A 66 year-old male with a history of hypertension and COPD presents with shortness of breath. He states that his symptoms are unimproved with home nebulizer treatments and denies fever, cough or new sputum production. On examination, he has stridor appreciated during inspiratory and expiratory phases.

Sound Characteristics

Respiratory Phase

Inspiratory

Supraglottic: negative intratracheal pressure during inspiration causes airway collapse.

Biphasic

Glottic/Subglottic: fixed obstruction not impacted by changes in luminal/thoracic pressure.

Expiratory

Intrathoracic: increased pleural pressure compresses the narrowed airway.

An Algorithm for the Diagnosis of Wheezing and Stridor

References

1. Sicari V, Zabbo CP. Stridor. [Updated 2021 Jul 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525995/
2. Patel PH, Mirabile VS, Sharma S. Wheezing. [Updated 2021 May 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482454/
3. Bohadana A, Izbicki G, Kraman SS. Fundamentals of lung auscultation. N Engl J Med. 2014;370(21):2053.
4. Orient JM, Sapira JD. Sapira’s Art & Science of Bedside Diagnosis. 4th ed. Wolters Kluwer Health/Lippincott Williams & Wilkins; 2010.

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A 67 year-old male with a history of hypertension and diabetes presents to the emergency department after a syncopal episode. He had been completing his normal morning routine when he developed a sensation of lightheadedness and awoke on the ground of his kitchen. He denies associated chest pain, palpitations, diaphoresis, or recent illness. He has no known sick contacts nor exposures to individuals undergoing evaluation for COVID-19.

On arrival in the emergency department, the patient was noted to be hypoxic with pulse oximetry measuring 74%. He was placed on supplemental oxygen via non-rebreather with improvement of oxygen saturation to 94%. Examination demonstrated diminished alertness (requiring constant stimulation for responses) and generalized motor weakness. Cardiac and pulmonary examinations were unremarkable with the exception of tachypnea and no extremity edema was appreciated.

A chest radiograph was obtained which demonstrated platelike atelectasis. An arterial blood gas was obtained with PaO₂ of 72mmHg suggesting a prominent A-a gradient. CT pulmonary angiography was obtained:

Upon return, the patient’s mental status worsened associated with hypotension and he was intubated for airway protection and received systemic thrombolysis. He was subsequently taken for emergent endovascular treatment of massive pulmonary embolus.

An Algorithm for the Differential Diagnosis of Hypoxemia & Hypoxia^1-7

Hypoxemia is defined as low PaO₂ while hypoxia is insufficient global or local tissue oxygen content.

References

1. Stapczynski J. Respiratory Distress. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e New York, NY: McGraw-Hill; . http://accessmedicine.mhmedical.com/content.aspx?bookid=2353&sectionid=219642010. Accessed April 12, 2020.
2. Gas Transport & pH. In: Barrett KE, Barman SM, Brooks HL, Yuan JJ. eds. Ganong’s Review of Medical Physiology, 26e New York, NY: McGraw-Hill; . http://accessmedicine.mhmedical.com/content.aspx?bookid=2525&sectionid=204297654. Accessed April 12, 2020.
3. Loscalzo J. Hypoxia and Cyanosis. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison’s Principles of Internal Medicine, 20e New York, NY: McGraw-Hill; . http://accessmedicine.mhmedical.com/content.aspx?bookid=2129&sectionid=192012521. Accessed April 12, 2020.
4. West NE, Lechtzin N. Chapter 93. Hypoxia. In: McKean SC, Ross JJ, Dressler DD, Brotman DJ, Ginsberg JS. eds. Principles and Practice of Hospital Medicine New York, NY: McGraw-Hill; 2012. http://accessmedicine.mhmedical.com/content.aspx?bookid=496&sectionid=41304065. Accessed April 12, 2020.
5. Pulmonary Physiology. In: Kibble JD, Halsey CR. eds. Medical Physiology: The Big Picture New York, NY: McGraw-Hill; 2014. http://accessmedicine.mhmedical.com/content.aspx?bookid=1291&sectionid=75576764. Accessed April 12, 2020.
6. Petersson, J., Glenny, R. (2014). Gas exchange and ventilation–perfusion relationships in the lung European Respiratory Journal 44(4), 1023-1041. https://dx.doi.org/10.1183/09031936.00037014
7. Morchi, R. (2011). Diagnosis Deconstructed: The Case of the Patient with No Chief Complaint Emergency Medicine News XXXIII(3)
   Rodríguez-Roisin, R., Roca, J. (2005). Mechanisms of hypoxemia Intensive Care Medicine 31(8), 1017-1019. https://dx.doi.org/10.1007/s00134-005-2678-1

