How common are neurological symptoms in patients with Covid-19 infection?

Although we usually think of it as primarily a respiratory tract disease, neurological manifestations with Covid-19 are not at all uncommon,1-6 occurring in over one-third of hospitalized patients with Covid-19 according to one medRxiv report.1

In a Chinese study1 involving 214 hospitalized patients with Covid-19, 36.4% had 1 or more neurological symptoms, with the majority involving the central nervous system (CNS) (25.0%), of which the most common complaints were dizziness (17%) and headache (13.0%). Some patients (9.0%) had cranial nerve/peripheral nerve complaints of which the most common were difficulty with taste (hypogeusia) (6.0%) and sense of smell (hyposmia) (5.0%).  A fewer number of patients had impaired consciousness, acute cerebrovascular disease (including ischemic stroke and cerebral hemorrhage). Although not strictly-speaking a neurological manifestation, the study also reported “muscle injury” in ~20.0% of patients     (defined as myalgia plus CK >200 IU/L).

Descriptions of Covid-19 encephalopathy, including one associated with acute hemorrhagic necrotizing process, are also beginning to appear in the literature.3-5 Reports of “Neuro-Covid-19 units” in Italy further underlines the common occurrence of neurological symptoms in these patients.6

More than one mechanism for neurological complications in Covid-19 are likely,  including:1-2

  1. Direct viral invasion into the CNS which could explain the associated headache, high fever, vomiting, convulsions, and consciousness disorders. Some have reported normal CSF parameters but a report of PCR positive CSF suggests direct injury from the virus itself.2 Covid-19 virus may gain access to the CNS through direct invasion of neuronal pathways (eg. olfactory nerve given recent reports of difficulty with sense of smell) or through blood circulation.
  2. Indirect CNS injury through extreme systemic derangements such as hypoxia, or immune/inflammatory response-related injury (eg, through cytokines, hypercoagulability related to infection). Some have also posited that binding of Covid-19 virus to ACE2 may cause abnormally elevated blood pressure and increase the risk of cerebral hemorrhage.2

The fact that Covid-19 is so versatile and affects the nervous system as well shouldn’t surprise us. Neurological complications have been reported with couple of other related respiratory Coronaviruses such as those of SARS and MERS.2

 

Bonus pearl: Did you know that as early 1970-80s some coronaviruses were shown to cause “nasoencephalopathy” when injected intranasally in mice with subsequent spread to the CNS through the olfactory nerve?7 Maybe we shouldn’t be too surprised that sense of smell is impaired in some Covid-19 patients. If we could only stop the virus at the nose!

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References

  1. 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
  2. Wu Y, Xu X, Chen Z, et al. Nervous system involvement after infection with COVID-19 and other coronaviruses. Brain, Behavior, and Immunity 2020, March 30. https://www.sciencedirect.com/science/article/pii/S0889159120303573
  3. Xiang et al. 2020. First case of 2019 novel Coronavirus disease with encephalitis. ChinaXiv, T202003 (2020), p. 00015 (obtained from reference 2).
  4. Poyiadji N, Shain G, Noujaim D, et al. COVID-19-associated acute hemorrhagic necrotizing encephalopathy: CT and MRI features. Radiology 2020 https://pubs.rsna.org/doi/10.1148/radiol.2020201187
  5. Filatov A, Sharma P, Hindi F, et al. Neurological complications of coronavirus (COVID-19): encephalopathy. Cureus 12(3): e7352. DOI 10.7759/cureus.7352 https://www.cureus.com/articles/29414-neurological-complications-of-coronavirus-disease-covid-19-encephalopathy
  6. Talan J. COVID-19: Neurologists in Italy to Colleagues in US: Look for poorly-defined neurologic conditions in patients with the Coronavirus. Neurology Today 2020, March 27. https://journals.lww.com/neurotodayonline/blog/breakingnews/pages/post.aspx?PostID=920
  7. 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

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 neurological symptoms in patients with Covid-19 infection?

What findings should I look for in the chest imaging of my patients with the novel Coronavirus disease/Covid-19?

Chest imaging is often obtained to evaluate for pneumonia and progressive lung injury due to Covid-19. Given the concerns over healthcare worker exposure and environmental contamination, radiographic imaging should be minimized and obtained only when clinically indicated (1).

 
Routine chest radiograph: In a study involving over 1000 hospitalized patients with Covid-19, chest Xray abnormalities on admission were observed in about half of patients with nonsevere disease and three-quarters of those with severe disease (2). Many infiltrates are bilateral, patchy and peripheral in distribution (2,3).

