My 65 year old patient on chronic warfarin happens to have diffuse tracheobronchial calcification on her chest X-ray. Could warfarin be the culprit?

Absolutely! Although tracheobronchial calcification (TBC) is often found as part of normal aging process in the elderly, especially women, long-term warfarin use has also been implicated as a cause of TBC, even among those with less advanced age (1-4).

In a cohort of patients 60 years of age or older, radiographic evidence of trachea and bronchi calcification was found in 47% of patients on warfarin (mean age 64 years, mean duration of treatment 6 years) compared to 19% of controls (1). A positive correlation between the duration of warfarin therapy and increased levels of calcification was also found.  Fortunately, TBC is a benign finding and has no health consequences.

As for the mechanism for this rather intriguing phenomenon, the inhibition of a vitamin K-dependent protein that prevents calcification of cartilaginous tissue seems to be the most plausible (1). Although we often think of vitamin-K dependent factors in relation to the coagulation cascade, several vitamin K-dependent proteins also play an important role in the inhibition of calcification in soft tissues and blood vessels (eg, matrix Gla protein-MGP) (5,6).

In fact, rats maintained on warfarin undergo calcification of cartilage and elastic connective tissue, while exposure of the fetus to warfarin during pregnancy is associated with calcifications in and around joints, airway and nasal cartilages (4,7). These observations further support a causative role of warfarin in inducing TBC.

 

Bonus Pearl: Did you know that MGP deficiency in humans is known as the Keutel syndrome, a rare autosomal recessive disease characterized by several characteristic physical features, including severe cartilage calcifications and depressed nasal bridge?

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References

  1. Moncada RM, Venta LA, Venta ER, et al. Tracheal and bronchial cartilaginous rings: warfarin sodium-induced calcification. Radiology 1992;184:437-39. https://pubs.rsna.org/doi/10.1148/radiology.184.2.1620843
  2. Thoongsuwan N, Stern EJ. Warfarin-induced tracheobronchial calcification. J thoracic Imaging 2003;18:110-12. https://journals.lww.com/thoracicimaging/Abstract/2003/04000/Warfarin_Induced_Tracheobronchial_Calcification.12.aspx
  3. Nour SA, Nour HA, Mehta J, et al. Tracheobronchial calcification due to warfarin therapy. Am J Respir Crit Care Med 2014;189:e73. https://www.atsjournals.org/doi/full/10.1164/rccm.201305-0975IM
  4. Joshi A, Berdon WE, Ruzal-Shapiro C, et al. CT detection of the tracheobronchial calcification in an 18 year-old on maintenance warfarin sodium therapy. AJR Am J Roentgenol 2000;175:921-22. https://www.ajronline.org/doi/full/10.2214/ajr.175.3.1750921
  5. Wen L, Chen J, Duan L, et al. Vitamin K-dependent proteins involved in bone and cardiovascular health (review). Molecular Medicine Reports 2018;18:3-15. https://www.spandidos-publications.com/mmr/18/1/3/abstract \
  6. Theuwissen E, Smit E, Vermeer C. The role of vitamin K in soft-tissue calcification. Adv Nutr 2012; 3:166-173. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3648717/pdf/166.pdf

7.      Price PA, Williamson MK, Haba T, et al. Excessive mineralization with growth plate closure in rats on chronic warfarin treatment. Proc Natl Acad Sci  U.S.A 1982;79:7734-8. https://www.ncbi.nlm.nih.gov/pubmed/6984192

My 65 year old patient on chronic warfarin happens to have diffuse tracheobronchial calcification on her chest X-ray. Could warfarin be the culprit?

My patient with primary Sjogren’s syndrome has now been diagnosed with COPD despite lack of a significant smoking history. Is there a connection between Sjogren’s syndrome and COPD?

Increasing body of evidence suggests that COPD in patients with primary Sjögren’s syndrome (PSS) is not uncommon even among those who never smoked (1).

 
A 2015 study of patients with PSS reported that overall 41% of patients with PSS, including 30% of those who never smoked, fulfilled the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD. More specifically, pulmonary function tests (PFTs) showed decreased vital capacity (VC), forced expiratory volume in 1 second (FEV-1)  and DLCO in patients with PSS. Importantly, lab inflammatory and serological features were poorly associated with PFT results, while radiographic signs of interstitial lung disease (ILG) were absent in one-half of patients with PSS and COPD (1).

