Inpatient Rheumatology Consultation Prompted by Positive Autoantibodies in Patients Receiving Intravenous Immunoglobulin Therapy: A Case Series and Literature Review.

Intravenous immunoglobulin (IVIG) is a therapeutic preparation used in the treatment of multiple diseases. Autoimmune testing with antinuclear antibody (ANA) screening is often obtained for some of these conditions, but only after initiation of IVIG treatment. This can present a diagnostic dilemma in hospitalized patients and may trigger a rheumatology consultation. We describe our consultative inpatient two-year experience with five such patients and review the pertinent literature. A retrospective chart review of rheumatology inpatient consultations between 6-2018 and 6-2020 at our academic tertiary care hospital for post-IVIG positive serologies was performed. A pertinent literature review was performed. Five patients had a positive ANA and other autoantibodies detected in their serum after they received IVIG for non-rheumatological conditions. None of these patients met the criteria for a connective tissue disease. The literature review identified a total of 58 patients from case reports and case series, several of whom tested positive for ANA and other antibodies after receiving IVIG. Studies assessing specific IVIG products detected multiple autoantibodies in the donor pool. Autoimmune testing is initiated on inpatients receiving IVIG for non-rheumatological conditions. If an autoantibody ANA screen is positive, a rheumatology consultation may be requested. In the absence of pre-IVIG antibody tests it is difficult to interpret post-IVIG-positive antibodies. Whether such positive antibodies are of clinicopathological significance is determined by clinical judgment and time.

Secondary encephalocele in an adult leading to subdural empyema.

Brain abscesses are an uncommon but potentially fatal infection. They can spread directly from an adjacent source or hematogenously from a distant source. Encephaloceles represent a rare form of neural tube defects that can potentially be complicated by the development of meningitis or brain abscess. We report a case of a 63-year-old female who presented with bilateral lower extremity weakness and was ultimately found to have a Streptococcus pneumoniae subdural empyema and an associated frontal lobe encephalocele extending through the left frontal sinus. She was treated with surgical drainage, intravenous antimicrobials, and ultimately surgical repair of the encephalocele. This report highlights a unique presentation of brain abscess. Clinicians should be aware of this potential infectious complication of a neural tube defect.

Purulent Pericarditis Caused by Bacteroides fragilis: A Rare Complication of Cholangitis.

Bacterial infection is a rare cause of pericarditis especially in the post-antibiotic era. When compared to viral or idiopathic etiologies, purulent pericarditis carries a higher risk for complications. While most cases are due to Staphylococcus aureus, we present a rare case of pericarditis due to Bacteroides fragilis originating from a liver abscess and leading to pericardial effusion. Our case highlights the need to maintain a high clinical suspicion of bacterial infection when patients present with sepsis and have evidence of pericarditis.

Left Ventricular Noncompaction: A Rare Case of Nonischemic Cardiomyopathy.

Isolated left ventricular noncompaction (LVNC) is a rare form of cardiomyopathy that is characterized by deep intertrabecular recesses and abnormal trabeculations that can be observed on transthoracic echocardiogram (TTE) or cardiac MRI (CMR) studies. Our case describes a 41-year-old male who presented with exertional chest pain and was discovered to have significantly reduced left ventricular ejection fraction (LVEF) which was nonischemic in etiology as confirmed by cardiac catheterization. Subsequent evaluation with CMR imaging revealed noncompaction of the left ventricle. The patient received defibrillation and lifelong anticoagulation given his elevated risk of sudden cardiac death (SCD). This case highlights the importance of considering unconventional etiologies of cardiomyopathy when investigating new-onset heart failure as well as the necessity of life-saving measures such as anticoagulation and defibrillator implantation in view of arrhythmogenic structural heart diseases.

Spontaneous Hemorrhagic Pericardial and Pleural Effusion in a Patient Receiving Apixaban.

Direct oral anticoagulants (DOACs) are used for many conditions where anticoagulation is needed such as non-valvular atrial fibrillation, deep vein thrombosis (DVT) and pulmonary embolism (PE). These novel agents have become popular since they do not require monitoring of therapeutic levels and there is a lower risk of certain bleeding complications when compared to warfarin. However, the efficacy and side effect profile of these agents have not been widely studied in certain patient cohorts, namely cancer patients and patients on immunomodulators or hormone analogs. We present a case of a patient with a history of malignancy and autoimmune disease who developed pericardial and pleural effusions shortly after initiating apixaban for treatment of a PE. In addition, we aim to increase awareness of the role that the newly available reversal agents for anticoagulants would offer in the acute management of hemorrhagic pericardial and pleural effusions caused by DOACs in patients with and without malignancy.

Kidney Proximal Tubule Lipoapoptosis Is Regulated by Fatty Acid Transporter-2 (FATP2).

Albuminuria and tubular atrophy are among the highest risks for CKD progression to ESRD. A parsimonious mechanism involves leakage of albumin-bound nonesterified fatty acids (NEFAs) across the damaged glomerular filtration barrier and subsequent reabsorption by the downstream proximal tubule, causing lipoapoptosis. We sought to identify the apical proximal tubule transporter that mediates NEFA uptake and cytotoxicity. We observed transporter-mediated uptake of fluorescently labeled NEFA in cultured proximal tubule cells and microperfused rat proximal tubules, with greater uptake from the apical surface than from the basolateral surface. Protein and mRNA expression analyses revealed that kidney proximal tubules express transmembrane fatty acid transporter-2 (FATP2), encoded by Slc27a2, but not the other candidate transporters CD36 and free fatty acid receptor 1. Kidney FATP2 localized exclusively to proximal tubule epithelial cells along the apical but not the basolateral membrane. Treatment of mice with lipidated albumin to induce proteinuria caused a decrease in the proportion of tubular epithelial cells and an increase in the proportion of interstitial space in kidneys from wild-type but not Slc27a2-/- mice. Ex vivo microperfusion and in vitro experiments with NEFA-bound albumin at concentrations that mimic apical proximal tubule exposure during glomerular injury revealed significantly reduced NEFA uptake and palmitate-induced apoptosis in microperfused Slc27a2-/- proximal tubules and Slc27a2-/- or FATP2 shRNA-treated proximal tubule cell lines compared with wild-type or scrambled oligonucleotide-treated cells, respectively. We conclude that FATP2 is a major apical proximal tubule NEFA transporter that regulates lipoapoptosis and may be an amenable target for the prevention of CKD progression.