 
Chest CT (without IV contrast):  CT abnormalities on admission have been observed in 84% of patients with nonsevere and 94% of patients with severe disease (2). Ground glass opacities (GGOs) and consolidation have been reported in the majority of patients. Infiltrates are often bilateral, peripheral, and posterior in distribution ( 2-5).

Compared to other causes of pneumonia, the most discriminating features of Covid-19 pneumonia on CT include peripheral distribution of infiltrates (80% vs 57%) and GGOs (91% vs 68%) (5).

CT findings are time dependent. Early during the course of infection, peripheral focal or bilateral multifocal GGOs are frequently observed, later giving rise to “crazy paving” and consolidation with occasional “reverse halo sign” as the disease progresses (see Bonus Pearl below), peaking around 9-13 days (6,7) . Pleural effusion and lymphadenopathy are uncommon (5,7).

 
Point of care ultrasound (POCUS): This relative newcomer offers a potentially useful and rapid means of evaluating for pneumonia or lung injury in Covid-19 and may be more sensitive than chest Xray. Its findings are not specific for Covid-19 lung pathology, however. In a preliminary report involving 12 patients with Covid-19 pneumonia (without ARDS) who underwent POCUS, a diffuse B-line pattern with spared areas was seen in all patients (8,9). Strict adherence to proper isolation precautions and decontamination of the ultrasound probe are essential.

 

Bonus Pearl: “Crazy paving” pattern on CT refers to GGOs with superimposed interlobular septal thickening and intralobular septal thickening, while “reversed halo sign” is a central GGO surrounded by denser consolidation of crescentic shape ring at least 2 mm in thickness (reference 7 has nice photos).

 

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References
1. ACR recommendations for the use of chest radiography and computed tomography (CT) for suspected COVID-19 infection. March 19, 2020. https://www.acr.org/Advocacy-and-Economics/ACR-Position-Statements/Recommendations-for-Chest-Radiography-and-CT-for-Suspected-COVID19-Infection
2. Guan WJ, Zheng-yi N, Hu Y, et al. Clinical characteristics of Coronavirus disease 2019 in China. N Engl J Med 2020; February 28. https://www.nejm.org/doi/full/10.1056/NEJMoa2002032
3. Ai T, Yang Z, Hou H, et al. Correlation of chest CT and RT-PCR testing in Coronavirus disease 2019 (COVID-19) in China: A report of 1014 cases. Radiology 2020. https://pubs.rsna.org/doi/10.1148/radiol.2020200642
4. Yoon SH, Lee KH, Kim JY, et al. Chest radiographic and CT findings of the 2019 Novel Coronavirus disease (COVID-19): Analysis of nine patients treated in Korea. Korean J Radiol 2020;21 :494-500. https://www.kjronline.org/Synapse/Data/PDFData/0068KJR/kjr-21-494.pdf
5. Bai HX, Hsieh B, Xiong Z, et al. Performance of radiologists in differentiating COVID-19 from viral pneumonia on chest CT. https://pubs.rsna.org/doi/10.1148/radiol.2020200823
6. Kanne JP, Little BP, Chung JH, et al. Essentials for radiologists on COVID-19: An update—Radiology scientific expert panel. Radiology 2020; February 27. https://pubs.rsna.org/doi/10.1148/radiol.2020200527

7. Bernheim A, Mei X, Huang M, et al. Chest CT findings in Coronavirus Disease-19 (COVID-19):Relations to duration of infection. Radiology 2020 Feb 20:200463.  https://pubs.rsna.org/doi/pdf/10.1148/radiol.2020200463
8. Poggiali E, Dacrema A, Bastoni D, et al. Can lung US help critical care clinicians in the early diagnosis of novel Coronavirus (COVID-19) pneumonia? Radiology 2020; https://www.ncbi.nlm.nih.gov/pubmed/32167853

9. Peng QY, Wang XT, Zhang LN, et al. Findings of lung ultrasonography of novel Coronavirus pneumonia during the 2019-2020 epidemic. Intensive Care Med 2020. https://doi.org/10.1007/s00134-020-05996.

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 findings should I look for in the chest imaging of my patients with the novel Coronavirus disease/Covid-19?

Are NSAIDS contraindicated in patients with 2019 novel Coronavirus infection (Covid-19)?