 
A longitudinal study with a mean follow-up of 11 years found a 37% rate of development of COPD among patients with PSS (2). Another related study reported a poor correlation between respiratory symptoms and COPD disease as assessed by PFTs in PSS, with the authors recommending that PFTs be performed “liberally” in all patients with PSS regardless of symptoms (3).

 
Lastly, a population-based cohort study of female adults found significantly higher rate of COPD among patients with PSS compared to controls (4).

 
Although the exact pathogenic mechanism behind PSS-associated COPD is unclear, xerotrachea and impaired mucocilliary clearance, as well as inflammatory infiltrates in the exocrine glands of the airways, all leading to physical obstruction and bronchial hyperreactivity have been suggested (1).

 

Bonus Pearl: Did you know that COPD is associated with many other autoimmune diseases (eg, rheumatoid arthritis and systemic lupus erythematosus), and a genetic link has been implicated between COPD and autoimmunity? (5,6).

 

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References
1. Nilsson AM, Diaz S, Theander E, et al. Chronic obstructive pulmonary disease is common in never-smoking patients with primary Sjögren’s syndrome. J Rheumatol 2015;42:464-71. https://www.researchgate.net/publication/270907531_Chronic_Obstructive_Pulmonary_Disease_Is_Common_in_Never-smoking_Patients_with_Primary_Sjogren_Syndrome
2. Mandl T, Diaz S, Ekberg O, et al. Frequent development of chronic obstructive pulmonary disease in primary SS-result of a longitudinal follow-up. Rheumatology 2012;51:941-46. https://www.researchgate.net/publication/221760110_Frequent_development_of_chronic_obstructive_pulmonary_disease_in_primary_SS-results_of_a_longitudinal_follow-up
3. Bolmgren VS, Olssson P, Wollmer P, et al. Respiratory symptoms are poor predictors of concomitant chronic obstructive pulmonary disease in patients with primary Sjögren’s syndrome. Rheumatol Int 2017;37:813-18. https://link.springer.com/content/pdf/10.1007/s00296-017-3678-5.pdf
4. Shen TC, Wu BR, Chen HJ, et al. Risk of chronic obstructive pulmonary disease in female adults with primary Sjögren’s syndrome. A nationwide population-based cohort study. Medicine 2016; 95:1-6. http://europepmc.org/abstract/MED/26962839
5. Hemminki K, Liu X, Ji J et al. Subsequent COPD and lung cancer in patients with autoimmune disease. Eur Respir J 2011;37:463-74. https://www.ncbi.nlm.nih.gov/pubmed/21282811
6. Ji X, Niu X, Qian J, et al. A phenome-wide association study uncovers a role for autoimmunity in the development of chronic obstructive pulmonary disease. Resp Cell Mol Biol 2018;58:777-79. https://www.atsjournals.org/doi/10.1165/rcmb.2017-0409LE

My patient with primary Sjogren’s syndrome has now been diagnosed with COPD despite lack of a significant smoking history. Is there a connection between Sjogren’s syndrome and COPD?

My patient with inferior myocardial infarction with Q-waves 2 years ago now has no evidence of Q waves on his EKG. Can Q-waves from myocardial infarction really regress over time?

Short answer: Yes! Q-waves may regress following transmural myocardial infarction (ATMI) and in fact this phenomenon may not be as unusual as once thought, occurring in 7-15% of patients (1,2).

 
A prospective study involving patients with ATMI evaluated by coronary angiography and followed for an average of 65 months found an 11% rate of loss of Q-waves over an average of 14 months after ATMI. Factors associated with loss of Q-waves included lower peak creatine kinase values, lower left ventricular end-diastolic pressures, higher ejection fractions, fewer ventricular aneurysms and lower rate of congestive heart failure, all leading to the authors’ conclusion that Q-wave loss may be related to a smaller infarct size (1).

 
Similar findings were reported from patients enrolled in the Aspirin Myocardial Infarction Study with a loss of a previously documented diagnostic Q-wave confirmed in 14.2% of participants over an average of 38 months. Mortality among patients who lost Q-waves was not significantly different than among those with persistent Q-waves in a single infarct location (2).

