Should I consider a direct oral anticoagulant (DOAC) for my patient with pancreatic cancer and pulmonary embolism?

Classically, anticoagulant (AC) of choice in active malignancy with venous thromboembolism (VTE) has been low-molecular weight heparin (LMWH) (eg, enoxaparin) because of trials showing its superiority over warfarin. But now the pendulum is swinging toward DOACs as an alternative mode of treatment.

A 2018 trial found that oral edoxaban (an Xa inhibitor) was noninferior to subcutaneous dalteparin (a LMWH) with the composite outcome of recurrent VTE or major bleeding.1 Overall, recurrent VTE was significantly lower in edoxaban (7.9% vs 11.3%) but had higher major bleeding (6.9% vs 4.05). Of note, edoxaban was initiated after 5 days of treatment with LMWH.

More recently, the 2020 Caravaggio trial, showed non-inferiority of apixaban (at a dose of 10 mg twice daily for the first 7 days, followed by 5 mg twice daily) to dalteparin with recurrent VTE of 5.6% in the apixaban group vs 7.9% in the dalteparin.2 There was no significant difference in rates of major bleeding (3.8% vs 4%). A prior small study, the ADAM-VTE trial, compared apixaban to dalteparin in patients with malignancy and VTE.3 Apixaban had significantly lower VTE recurrence rates (0.7% to 6.3%) and non-significant lower major bleeding (0% vs 1.4%, p=0.138) consistent with the newer and larger trial. Of note, this trial excluded patients with brain tumor and had few patients with upper GI or hematologic malignancy.  

In addition, a pilot study, the SELECT-D trial, compared rivaroxaban to dalteparin.4 Rivaroxaban had significantly lower VTE recurrence (4% vs 11%), without a significant increase in major bleeding (6% vs 4%), but had an increased number of clinically relevant non-major bleeds (13% vs 4%), particularly in cancers of the upper GI tract.

Although decision regarding use of DOACs in patients with malignancy should be made on case-by-case basis, they are increasingly considered for treatment of VTE in this patient population with the strongest evidence supporting apixaban or the initial use of LMWH for 5 days followed by edoxaban.  

Contributed by Sean Mendez MD, Mass General Hospital, Boston, MA.

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References:  

  1. Raskob GE, van Es N, Verhamme P, Carrier M, Di Nisio M, Garcia D, Grosso MA, Kakkar AK, Kovacs MJ, Mercuri MF, Meyer G, Segers A, Shi M, Wang TF, Yeo E, Zhang G, Zwicker JI, Weitz JI, Büller HR. Edoxaban for the Treatment of Cancer-Associated Venous Thromboembolism. N Engl J Med. 2018 Feb 15;378(7):615-624. doi: 10.1056/NEJMoa1711948. Epub 2017 Dec 12. PubMed PMID: 29231094.
  2. McBane Ii R, Loprinzi CL, Ashrani A, Perez-Botero J, Leon Ferre RA, Henkin S, Lenz CJ, Le-Rademacher JG, Wysokinski WE. Apixaban and dalteparin in active malignancy associated venous thromboembolism. The ADAM VTE Trial. Thromb Haemost. 2017 Oct 5;117(10):1952-1961. doi: 10.1160/TH17-03-0193. Epub 2017 Aug 24. PubMed PMID: 28837207.
  3. Agnelli G, Becattini C, Meyer G, Muñoz A, Huisman MV, Connors JM, Cohen A, Bauersachs R, Brenner B, Torbicki A, Sueiro MR, Lambert C, Gussoni G, Campanini M, Fontanella A, Vescovo G, Verso M. Apixaban for the Treatment of Venous Thromboembolism Associated with Cancer. N Engl J Med. 2020 Mar 29;. doi: 10.1056/NEJMoa1915103. [Epub ahead of print] PubMed PMID: 32223112.
  4. Young AM, Marshall A, Thirlwall J, Chapman O, Lokare A, Hill C, Hale D, Dunn JA, Lyman GH, Hutchinson C, MacCallum P, Kakkar A, Hobbs FDR, Petrou S, Dale J, Poole CJ, Maraveyas A, Levine M. Comparison of an Oral Factor Xa Inhibitor With Low Molecular Weight Heparin in Patients With Cancer With Venous Thromboembolism: Results of a Randomized Trial (SELECT-D). J Clin Oncol. 2018 Jul 10;36(20):2017-2023. doi: 10.1200/JCO.2018.78.8034. Epub 2018 May 10. PubMed PMID: 29746227.