Despite recent internet reports of the association of non-steroidal anti-inflammatory drugs (NSAIDs) with worsening symptoms among patients with Covid-19 (1), firm clinical evidence to support such claims is currently lacking. However, there are some theoretical reasons why it may still be best to avoid NSAIDs in this condition due to their potential adverse impact on the innate and adaptive immune responses as well as their antipyretic properties (2-9).

 
Blunting of the innate immune response: Certain NSAIDs (eg, ibuprofen, naproxen and celecoxib) inhibit cyclooxygenase enzyme-2 (COX-2) and impair production of several pro-inflammatory cytokines important in fighting infections, such as tumor necrosis factor, interleukin 1 and 6, as well as interferon, an antiviral cytokine (2,6,8). COX-2 has been shown to be important in controlling viral replication in influenza (4). Ibuprofen has been associated with inhibitory effects on a variety of polymorphonuclear functions, including chemotaxis (2).

 
Impact on adaptive immune response: COX-2 inhibition may be associated with impaired neutralizing antibody production (3,4,8). Potential mechanisms include modulation of cytokine expression, nitric-oxide production, and antigen processing/presentation and T lymphocyte activation (3,8).

 
Antipyretic effect: NSAIDs are often given for treatment of fever which is an evolutionary host response to infection. A meta-analysis of animal studies evaluating the impact of antipyretics (including aspirin, NSAIDs, and acetaminophen) in influenza found lower survival in animals treated with antipyretics (9). Longer duration of viral shedding has also been associated with the use of aspirin or acetaminophen in rhinovirus infection (9).

 
Formal epidemiologic and experimental studies are sorely needed to evaluate the safety of NSAIDS in Covid-19.  

 

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References
1. Kolata G. Is ibuprofen really risky for Coronavirus patients? NY Times, March 17, 2020. https://www.nytimes.com/2020/03/17/health/coronavirus-ibuprofen.html
2. Graham NMH, Burrell CJ, Douglas RM, et al. Adverse effects of aspirin, acetaminophen and ibuprofen on immune function, viral shedding, and clinical status in rhinovirus-infected volunteers. J Infect Dis 1990;162:1277-1282. https://academic.oup.com/jid/article/162/6/1277/918184
3. Culbreth MJ, Biryunkov S, Shoe JL, et al. The use of analgesics during vaccination with a live attenuated Yersinia pestis vaccine alters the resulting immune response in mice. Vaccines 2019;7, 205; doi:10.3390/vaccines7040205 https://www.mdpi.com/2076-393X/7/4/205
4. Ramos I, Fernandez-Sesma A. Modulating the innate immune response to influenza A virus:potential therapeutic use of anti-inflammatory drugs. Frontiers in Immunology. July 2015. Volume 6. Article 361. https://www.ncbi.nlm.nih.gov/pubmed/26257731
5. Falup-Pecurariu O, Man SC, Neamtu ML, et al. Effects of prophylactic ibuprofen and paracetamol administration on the immunogenicity and reactogenicity of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugated vaccine(PHID-CV) co-administered with DTPa-combined vaccines in children:An open-label, randomized, controlled, non-inferiority trial. Human Vaccines & Immunotherapeutics 2017;13: 649-660. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5360152/
6. Housby JN, Cahill CM, Chu B, et al. Non-steroidal anti-inflammatory drugs inhibit the expression of cytokines and induce HSP70 in human monocytes. Cytokine 1999;11:347-58. https://www.ncbi.nlm.nih.gov/pubmed/30186359
7. Agarwal D, Schmader KE, Kossenkov AV, et al. Immune response to influenza vaccination in the elderly is altered by chronic medication use. Immunity & Ageing 2018;15:19. https://www.ncbi.nlm.nih.gov/pubmed/30186359
8. Bancos S, Bernard MP, Topham DJ, et al. Ibuprofen and other widely used non-steroidal anti-inflammatory drugs inhibit antibody production in human cells. Cell Immunol 2009;258:18-28. https://www.ncbi.nlm.nih.gov/pubmed/19345936
9. Eyers S, Weatherall M, Shirtcliffe P, et al. The effect on mortality of antipyretics in the treatment of influenza infection: systematic review and meta-analysis. J R Soc Med 2010;103:403-11. https://www.ncbi.nlm.nih.gov/pubmed/20929891

 

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!

Are NSAIDS contraindicated in patients with 2019 novel Coronavirus infection (Covid-19)?

Key clinical pearls in the medical management of hospitalized patients with coronavirus (Covid-19) infection

First, a shout-out to dedicated healthcare workers everywhere who have selflessly given of themselves to care for the sick during this pandemic. Thank you! Together, I know we will get through it!

