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?

My patient with jaundice complains of abdominal fullness. How useful is the history or physical exam when assessing for ascites?

Even in the age of ultrasound, history and physical exam can be useful in assessing for ascites.

History is a good place to start. Of all the questions we often ask when we suspect ascites (eg, increasing abdominal girth, weight gain and ankle swelling), lack of report of ankle swelling is probably the most helpful in excluding ascites (negative likelihood ratio [LR-], 0.1 in a study involving men), followed by no increase in abdominal girth (LR-, 0.17). Conversely, patient reported ankle swelling or increasing abdominal girth may be helpful in suspecting ascites (LR+ 4.12 and 2.8, respectively). 1

Of the various physical signs and maneuvers, absence of peripheral edema is highly associated with the lack of ascites, followed by lack of shifting dullness or fluid wave (LR-, 0.2, 0.3, 0.4, respectively). The presence of a fluid wave may be the most helpful in suspecting ascites, followed by peripheral edema, and shifting dullness (LR+ 6.0, 3.8, 2.7, respectively). 1  Relatively high sensitivities have been reported for shifting dullness (83-88%), while relatively high specificities have been reported for the fluid wave test (82-90%).2,3 An elevated INR may also improve the positive predictive value of shifting dullness and fluid waves.4

So if you don’t get a history of ankle edema and find no evidence of peripheral edema or shifting dullness on exam, the likelihood of ascites is pretty low. On the other hand, if you find a positive fluid wave, you can be pretty sure that the patient has ascites.

Of course, the actual likelihood of detecting ascites also depends on several other factors, including your pre-test probability and the volume of the ascites in the abdominal cavity, with at least ~500 ml of ascites necessary before it can be detected on exam (vs ~100 ml for ultrasound). 2,5

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References

  1. Williams JW, Simetl DL. Does this patient have ascites? How to divine fluid in the abdomen. JAMA 1992;267: 2645-48. https://jamanetwork.com/journals/jama/fullarticle/397285
  2. Cattau EL, Benjamin SB, Knuff TE, et al The accuracy of the physical examination in the diagnosis of suspected ascites. JAMA 1982;247:1164-66. https://www.ncbi.nlm.nih.gov/pubmed/7057606
  3. Cummings S, Papadakis M, Melnick J, et al. The predictive value of physical examinations for ascites. West J Med 1985;142:633-36. https://www.ncbi.nlm.nih.gov/pubmed/3892916
  4. Fitzgerald FT. Physical diagnosis versus modern technology. A review. West J Med 1990;152:377-82. https://www.ncbi.nlm.nih.gov/pubmed/2190412
  5. CDC. Assessment for ascites. https://www.cdc.gov/dengue/training/cme/ccm/Assess%20for%20Ascites_F.pdf. Accessed November 13, 2019.
My patient with jaundice complains of abdominal fullness. How useful is the history or physical exam when assessing for ascites?

My 70 year old male patient is admitted with 1 day of fever, dysuria, and urinary frequency and urgency, but has a negative urine dipstick test for nitrites and leukocyte esterase. Could he still have acute bacterial prostatitis?

Short answer: Yes! In fact, no routine clinical imaging test can adequately rule out prostatic involvement in men with urinary tract infection (UTI) symptoms (1)! 

Although the presence of nitrites and leukocyte esterase (LE) may have a high positive predictive value for acute bacterial prostatitis (ABP) (~95%), their combined absence has a negative predictive value of only ~70%; ie, we may miss about one-third of patients with UTI symptoms if we relied solely on the results of nitrite and LE urine dipstick (2,3). Negative nitrites alone has a negative predictive value of only ~ 45%, while a negative LE has a negative predictive value of ~60% (3).

To evaluate for ABP, our patient should undergo rectal exam for prostatic tenderness, as should all men with UTI symptoms. The finding of a tender prostate in this setting is supportive of ABP, although its absence will still not rule out this diagnosis because the reported sensitivity of rectal exam may vary from 9% to 100% in ABP (1).

 
Although there may not be a general agreement on the definition of ABP, 2 studies utilizing indium-labeled leukocyte scintigraphy or a combination of PSA levels and transrectal ultrasound have provided evidence for frequent prostatic involvement in men with UTI symptoms (4,5).  In these studies, an inflammatory reaction within the prostate was seen in the majority of cases, even when the digital rectal examination was not painful or when clinicians diagnosed pyelonephritis without prostatitis.

Bonus pearl: Did you know that the lifetime probability of a man receiving a diagnosis of prostatitis is >25% (1)? 