 
These observations suggest that Q-waves in the setting of ATMI may not necessarily be pathognomonic of myocardial necrosis and, at least in some instances, may be due to tissue ischemia, edema and inflammation causing reversible myocardial and electrical stunning (3). Of interest, reversible Q-waves have also been reported in acute myocarditis (4).

Bonus Pearl: Did you know that the EKG waves P and Q were likely named by Einthoven, the inventor of EKG, after the designation of the same letters by Descartes, the father of analytical geometry, in describing refraction points? (5). 

 

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References
1. Coll S, Betriu A, De Flores T, et al. Significance of Q-wave regression after transmural acute myocardial infarction. Am J Cardiol 1988;61:739-42.
2. Wasserman AG, Bren GB, Ross AM, et al. Prognostic implications of diagnostic Q waves after myocardial infarction. Circulation 1982;65:1451-55.
3. Barold SS, Falkoff MD, Ong LS, et al. Significance of transient electrocardiographic Q waves in coronary artery disease. Cardiol Clin 1987;5:367-80.
4. Dalzell JR, Jackson CE, Gardner RS. Masquerade: Fulminant viral myocarditis mimicking a Q-wave anterolateral myocardial infarction. Am J Med 2009. Doi:10.1016/j.amjmed.2009.01.015.

5. Hurst, JW.  Naming of the waves in the ECG, with a brief account of their genesis. Circulation 1998;98:1937-42. 

 

My patient with inferior myocardial infarction with Q-waves 2 years ago now has no evidence of Q waves on his EKG. Can Q-waves from myocardial infarction really regress over time?

My elderly patient on anticoagulation for non-valvular atrial fibrillation was admitted for evaluation of a fall. Should I discontinue her anticoagulation long term because of potential for intracranial hemorrhage from future falls?

Although there may always be hesitation in resuming anticoagulation (AC) in patients with non-valvular atrial fibrillation (NVAF) and recent fall(s), the weight of the evidence suggests that most patients are still more likely to benefit from AC than be adversely impacted by intracranial hemorrhage.

 
An often-quoted systematic review article on the risks and benefits of anti-thrombotic (AC or aspirin) therapy in patients with NVAF at risk estimated that persons taking warfarin must fall 295 times in 1 year for warfarin to not be the optimal therapy for reducing the risk of stroke (1). The authors concluded that “a history of and/or the presence of risk factors for falls should not be considered important factors in the decision whether to offer antithrombotic (especially warfarin) therapy to elderly patients with atrial fibrillation”.

 
In another study involving older adults with NVAF, although a history of falls or documented high risk of falling was associated with a risk of intracranial hemorrhage, this risk did not differ among patients treated with warfarin, aspirin or no antithrombotic therapy (2).

 
Ultimately, the decision to prescribe AC in patients with NVAF at risk for falls should be made based on shared decision making with patients and caregivers. However, in the absence of absolute contraindications for AC in these patients (eg, intracranial hemorrhage or neurosurgical procedure with high risk for bleeding within the past 30 days, an intracranial neoplasm or vascular abnormality with high risk of bleeding, recurrent life-threatening gastrointestinal or other bleeding events, and severe bleeding disorders), perceived or actual risk of falls by itself should not automatically exempt a patient from receiving AC in NVAF (3).

 

Although much of the data on the relative risk of bleeding against prevention of strokes has been derived from studies involving warfarin, it is reassuring that the risk of intracranial bleed has been lower than that of warfarin for several newer non-vitamin K antagonist direct oral anticoagulants (NOACs or DOACs),  including dabigatran, rivaroxaban, edoxaban and apixaban (4). 

 

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References

1. Man-Son-Hing M, Nichol G, Lau A, et al. Choosing antithrombotic therapy for elderly patiets with atrial fibrillation who are at risk for falls. Arch Intern Med 1999;159:677-685.
2. Gage BF, Birman-Deych E, Kerzner R, et al. Incidence of intracranial hemorrhage in patients with atrial fibrillation who are prone to fall. Am J Med 2005;118:612-617.
3. Hagerty T, Rich MW. Fall risk and anticoagulation for atrial fibrillation in the elderly: a delicate balance. Clev Clin J 2017;84:35-40.

4. Lopez RD, Guimaraes PO, Kolls BJ, et al. Intracranial hemorrhage in patietns with atrial fibrillation receiving anticoagulation therapy. Blood 2017;129:2980-87. 

