Current Medical Issues

CME QUIZ
Year
: 2020  |  Volume : 18  |  Issue : 2  |  Page : 147--148

Ocular myasthenia gravis and thymoma


Jamir Pitton Rissardo, Ana Letícia Fornari Caprara 
 Medicine Department, Federal University of Santa Maria, Santa Maria, Rio Grande Do Sul, Brazil

Correspondence Address:
Dr. Jamir Pitton Rissardo
Rua Elpídio De Menezes, 195, Santa Maria, Rio Grande Do Sul
Brazil




How to cite this article:
Rissardo JP, Caprara AL. Ocular myasthenia gravis and thymoma.Curr Med Issues 2020;18:147-148


How to cite this URL:
Rissardo JP, Caprara AL. Ocular myasthenia gravis and thymoma. Curr Med Issues [serial online] 2020 [cited 2022 Oct 3 ];18:147-148
Available from: https://www.cmijournal.org/text.asp?2020/18/2/147/282784


Full Text



 Case Scenario



A 43-year-old female presenting with double vision was admitted to our hospital. She reported that this symptom started within 1 month and have periods of exacerbation with worsening throughout the day. Her family history was unremarkable and negative for neurological disorders. She had well-controlled essential hypertension with a changing lifestyle. On neurological examination, the inspection showed ptosis without other cranial nerve abnormalities. The sustained upgaze test reveals the weakness of the levator palpebrae with intensification of ptosis. Laboratory tests were within normal limits. Brain magnetic resonance imaging was normal. Computed tomography (CT) of the abdomen and chest was performed [Figure 1].{Figure 1}

 Questions



What are the findings in the CT scans of the chest and abdomen?What is the most likely diagnosis taking into account this clinical scenario?

 View Answer

 Answers



CT scans showing a well-delimitated lesion with soft-tissue density of 3.4 cm × 2.9 cm × 1.6 cm localized in the anterior mediastinum suggestive of thymus gland origin (arrowing) [Figure 2]Ocular myasthenia gravis (MG) associated with thymoma.{Figure 2}

MG is an autoimmune disorder classified as a hypersensitivity Type II reaction related to antibody-dependent cellular cytotoxicity, in which the antibodies block or destroy the nicotinic acetylcholine receptors at the neuromuscular junction. In the last decades, the epidemiology of the disease has been changing with an increase in the number of cases that probably happened due to improved study quality and diagnostic ascertainments. Even though these factors, the incidence of MG varies from 1.7 to 21.3 cases per million person-years.[1]

The general presentation of MG is the beginning with ocular symptoms that ptosis and diplopia occur with the involvement of the muscle in more than 75% of the cases. Other characteristics commonly seen with MG are worsening with an effort, exacerbation periods, and severe cases, the involvement of the respiratory system. Thymoma is one of the most common diseases associated with MG. In our case after the CT scan, the biopsied histology of the lesion showed epithelial cells of the thymus. It is worthy of mentioning that when MG is associated with thymoma, the patient will have a significant increase in have hyperthyroidism or Hashimoto's disease.[2] Thymic abnormalities are common in patients with MG: more than half has a thymic disease including thymic hyperplasia, and about 10% has thymoma.[3]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Carr AS, Cardwell CR, McCarron PO, McConville J. A systematic review of population based epidemiological studies in myasthenia gravis. BMC Neurol 2010;10:46.
2Berrih-Aknin S, Frenkian-Cuvelier M, Eymard B. Diagnostic and clinical classification of autoimmune myasthenia gravis. J Autoimmun 2014;48-49:143-8.
3Liu CJ, Chang YS, Teng CJ, Chen TJ, Ou SM, Tzeng CH, et al. Risk of extrathymic cancer in patients with myasthenia gravis in Taiwan: A nationwide population-based study. Eur J Neurol 2012;19:746-51.