**2. Clinical features**

The cardinal features of the initial course of MG are the transient or persistent weakness and abnormal fatigability of skeletal muscles that are typically least severe in the morning and after rest and worst as the day progresses and after repetitive activities [1, 3, 5] (**Table 1**).

The weakness, which is mostly asymmetrical, specifically affects the extraocular, bulbar, and proximal limb or truncal musculature and, in more rare cases, the respiratory muscles [3–5].

In about two-thirds of the patients with MG, the presenting symptoms are unilateral or asymmetrical ptosis and/or diplopia due to the involvement of extrinsic ocular muscles [2–4].

Over 15% of patients show (as an initial MG symptom) bulbar weakness, leading to slurred or nasal speech, voice alterations, or difficulty in chewing or swallowing; neck and extremity weaknesses are flagged as complaints in about 5% of patients [2, 5, 7, 10].

Importantly, careful questioning frequently reveals evidence of earlier subtle myasthenic manifestations, such as repeated purchases of eyeglasses to correct blurred vision or avoidance of foods that became difficult to chew or swallow. Also, family members may observe a changed, sleepy or sad, facial appearance caused by ptosis or facial weakness [1].

It has to be mentioned that, in MG, cognition, coordination, and tendon reflexes are normal. Also, local muscle atrophy is rarely seen in myasthenic patients, being reported especially in MuSK-antibody MG patients [1, 2, 5, 6].

#### **2.1 Ocular symptoms**

Ocular symptoms are the most frequent manifestations of MG, ultimately being present in 90% of patients [6]. The major ocular symptoms associated with MG are

**93**

*Clinical Presentation of Myasthenia Gravis DOI: http://dx.doi.org/10.5772/intechopen.86566*

• Ptosis

• Face • Chewing • Swallowing • Neck

• -Legs

Ocular muscles • Diplopia

Limbs muscles • -Arms

Bulbar muscles • Articulation

**Level Symptoms Early onset** 

• -Hands and fingers

ing, and especially in bright sunlight [1].

*Clinical manifestations of myasthenia gravis.*

glasses [1, 3].

**Table 1.**

normal [1].

it is bilateral [1, 3].

contralateral eye [5].

**2.2 Bulbar symptoms**

while eating [1, 3, 6].

fluctuating ptosis (often with compensatory wrinkling of the forehead), diplopia, and, in milder cases, blurry vision [3, 5]. These manifestations may be intermittent in the early stages, typically becoming worse in the evening, while reading or driv-

Generalized +/− +/− +/− + Respiration +/− +/− +/− +/−

**<40 years**

++ ++

++ + +/− +/− +/−

+ + ++ **Late onset >40 years**

++ +

+/− +/− +/− +/− +/−

+/− +/− +/− **Thymoma**

+/− +/−

+/− +/− +/− +/− +/−

+/− +/− +/−

In MG a certain degree of photophobia is seen, commonly worsening the ptosis and/or diplopia; as a consequence, some patients often choose to wear dark sun-

Weakness involving one or more ocular muscles is, by definition, asymmetric, fluctuating, and fatigable [1]. The most frequently affected extraocular muscle is the medial rectus [3]. Furthermore, in MG, the pattern of weakness cannot be correlated with lesions of one or more nerves, and the pupillary responses are

Asymmetric ptosis of the alternating sides over time is considered pathognomonic of MG. In some cases, ptosis can be severe enough to totally occlude vision if

Weakness of the orbicularis oculi muscles, frequently seen in MG patients, leads to incomplete closure of the eyelids, which produces discomfort by allowing soap or water in the eyes during bathing [1, 5]. It should also be mentioned that the weakness of lateral and medial recti can determine a pseudo-internuclear ophthalmoplegia with limited adduction of one eye and nystagmus of the abducting

In about 15% of patients [11] with MG, bulbar symptoms, generally manifested as oropharyngeal muscle weakness, are evident from the beginning [12]; during the course of the disease, bulbar muscle involvement can be found in 60% of patients [3]. The characteristic bulbar symptoms seen in MG include fatigable chewing (particularly solid food) and swallowing (particularly liquids), dysarthria, and inadequate maintenance of the upper airway. Typically, the time needed for eating a meal increases, and conversation becomes difficult, especially


#### *Clinical Presentation of Myasthenia Gravis DOI: http://dx.doi.org/10.5772/intechopen.86566*

#### **Table 1.**

*Thymus*

several years [3, 6].

disease [3].