Although our understanding of Covid-19 infection is far from complete, in the spirit of clarity and brevity of my posts on Pearls4Peers, here are some key points I have gleaned from review of existing literature and the CDC that may be useful as we care for our hospitalized patients with suspected or confirmed Covid-19 infection.

  • Isolation precautions.1 Per CDC, follow a combination of airborne (particularly when aerosol generating procedures is anticipated, including nebulizer treatment) and contact precaution protocols. Routinely use masks or respirators, such as N-95s (subject to local availability and policy) and eye protection. Don gowns (subject to local availability and policy) and gloves and adhere to strict hand hygiene practices.

 

  • Diagnostic tests1-9
    • Laboratory tests. Routine admission labs include CBC, electrolytes, coagulation panels and liver and renal tests. Other frequently reported labs include LDH, C-reactive protein (CRP) and procalcitonin. Testing for high sensitivity troponin I has also been performed in some patients, presumably due to concern over ischemic cardiac injury or myocarditis.2 Check other labs as clinically indicated.
    • Chest radiograph/CT chest. One or both have been obtained in virtually all reported cases with CT having higher sensitivity for detection of lung abnormalities.
    • EKG. Frequency of checking EKGs not reported in many published reports thought 1 study reported “acute cardiac injury” in some patients, based in part on EKG findings.4 Suspect we will be checking EKGs in many patients, particularly those who are older or are at risk of heart disease.
    • Point-of-care ultrasound (POCUS). This relatively new technology appears promising in Covid-19 infections, including in rapid assessment of the severity of pneumonia or ARDS at presentation and tracking the evolution of the disease. 9 Don’t forget to disinfect the probe between uses!

 

  • Treatment 1-8
    • Specific therapies are not currently available for treatment of Covid-19 infections, but studies are underway.
    • Supportive care includes IV fluids, 02 supplementation and nutrition, as needed. Plenty of emotional support for patients and their families will likely be needed during these times.
    • Antibiotics have been used in the majority of reported cases, either on admission or during hospitalization when superimposed bacterial pneumonia or sepsis could not be excluded.
      • Prescribe antibiotics against common community-acquired pneumonia (CAP) pathogens, including those associated with post-viral/influenza pneumonia such as Streptococcus pneumoniae (eg, ceftriaxone), and Staphylococcus aureus (eg, vancomycin or linezolid if MRSA is suspected) when concurrent CAP is suspected.
      • Prescribe antibiotics against common hospital-acquired pneumonia (HAP) (eg, vancomycin plus cefepime) when HAP is suspected.
    • Corticosteroids should be avoided because of the potential for prolonging viral replication, unless indicated for other reasons such as COPD exacerbation or septic shock. 1
    • Monitor for deterioration in clinical status even when your hospitalized patient has relatively minor symptoms. This is because progression to lower respiratory tract disease due to Covid-19 often develops during the 2nd week of illness (average 9 days).
    • ICU transfer may be necessary in up to 30% of hospitalized patients due to complications such as ARDS, secondary infections, and multi-organ failure.

 

Again, thank you for caring for the sick and be safe! Feel free to leave comments or questions.

 

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References

  1. CDC. Interim clinical guidance for management of patients with confirmed coronavirus disease (COVID-19). https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html
  2. Ruan Q, Yang K, Wang W, Jiang L, et al. Clinical predictors of mortality due to COVID-19 based on analysis of data of 150 patients with Wuhan, China. Intensive Care Med 2020. https://link.springer.com/article/10.1007/s00134-020-05991-x
  3. Holshue ML, BeBohlt C, Lindquist S, et al. First case of 2019 novel coronavirus in the United States. N Engl J Med 2020;382:929-36. https://www.nejm.org/doi/full/10.1056/NEJMoa2001191
  4. Huang C, Wang Y, Li Xingwang, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet 2020;395:497-506. https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(20)30183-5.pdf
  5. Young BE, Ong SWX, Kalimuddin S, et al. Epideomiologic features and clinical course of patients infected with SARS-CoV-2 Singapore. JAMA, March 3, 2020. Doi.10.1001/jama.2020.3204 https://www.ncbi.nlm.nih.gov/pubmed/32125362
  6. Chen N, Zhou M, Dong X, et al. Epidemiological and clinical chacteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet 2020;395:507-13. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30211-7/fulltext
  7. Guan W, Ni Z, Hu Y, et al. Clinical characteristics of coronavirus disease 2019 in China. N Engl Med 2020, Feb 28, 2020. https://www.nejm.org/doi/full/10.1056/NEJMoa2002032
  8. Zhang J, Zhou L, Yang Y, et al. Therapeutic and triage strategies for 2019 novel coronavirus disease in fever clinics. Lancet 2020;8: e11-e12. https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30071-0/fulltext 9.
  9. Peng QY, Wang XT, Zhang LN, et al. Findings of lung ultrasonography of novel corona virus pneumonia during the 2019-2020 epidemic. Intensive Care Med 2020. https://doi.org/10.1007/s00134-020-05996-
Key clinical pearls in the medical management of hospitalized patients with coronavirus (Covid-19) infection

