Empyema necessitans is a rare complication of a pleural effusion that occurs when infected fluid dissects into the chest wall from the pleural space. Mycobacterium tuberculosis and Actinomyces israelii have previously been the most commonly reported etiologic agents. This case presents an empyema necessitans secondary to methicillin-resistant Staphylococcus aureus (MRSA) following an influenza A infection in a child.

Pseudohypoaldosteronism type 1 (PHA1) may manifest in the neonatal period as a life-threatening saltwasting syndrome providing challenges in recognition and treatment. This case describes a newborn who developed severe dehydration and electrolyte imbalances and subsequently was found to have a novel SCNN1B gene variant resulting in autosomal recessive systemic PHA1.

The widely used anticoagulant Coumadin (R/S-warfarin) undergoes oxidation by cytochromes P450 into hydroxywarfarins that subsequently become conjugated for excretion in urine. Hydroxywarfarins may modulate warfarin metabolism transcriptionally or through direct inhibition of cytochromes P450 and thus, UGT action toward hydroxywarfarin elimination may impact levels of the parent drugs and patient responses. Nevertheless, relatively little is known about conjugation by UDP-glucuronosyltransferases in warfarin metabolism. Herein, we identified probable conjugation sites, kinetic mechanisms and hepatic UGT isoforms involved in microsomal glucuronidation of R- and S-7-hydroxywarfarin. Both compounds underwent glucuronidation at C4 and C7 hydroxyl groups based on elution properties and spectral characteristics. Their formation demonstrated regio- and enantioselectivity by UGTs and resulted in either Michaelis-Menten or substrate inhibition kinetics. Glucuronidation at the C7 hydroxyl group occurred more readily than at the C4 group, and the reaction was overall more efficient for R-7-hydroxywarfarin due to higher affinity and rates of turnover. The use of these mechanisms and parameters to model in vivo clearance demonstrated that contributions of substrate inhibition would lead to underestimation of metabolic clearance than that predicted by Michaelis-Menten kinetics. Lastly, these processes were driven by multiple UGTs indicating redundancy in glucuronidation pathways and ultimately metabolic clearance of R- and S-7-hydroxywarfarin.

Necrotizing enterocolitis is a disease process of intestinal disruption which has been associated with gastrointestinal microbial alterations after antibiotic exposure. Treatment guidelines and antibiotic exposure for congenital syphilis have historically been based on limited evidence. This case presents a term infant who developed necrotizing enterocolitis after treatment for congenital syphilis.

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