A Rare Association between Myasthenia Gravis and a Growth Hormone Secreting Pituitary Macroadenoma: A Single Case Report

Contemporaneous Presentation of Ocular Myasthenia Gravis With Pituitary Apoplexy: A Diagnostic Dilemma

Pituitary apoplexy is a life-threatening condition caused by a rapid expansion of the pituitary tumor due to hemorrhage or infarction. It usually presents with acute onset severe headache and can also be associated with visual field defects and ophthalmoplegia. Similarly, ocular myasthenia gravis, which is an autoimmune condition causing muscle fatiguability, also presents with ophthalmoplegia, commonly ptosis and diplopia. A 53-year-old male patient with a past history of adrenal insufficiency presented with acute onset headache. On examination, he had bilateral asymmetrical partial ptosis and left-side medial rectus palsy with mild fatiguability. He had normal visual fields and sparing of the pupils. Acetylcholine receptor antibodies were positive but failed to demonstrate a decremental response in nerve conduction studies. The patient was started on neostigmine on clinical suspicion of ocular myasthenia gravis. A magnetic resonance imaging (MRI) scan of the brain was arranged to look for any intracranial pathology for persistent headache and it revealed evidence of pituitary apoplexy with compression of optic chiasm and partial obliteration of bilateral cavernous sinuses. In view of MRI findings, a diagnosis of pituitary apoplexy with third cranial nerve involvement was considered the first differential diagnosis, and the patient was started on replacement hormones while temporarily withholding neostigmine. Following multidisciplinary input, it was decided to manage the patient conservatively. A repeat MRI brain was planned to assess the evolution which revealed resolution of pituitary apoplexy. Despite this, the patient continued to have ophthalmoplegia and fatigable partial ptosis. Pyridostigmine was restarted following which the patient fully recovered, confirming the diagnosis of ocular myasthenia gravis presenting concomitantly with pituitary apoplexy.

Machine learning-based algorithms applied to drug prescriptions and other healthcare services in the Sicilian claims database to identify acromegaly as a model for the earlier diagnosis of rare diseases

Acromegaly is a rare disease characterized by a diagnostic delay ranging from 5 to 10 years from the symptoms' onset. The aim of this study was to develop and internally validate machine-learning algorithms to identify a combination of variables for the early diagnosis of acromegaly. This retrospective population-based study was conducted between 2011 and 2018 using data from the claims databases of Sicily Region, in Southern Italy. To identify combinations of potential predictors of acromegaly diagnosis, conditional and unconditional penalized multivariable logistic regression models and three machine learning algorithms (i.e., the Recursive Partitioning and Regression Tree, the Random Forest and the Support Vector Machine) were used, and their performance was evaluated. The random forest (RF) algorithm achieved the highest Area under the ROC Curve value of 0.83 (95% CI 0.79-0.87). The sensitivity in the test set, computed at the optimal threshold of predicted probabilities, ranged from 28% for the unconditional logistic regression model to 69% for the RF. Overall, the only diagnosis predictor selected by all five models and algorithms was the number of immunosuppressants-related pharmacy claims. The other predictors selected by at least two models were eventually combined in an unconditional logistic regression to develop a meta-score that achieved an acceptable discrimination accuracy (AUC = 0.71, 95% CI 0.66-0.75). Findings of this study showed that data-driven machine learning algorithms may play a role in supporting the early diagnosis of rare diseases such as acromegaly.

Myasthenia gravis presenting as bilateral pseudointernuclear ophthalmoplegia in a patient with an incidental prolactinoma

Myasthenia gravis (MG) is a rare and potentially dangerous autoimmune condition, which affects the acetylcholine receptors at the neuromuscular junction of skeletal muscle. MG's diverse symptomatology may readily masquerade as other neurological conditions, posing a diagnostic challenge to clinicians. We describe a 24-year old man who presented to the emergency department with a new onset internuclear ophthalmoplegia. After a series of investigations, we eventually arrived at a diagnosis of MG with pseudointernuclear ophthalmoplegia with an incidentally detected prolactinoma. We explore the literature regarding the pathophysiology of pseudointernuclear ophthalmoplegia, the link between prolactin and autoimmunity and the association between prolactinoma and MG.