When should I suspect invasive pulmonary aspergillosis in my patient with COPD exacerbation?

Think of invasive pulmonary aspergillosis (IPA) in your patient when she or he has a COPD exacerbation that appears refractory to broad-spectrum antibiotics and high doses of steroids. Heighten your suspicion even more in patients with severe-steroid dependent COPD, presence of a new pulmonary infiltrate or isolation of Aspergillus spp from respiratory cultures. 1

It’s worth remembering that although dyspnea and bronchospasm are found in most COPD patients with IPA, in contrast to haematological patients, fever, chest pain and hemoptysis are usually absent in this patient population.1

Diagnosis of IPA in this patient population is challenging for several reasons including: 1. A definitive or “proven” diagnosis requires histopathologic evidence of Aspergillus invasion of lung tissue which is not possible without subjecting an already fragile patient to invasive procedures (eg, lung aspiration or biopsy); 2. In contrast to IPA in highly susceptible immunocompromised patients with cancer and recipients of hematopoietic stem cell transplants, standardized definition of IPA in patients with COPD is lacking; 1,3 and 3. Frequent colonization of the respiratory tract of COPD patients with Aspergillus spp (16.3 per 1000 COPD admission in 1 study) 4,5, makes it difficult to diagnose IPA based on cultures alone.

Aside from respiratory cultures, another non-invasive test, serum galactomannan (GM, a polysaccharide antigen that exists primarily in the cell walls of Aspergillus spp and released into the blood during its growth phase 6) may have some utility in suggesting IPA in COPD patients, albeit with a mediocre sensitivity (~30-60%) but respectable specificity (>80 %). In contrast, bronchoalveolar lavage fluid GM may have better sensitivity  (~75%-90%) with similar specificity as that of serum GM in the diagnosis of IPA in these patients 7-8

Bonus pearl: Did you know that the incidence of IPA appears to be increasing in COPD patients requiring ICU admission, with reported mortality rates of 67% to 100%? 7

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References

  1. Bulpa P, Dive A, Sibille Y. Invasive pulmonary aspergillosis in patients with chronic obstructive pulmonary disease. Eur Res J 2007;30:782-800. https://www.ncbi.nlm.nih.gov/pubmed/17906086
  2. Bulpa P, Bihin B, Dimopoulos G, et al. Which algorithm diagnoses invasive pulmonary aspergillosis best in ICU patietns with COPD? Eur Resir J 2017;50:1700532 https://www.ncbi.nlm.nih.gov/pubmed/28954783
  3. Barberan J, Garcia-Perez FJ, Villena V, et al. Development of aspergillosis in a cohort of non-neutropenic, non-transplant patients colonized by Aspergillus spp. BMC Infect Dis 2017;17:34. https://link.springer.com/article/10.1186/s12879-016-2143-5
  4. Guinea J, Torres-Narbona M, Gijon P, et al. Pulmonary aspergillosis in patients with chronic obstructive pulmonary disease: incidence, risk factors, and outcome. Clin Microbiol Infect 2010; 16:870-77. https://www.sciencedirect.com/science/article/pii/S1198743X14617432
  5. Blot Stijn I, Taccone FS, Van den Abeele A-M, et al. A clinical algorithm to diagnose invasive pulmonary aspergillosis in critically ill patients. Am J Respir Crit Care Med 202;186:56-64. https://www.atsjournals.org/doi/full/10.1164/rccm.201111-1978OC
  6. Pfeiffer CD, Fine JP, Safdar N. Diagnosis of invasive aspergillosis using a galactomannan assay: a meta-analysis. Clin Infect Dis 2006;42:1417-27. https://academic.oup.com/cid/article/42/10/1417/278148
  7. He H, Ding L, Sun B, et al. Role of galactomannan determinations in bronchoalveolar lavage fluid samples from critically ill patients with chronic obstructive pulmonary disease for the diagnosis of invasive pulmonary aspergillosis: a prospective study. Critical Care 2012;16:R138. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5066034/
  8. Zhou W, Li H, Zhang Y, et al. Diagnostic value of galactomannan antigen test in serum and bronchoalveolar lavage fluid samples from patients with nonneutropenic invasive pulmonary aspergillosis. J Clin Microbiol 2017;55:2153-61. https://www.ncbi.nlm.nih.gov/pubmed/28446576
When should I suspect invasive pulmonary aspergillosis in my patient with COPD exacerbation?