My elderly patient on anticoagulation for non-valvular atrial fibrillation was admitted for evaluation of a fall. Should I discontinue her anticoagulation long term because of potential for intracranial hemorrhage from future falls?

My patient with diabetes mellitus is now admitted with pneumonia. Does diabetes increase the risk of pneumonia requiring hospitalization?

The weight of the evidence to date suggests that diabetes mellitus (DM) does increase the risk of pneumonia-related hospitalization.1-3

A large population-based study involving over 30,000 patients found an adjusted relative risk (RR) of hospitalization with pneumonia of 1.26 (95% C.I 1.2-1.3) among patients with DM compared to non-diabetics.  Of note, the risk of pneumonia-related hospitalization was significantly higher in type 1 as well as type 2 DM and among patients whose A1C level was ≥9.1  Another population-based study found a high prevalence of DM (25.6%) in patients hospitalized with CAP, more than double that in the population studied.2  A 2016 meta-analysis of observational studies also found increased incidence of respiratory tract infections among patients with diabetes (OR 1.35, 95% C.I. 1.3-1.4).

Not only does DM increase the risk of pneumonia-related hospitalization, but it also appears to adversely affect its outcome with increased in-hospital mortality.2 Among patients with type 2 DM,  excess mortality has also been reported at 30 days, 90 days and 1 year following hospitalization for pneumonia. 4,5 More specifically, compared to controls with CAP, 1 year mortality of patients with DM was 30% (vs 17%) in 1 study. 4

Potential reasons for the higher incidence of pneumonia among patients with DM include increased risk of aspiration (eg, in the setting of gastroparesis, decreased cough reflex), impaired immunity (eg, chemotaxis, intracellular killing), pulmonary microangiopathy and coexisting morbidity. 1,3,5,6

Bonus Pearl: Did you know that worldwide DM has reached epidemic levels, such that if DM were a nation, it would surpass the U.S. as the 3rd most populous country! 7

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References

  1. Kornum JB, Thomsen RW, RUS A, et al. Diabetes, glycemic control, and risk of hospitalization with pneumonia. A population-based case-control study. Diabetes Care 2008;31:1541-45. https://www.ncbi.nlm.nih.gov/pubmed/17595354
  2. Martins M, Boavida JM, Raposo JF, et al. Diabetes hinders community-acquired pneumonia outcomes in hospitalized patients. BMJ Open Diabetes Research and Care 2016;4:e000181.doi:10.1136/bmjdrc-2015000181. https://drc.bmj.com/content/4/1/e000181
  3. Abu-Ahour W, Twells L, Valcour J, et al. The association between diabetes mellitus and incident infections: a systematic review and meta-analysis of observational studies. BMJ Open Diabetes Research and Care 2017;5:e000336. https://drc.bmj.com/content/5/1/e000336. 
  4. Falcone M, Tiseo G, Russo A, et al. Hospitalization for pneumonia is associated with decreased 1-year survival in patients with type 2 diabetes. Results from a prospective cohort study. Medicine 2016;95:e2531. https://www.ncbi.nlm.nih.gov/pubmed/26844461
  5. Kornum JB, Thomsen RW, Rus A, et al. Type 2 diabetes and pneumonia outcomes. A population-based cohort study. Diabetes Care 2007;30:2251-57. https://www.ncbi.nlm.nih.gov/pubmed/17595354
  6. Koziel H, Koziel MJ. Pulmonary complications of diabetes mellitus. Pneumonia. Infect Dis Clin North Am 1995;9:65-96. https://www.ncbi.nlm.nih.gov/pubmed/7769221
  7. Zimmet PZ. Diabetes and its drivers: the largest epidemic in human history? Clinical Diabetes and Endocrinology 2017;3:1 https://clindiabetesendo.biomedcentral.com/articles/10.1186/s40842-016-0039-3  

 

My patient with diabetes mellitus is now admitted with pneumonia. Does diabetes increase the risk of pneumonia requiring hospitalization?

Why is the bicuspid aortic valve of my middle age patient with endocarditis so heavily calcified?

Congenital bicuspid aortic valve (BAV) is a significant risk factor for valvular calcification, occurring about 20 years earlier than people with normal tricuspid aortic valve as they age. In fact, despite its prevalence of only 1-2% in the population, BAV may account for 50% of aortic valve stenosis (1).