Also see a related P4P pearl: Acute prostatitis and u/a

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References
1. Etienne M, Chavanet P, Sibert L, et al. Acute bacterial prostatitis: heterogeneity in diagnostic criteria and management. Retrospective multicentric analysis of 371 patients diagnosed with acute prostatitis. BMC Infect Dis 2008, 8:12 doi:10.1186/1471-2334-8-12. https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-8-12
2. Lipsky BA, Byren I, Hoey CT. Treatment of bacterial prostatitis. Clin Infect Dis 2010;50:1641-1652. https://academic.oup.com/cid/article/50/12/1641/305217
3. Etienne M, Pestel-Caron M, Chavanet P, et al. Performance of the urine leukocyte esterase and nitrite dipstick test for the diagnosis of acute prostatitis. Clin Infect Dis 2008; 46:951-53. https://academic.oup.com/cid/article/46/6/951/351423
4. Velasco M, Mateos JJ, Martinez JA, et al. Accurate topographical diagnosis of urinary tract infection in male patients with (111)indium-labelled leukocyte scintigraphy. Eur J Intern Med 2004;15:157-61. https://www.ncbi.nlm.nih.gov/pubmed/15245717
5. Ulleryd P, Zackrisson B, Aus G, et al. Prostatic involvement in men with febrie urinary tract infection as measured by serum prostate-specific antigen and transrectal ultrasonography. BJU Int 1999;84:470-74. https://onlinelibrary.wiley.com/doi/full/10.1046/j.1464-410x.1999.00164.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!

My 70 year old male patient is admitted with 1 day of fever, dysuria, and urinary frequency and urgency, but has a negative urine dipstick test for nitrites and leukocyte esterase. Could he still have acute bacterial prostatitis?

My elderly patient with abdominal pain has a negative Murphy’s sign on physical exam. How accurate is Murphy’s sign in diagnosing cholecystitis?

Not as accurate as we might like! In fact, no single clinical finding has been found to carry sufficient weight in ruling in or excluding cholecystitis and Murphy’s sign (inability to take a deep breath due to pain upon palpation of the right upper quadrant) is no exception. 1

A meta-analysis of patients with Murphy’s sign reported a sensitivity of 65% and a specificity of 87% (positive LR 2.8, negative LR 0.4, with 95% C.I. including 1.0 in both). 1,2  However, among the elderly (mean age 79 y), the sensitivity may be as slow as 48% 2 and in patients with gangrenous cholecystitis as low as 33%.3  

In contrast, Murphy’ s sign elicited at the time of ultrasound of the gallbladder (ie,“sonographic Murphy’s) is generally thought to very sensitive  (>90%) for acute cholecystitis;3,4 1 study reported a sensitivity of 63%, however (specificity 94%).5  Remember that altered mental status may also mask sonographic Murphy’s sign. 

Indirect fist percussion of the liver has been suggested by some authors as a more sensitive alternative to Murphy’s sign (100% vs 80%) in a small series of patients with cholecystitis.2

Bonus pearl: Did you know that another technique originally described by the famed American surgeon, John Murphy, to diagnose acute cholecystitis consisted of the “hammer stroke maneuver” in which percussion of the right midsubcostal region with the bent middle finger of the left hand was performed using the right hand to strike the dorsum of the left hand with hammer-like blows? 6

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References

  1. Trowbridge RL, Rutkowski NK, Shojania KG. Does this patient have acute cholecystitis. JAMA 2003;289:80-86. https://jamanetwork.com/journals/jama/article-abstract/195707
  2. Ueda T, Ishida E. Indirect fist percussion of the liver is a more sensitive technique for detecting hepatobiliary infections than Murphy’s sign. Current Gerontol Geriat Res, Volume 2015, Article ID 431638. https://www.hindawi.com/journals/cggr/2015/431638/
  3. Simeone JF, Brink JA, Mueller PR, et al. The sonographic diagnosis of acute gangrenous cholecystitis. The importance of the Murphy sign. AJR 1989;152:289-90. https://www.ncbi.nlm.nih.gov/pubmed/2643262
  4. O’Connor OJ, Maher MM. Imaging of cholecystitis. AJR 2011;196:W36774. https://www.ajronline.org/doi/full/10.2214/AJR.10.4340
  5. Rallis PW, Lapin SA, Quinn MF, et al. Prospective evaluation of the sonographic Murphy sign in suspected acute cholecystitis. J Clin Ultrasound 1982;10:113-5. https://www.ncbi.nlm.nih.gov/pubmed/6804512
  6. Salati SA, al Kadi A. Murphy’s sign of cholecystitis-a brief revisit. Journal of Signs and Symptoms 2012;1:53-6. https://www.researchgate.net/publication/230820198_Murphy’s_sign_of_cholecystitis-_a_brief_revisit

 

 

My elderly patient with abdominal pain has a negative Murphy’s sign on physical exam. How accurate is Murphy’s sign in diagnosing cholecystitis?