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A 38 year-old male with a history of hypertension presents to the emergency department with fever, cough and shortness of breath. He notes 4 days of symptoms which have been gradually worsening despite over-the-counter treatments. He denies recent travel or sick contacts. While he attempted to remain isolated – his symptoms grew intolerable.

On arrival in the emergency department, vital signs were notable for tachycardia and hypoxia (SpO2 85%, improving to 92% on 4L by nasal cannula). Physical examination demonstrated tachypnea and accessory muscle use but clear lung fields, and no extremity edema nor jugular venous distension. A chest radiograph revealed patchy airspace opacities. A presumptive diagnosis of COVID-19 pneumonia was made.

While awaiting hospitalization, the patient’s hypoxia worsened though he remained otherwise alert and oriented. He was placed on 15L via non-rebreather and instructed regarding self-prone positioning. He was admitted to the intensive care unit.

An Algorithm for the Management of COVID-19 Hypoxic Respiratory Failure^1-6

References

1. Whittle, J., Pavlov, I., Sacchetti, A., Atwood, C., Rosenberg, M. (2020). Respiratory Support for Adult Patients with COVID‐19 Journal of the American College of Emergency Physicians Open https://dx.doi.org/10.1002/emp2.12071
2. Hui, D., Chow, B., Chu, L., Ng, S., Lee, N., Gin, T., Chan, M. (2012). Exhaled Air Dispersion during Coughing with and without Wearing a Surgical or N95 Mask PLoS ONE  7(12), e50845. https://dx.doi.org/10.1371/journal.pone.0050845
3. Hui, D., Chow, B., Lo, T., Ng, S., Ko, F., Gin, T., Chan, M. (2015). Exhaled Air Dispersion During Noninvasive Ventilation via Helmets and a Total Facemask Chest  147(5), 1336-1343. https://dx.doi.org/10.1378/chest.14-1934
4. Hui, D., Chow, B., Lo, T., Tsang, O., Ko, F., Ng, S., Gin, T., Chan, M. (2019). Exhaled air dispersion during high-flow nasal cannula therapy versus CPAP via different masks European Respiratory Journal  53(4), 1802339. https://dx.doi.org/10.1183/13993003.02339-2018
5. Sun, Q., Qiu, H., Huang, M., Yang, Y. (2020). Lower mortality of COVID-19 by early recognition and intervention: experience from Jiangsu Province Annals of Intensive Care  10(1), 33. https://dx.doi.org/10.1186/s13613-020-00650-2
6. Roca, O., Caralt, B., Messika, J., Samper, M., Sztrymf, B., Hernández, G., García-de-Acilu, M., Frat, J., Masclans, J., Ricard, J. (2018). An Index Combining Respiratory Rate and Oxygenation to Predict Outcome of Nasal High-Flow Therapy American Journal of Respiratory and Critical Care Medicine  199(11), 1368-1376. https://dx.doi.org/10.1164/rccm.201803-0589oc

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A 43 year-old female with no reported medical history presents with shortness of breath. She notes 2 months of gradually worsening symptoms associated with unproductive cough and intermittent subjective fevers. Symptoms are worsened with activity and when laying flat. She has no history of similar symptoms in the past.

Vital signs are notable for tachycardia, tachypnea and hypoxia. Examination demonstrates absent breath sounds in the entire right lung field. A plain chest radiograph is obtained and shown below. The patient was placed on non-invasive positive pressure with minimal improvement and an emergent therapeutic thoracentesis was performed. Pleural fluid was exudative and a large volume was submitted for cytology.