 
Two potential mechanisms could account for the propensity of patients with BAV to develop valve calcification. First, genetic mutations that  account for some of the cases of BAV disease, may also be associated with valvular calcification (1). NOTCH1 mutation is one such candidate causing early developmental defect in the aortic valve, while later causing de-repression of calcium deposition (2). A mutation of the gene for endothelial nitric oxide synthase (eNOS) involved in preventing calcification in animal and tissue experiments may be another factor (3,4).

 
Besides genetic explanations, alteration in the mechanical force environments of the BAV itself likely plays an important part in the premature degeneration and calcification of the valve (1). Stenotic and skewed forward flow along with increased jet velocity may increase shear forces on the valve. The resultant inflammatory response and apoptosis could lead to a diseased valve, not unlike what may be seen with tricuspid aortic valve under similar circumstances (5). Perhaps more fascinating is the observation that fluid shear itself may influence bone morphogenetic protein expression, further contributing to valvular calcification (6).

 

Bonus Pearl: Did you know that the risk of infective endocarditis may be much higher (>20-fold) among patients with BAV compared to those with triscuspid aortic valve (7)?

 

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References
1. Yap CH, Saikrishanan N, Tamilselvan G, et al. The congenital bicuspid aortic valve can experience high-frequency unsteady shear stresses on its leaflet surface. Am J Physiol Heart Circ Physiol 2012; 303:H721-H731. doi:10.1152/ajpheart.00829.2011. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3468455/
2. Nigam V, Srivastava D. Notch 1 represses osteogenic pathways in aortic valve cells. J Mol Cell Cardiol 2009;47:828-34. https://www.ncbi.nlm.nih.gov/pubmed/19695258
3. Rajamannan NM, Subramanian M, Stock SR, et al. Atorvastatin inhibits calcification and enhances nitric oxide synthase production in the hypercholesterolaemic aortic valve disease. Heart 2005;91:806-10. https://www.ncbi.nlm.nih.gov/pubmed/15894785
4. Kennedy JA, Hua X, Mishra K, et al. Inhibition of calcifying nodule formation in cultured porcine aortic valve cells by nitric oxide donors. Eur J Pharmacol 2009;602:28-35. https://www.ncbi.nlm.nih.gov/pubmed/19056377
5. Wallby L, Janerot-Sjöberg B, Steffensen T, Broqvist M. T lymphocyte infiltration in non-rheumatic aortic stenosis: a comparative descriptive study between tricuspid and bicuspid aortic valves. Heart 88: 348–351, 2002. https://www.ncbi.nlm.nih.gov/pubmed/12231589
6. Sorescu GP, Song H, Tressel SL, et al. Bone morphogenic protein 4 produced in endothelial cells by oscillatory shear stress induces monocyte adhesion by stimulating reactive oxygen species production from a nox1-based NADPH oxidase. Circ Res 2004;84:773-79. https://www.ncbi.nlm.nih.gov/pubmed/15388638
7. Kiyota Y, Corte AD, Vieira VM, et al. Risk and outcomes of aortic valve endocarditis among patients with bicuspid and tricuspid aortic valves. Open Heart J 2017;4:e000545. Doi:10.1136/opnhrt-2016-000545. https://openheart.bmj.com/content/openhrt/4/1/openhrt-2016-000545.full.pdf

Why is the bicuspid aortic valve of my middle age patient with endocarditis so heavily calcified?

Is there a connection between trehalose, a natural sugar found in many foods, and Clostridioides difficile disease (CDD)?

There is experimental and epidemiological evidence that trehalose in the diet may enhance the virulence of the epidemic strains (eg. Ribotype 027) of C. difficile (1). 
Many of us may not be familiar with trehalose. It’s a disaccharide composed of 2 glucose molecules and found widely in nature, including bacteria, fungi (eg mushrooms, Brewer’s yeast), plants, insects, other invertebrates, but not vertebrates (2).

Since its approval by the FDA as a natural food additive in 2000, trehalose is increasingly used for its unique properties (including flavor enhancer and moisture stabilizer) in a variety of foods, including ice cream, pasta, ground beef, and sushi. Although in humans trehalose is enzymatically broken down to glucose by the brush borders of intestinal mucosa, intact trehalose is also found in the lower GI tract where C. difficile thrives.

