Acute appendicitis in the setting of Clostridium difficile colitis: case report and review of the literature

A 72-year-old man was hospitalized for exacerbation of chronic obstructive pulmonary disease and was treated with oral prednisone and 7 days of moxifloxacin. Five days after completing the antibiotic course, he developed watery diarrhea and diffuse, crampy abdominal pain. On presentation he was afebrile, and abdominal examination revealed diffuse tenderness without peritoneal signs. Stool tested positive for Clostridium difficile toxin A by enzyme-linked immunosorbent assay. Despite starting oral metronidazole, the patient developed a fever of 101.2 degrees F 36 hours after his initial episode of diarrhea, 12 hours after admission. His abdominal pain intensified and became localized to the right and left lower quadrants. Computed tomography scan revealed both a thickened cecal wall and an edematous appendix with ileocecal stranding consistent with appendicitis. Appendectomy was performed, and the appendix was found to be suppurative in appearance and nonperforated. The cecum had mild edema and erythema, whereas the colon and rectum were grossly unaffected. Pathology examination revealed exudative material in the appendiceal lumen and a diffuse transmural inflammatory cell infiltrate. The patient had an uneventful recovery and continued to improve on oral metronidazole. Although Clostridium difficile colitis and appendicitis are each very common independently, C. difficile as an etiology of appendicitis is exceedingly rare. A review of the literature revealed 2 prior cases. We speculate that this association is underdiagnosed, because milder cases might respond to antibiotic therapy alone, and severe cases might involve the entire colon and require total colectomy. In each scenario, the involvement of the appendix might be overlooked.     

Opposite sorting of tissue factor in human umbilical vein endothelial cells and Madin-Darby canine kidney epithelial cells

Tissue factor (TF) is a 48-kD transmembrane glycoprotein that triggers the extrinsic pathway of blood coagulation by interacting with the plasma coagulation factor VII (FVII). TF is also a true receptor in that a cellular signal is generated when activated FVII (FVIIa) binds to TF. For both of these functions, the cellular surface distribution of TF is important, since FVII is primarily available on the apical side of vascular endothelial cells and on the basolateral side of epithelial cells lining the internal and external surfaces. We show that in endothelial cells, TF (both antigen and procoagulant activity) is sorted to the apical surface, whereas in wild-type and stably transfected Madin-Darby canine kidney epithelial cells (MDCK), which form tight junctions and express TF constitutively, TF antigen is on the basolateral surface. No significant clotting activity is detectable on this surface. Truncated TF (cytoplasmic tail residues 246 to 263 deleted) is sorted as wild-type in MDCK cells.     

Increasing the use of second-line therapy is a cost-effective approach to prevent the spread of drug-resistant HIV: a mathematical modelling study

Introduction

Earlier antiretroviral therapy (ART) initiation reduces HIV-1 incidence. This benefit may be offset by increased transmitted drug resistance (TDR), which could limit future HIV treatment options. We analyze the epidemiological impact and cost-effectiveness of strategies to reduce TDR.

Methods

We develop a deterministic mathematical model representing Kampala, Uganda, to predict the prevalence of TDR over a 10-year period. We then compare the impact on TDR and cost-effectiveness of: (1) introduction of pre-therapy genotyping; (2) doubling use of second-line treatment to 80% (50–90%) of patients with confirmed virological failure on first-line ART; and (3) increasing viral load monitoring from yearly to twice yearly. An intervention can be considered cost-effective if it costs less than three times the gross domestic product per capita per quality adjusted life year (QALY) gained, or less than $3420 in Uganda.

Results

The prevalence of TDR is predicted to rise from 6.7% (interquartile range [IQR] 6.2–7.2%) in 2014, to 6.8% (IQR 6.1–7.6%), 10.0% (IQR 8.9–11.5%) and 11.1% (IQR 9.7–13.0%) in 2024 if treatment is initiated at a CD4 <350, <500, or immediately, respectively. The absolute number of TDR cases is predicted to decrease 4.4–8.1% when treating earlier compared to treating at CD4 <350 due to the preventative effects of earlier treatment. Most cases of TDR can be averted by increasing second-line treatment (additional 7.1–10.2% reduction), followed by increased viral load monitoring (<2.7%) and pre-therapy genotyping (<1.0%). Only increasing second-line treatment is cost-effective, ranging from $1612 to $2234 (IQR $450-dominated) per QALY gained.

Conclusions

While earlier treatment initiation will result in a predicted increase in the proportion of patients infected with drug-resistant HIV, the absolute numbers of patients infected with drug-resistant HIV is predicted to decrease. Increasing use of second-line treatment to all patients with confirmed failure on first-line therapy is a cost-effective approach to reduce TDR. Improving access to second-line ART is therefore a major priority.     

Undulating tongue in Wilson's disease

We report an unusual occurrence of involuntary movement involving the tongue in a patient with confirmed Wilson''s disease (WD). She manifested with slow, hypophonic speech and dysphagia of 4 months duration, associated with pseudobulbar affect, apathy, drooling and dystonia of upper extremities of 1 month duration. Our patient had an uncommon tongue movement which was arrhythmic. There was no feature to suggest tremor, chorea or dystonia. It might be described as athetoid as there was a writhing quality, but of lesser amplitude. Thus, the phenomenology was uncommon in clinical practice and the surface of the tongue was seen to “ripple” like a liquid surface agitated by an object or breeze. Isolated lingual dyskinesias are rare in WD. It is important to evaluate them for WD, a potentially treatable disorder.     

Long-term experience with liver transplantation for hepatocellular carcinoma

Background  

The effect of the model for end-stage liver disease (MELD) system on the post-transplant survival of patients with hepatocellular carcinoma (HCC) has not been fully elucidated. Our objective is to review the results of liver transplantation (LT) for HCC at the Massachusetts General Hospital over a period of 12 years, with special emphasis on the effect of the MELD system.     

Effects of medications on hypoxia-inducible factor in the retina: A review

Hypoxia-inducible factor (HIF) plays a critical role in the mechanisms that allow cells to adapt to various oxygen levels in the environment. Specifically, HIF-1⍺ has shown to be widely involved in cellular repair, survival, and energy metabolism. HIF-1⍺ has also been found in increased levels in cancer cells, highlighting the importance of balance in the hypoxic response. Promoting HIF-1⍺ activity as a potential therapy for degenerative diseases and inhibiting HIF-1⍺ as a therapy for pathologies with overactive cell proliferation are actively being explored. Digoxin and metformin, HIF-1⍺ inhibitors, and deferoxamine and ⍺-ketoglutarate analogues, HIF-1⍺ activators, are being studied for application in age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. However, these same medications have retinal toxicities that must be assessed before implementation of therapeutic care. Herein, we highlight the duality of therapeutic and toxic potential of HIF-1⍺ that must be carefully assessed prior to its clinical application in retinal disorders.