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Should I consider a direct oral anticoagulant (DOAC) for my patient with pancreatic cancer and pulmonary embolism?

My 75 year old patient has an arterial oxygen tension (Pa02) less than 90 mmHg on room air. Does age affect PaO2?

Short answer: Yes! Most studies of blood gas concentrations have demonstrated a decrease in oxygen tension with age.1

Earlier studies have demonstrated a linear decrease in oxygen tension based on observations that included relatively small number of patients over the age of 60. 1 More recently, however, in a study of 532 consecutive patients admitted for elective surgery without overt cardiac, pulmonary, or metabolic disease, obesity or smoking, the mean PaO2 differed by age group as follows:

  • <30 years: 98.4 mmHg
  • 30-50 years: 88.7 mmHg
  • 51-70 years: 81.0 mmHg
  • >70 years: 76.5 mmHg

After age 70 years, decline in Pa02 may slow down or actually reverse, likely related to the “survival of the fittest” in more advanced years. 1,2 Some have suggested accepting a PaO2 80-85 mmHg as normal for subjects > 65 years of age. 3

The decrease in PaO2 with age is a result of increased heterogeneity of ventilation/perfusion ratio, especially reduced ventilation in the dependent parts of the lung. 3 Aging is also associated with a decrease in chest wall compliance, muscle (including the diaphragm) strength, forced expiratory volume in 1 second (FEV1), vital capacity, and diffusing capacity of carbon monoxide (DLC0)/alveolar volume.  

In addition, aging is associated with a reduction in response to hypoxia and hypercarbia, making older patients particularly vulnerable to complications from  heart failure and pneumonia4, especially in the current Covid-19 era.

Bonus Pearl: Did you know that poor response to hypoxic or hypercarbic states in the elderly is likely related to an age-related decline in efferent neural output to respiratory muscles?4

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References

  1. Blom H, Mulder M, Verwej W. Arterial oxygen tension and saturation in hospital patients: effect of age and activity. BMJ 1988;297:720-2. Doi:10.1136/bmj.297.6650.720 https://www.bmj.com/content/297/6650/720   
  2. Delclaux B, Orcel B, Housset B, et al. Arterial blood gases in elderly persons with chronic obstructive pulmonary disease (COPD). Eur Respir J 1994;7:856-61. https://www.researchgate.net/publication/15147788_Arterial_blood_gases_in_elderly_persons_with_chronic_obstructive_pulmonary_disease_COPD
  3. Janssens JP, Pache JC, Nicod LP. Physiological changes in respiratory function associated with ageing. Eur Respir J 1999;13:197-205. https://www.researchgate.net/publication/12689073_Physiological_changes_in_respiratory_function_associated_with_ageing
  4. Sharma G, Goodwin J. Effect of aging on respiratory system physiology and immunology. Clin Interventions in Aging 2006;1:253-60. https://pubmed.ncbi.nlm.nih.gov/18046878/

 

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

 

My 75 year old patient has an arterial oxygen tension (Pa02) less than 90 mmHg on room air. Does age affect PaO2?

What do eyes, nose, and toes have to do with Covid-19?

Increasingly, we are finding out that the clinical manifestations of Covid-19 are not limited to the respiratory tract and that several other areas of the body, including the eyes, nose, and toes, may also be affected.

Eyes: In a study1 of 38 patients with Covid-19, 12 (32%) had eye manifestations consistent with conjunctivitis (or “pink eye”), including conjunctival hyperemia, chemosis, epiphora (watering eyes) and increased secretions; none had blurred vision. Most patients had more severe manifestations of Covid-19. Tears from 2 patients tested positive for Covid-19 virus (SARS-Co-V-2) by PCR.