 
In a series of intriguing experiments involving the interaction between trehulose and C. difficile published in Nature in 2018, Collins et al found that RT027 strain of C. difficile had acquired unique mechanisms to metabolize low concentrations of trehalose and that dietary trehalose increased its virulence associated with high mortality in a mouse model of infection even in the absence of antibiotic exposure. They further demonstrated that when human diet was simulated (eg, at concentrations suggested in ice cream), trehalose levels in the cecum of the mice were sufficient to induce production of the enzyme phosphotrehalase by the same strain in vitro by over 400X in the absence of antibiotics and by over 1000X in the presence of antibiotics. Similar results were found in the ileostomy fluid samples of 2 of 3 volunteers consuming normal diet (1). 

 
Equally fascinating is the epidemiological evidence that the timelines of trehalose adoption as a food additive in 2000, subsequent uptick in the number CDDs in the US, as well as the spread of RT027 strain in many countries seem to overlap (1).

 
These observations may at least partially explain the frequently severe nature of CDD during the past 2 decades as well why a significant proportion (up to a-third) of patient with CDD appear to have no recent exposure to antibiotics or hospitalization (3-5).  An epidemiological study examining the dietary habits of patients with CDD without apparent risk factors is in order. Stay tuned!

 
Bonus Pearl: Did you know that trehalose is classified as “generally regarded as safe” (GRAS)  natural food additive by the FDA and may be listed as “added sugar” or “natural flavor” on the food packaging?

 

References
1. Collins J, Robinson C, Danhof H, et al. Dietary trehalose enhances virulence of epidemic Clostridium difficile. Nature 2018;553;291-96. https://www.nature.com/articles/nature25178
2. Avonce N, Mendoza-Vargas A, Morett E, et al. Insights on the evolution of trehalose biosynthesis. BMC Evol Biol 2006;6:109. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1769515/
3. Wilcox MH, Mooney L, Bendall R, Settle CD et al. A case-control study of community-associated Clostridium difficile infection. J Antimicrob Chemother 2008;62:388-96. https://www.researchgate.net/publication/5419268_A_case-control_study_of_community-associated_Clostridium_difficile_infection
4. Severe Clostridium difficile-associated disease in populations previously at low risk. MMWR2005;54:1201-5. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5447a1.htm
5. Halvorson SAC, Cedfeldt AS, Hunter AJ. Fulminant, non-antibiotic associated Clostridium difficile colitis following Salmonella gastroenteritis. J Gen Intern Med 2010;26:95-7.

 

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Is there a connection between trehalose, a natural sugar found in many foods, and Clostridioides difficile disease (CDD)?

Is meropenem a good choice of antibiotic for treatment of my patient’s intraabdominal infection involving enterococci?

Although meropenem is a broad spectrum antibiotic that covers many gram-negative and gram-positive organisms as well as anaerobes, its activity against enterococci is generally poor and leaves much to be desired.

In a study of ampicillin-sensitive E. faecalis isolates from hospitalized patients, only 36% of isolates were considered susceptible (MIC≤4 mg/L); activity against E. faecium isolates was similarly poor.1 Several other studies have reported the suboptimal activity of meropenem against both E. faecalis and E. faecium, 2-4 with susceptibility rates as low as 8.6% depending on the MIC break point used.3

A popular textbook and a handbook on infectious diseases also do not recommend the use of meropenem for treatment of enterococcal infections. 5,6

Of interest, the package insert states that meropenem is indicated for complicated skin and soft tissue infections due to a variety of organisms, including E. faecalis (vancomycin-susceptible isolates only), but not for complicated intra-abdominal infections or meningitis due this organism.7

In our patient with intraabdominal infection,  we may consider piperacillin-tazobactam instead.  Piperacillin-tazobactam is a broad spectrum antibiotic with excellent coverage against anaerobes and ampicillin-susceptible E. faecalis.1,8  

 