Whiteout right lung field

An Algorithm for the Analysis of Pleural Fluid

References

1. Light RW, Girard WM, Jenkinson SG, George RB. Parapneumonic effusions. Am J Med. 1980;69(4):507-512.
2. Heffner JE, Brown LK, Barbieri CA. Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Primary Study Investigators. Chest. 1997;111(4):970-980. doi:10.1378/chest.111.4.970.
3. Romero S, Martinez A, Hernandez L, et al. Light’s criteria revisited: consistency and comparison with new proposed alternative criteria for separating pleural transudates from exudates. Respiration. 2000;67(1):18-23. doi:10.1159/000029457.
4. Light RW. Clinical practice. Pleural effusion. N Engl J Med. 2002;346(25):1971-1977. doi:10.1056/NEJMcp010731.
5. Sahn SA, Huggins JT, San Jose E, Alvarez-Dobano JM, Valdes L. The Art of Pleural Fluid Analysis. Clinical Pulmonary Medicine. 2013;20(2):77-96. doi:10.1097/CPM.0b013e318285ba37.
6. Light RW. The Light criteria: the beginning and why they are useful 40 years later. Clinics in Chest Medicine. 2013;34(1):21-26. doi:10.1016/j.ccm.2012.11.006.
7. Aggarwal AN, Agarwal R, Sehgal IS, Dhooria S, Behera D. Meta-analysis of Indian studies evaluating adenosine deaminase for diagnosing tuberculous pleural effusion. Int J Tuberc Lung Dis. 2016;20(10):1386-1391. doi:10.5588/ijtld.16.0298.

The post Pleural Fluid appeared first on Differential Diagnosis of.

A 68 year-old male with a history of hypertension, diabetes, hyperlipidemia, chronic obstructive pulmonary disease and congestive heart failure (CHF) with depressed ejection fraction presents via ambulance with a chief complaint of shortness of breath. EMS reports that the patient was tachypneic and saturating 80% on ambient air on their arrival. En route, he received nebulized albuterol, nitroglycerin and was started on non-invasive positive pressure ventilation (NI-PPV).

On arrival, he remains uncomfortable-appearing with a respiratory rate of 35 breaths/min and accessory muscle use. His heart rate is 136bpm, blood pressure is 118/85mmHg, and he is saturating 95% on an FiO2 of 100%. Attempts to obtain a history are limited due to difficulty comprehending his responses with the PPV mask on, and prompt desaturation with it off. Lung auscultation is similarly challenging due to ambient and transmitted sounds, although basilar crackles and diffuse expiratory wheezing are appreciated. Cardiovascular examination reveals a rapid and irregularly irregular rhythm. Assessment of jugular venous distension is limited due to the patient’s body habitus and the presence of mask straps around the patient’s neck. Lower extremities demonstrate 2+ pitting edema, symmetric bilaterally. Intravenous access is established and laboratory tests are sent. The ECG technician and portable chest x-ray are called.

The case presentation above demonstrates a common emergency department scenario: a critically-ill patient with undifferentiated dyspnea. Specifically, the scenario reveals a situation where the physical examination is either obfuscated by technical challenges or otherwise indeterminate. The patient is at risk for deterioration and targeted intervention is mandatory. If a COPD exacerbation is assumed, additional nebulized breathing treatments are indicated – a potentially costly jolt of beta agonists if the patient’s atrial fibrillation and rapid ventricular response are the consequence of decompensated systolic heart failure. Take the route of decompensated CHF and prompt afterload reduction with diuresis would be next – if incorrect, not only would the primary cause go untreated, but his tenuously-maintained blood pressure may suffer.

Algorithm for the Use of Ultrasound in the Evaluation of Dyspnea

1. Lung Ultrasound

An approach incorporating point-of-care ultrasonography may be useful. First, a thoracic ultrasound is performed where certain causative etiologies might be identified immediately – for example absent lung sliding suggesting pneumothorax, or signs of generalized or subpleural consolidation.

The POCUS Atlas
The ultrasound images and videos used in this post come from The POCUS Atlas, a collaborative collection focusing on rare, exotic and perfectly captured ultrasound images.

Pneumothorax

Hepatization

Shred Sign

Pleural Effusion

2. Cardiac Ultrasound

Other findings on lung ultrasound may point to causes that are not primarily pulmonary. For example, if diffuse B-lines are encountered a focused cardiac ultrasound can be performed to grossly evaluate ejection fraction and estimate right atrial pressure.