Nose: Altered sense of smell was reported in 4 of 9 mild Covid-19 cases, 2 without rhinitis.2 Loss of sense of smell or anosmia has been reported in 30% or more of patients as their major presenting symptom of Covid-19 in otherwise mild cases by the British Rhinological Society (unpublished data).3  Another study found a 5% prevalence of hyposmia (unpublished).4 In addition to infecting mucosal surfaces inside the nose, the coronaviruses may infect nerve cells.5 Fortunately, sense of smell alterations appear temporary.

Toes: Findings that may mimic frostbite or chilblains with erythema or bluish/purplish discoloration of toes along with pain, itching or burning have been described in patients with Covid-19.6,7 Anecdotally, many cases been observed in relatively healthy or younger patients.  Whether these changes are due to known coagulation and/or endothelial derangements in Covid-19 or other causes is not clear.8,9

Bonus Pearl: Did you know that ACE2 receptors have reportedly been found in abundance in the testes (not ovaries)10 and testicular pain has also been reported in a Covid-19 patient seen without respiratory symptoms?11

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 References

  1. Wu P, Duan F, Luo C, et al. Characteristics of ocular findings of patients with coronavirus disease 2019 (COVID-19) in Hubei province, China. JAMA Ophthalmology 2020; March 31. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2764083
  2. Wolfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-2019. Nature 2020;April 1. https://www.nature.com/articles/s41586-020-2196-x
  3. Hopkins C, Kumar N. Loss of sense of smell as marker of COVID-19 infection. https://www.entuk.org/sites/default/files/files/Loss%20of%20sense%20of%20smell%20as%20marker%20of%20COVID.pdf
  4. Mao L, Wang M, Chen S, et al. Neurological manifestations of hospitalized patients with COVID-19 in Wuhan, China: a retrospective case series study. https://www.medrxiv.org/content/10.1101/2020.02.22.20026500v1
  5. Perlman S, Jacobsen G, Afifi A. Spread of a neurotropic murine Coronavirus into the CNS via the trigeminal and olfactory nerves. Virology 1989;170:556-560 https://www.sciencedirect.com/science/article/pii/0042682289904467
  6. Mazzotta F, Troccoli T, Bonifazi E. A new vasculitis at the time of COVID-19. Eur J Ped Dermatol 2020. https://www.ejpd.com/images/nuova-vasculite-covid-ENG.pdf
  7. Lee YJ. “Covid toes” might be the latest unusual sign that people are infected with the novel coronavirus. April 23, 2020. https://www.businessinsider.com/covid-toes-frostbite-coronavirus-skin-lesion-discolored-swollen-feet-2020-4
  8. Zhang Y, Xiao M, Zhang S, et al. Coagulopathy and antiphospholipid antibodies in patients with Covid-19. N Eng J Med 2020;382:e38. https://www.nejm.org/doi/full/10.1056/NEJMc2007575
  9. Varga Z, Flammer AJ, Steiger P, et al. Endothelial cell infection and endothelial cell infection and endotheliitis in COVID-19. Lancet 2020; April 17. https://www.thelancet.com/action/showPdf?pii=S0140-6736%2820%2930937-5
  10. Kim J, Thomsen T, Sell N, et al. Abdominal and testicular pain: an atypical presentation of COVID-19. Am J Emerg Med 2020 https://doi.org/10.1016/j.ajem.2020.03.052
  11. Fan C, Li K, Ding Y, et al. ACE2 expression in kidney and testis may cause kidney and testis damage. medRxiv 2020. https://doi.org/10.1101/2020.02.12.20022418.t
     

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

 

What do eyes, nose, and toes have to do with Covid-19?

How common are acute kidney abnormalities in patients with Covid-19?

Although early reports suggested a low incidence (3-9%) of AKI among Covid-19 patients, more recent studies have shown higher frequencies of renal abnormalities, including albuminuria and hematuria (1).

 
A study of 59 patients with Covid-19 reported that 34% had “massive albuminuria” on the first day of admission, and 63% developed proteinuria during their hospitalization (2 [unpublished]). BUN was elevated in 27% of patients and in two-thirds of those who died. In another study involving 710 patients with Covid-19, nearly one-half had proteinuria and hematuria and a quarter had hematuria on admission. Overall, around 15% of patients had an elevated serum creatinine and BUN (3).