My patient with COPD exacerbation has an elevated venous blood PCO2. How accurate is the peripheral venous blood gas PC02 in patients with hypercarbia?

Short answer: Not as accurate as we might like! An elevated venous pC02 is a good indicator of the presence of arterial hypercarbia but beyond that if you really want to know what the arterial pC02 is in your patient with hypercarbia, you should get an arterial blood gas (ABG).

 
A meta-analysis of studies involving patients with COPD presenting to the emergency department (ED) found a good agreement for pH and bicarbonate values between arterial and venous blood gases but not for pC02 or p02 (1). More specifically, the 95% limit of agreement varied widely from -17 to +26 mmHg between venous and arterial pC02 (average difference ~6.0 mm). In the same study, a venous pC02 of ~45 mmHg or less correctly identified patients who were hypercarbic based on ABG. Similar results have been reported by other studies involving patients with COPD exacerbation (2,3).

 
Another meta-analysis involving all comers (COPD and non-COPD patients) concluded that venous pC02 should not be used as a substitute for arterial pC02 when accurate pC02 is required (4). In fact, they emphasized that venous pC02 was not always greater than arterial pC02!

 
Bonus pearl: Did you know that an unexpectedly low bicarbonate level in a patient with COPD and CO2 retention should alert us to the possibility of concurrent metabolic acidosis (eg, due to lactic acidosis, uremia)?

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References
1. Lim BL, Kelly AM. A meta-analysis on the utility of peripheral venous blood gas analyses in exacerbations of chronic obstructive pulmonary disease in the emergency department. Eur J Emerg Med 2010;17:246-48. https://journals.lww.com/euro-emergencymed/Abstract/2010/10000/A_meta_analysis_on_the_utility_of_peripheral.2.aspx
2. McCanny P, Bennett K, Staunton P, et a. Venous vs arterial blood gases in the assessment of patients presenting with an exacerbation of chronic obstructive pulmonary disease. Am J Emerg Med 2012;30:896-900. https://www.sciencedirect.com/science/article/abs/pii/S0735675711002865
3. McKeevere TM, Hearson G, Housely G, et al. Using venous blood gas analysis in the assessment of COPD exacerbations: a prospective cohort study. Thorax 2016;71:210-15. https://www.researchgate.net/publication/285545995_Using_venous_blood_gas_analysis_in_the_assessment_of_COPD_exacerbations_A_prospective_cohort_study
4. Byrne AL, Bennett M, Chatterji R, et al. Peripheral venous and arterial blood gas analysis in adults:are they comparable? A systematic review and meta-analysis. Respirology 2014;19:168-75. https://onlinelibrary.wiley.com/doi/full/10.1111/resp.12225

My patient with COPD exacerbation has an elevated venous blood PCO2. How accurate is the peripheral venous blood gas PC02 in patients with hypercarbia?

When should I consider Pseudomonas aeruginosa as a cause of respiratory tract infection in my hospitalized patient with COPD exacerbation?

The most consistent risk factor for isolation of P. aeruginosa from sputum of adults with COPD is the presence of more advanced pulmonary disease (eg, FEV-1 <35%-50% of predicted value) or functional impairment (1-5).

 

Chronic corticosteroid use is also frequently cited as an important predictor of respiratory tract colonization/infection due to P. aeruginosa in patients with COPD, while the data on antibiotic use during the previous months have been conflicting (2,4). Other risk factors may include prior isolation of P. aeruginosa and hospital admission during the previous year (1).
A prospective study of patients hospitalized for COPD exacerbation found P. aeruginosa to be the most frequently isolated organism, growing from 26% of validated sputum samples at initial admission, followed by Streptococcus pneumoniae and Hemophilus influenzae. In the same study, bronchiectasis (present in up to 50% of patients with COPD) was not shown to be independently associated with the isolation of P. aeruginosa (1).
Of interest, compared to the patients without P. aeruginosa, patients hospitalized for acute exacerbation of COPD and isolation of P. aeruginosa from sputum have significantly higher mortality: 33% at 1 year, 48% at 2 years and 59% at 3 years (5).

