Myasthenia gravis (MG) is an autoimmune disorder characterized by impaired neuromuscular transmission, resulting in fluctuating muscle weakness and fatigability. We present a case of a middle-aged man diagnosed with thymoma-associated MG, highlighting the diagnostic challenges faced.A 52-year-old man presented with progressive upper limb weakness, hand rigidity, and intermittent slurred speech. Despite the complaints, neurological and speech examinations were normal, as well as a cranial CT and upper-limb electromyography (EMG). Over several months, his symptoms persisted, with fatigability during sustained or overhead activities, prompting referral to Neurology. Meanwhile, he developed urgency urinary incontinence and was started on trospium chloride. Days later, he experienced worsening of symptoms, requiring hospitalization with evaluation that confirmed thymoma-associated MG.This case describes an infrequent MG presentation, with limb-predominant episodic symptoms and initial normal investigations, leading to diagnostic uncertainty. It also reflects the impact of medication in exacerbating MG.MG may present with subtle symptoms and normal investigations, but fatigability should prompt consideration of neuromuscular disorders. Beware of medications that can exacerbate MG is crucial to prevent iatrogenic symptoms.MG is an uncommon disorder, typically affecting ocular or bulbar muscles. Limb involvement may also occur, affecting the upper limbs more than the lower limbs. In the early stages, symptoms may be episodic, but they worsen over time. Several medications can exacerbate MG symptoms and should be avoided. In this case, symptoms progressed over months, and despite the initial tests performed being normal, a neuromuscular disorder was suspected, and a Neurology referral was made. The introduction of trospium chloride, an antimuscarinic drug, contributed to a clinical worsening, leading to hospitalization and enabling the diagnosisFamily Doctors play a key role in the early recognition of many disorders. In this case, although a neurological condition was suspected, delays in specialist evaluation prolonged the diagnostic process. Additionally, it highlights the importance of recognizing medications that can exacerbate myasthenic symptoms, ensuring safer and more effective management of patients with suspected or confirmed myasthenia gravis.