 
Possible explanations for renal manifestations of Covid-19 include sepsis, cytokine storm, secondary infections, and direct cellular injury due to the virus itself (1, 4). Interestingly, SARS-CoV-2 has been reportedly isolated from the urine sample of a Covid-19 patient (1). This should not be surprising given the presence of ACE2 receptors in the proximal tubules and, at lower concentrations, in the glomeruli (5).

 
An autopsy study of patients with Covid-19 found evidence of diffuse proximal tubule injury with the loss of brush border, vascular degeneration but no vasculitis, interstitial inflammation or hemorrhage. Coronavirus particles were found in the tubular epithelium and podocytes (6).

 
Bonus Pearl: Did you know that proteinuria (2-3+) and hematuria are independent risk factors for in-hospital mortality (3)?

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References
1. Naicker S, Yang CW, Hwang SJ. The novel coronavirus 2019 epidemic and kidneys. Kidney International 2020, May. DOI: https://doi.org/10.1016/j.kint.2020.03.001
2. Li Z, Wu M, Guo J, et al. Caution on kidney dysfunctions of 2019-nCoV patients . medRxiv 2020.02.08.20021212
3. Cheng Y, Luo R, Wang K, et al. Kidney disease is associated with in-hospital death of patients with COVID-19. Kidney International 2020;97:829-38.
4. Su H, Yang M, Wan C, et al. Renal histopathological analysis of 26 postmortem findings of patients with COVID-19 in China. Kidney International 2020, April 9. https://www.sciencedirect.com/science/article/pii/S0085253820303690  
5. Mizuiri S, Ohashi Y. ACE and ACE2 in kidney disease. World J Nephrol 2015;4:74-82. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4317630/
6. Cheng N, Zhou M, Dong X, et al. Kidney impairment is associated with in-hospital death of COVID-19 patients. medRxive 2020 .0218.20023242. https://doi.org/10.1101/2020.02.18.20023242.

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 
.

How common are acute kidney abnormalities in patients with Covid-19?

How often is the liver affected by Covid-19?

Abnormal liver enzymes in patients with Covid-19 are common, particularly in those with severe disease.

 
Elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) have been reported in 14-53% of patients in several case series. More severe cases appear to have a higher prevalence of AST elevation (1). As some cases also have elevated creatine kinase (CK), the relative contribution of muscles to these enzyme abnormalities is unclear (2).

 
A small study involving ICU patients with Covid-19 reported a prevalence of elevated AST of 62% compared to 25% in non-ICU patients (3). Other studies have confirmed lower incidence of AST abnormality among patients with mild or subclinical disease (4,5).

 
Although much of the published reports of liver injury in Covid-19 have revolved around AST and ALT abnormalities, gamma-glutamyl transferase (GGT) may also be elevated. GGT was abnormal in 54% of patients with Covid-19 during their hospitalization with alkaline phosphatase elevation reported in ~2.0% (1, unpublished reports). Elevation of total bilirubin has also been reported occasionally (1).

 
Although the exact mechanism(s) of Covid-19-related is unclear, direct viral infection of liver cells is one possibility as viremia has been documented in some cases (1). Of interest, a related coronavirus, SARS-CoV-1 has been shown to infect liver tissue and cholangiocytes may express ACE2 receptors, a prime target for Covid-19 virus (1,6,7, unpublished reports).

 

Despite these observations, to date, viral inclusions have not been demonstrated in the liver. Other possible causes of liver injury in Covid-19 include innate immune dysregulation, cytokine storm, hypoxia and drugs (1,2).

 

