We describe a patient with myasthenia gravis and thymoma who developed recurrent severe myasthenic crises associated with the use of combination chemotherapy.
Thymoma is associated with a wide spectrum of autoimmune paraneoplastic syndromes, though it is uncommon for multiple paraneoplastic syndromes to be present in a single individual. We report a rare case of an elderly gentleman who was found to have thymoma-associated myasthenia gravis and LGI1-encephalitis with myokymia, who presented with nephrotic syndrome (minimal change glomerulopathy) after thymectomy. The latter two paraneoplastic syndromes had manifested when prednisolone was tapered down to low dose. This case serves to remind neurologists that apart from paraneoplastic neurological manifestations, thymoma may also be associated with renal disease. Nephropathy in myasthenia patients with thymoma should be properly evaluated, as it is treatable with immunotherapy, and it may even occur post-thymectomy.
Myasthenia gravis (MG) is a rare autoimmune disorder
characterised by fluctuating and variable combination
of muscle weakness and fatigue. Most cases are due to
T-cell mediated autoantibodies against post-synaptic
acetylcholine receptors (AChR-Ab), thus preventing
acetylcholine from binding and signalling skeletal
muscle to contract.1
The annual incidence is 7-23 new cases per million.1
It can occur at any age but with two peaks; an earlyonset
(20-40 years) female-predominant and a late-onset
(60-80 years) male-predominant peak. MG is classified
into ocular and generalised (80%). More than half the
patients initially present with ptosis and diplopia but half
will progress to generalised disease with involvement of
bulbar, limb and respiratory weakness. Those presenting
as generalised MG can also develop eye signs later.1
It is important to recognise MG early because it is
highly treatable. Untreated disease leads to permanent
weakness.2 Treatment reduces mortality from lifethreatening
myasthenic crisis.1,3 Misdiagnosis leads to
potentially harmful interventions and inappropriate
management.4,5 Diagnosis in late-onset MG is easily
missed2,3,4,5 because of overlapping symptoms with
other diseases common in the elderly. We report a case
of delay and misdiagnosis in an elderly patient with
co-morbidities. (Copied from article).
Respiratory distress after thyroidectomy and thymectomy can be challenging. We encountered a 70-year-old lady with a long-standing goiter with concomitant thymoma. She underwent the surgery and developed respiratory distress upon extubation with loss of laryngeal sensation causing severe aspiration. She was diagnosed myasthenia gravis and symptoms resolved with MG treatments.
Congenital myasthenic syndrome (CMS) is a heterogeneous group of inherited disorder which does not associate with anti-acetylcholine receptor (AChR) antibody. The presence of AChR autoantibody is pathogenic and highly sensitive and specific for autoimmune myasthenia gravis (MG). We describe 2 children from unrelated families who presented with hypotonia, ptosis and fatigability in early infancy with anti-AChR antibodies detected via ELISA on 2 separate occasions in the sera. Both were treated as refractory autoimmune MG due to poor clinical response to acetylcholinesterase inhibitor and immunotherapy. In view of the atypical clinical features, genetic studies of CMS were performed and both were confirmed to have novel pathogenic mutations in the COLQ gene. To the best of our knowledge, the presence of anti-AChR antibody in COLQ-related CMS has never been reported in the literature. The clinical presentation of early onset phenotype, and refractoriness to acetylcholinesterase inhibitor and immunotherapy should prompt CMS as a differential diagnosis.
Myasthenia gravis (MG) is an autoantibody-mediated disorder affecting the neuromuscular junction causing characteristic fatigable muscle weakness. Though it can be associated with tumours of the thymus as well as thyroid disorders, it is rare for both to coexist. The exact prevalence of thyroid carcinoma in MG with thymoma is not known but only about a dozen cases have been reported in the literature. We report a case of a 38-year-old Myanmar lady who presented with weakness and breathlessness due to MG with neck swelling. On examination, she had fatigable proximal muscle weakness and thyroid enlargement with no obvious features of hyperthyroidism. Mediastinal widening and an enlarged thyroid gland were noted on her chest X-ray and chest CT. A subtotal thyroidectomy and thymectomy were done. The histology showed follicular carcinoma of the thyroid and benign thymoma. The majority of the reported cases of thyroid carcinoma in association with MG were papillary carcinoma. Follicular carcinoma thyroid associated with MG has not yet been reported in the literature.
We report a patient who presented with severe cold-induced allodynia and hyperhidrosis, and found to have acquired neuromyotonia (Isaacs syndrome) with high voltage-gated potassium channel (VGKC) antibody titre,positive contactin-associated protein 2 (CASPR2) and leucine-rich glioma-inactivated 1 (LGI1) antibodies. The patient also had positive anti-dsDNA and acetylcholine receptor (AChR) antibodies without clinical features of SLE or myasthenia gravis, suggesting a strong underlying autoimmune tendency. CT thorax showed no thymoma. Her symptoms improved with intravenous immunoglobulin infusion but recurred despite maintenance oral corticosteroids and carbamazepine. She has since been on regular IVIG infusions. Cold allodynia is an unusual presentation in acquired neuromyotonia.
Introduction: The association of myasthenia gravis (MG) with other autoimmune diseases including autoimmune thyroid disease (ATD) is well recognised, although rare. The occurrence of both diseases can occur in two ways: either disease preceding the other, or concurrently. The presentation of MG in association with ATD can range from ocular to generalised disease.
Case Summary: A 26-year-old Malay female with persistent hyperthyroidism secondary to Hashimoto's thyroiditis in multinodular goitre was diagnosed with generalised MG after 2 years. She presented with right eye ptosis (ocular) and difficulty in swallowing and chewing (bulbar). The diagnosis of MG was confirmed by fatigability testing, electromyography and the presence of AChR antibodies. Her symptoms showed improvement with pyridostigmine (Mestinon) 60 mg 6-hourly. Her antithyroid drug was tapered down according to her thyroid function test. Throughout a year of follow-ups, her hyperthyroidism and fatigability symptoms improved with treatment. She was later counselled for total thyroidectomy and thymectomy.
Conclusion: Myasthenia gravis and hyperthyroidism may present with similar symptoms such as dysphagia due to neuromuscular weakness or fatigue. When the diseases occur together, one of the diagnoses may be missed. Therefore, the occurrence of new symptoms in a patient with underlying ATD should should trigger the early identification of other autoimmune diseases by primary care doctors.