Acute suppurative thyroiditis seeded from infective endocarditis and intravenous drug use.

Acute suppurative thyroiditis (AST) is a rare infection of the thyroid gland, and most patients are euthyroid upon presentation. We present an interesting case of a 42-year-old man with a history of intravenous drug use (IVDU) and poorly controlled type 2 diabetes mellitus who was admitted for sepsis and thyrotoxicosis from infective endocarditis (IE), AST, prostate abscess, and pyelonephritis. He suffered from a cerebral vascular accident (CVA) from septic embolic showering. Thyroid-stimulating hormone (TSH) was <0.10 mIU/L, and free thyroxine (T4) levels were>90 pmol/L. Methicillin-resistant Staphylococcus aureus (MRSA) was cultured in the patient's blood and urine. He was treated with prompt intravenous (IV) antimicrobials and source control from a transurethral resection of the prostate. This case demonstrates that AST can be a potential complication of IE and IVDU.

First-Degree Atrioventricular Block with Tachycardia from Paliperidone and Mirtazapine Overdose.

BACKGROUND: Paliperidone and mirtazapine are psychotropic agents associated with proarrhythmic effects. CASE PRESENTATION: A 21-year-old woman was admitted to the intensive care unit on two separate occasions for attempting suicide by overdosing on paliperidone and mirtazapine. During both admissions, the patient had atypical chest pain and a first-degree atrioventricular block (AVB) with paradoxical sinus tachycardia, which resolved with the discontinuation of paliperidone and mirtazapine and aggressive intravenous fluids. CONCLUSION: Drug-induced first-degree AVB from paliperidone and mirtazapine should be on the differential diagnosis in patients on paliperidone and/or mirtazapine who present with chest pain, tachycardia or new-onset first-degree AVB. LEARNING POINTS: Paliperidone and mirtazapine are associated with first-degree heart block, which may be a harbinger of torsades de pointes and ventricular fibrillation.Paliperidone and mirtazapine may potentiate each other's proarrhythmic effects since the metabolism of both involve the cytochrome P450 2D6 enzyme.A history of psychiatric illness makes it difficult to rule out atypical chest pain without ECG or troponins and often leads to increased resource utilization, even during times of heavy use like the COVID-19 pandemic.

Plasmacytoid variant of urothelial carcinoma of the bladder manifesting as bilateral ureteral and small bowel obstruction.

Plasmacytoid urothelial carcinoma (PUC) is a rare variant of bladder cancer characterized by distinct histopathology and advanced stage at diagnosis. Multimodal treatment is usually indicated. We present a case of PUC causing bilateral ureteral obstruction with subsequent renal failure followed shortly by malignant small bowel obstruction, demonstrating the need for a high degree of clinical suspicion in diagnosis of this aggressive subtype. Moreover, the local invasiveness of the disease cannot be understated, given that it can rapidly spread with little radiologic evidence of progression until it is at an advanced stage.

Dynamics and stability of a three-dimensional model of cell signal transduction.

In this paper, we consider a three-dimensional model of cell signal transduction. In this model, the deactivation of signalling proteins occur throughout the cytosol and activation is localized to specific sites in the cell. We use matched asymptotic expansions to construct the dynamic solutions of signalling protein concentrations. The result of the asymptotic analysis is a system of ordinary differential equations. This reduced system is compared to numerical simulations of the full three-dimensional system. As well, we consider the stability of equilibrium solutions. We find that the systems under consideration may undergo sustained oscillations, hysteresis and other complex behaviors. The simulations of the full three-dimensional system agree with simulations of the reduced ordinary differential equations.

Model of cell signal transduction in a three-dimensional domain.

Intracellular signalling molecules form pathways inside the cell. These pathways carry a signal to target proteins which results in cellular responses. We consider a spherical cell with two internal compartments containing localized activating enzymes where as deactivating enzymes are spread uniformly through out the cytosol. Two diffusible signalling molecules are activated at the compartments and later deactivated in the cytosol due to deactivating enzymes. The two signalling molecules are a single link in a cascade reaction and form a self regulated dynamical system involving positive and negative feedback. Using matched asymptotic expansions we obtain approximate solutions of the steady state diffusion equation with a linear decay rate. We obtain three-dimensional concentration profiles for the signalling molecules. We also investigate an extension of the above system which has multiple cascade reactions occurring between multiple signalling molecules. Numerically, we show that the speed of the signal is an increasing function of the number of links in the cascade.