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References
1. Zhang C, Shi L, Wang FS. Liver injury in COVID-19:management and challenges. Lancet Gastroenterol Hepatol 2020; March 4. https://doi.org/10.1016/S2468-1253(20)30057-1
2. Bangash MN, Patel J, Parekh D. COVID-19 and the liver: little cause for concern. Lancet Gastroenterol Hepatol 2020;March 20. https://doi.org/10.1016/52468-1253(20)30084-4
3. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet 2020;395:497-506. https://pubmed.ncbi.nlm.nih.gov/31986264/
4. Guan WJ, Ni ZY, Hu Y, et al. Clinical characteristics of 2019 novel coronavirus infection in China. N Engl J Med 2020;published online Feb 28. DOI:10.1056/NEJMoa2003032
5. Shi H, Han X, Jiang N, et al. Radiological findings from 81 patients with COVID-19 pneumonia in Wuhan, China: a descriptive study. Lancet Infect Dis 2020; published onlineFeb 24. DOI:10.1016/S1473-3099(20)30086-4 (lancet 8)
6. Chai X, Hu L, Zhang Y, et al. Specific ACE2 expression in cholangiocytes may cause liver damage after 209-nCoV infection. bioRxiv 2020;published online Feb 4. https://doi.org/10.1101/2020.02.03.931766.
7. Xu Z, Shi L, Wang Y, et al. Pathological findings of COVID-19 associated with acute respiratory distress syndrome. Lancet Respir Med 2020; published online Feb 18. DOI:10.1016/S2213-2600(20)30076-X

 

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

How often is the liver affected by Covid-19?

How common are cardiac complications in Covid-19?

Although we often think of Covid-19 as a respiratory disease, cardiovascular complications are not uncommon.

Myocardial injury based on elevated cardiac troponin levels have been reported in ~20% of patients with Covid-19.1,2 Among deceased patients with Covid-19 without underlying cardiovascular disease, ~12.0% have been reported to have “substantial heart damage” based on elevated levels of troponins or cardiac arrest.1  

Arrythmias have also been reported in a significant number of patients (~20.0% in those on invasive mechanical ventilation). 3,4

Reports of Covid-19-associated acute onset heart failure, myocardial infarction, myocarditis and pericarditis have also appeared in the literature. 4-6

Proposed mechanisms of acute myocardial injury include direct binding of the virus to ACE2 receptors which are present not only in the lungs but also cardiac endothelial and smooth muscle cells of myocardial vessels as well as in cardiac myocytes. 1,7,8 Myocardial injury may also be a consequence of Covid-19-related cytokine storm or respiratory insufficiency.1

Interestingly, patient with heart failure have increased expression of ACE2 which may make them particularly vulnerable to myocardial injury and failure after Covid-19 infection. 8

Bonus Pearl: Did you know that a type of perivascular mural cell called “pericyte” makes up a significant part of the myocardium and—in contrast to relatively low expression of ACE2 in cardiac myocytes— expresses ACE2 at high levels, potentially serving as an important target for Covid-19 virus? 8

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 References

  1. Zheng YY, Ma YT, Zhang JY, et al. Covid-19 and the cardiovascular system. Nature Rev 2020, May. https://www.nature.com/articles/s41569-020-0360-5
  2. Yang xz, Yu Y, Xu J, et al. Clinical course and outcomes of critically ill patients with SARS-CoV-2 pneumonia in Wuhan, China: a single-centered, retrospective, observational study. Lancet Respir Med 2020, Feb 24. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102538/
  3. Goyal P, Choi JJ, Pinheiro LC, et al. Clinical characteristics of Covid-19 in New York City 2010. N Engl J Med 2020. DOI: 10.1056/NEJMc2010419 https://www.nejm.org/doi/full/10.1056/NEJMc2010419
  4. Covid-19 clinical guidance for the cardiovascular care team. American College of cardiology 2020. https://www.acc.org/~/media/665AFA1E710B4B3293138D14BE8D1213.pdf
  5. Hu H, Ma F, Wei X, et al. Coronavirus fulminant myocarditis treated with glucocorticoid and human immunoglobulin. Eur Heart J 2020. https://pubmed.ncbi.nlm.nih.gov/32176300/
  6. Hua A, O’Gallaher KO, Sado D. Life-threatening cardiac tamponade complicating myo-pericarditis in Covid-19. Eur Heart J 2020. https://academic.oup.com/eurheartj/article/doi/10.1093/eurheartj/ehaa253/5813280
  7. Gallager PE, Ferrario CM, Tallant EA. Regulation of ACE2 in cardiac myocytes and fibroblasts. Am J Physiol heart Circ Physiol 2008;295:H2373-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614534/
  8. Chen L, Li X, Chen M, et al. The ACE2 expression in human heart indicates new potential mechanism of heart injury among patients infected with SARS-CoV-2. Cardiovasc Res 2020, March 13. https://academic.oup.com/cardiovascres/article/doi/10.1093/cvr/cvaa078/5813131

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

How common are cardiac complications in Covid-19?