**2. Clinical features**

activities [1, 3, 5] (**Table 1**).

respiratory muscles [3–5].

ocular muscles [2–4].

of patients [2, 5, 7, 10].

**2.1 Ocular symptoms**

ptosis or facial weakness [1].

The maximum severity of MG manifestations is usually reported during the first year in two-thirds of patients [1]. Additionally, it has become evident that, in general, the illness tends to stabilize, improve (57%), or even resolve (13%) after

It is important to emphasize that in MG, symptoms may worsen in certain conditions including stress, systemic illness (especially upper respiratory infections), hypo−/hyperthyroidism, pregnancy, menstrual cycle, exposure to heat, operative procedures, drugs affecting NMT, and fever [1, 5, 8]. However, in the majority of cases, no precipitating factor can be found [3, 5]. A severe exacerbation requiring endotracheal intubation with mechanical ventilation is defined as myasthenic crisis

The treatment used in MG includes symptomatic treatment (acetylcholinesterase inhibitors), rapid short-term immunomodulating therapies (plasmapheresis and intravenous immunoglobulin), chronic long-term immunomodulating treatment (glucocorticoids and/or other immunosuppressive agents), and, in selected patients, surgical treatment (thymectomy). In all cases, MG management should be individualized according to patient characteristics and the severity of the

Currently, the mortality of MG is extremely low, considering that only among the 19% of the patients with severe generalized MG also need endotracheal intuba-

The cardinal features of the initial course of MG are the transient or persistent weakness and abnormal fatigability of skeletal muscles that are typically least severe in the morning and after rest and worst as the day progresses and after repetitive

The weakness, which is mostly asymmetrical, specifically affects the extraocular, bulbar, and proximal limb or truncal musculature and, in more rare cases, the

In about two-thirds of the patients with MG, the presenting symptoms are unilateral or asymmetrical ptosis and/or diplopia due to the involvement of extrinsic

Over 15% of patients show (as an initial MG symptom) bulbar weakness, leading to slurred or nasal speech, voice alterations, or difficulty in chewing or swallowing; neck and extremity weaknesses are flagged as complaints in about 5%

Importantly, careful questioning frequently reveals evidence of earlier subtle myasthenic manifestations, such as repeated purchases of eyeglasses to correct blurred vision or avoidance of foods that became difficult to chew or swallow. Also, family members may observe a changed, sleepy or sad, facial appearance caused by

It has to be mentioned that, in MG, cognition, coordination, and tendon reflexes are normal. Also, local muscle atrophy is rarely seen in myasthenic patients, being

Ocular symptoms are the most frequent manifestations of MG, ultimately being present in 90% of patients [6]. The major ocular symptoms associated with MG are

reported especially in MuSK-antibody MG patients [1, 2, 5, 6].

(Class V myasthenia by MG Foundation of America) [5].

tion; the mortality can reach 8% despite ventilation [5, 6, 9].

**92**

*Clinical manifestations of myasthenia gravis.*

fluctuating ptosis (often with compensatory wrinkling of the forehead), diplopia, and, in milder cases, blurry vision [3, 5]. These manifestations may be intermittent in the early stages, typically becoming worse in the evening, while reading or driving, and especially in bright sunlight [1].

In MG a certain degree of photophobia is seen, commonly worsening the ptosis and/or diplopia; as a consequence, some patients often choose to wear dark sunglasses [1, 3].

Weakness involving one or more ocular muscles is, by definition, asymmetric, fluctuating, and fatigable [1]. The most frequently affected extraocular muscle is the medial rectus [3]. Furthermore, in MG, the pattern of weakness cannot be correlated with lesions of one or more nerves, and the pupillary responses are normal [1].

Asymmetric ptosis of the alternating sides over time is considered pathognomonic of MG. In some cases, ptosis can be severe enough to totally occlude vision if it is bilateral [1, 3].

Weakness of the orbicularis oculi muscles, frequently seen in MG patients, leads to incomplete closure of the eyelids, which produces discomfort by allowing soap or water in the eyes during bathing [1, 5]. It should also be mentioned that the weakness of lateral and medial recti can determine a pseudo-internuclear ophthalmoplegia with limited adduction of one eye and nystagmus of the abducting contralateral eye [5].
