first years of childhood, although they may not be recognized until adulthood. Classification +<unk>  Foundation of America Clinical Classification Class Description I Any eye muscle weakness, possible ptosis, no other evidence of muscle weakness elsewhere II Eye muscle weakness of any severity, mild weakness of other muscles IIa Predominantly limb or axial muscles IIb Predominantly bulbar and/or respiratory muscles III Eye muscle weakness of any severity, moderate weakness of other muscles IIIa Predominantly limb or axial muscles IIIb Predominantly bulbar and/or respiratory muscles IV Eye muscle weakness of any severity, severe weakness of other muscles IVa Predominantly limb or axial muscles IVb Predominantly bulbar and/or respiratory muscles V Intubation needed to maintain airway When diagnosed with<unk> , a person is assessed for his or her neurological status and the level of illness is established. This is usually done using the accepted<unk>  Foundation of America Clinical Classification scale. Physical examination During a physical examination to check for<unk> , a doctor might ask the person to perform repetitive movements. For instance, the doctor may ask one to look at a fixed point for 30 seconds and to relax the muscles of the forehead, because a person with<unk>  and ptosis of the eyes might be involuntarily using the forehead muscles to compensate for the weakness in the eyelids. The clinical examiner might also try to elicit the "curtain sign" in a person by holding one of the person's eyes open, which in the case of<unk>  will lead the other eye to close. Blood tests If the diagnosis is suspected, serology can be performed: * One test is for antibodies against the acetylcholine receptor; the test has a reasonable sensitivity of 80–96%, but in ocular<unk> , the sensitivity falls to 50%. * A proportion of the people without antibodies against the acetylcholine receptor have antibodies against the MuSK protein. * In specific situations, testing is performed for Lambert-Eaton syndrome. Electrodiagnostics A chest CT-scan showing a thymoma (red circle) Photograph of a person showing right partial ptosis (left picture), the left lid shows compensatory pseudo lid retraction because of equal innervation of the m. levator palpabrae superioris (Hering's law of equal innervation): Right picture: after an edrophonium test, note the improvement in ptosis. Muscle fibers of people with<unk>  are easily fatigued, which the repetitive nerve stimulation test can help diagnose. In single-fiber electromyography, which is considered to be the most sensitive (although not the most specific) test for<unk> , a thin needle electrode is inserted into different areas of a particular muscle to record the action potentials from several samplings of different individual muscle fibers. Two muscle fibers belonging to the same motor unit are identified, and the temporal variability in their firing patterns is measured. Frequency and proportion of particular abnormal action potential patterns, called "jitter" and "blocking", are diagnostic. Jitter refers to the abnormal variation in the time interval between action potentials of adjacent muscle fibers in the same motor unit. Blocking refers to the failure of nerve impulses to elicit action potentials in adjacent muscle fibers of the same motor unit. Ice test Applying ice for 2–5 minutes to the muscles reportedly has a sensitivity and specificity of 76.9% and 98.3%, respectively, for the identification of<unk> . Acetylcholinesterase is thought to be inhibited at the lower temperature, which is the basis for this diagnostic test. This generally is performed on the eyelids when ptosis is present and is deemed positive if a ≥2-mm rise in the eyelid occurs after the ice is removed. Edrophonium test This test requires the intravenous administration of edrophonium chloride or neostigmine, drugs that block the breakdown of acetylcholine by cholinesterase (acetylcholinesterase inhibitors). This test is no longer typically performed, as its use can lead to life-threatening bradycardia (slow heart rate) which requires immediate emergency attention. Production of edrophonium was discontinued in 2008. Imaging A chest X-ray may identify widening of the mediastinum suggestive of thymoma, but computed tomography or magnetic resonance imaging (MRI) are more sensitive ways to identify thymomas and are generally done for this reason. MRI of the cranium and orbits may also be performed to exclude compressive and inflammatory lesions of the cranial nerves and ocular muscles. Pulmonary function test The forced vital capacity may be monitored at intervals to detect increasing muscular weakness. Acutely, negative inspiratory force may be used to determine adequacy of ventilation; it is performed on those individuals with<unk> .
Myasthenia gravis
Guillain–Barré syndrome
Congenital myasthenic syndrome
Botulism
Neurasthenia
Organophosphate poisoning
Polymyositis
Brainstem stroke syndrome