How common are gastrointestinal symptoms in Covid-19?

Although GI symptoms such as diarrhea or nausea were initially thought to be uncommon among Covid-19 patients,1,2 more recent reports suggest that GI symptoms are relatively common.3-8

A review article found that as many as 50.0% of Covid-19 patients had diarrhea, ~30.0% had nausea, ~14.0% had gastrointestinal bleed, and 6.0% had abdominal pain. In a case series from New York City, ~25.0% of patients presented with diarrhea, while ~20.0% had nausea and vomiting. 9 

Some patients may have GI symptoms in the absence of any respiratory complaints.  Fecal tests for RNA  have found nearly one-third to a half of patients with Covid-19 shedding the virus, with some patients testing positive even after  respiratory specimens test negative.8 How often these patients harbor viable or infectious virus is not known, however.

Some have reported that as the severity of the disease worsens so do the GI symptoms.3 GI symptoms have also been associated with later presentation of Covid-19, higher liver enzymes and longer prothrombin time.3

Although the exact mechanism of GI symptoms in Covid-19 is unclear, direct invasion of virus is a plausible explanation. Indeed, potential targets for SARS-CoV-2 virus, the ACE2-expressing cells, have been identified in the GI tract, including the esophagus, gastric, intestinal and colonic epithelial cells.5,8  

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 References

 

  1. Guan WJ, Ni ZY, Hu Y, et al. Clinical characteristics of Coronavirus disease 2019 in China. N Eng J Med 2020, Feb 28. https://www.nejm.org/doi/full/10.1056/NEJMoa2002032
  2. Young BE, Ong SWX, Kalimuddin S, et al. Epidemiologic features and clinical course of patients infected with SARS-CoV-2 in Singapore. JAMA. March 3, 2020. (17% diarrhea) https://jamanetwork.com/journals/jama/fullarticle/2762688
  3. Pan L, Mu M, Yang P, et al. Clinical characteristics of COVID-19 patients with digestive symptoms in Hubei, China: a descriptive, cross-sectional, multicenter study. Am j Gastroenterol 2020. https://journals.lww.com/ajg/Documents/COVID_Digestive_Symptoms_AJG_Preproof.pdf
  4. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novle coronavirus in Wuhan, China. Lancet 2020;395:497-506. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30183-5/fulltext
  5. Gu J, Han B, Wang J. COVID-19: Gastrointestinal manifestations and potential fecal-oral transmission. J Gastroenterol https://www.gastrojournal.org/article/S0016-5085(20)30281-X/pdf
  6. Wolfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with Covid-2019. Nature, April 1, 2020. https://doi.org/10.1038/a41586-020-2196-x
  7. Xiao F, Tang M, Zheng X, et al. Evidence of gastrointestinal infection of SARS-CoV-2. Gastroenterology 2020, March 3. https://www.sciencedirect.com/science/article/pii/S0016508520302821?via%3Dihub
  8. Tian Y, Rong L, Nian W, et al. Review article: gastrointestinal features in COVID-19 and the possibility of faecal transmission. Aliment Pharmacol Ther 2020;March 29. https://doi.org/10.1111/apt.15731
  9. Goyal P, Choi JJ, Pinheiro LC, et al. Clinical characteristics of Covid-19 in New York City. N Engl J Med 2020.  https://www.nejm.org/doi/full/10.1056/NEJMc2010419

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

How common are gastrointestinal symptoms in Covid-19?

Is my patient with Covid-19 immune to future infections due to the same virus?

Since Covid-19 is a new disease, it is unclear if our body’s immune response can protect us from future infections, and if so, for how long.