References

  1. Endtz HP, van Dijk WC, Verbrugh HA, et al. Comparative in-vitro activity of meropenem against selected pathogens from hospitalized patients in the Netherlands. J Antimicrob Chemother 1997;39:149-56. https://www.ncbi.nlm.nih.gov/pubmed/9069534
  2. Pfaller MA, Jones RN. A review of the in vitro activity of meropenem and comparative antimicrobial agents tested against 30,254 aerobic and anaerobic pathogens isolated world wide. Diag Microbiol Infect Dis 1997;28:157-63. https://www.ncbi.nlm.nih.gov/pubmed/9327242
  3. Hallgren A, Abednazari H, Ekdahl C, et al. Antimicrobial susceptibility patterns of enterococci in intensive care units in Sweden evaluated by different MIC breakpoint systems. J Antimicrob Chemother 2001;48:53-62. https://www.ncbi.nlm.nih.gov/pubmed/11418512
  4. Hoban DJ, Jones RN, Yamane N, et al. In vitro activity of three carbapenem antibiotics comparative studies with biapenem (L-627), imipenem, and meropenem against aerobic pathogens isolated worldwide. Diag Microbiol Infect Dis 993;17:299-305.https://www.ncbi.nlm.nih.gov/pubmed/8112045
  5. Chambers HF. Carbapenem and monobactams. In Mandell GL et al. eds. Principles and practice of infectious diseases. 2010, pp 341-45.
  6. Cunha CB, Cunha BA. Antibiotic essentials. 2017, pp 689-91.
  7. Meropenem.http://online.lexi.com/lco/action/doc/retrieve/docid/patch_f/7253?searchUrl=%2Flco%2Faction%2Fsearch%3Fq%3Dmeropenem%26t%3Dname
  8. Perry CM, Markham A. Piperacillin/tazobactam. Drugs 1999;57:805-43. https://link.springer.com/article/10.2165%2F00003495-199957050-00017

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Is meropenem a good choice of antibiotic for treatment of my patient’s intraabdominal infection involving enterococci?

My postop patient now has fever with atelectasis on her chest X-ray one day after surgery. Does atelectasis cause fever?

Although fever and atelectasis often coexist during the early postop period, there is no evidence that atelectasis causes fever.

A 2011 systematic analysis of 8 published studies found that all but 1 study failed to find a significant association between postop fever and atelectasis.A 1988 study reported a significant association between postop fever during the first 48 h and atelectasis on day 4 postop, but not each postop day.2  Even in this study, however, fever as a predictor of atelectasis performed poorly with a sensitivity of 26%, specificity of 75% and accuracy of 43%.

In another study involving postop cardiac surgery patients, despite a fall in the incidence of fever from day 0 to day 2, the incidence of atelectasis based on serial chest X-rays actually  increased. 3

Experimental studies in dogs and cats in the 1960s also support the lack of a causative relationship between atelectasis and fever. 4,5 Although fever was observed within 12 hrs of placement of cotton plugs in the left main bronchus of these animals, almost all animals also developed pneumonia distal to the plug.  Antibiotic treatment was associated with resolution of fever but not atelectasis.

So if it’s not atelectasis, what’s the explanation for early postop fever? The great majority of postop fevers during the first 4 days postop are unlikely to be related to infections. Instead, a more plausible explanation is the inflammatory response to the tissue injury as a result of the surgery itself causing release of cytokines (eg, interleukin-1 and -6 and tumor necrosis factor) associated with fever. 6

References

  1. Mavros MN, Velmahos GC, Falagas ME. Atelectasis as a cause of postoperative fever. Where is the clinical evidence? CHEST 2011;140:418-24. https://www.ncbi.nlm.nih.gov/pubmed/21527508
  2. Roberts J, Barnes W, Pennock M, et al. Diagnostic accuracy of fever as a measure of postoperative pulmonary complications. Heart Lung 1988;17:166-70. https://www.ncbi.nlm.nih.gov/pubmed/3350683
  3. Engoren M. Lack of association between atelectasis and fever. CHEST 1995;107:81-84. https://www.ncbi.nlm.nih.gov/pubmed/7813318
  4. Lansing AM, Jamieson WG. Mechanisms of fever in pulmonary atelectasis. Arch Surg 1963;87:168-174. https://jamanetwork.com/journals/jamasurgery/fullarticle/561080
  5. Jamieson WG, Lansing AM. Bacteriological studies in pulmonary atelectasis. Arch Surg 1963;87:1062-66. https://www.ncbi.nlm.nih.gov/pubmed/14063816
  6. Narayan M, Medinilla SP. Fever in the postoperative patient. Emerg Med Clin Nam 2013;31:1045-58. https://www.ncbi.nlm.nih.gov/pubmed/24176478 

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My postop patient now has fever with atelectasis on her chest X-ray one day after surgery. Does atelectasis cause fever?