B-Lines

Depressed EF

Dilated IVC

3. Venous Ultrasound

Finally, if the lung ultrasound is largely unremarkable (A-lines), a sequence of ultrasonographic findings including right ventricular dilation and the presence of a deep venous thrombosis would point to pulmonary embolism as the diagnosis.

DVT

RV Dilation

References

1. Lichtenstein DA, Mezière GA, Lagoueyte J-F, Biderman P, Goldstein I, Gepner A. A-lines and B-lines: lung ultrasound as a bedside tool for predicting pulmonary artery occlusion pressure in the critically ill. Chest. 2009;136(4):1014-1020. doi:10.1378/chest.09-0001.
2. Copetti R, Soldati G, Copetti P. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovasc Ultrasound. 2008;6(1):16. doi:10.1186/1476-7120-6-16.
3. Gallard E, Redonnet J-P, Bourcier J-E, et al. Diagnostic performance of cardiopulmonary ultrasound performed by the emergency physician in the management of acute dyspnea. Am J Emerg Med. 2015;33(3):352-358. doi:10.1016/j.ajem.2014.12.003.
4. Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014;4(1):1. doi:10.1186/2110-5820-4-1.
5. Zanobetti M, Scorpiniti M, Gigli C, et al. Point-of-Care Ultrasonography for Evaluation of Acute Dyspnea in the ED. Chest. 2017;151(6):1295-1301. doi:10.1016/j.chest.2017.02.003.
6. Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134(1):117-125. doi:10.1378/chest.07-2800.
7. Images from The POCUS Atlas
8. Special thanks to Dr. Timothy Jang, Director Emergency Ultrasound Program, Director Emergency Ultrasound Fellowship, Associate Professor of Clinical Emergency Medicine, Department of Emergency Medicine at Harbor-UCLA

The post Ultrasound in Dyspnea appeared first on Differential Diagnosis of.

Findings in Selected Causes of Dyspnea

References

1. Braithwaite, S., & Perina, D. (2013). Dyspnea. In Rosen’s Emergency Medicine – Concepts and Clinical Practice (8th ed., Vol. 1, pp. 206-213). Elsevier Health Sciences.

The post Dyspnea appeared first on Differential Diagnosis of.

64F with a history of CAD, MI, CHF, CLL and rheumatoid arthritis who presented to the emergency department after transfer from a rehabilitation facility for respiratory distress. The patient reported several days of progressive shortness of breath with dyspnea on exertion. She also noted some associated orthopnea and lower extremity edema. The patient was recently hospitalized for similar symptoms and was diagnosed with CHF at the time. At the rehab facility, the patient became hypoxemic and hypertensive, reporting shortness of breath and chest pain prior to presentation.

Hospital Course:

The patient was initially managed with BiPAP and nitroglycerin continuous infusion, but was then stable on supplemental O2 via nasal cannula and was transitioned to long-acting nitrates and anti-hypertensives. The patient’s hypoxemic respiratory failure was initially attributed to acute exacerbation of left-ventricular heart failure, and the patient was managed with spot diuresis. However, there was no symptomatic improvement and the patient became hypernatremic so diuresis was held as alternative diagnoses were explored.

A transthoracic echocardiogram showed preserved LVEF (50-55%), but some diastolic dysfunction and elevated PAP/RAP. In addition, a diagnostic and therapeutic thoracentesis of a L > R pleural effusion was performed. Pleural fluid studies were suggestive of a transudative process, though with some abnormal characteristics (including lymphocyte predominance, as well as presence of signet cells).

Rheumatology and pulmonology services were consulted for input and recommendations for further evaluation were appreciated. Per rheumatology, the patient’s diagnosis of rheumatoid arthritis may not be consistent with her presentation or prior serologic studies. Her pleural fluid analysis was also not consistent with rheumatoid disease. According to pulmonary consult, the patient’s hypoxemia remains most consistent with left ventricular dysfunction though primary pulmonary processes cannot be excluded (and would warrant further evaluation with imaging and pulmonary function testing).