In a MedRxiv study involving 175 Covid-19 recovered patients (median age 50 y) with mild symptoms, the production of neutralizing antibodies (Nab) varied, with ~30% of patients considered to have “very low level” titers. So at least a subset of patients with mild symptoms may not produce adequate antibodies against Covid-19 despite seemingly uncomplicated recovery.  Whether these patients are at risk of re-infection with Covid-19 virus remains to be seen.1

In a study involving patients with Covid-19 (median age 62 y) of variable severity, the rate of seropositivity at 2-4 weeks was 88% or higher. However, despite development of antibodies against surface spike protein and internal nucleoproteins of SARS-CoV-2, the Covid-19 virus, viral RNA could be detected in the throat samples from a third of patients for 20 days or longer.2

In another study involving mild Covid-19 cases, despite seroconversion after 7 days in 50% of patients and after 14 days in 100% of patients, no rapid decline in pharyngeal viral load was noted. These findings raised doubts about the role of antibodies in clearing the virus.3

Somewhat more encouraging is the finding that experimentally infected monkeys rechallenged with Covid-19 virus after full recovery 28 days following initial infection seem to be protected against Covid-19.4 So there may be some protection for couple of weeks at least! 

Ultimately, whether immunity to Covid-19 will be like seasonal coronaviruses that cause common colds with unpredictable protection after 1 year, or more similar to that of SARS virus with persistence of antibodies for ~2-3 years, only time will tell. 4,5

Stay tuned!

 

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References

  1. Neutralizing antibody responses to SARS-CoV-2 in a COVID-19 recovered patient cohort and their implications. MedRxiv preprint doi: https://doi.org/10.1101/2020.03.30.20047365
  2. To KKW, Tsang OWTY, Leung WS, et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet 2020; March 23. https://doi.org/10.1016/S1473-3099 (20)30196-1
  3. Wolfel R, Corman VM, Gugggemos W, et al. Virological assessment of hospitalized patients with COVID-2019. Nature https://doi.org/10.1038/s42586-020-2196-x (2020) .
  4. Bao L, Deng W, Gao H, et al. Reinfection could not occur in SARS-CoV-2 infected rhesus macaques. bioRxiv doi: https://dli.org/10.1101/2020.03.13.990226.
  5. Callow KA, Parry HF, Sergeant M. et al. The time course of the immune response to experimental coronavirus infection of man. Epidemiol Infect 1990;105:435-46. https://www.ncbi.nlm.nih.gov/pubmed/2170159
  6. McKenna S. What immunity to COVID-19 really means? Scientific American, April 10, 2020. https://www.scientificamerican.com/article/what-immunity-to-covid-19-really-means/

 

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Is my patient with Covid-19 immune to future infections due to the same virus?

How can people with a respiratory virus such as Covid-19 be contagious even when they don’t cough or sneeze?

Couple of factors likely play a role in the transmission of respiratory viruses such as Covid-19 even in the absence of respiratory symptoms: 1. Generation of small droplets through everyday activities such as talking and breathing; 2. Presence of infectious virus in the respiratory tract before onset of symptoms.1-4

Small droplet generation during every day activity: Normal human speech and breathing can yield small particles or droplets that are too small to see by naked eye but are perfectly capable of serving as vehicles for aerial transport (more like hot air balloons than 737’s!) of a variety of communicable respiratory pathogens. 1  These small particles are believed to originate from the mucosal layers coating the respiratory tract as well as from vocal cord adduction and vibration within the larynx.1

In some cool experiments involving normal volunteers,1 the rate of particle emission during normal human speech positively correlated with the loudness of voice, ranging from 1-50 particles/second, irrespective of the language spoken (English, Spanish, Mandarin, or Arabic).  Perhaps, equally intriguing was identification of “speech superemitters”, consistently releasing an order of magnitude more particles than other participants.

Simply counting out loud has been associated with around 2-10 times as many total particles emitted as a single cough, 2 and the percentage of airborne droplet nuclei generated by singing is several times more than that emitted during normal talking and more like that of coughing! 3 Given, these observations, perhaps, the unfortunate outbreak of Covid-19 among members of a church choir in state of Washington 5 is not totally unexpected.

Presence of infectious virus in persons without symptoms:  An estimated 18% to 75% of patients testing positive for Covid-19 have no symptoms. This of course means that irrespective of whether symptoms ever develop, persons with Covid-19 may serve as a source of infection, by just breathing, talking, or singing when around susceptible people.

For these reasons, social distancing and wearing of masks during a pandemic makes sense!