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References
1. Garcia-Vidal C, Almagro P, Romani V, et al. Pseudomonas aeruginosa in patients hospitalized for COPD exacerbation: a prospective study. Eur Respir J 2009;34:1072-78. https://www.ncbi.nlm.nih.gov/pubmed/19386694
2. Murphy TF. Pseudomonas aeruginosa in adults with chronic obstructive pulmonary disease. Curr Opin Pulm Med 2009;15:138-42. https://www.ncbi.nlm.nih.gov/pubmed/19532029
3. Miravitlles M, Espinosa C, Fernandez-Laso E, et al. Relationship between bacterial flora in sputum and functional impairment in patients with acute exacerbations of COPD. Chest 1999;116:40-6. https://www.ncbi.nlm.nih.gov/pubmed/10424501
4. Murphy TF, Brauer AL, Eschberger K, et al. Pseudomonas aeruginosa in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2008;177:853-60. https://www.ncbi.nlm.nih.gov/pubmed/18202344
5. Almagro P, Silvado M, Garcia-Vidal C, et al. Pseudomonas aeruginosa and mortality after hospital admission for chronic obstructive pulmonary disease. Respiration 2012;84:36-43. https://www.karger.com/Article/FullText/331224

 

 

When should I consider Pseudomonas aeruginosa as a cause of respiratory tract infection in my hospitalized patient with COPD exacerbation?

My patient with acute exacerbation of heart failure and pulmonary edema also has pneumonia. How often do heart failure and pneumonia coexist?

More often than you might think! The relationship between pneumonia and heart failure (HF) appears bidirectional with pneumonia precipitating heart failure (HF) and HF predisposing to it.

Although It’s often quoted that acute respiratory tract infection accounts for 3-16% of patients hospitalized with decompensated heart failure (HF) (based primarily on small observational studies),1 a 2016 large prospective study involving nearly 100,000 HF admission from 305 US hospitals has reported “pneumonia/respiratory process” as the most common precipitating clinical factor, present in 28.2% of cases (arrhythmia and medication noncompliance came in as 2nd and 3rd).2

Interestingly, the same study reported that pneumonia/respiratory process was most prevalent among patients with preserved (≥50%) ejection fraction (EF) compared to those with borderline ( 40%-49%) or reduced (<40%) EF (33% vs 30% vs 24%, respectively). 2

Pulmonary edema may in turn predispose to bacterial pneumonia through adverse effects of edema fluid on lung bacterial defense mechanisms and establishment of a culture medium for bacterial growth by the presence of fluid in the alveolar space.3

So don’t be surprised if you have to treat for both!

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References

  1. Thomsen RW, Kasatpibal N, Riis A, et al. The impact of pre-existing heart failure on pneumonia prognosis: Population-based cohort study. J Gen Intern Med 2008;23:1407-13. https://www.ncbi.nlm.nih.gov/pubmed/18574639
  2. Kapoor JR, Kapoor R, Ju C, et al. Precipitating clinical factors, heart failure characterization, and outcomes in patients hospitalized with heart failure with reduced, borderline, and preserved ejection fraction. JACC 2016;4:464-72. https://www.scholars.northwestern.edu/en/publications/precipitating-clinical-factors-heart-failure-characterization-and 
  3. Harris GD, Woods DE, Fine R, et al. The effect of intraalveolar fluid on lung bacterial clearance. Lung 1980; 158;91-100 Harris GD, Woods DE, Fine R, et al. The effect of intraalveolar fluid on lung bacterial clearance. Lung 1980; 158;91-100. https://link.springer.com/article/10.1007/BF02713708

 

 

My patient with acute exacerbation of heart failure and pulmonary edema also has pneumonia. How often do heart failure and pneumonia coexist?

Is treatment of pneumococcal pneumonia with bacteremia any different than pneumococcal pneumonia without bacteremia?

In the absence of disseminated infection such as meningitis or endocarditis, there is no convincing evidence that bacteremic pneumococcal pneumonia (BPP) requires either longer course of IV or oral antibiotics.

