Chiefs’ Inquiry Corner – 12/7/2021

December 7, 2021

Chief residents of the NYU Langone Internal Medicine Residency give quick-and-easy, evidence-based answers to interesting questions posed by house staff, both in their clinics and on the wards.

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  (1→3)-β-d-Glucan (BDG) is a polysaccharide glucose polymer that is a constituent of the cell walls of many pathogenic fungi; detection of this compound in the peripheral blood with serum assay is important in the diagnosis of invasive fungal infections (with the notable exceptions of Mucorales and cryptocci, which release little to no BDG that can be detected on current serum assays). The measurement of BDG levels is based on the Limulus test-namely, factor G is a protease zymogen found in Limulus amoebae extracted from horseshoe crab species, which then reacts with BDG to initiate a coagulation cascade, and activity of this reaction is quantified using various analytic chemistry methods. Unfortunately, false-positive results can be a limiting factor in the usefulness of BDG assays-the assay may indeed be detecting BDG for reasons other than invasive fungal infection. BDG assays can be positive in people undergoing hemodialysis with cellulose membranes, being treated with blood products that have been filtered through cellulose depth filters containing BDG (such as immunoglobulin and albumin), with serosal exposure to glucan-containing gauze, or the administration of certain antibiotics that are either derived from fungal agents (such as ampicillin-clavulanic acid) or manufactured using a process involving cellulose filters that leach into the product. There have also been case reports of bacteremia interfering with the accuracy of BDG assays, although this has not been consistently characterized.  BDG assay is a valuable tool in helping to diagnose invasive fungal infections, but assays should be performed and interpreted in the proper clinical context; particularly for an unexpectedly positive assay, the possibility of a false-positive result should be considered.

References:  Reactivity of (1–>3)-beta-d-glucan assay with commonly used intravenous antimicrobials.

References: Detection of high serum levels of β-D-Glucan in disseminated nocardial infection: a case report
  Moderate hyperTG is defined as a TG level from 105-499. In these patients who do not have an elevated LDL-C or other indication for starting statin therapy (ie established ASCVD or DM), the first line treatment should be based on lifestyle modification. The lifestyle modifications best for elevated triglycerides is to consume foods with a low glycemic index with a target of <6% of calories coming from added sugar and <30-35% calories of total fat. It is also recommended to focus on changing the type of fat (reducing saturated fat, increasing poly or mono-unsaturated fats). Alcohol use should also be reviewed and should be limited to now more than 2 drinks/day in men and 1 drink/day in women. For overweight/obese patients, losing 5-10% of body weight can also help lower TGs. After pursuing non-pharmacologic measures, the AHA guidelines found that based on a review of several studies comparing EPA+DHA vs EPA only studies for HTG that there is a ≈20%–30% reduction in triglycerides without any concomitant LDL-C increase with 4 g/d prescription n-3 FA.

References:  Omega-3 Fatty Acids for the Management of Hypertriglyceridemia: A Science Advisory From the American Heart Association
 Uremic stomatitis is an uncommon manifestation of chronic kidney disease, with proposed mechanism to be irritation and chemical injury of the mucosa (most frequently the lateral edges of the tongue, dorsal or ventral sides of the tongue, floor of the mouth, and buccal mucosa) by ammonia/ammonium compounds formed by the hydrolysis of urea in saliva in the setting of profoundly elevated BUN (typically 150-300mg/dL). The lesions often appear as white plaques and are associated with pain, burning sensations, and/or dysgeusia. Treatment involves hemodialysis to address uremia and increased oral hygiene, including antiseptic mouthwashes, topical analgesics (such as viscous lidocaine), and antimicrobial/antifungal agents.

References: Uremic Stomatitis