Bonus Pearl: Did you know that infectious viral particles can be recovered from 40% of breath samples of patients with influenza? 6

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 References

  1. Asadi S, Wexler AS, Cappa CD, et al. Aerosol emission and superemission during human speech increase with voice loudness. Scientific Reports 2019;9:2348. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6382806/
  2. Loudon RG, Roberts RM. Droplet expulsion from the respiratory tract. Am Rev Resp Dis 1967;435-42. https://doi.org/10.1164/arrd.1967.95.3.435
  3. Loudon RG, Roberts MR. Singing and the dissemination of tuberculosis. Am Rev Resp Dis 1968;98:297-300. DOI: 10.1164/arrd.1968.98.2.297 https://www.atsjournals.org/doi/abs/10.1164/arrd.1968.98.2.297?journalCode=arrd
  4. Lai KM, Bottomley C, McNerney. Propagation of respiratory aerosols by the Vuvuzela. PLoS One 2011;6:e20086. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100331/
  5. Read R. A choir decided to go ahead with rehearsal. Now dozens of members have COVID-19 and two are dead. Los Angeles Times March 29, 2020. https://www.latimes.com/world-nation/story/2020-03-29/coronavirus-choir-outbreak
  6. Yan J, Grantham M, Pantelic J, et al. Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community. PNAS 2018;115:1081-1086 https://www.pnas.org/content/115/5/1081

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

How can people with a respiratory virus such as Covid-19 be contagious even when they don’t cough or sneeze?

Does a positive routine PCR test for Covid-19 virus mean the person is infectious?

Not necessarily! Although a positive routine PCR test for Covid-19 indicates the presence of the virus in a clinical specimen, it does not mean that the virus is still viable or transmissible, particularly as the patient may be recovering from Covid-19. Viral cultures are often needed to help answer this question. 1-5

In a study of 9 hospitalized patients with Covid-19, no viable Covid-19 virus could be found by culture in any specimen beyond 8 days following onset of symptoms despite a positive routine PCR for up to 13 days. Successful growth of the virus was dependent in part on viral load, with samples containing <106 copies/mL never yielding any viable virus.1  

In the same study, none of stools that were positive for Covid-19 virus by PCR were positive by culture.  The authors concluded that there is “little residual risk of infectivity” beyond day 10 of symptoms when sputum contains less than 100,000 viral RNA copies /ml.  Of note, the patients in this study were young- to middle-aged without significant underlying disease and had milder disease, so the results may not necessarily be generalizable to other patients with Covid-19. 1

The discrepancy between a positive PCR and negative culture has been seen with other respiratory pathogens,  such as respiratory syncytial virus (RSV) and influenza. In a study involving experimentally infected subjects with RSV, the average duration of viral shedding was 9.2 days by PCR compared to 7.2 days by viral culture.2 In another study involving patients with symptomatic influenza, virus could be detected for up to 7 days with PCR compared to 1-2 days by viral culture.3

Factors that may explain this discrepancy include suboptimal sample transport, low viral titers,  and the presence of neutralizing antibody in the clinical specimen.2,3

So, despite our incomplete knowledge, don’t assume that PCR positivity means the presence of live virus capable of transmitting Covid-19!

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References

  1. Wolfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-19. Nature 2020; April 1. https://www.nature.com/articles/s41586-020-2196-x
  2. Falsey AR, Formica MA, Treanor JJ, et al. Comparison of quantitative reverse transcriptase-PCR to viral culture for assessment of respiratory syncytial virus shedding. J Clin Microbiol 2003;41:4160-65. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC193781/pdf/0106.pdf
  3. Van Elden LJR, Nijhuis M, Schipper P, et al . Simultaneous detection of influenza viruses A and B using real-time quantitative PCR. J Clin Microbiol 2001;39:196-200. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC87701/
  4. Cangelosi GA, Meschke JS. Dead or alive:molecular assessment of microbial viability. App Environ Microbiol 2014;80:5884-91.
  5. European Centre for Disease Prevention and Control. Novel coronavirus (SARS-CoV-2). https://www.ecdc.europa.eu/en/publications-data/novel-coronavirus-sars-cov-2-discharge-criteria-confirmed-covid-19-cases

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

Does a positive routine PCR test for Covid-19 virus mean the person is infectious?