My patient with brain tumor suffered a myocardial infarction (MI) just before having a diagnostic brain surgery. Could the tumor have placed him at higher risk of a coronary event?

Yes! Arterial thromboembolism—just as venous thromboembolism— is more common in patients with cancer.

In a large 2017 epidemiologic study involving patients 66 years of age or older, the 6-month cumulative incidence of MI was nearly 3-fold higher in newly-diagnosed cancer patients compared to controls, with the excess risk resolving by 1 year. 1 These findings were similar to a previous report involving patients with newly-diagnosed cancer, although in that study the overall coronary heart disease risk remained slightly elevated even after 10 years. 2

In addition, the incidence of coronary events and unstable ischemic heart disease during the 2 year period prior to the diagnosis of cancer is 2-fold higher among cancer patients suggesting that ischemic heart disease may be precipitated by occult cancer. 3

The association of cancer and thromboembolic coronary events may be explained through several mechanisms, including development of a prothrombotic or hypercoagulable state through acute phase reactants, abnormal fibrinolytic activity and increased activation of platelets which are also significantly involved in the pathophysiology of acute coronary syndrome (ACS). 4 Coronary artery embolism from cancer-related marantic endocarditis may also occur.5

More specific to our case, primary brain tumors may be associated with a hypercoagulable state through expression of potent procoagulants such as tissue factor and tissue factor containing microparticles, with a subset producing carbon monoxide, another procoagulant. 6

So our patient’s MI prior to his surgery for brain tumor diagnosis might have been more than a pure coincidence!

Bonus Pearl: Did you know that cancer-related prothrombotic state, also known as  “Trousseau’s syndrome” was first described in 1865 by Armand Trousseau, a French physician who diagnosed the same in himself and died of gastric cancer with thrombotic complications just 2 years later? 7,8

References

  1. Navi BB, Reinder AS, Kamel H, et al. Risk of arterial thromboembolism in patients with cancer. JACC 2017;70:926-38. https://www.ncbi.nlm.nih.gov/pubmed/28818202
  2. Zoller B, Ji Jianguang, Sundquist J, et al. Risk of coronary heart disease in patients with cancer: A nationwide follow-up study from Sweden. Eur J Cancer 2012;48:121-128. https://www.ncbi.nlm.nih.gov/pubmed/22023886
  3. Naschitz JE, Yeshurun D, Abrahamson J, et al. Ischemic heart disease precipitated by occult cancer. Cancer 1992;69:2712-20. https://www.ncbi.nlm.nih.gov/pubmed/1571902
  4. Lee EC, Cameron SJ. Cancer and thrombotic risk: the platelet paradigm. Frontiers in Cardiovascular Medicine 2017;4:1-6. https://www.ncbi.nlm.nih.gov/pubmed/29164134
  5. Lee V, Gilbert JD, Byard RW. Marantic endocarditis-A not so benign entity. Journal of Forensic and Legal Medicine 2012;19:312-15. https://www.ncbi.nlm.nih.gov/pubmed/22847046
  6. Nielsen VG, Lemole GM, Matika RW, et al. Brain tumors enhance plasmatic coagulation: the role of hemeoxygenase-1. Anesth Analg 2014;118919-24. https://www.ncbi.nlm.nih.gov/pubmed/24413553
  7. Thalin C, Blomgren B, Mobarrez F, et al. Trousseau’s syndrome, a previously unrecognized condition in acute ischemic stroke associated with myocardial injury. Journal of Investigative Medicine High Impact Case Reports.2014. DOI:10.1177/2324709614539283. https://www.ncbi.nlm.nih.gov/pubmed/26425612
  8. Samuels MA, King MA, Balis U. CPC, Case 31-2002. N Engl J Med 2002;347:1187-94. https://www.nejm.org/doi/pdf/10.1056/NEJMcpc020117?articleTools=true

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My patient with brain tumor suffered a myocardial infarction (MI) just before having a diagnostic brain surgery. Could the tumor have placed him at higher risk of a coronary event?