In fact, although previously thought to have a worse prognosis, recent data have failed to demonstrate any difference in time to clinical stability, duration of hospital stay or community-associated pneumonia (CAP)-related mortality with BPP when other factors such as patient comorbidities and severity of disease are also considered1,2

Although many patients with CAP receive 7-10 days of antibiotic therapy, shorter durations as little as 5 days may also be effective3,4.  Generally, once patients with BPP have stabilized on parenteral therapy, a switch to an appropriate oral antibiotic (eg, a β-lactam or a respiratory quinolone such as levofloxacin) can be made safely5

Although large randomized-controlled studies of treatment of BPP are not available, a cumulative clinical trial experience with levofloxacin for patients with BPP reported a successful clinical response in >90% of patients (median duration of therapy 14 d)6. Resistance to levofloxacin and failure of treatment in pneumococcal pneumonia (with or without bacteremia), however, has been rarely reported7.

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References

  1. Bordon J, Peyrani P, Brock GN. The presence of pneumococcal bacteremia does not influence clinical outcomes in patients with community-acquired pneumonia. Chest 2008;133;618-624.
  2. Cilloniz C, Torres A. Understanding mortality in bacteremic pneumococcal pneumonia. J Bras Pneumol 2012;38:419-421.
  3. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis 2007;44:S27-72.
  4. Shorr F, Khashab MM, Xiang JX, et al. Levofloxacin 750-mg for 5 days for the treatment of hospitalized Fine Risk Class III/IV community-acquired pneumonia patients. Resp Med 2006;100:2129-36.
  5. Ramirez JA, Bordon J. Early switch from intravenous to oral antibiotics in hospitalized patients with bacteremic community-acquired Streptococcus pneumonia pneumonia. Arch Intern Med 2001;161:848-50.
  6. Kahn JB, Bahal N, Wiesinger BA, et al. Cumulative clinical trial experience with levofloxacin for patients with community-acquired pneumonia-associated pneumococcal bacteremia. Clin Infect Dis 2004;38(supp 1):S34-42.
  7. Davidson R, Cavalcanti R, Brunton JL, et al. Resistance to levofloxacin and failure of treatment of pneumococcal pneumonia. N Engl J Med 2002;346:747-50.
Is treatment of pneumococcal pneumonia with bacteremia any different than pneumococcal pneumonia without bacteremia?

How does azithromycin (AZ) benefit patients with severe COPD or cystic fibrosis (CF)?

AZ is a macrolide antibiotic which interferes with bacterial protein synthesis by binding to the 50S ribosomal subunit. It is often used to treat acute respiratory tract infections due to Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, as well as Mycoplasma, Chlamydia, and Legionella sp1. Although it has no in vitro activity against many aerobic gram-negative bacilli such as Pseudomonas aeruginosa, its chronic use has often been associated with a significant reduction in the frequency of disease exacerbations in patients with chronic bronchiectasis and colonization due to this organism, including patients with COPD or CF1-3.

Because P. aeruginosa is invariably macrolide-resistant, the beneficial effect of AZ in chronically infected or colonized patients must be due to factors other than its direct effect on bacterial replication.  Several mechanisms have been invoked including: 1. Inhibition of quorum-sensing dependent virulence factor and biofilm production 2.Blunting of host inflammatory response (eg, ↑IL-10, and ↓ IL-1ß, IL-6, IL-8, TNF-α, and ↓ chemotaxis); and 3. Enhanced antiviral response1.

The latter finding is quite unexpected but AZ appears to augment interferon response to rhinovirus in bronchial cells of COPD patients3.  With respiratory viruses (including rhinoviruses) causing 20-55% of all COPD exacerbations, perhaps this is another way AZ may help the host! Who would have thought!!

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References

  1. Vos R, Vanaudenaerde BM, Verleden SE, et al. Anti-inflammatory and immunomodulatory properties of azithromycin involved in treatment and prevention of chronic lung allograft rejection. Transplantation 2012;94:101-109.
  2. Cochrane review. Treatment with macrolide antibiotics for people with cystic fibrosis and chronic chest infection. Nov 14, 2012. http://www.cochrane.org/CD002203/CF_treatment-with-macrolide-antibiotics-for-people-with-cystic-fibrosis-and-chronic-chest-infection
  3. Menzel M, Akbarshahi H, Bjermer L, et al. Azithromycin induces anti-viral effects in cultured bronchial epithelial cells from COPD. Scientific Reports 2016; 6:28698. DOI:10.1038/srep 28698.

 

 

How does azithromycin (AZ) benefit patients with severe COPD or cystic fibrosis (CF)?