Physical Exam:

Labs/Studies:

• CBC: 11.2/10.2/32.7/179
• BMP: 141/3.9/103/30/15/0.85/107
• INR: 0.9
• BNP: 1857
• UA: WBC 4, RBC 29 , +Bacteria, UCr 90, UPr 14
• Rheum: CCP <16, ANCA neg, RF 936
• Pleural Fluid: LDH 98 (serum 237), Protein 2.8 (serum 6.0), Glucose 107
• Cytology: Reactive mesothelial cells, histiocytes, lymphocytes, signet cells

Imaging

CXR

There is a large left pleural effusion obscuring the lower half of the left hemi thorax. The cardiac silhouette is also obscured. There is pulmonary venous vascular congestion. There is also a right pleural effusion with fluid tracking into the minor fissure. Pulmonary interstitial edema is also noted.

CT Chest (High-Resolution):

• Bilateral, left greater than right, pleural effusions with adjacent atelectasis and collapse versus consolidation of the left lower lobe.
• Prominent main pulmonary artery measuring 3.3 cm in diameter, which can be seen with pulmonary arterial hypertension.

TTE:

• LVEF is 50-55%.
• Impaired left ventricular relaxation, which is associated with grade I/IV or mild diastolic dysfunction.
• Moderate aortic stenosis with mild regurgitation (AVA 1.4 cm3, mean gradient 14mmHg, peak velocity 2.4 m/s).
• Severe pulmonary hypertension (est PASP 52-62mmHg).
• The inferior vena cava appeared dilated and decreased <50% with respiration (RAP 10-20 mmHg).
• Minimal pericardial effusion without echocardiographic evidence of tamponade.

Assessment/Plan:

64F with history of CAD (prior MI), CHF, hypertension, CLL, hypothyroidism presented from a SNF with progressive shortness of breath, orthopnea and LE swelling, found to have bilateral (L>R) pleural effusion now s/p thoracentesis with transudative fluid.

#Acute hypoxic respiratory failure: Large pleural effusions, s/p thoracentesis with pleural fluid suggestive of transudative process. Most likely secondary to left ventricular diastolic dysfunction. Improved after thoracentesis and diuresis. High-resolution CT chest performed without evidence of autoimmune-related pulmonary fibrosis or ILD (though persistent pleural effusions, pulmonary vascular congestion).

#Pleural fluid signet cells: Identified on cytology, potentially related to history of untreated CLL or alternative primary malignancy.

#Left ventricular diastolic dysfunction, decompensated: Associated with pleural effusions and hypoxemic respiratory failure. Management with diuresis.

#Pulmonary Hypertension: Severe, noted on transthoracic echocardiography, may be secondary to hypoxemia associated with pleural effusions, consider repeat imaging once euvolemic or right-heart catheterization.

#Microscopic Hematuria: No evidence of infection, no symptoms suggestive of nephrolithiasis. No casts identified or significant proteinuria. Plan for renal ultrasound.

#Rheumatoid Arthritis: History of rheumatoid arthritis, on prednisone and hydroxychloroquine. Imaging without evidence of inflammatory arthropathy, RF elevated but CCP negative. Per rheumatology, the patient’s symptoms are not consistent with RA, continuing home medications while evaluation is ongoing. Pleural effusions unlikely associated with RA as transudative, and without monocyte predominance or low glucose.

Case 2: Malignant Pleural Effusion

• Protein: 2.6 (serum: 4.9)
• LDH: 1275 (serum: 219)
• Cytology: Malignant cells

Case 3: Traumatic Thoracentesis

• Protein: 2.7 (serum 6.4)
• LDH: 344 (serum 236)
• Cell count: 100,000 RBC

Case 4: Pneumonia

• Protein: 4.3 (serum 6.7)
• LDH: 377 (serum 108)
• pH: 7.46
• Glucose: 153
• Neutrophils: 84%

Etiology of Pleural Effusions: ¹

Clinical Features in the Diagnosis of Pleural Effusions and Identifying Etiology: ^1,2

Pleural effusions can be easily identified on chest radiography, physical examination findings include dullness to percussion, decreased tactile fremitus and decreased (or absent) breath sounds.

• Hemoptysis: Malignancy, PE, TB
• Weight Loss: Malignancy, TB
• Ascites: Cirrhosis, ovarian cancer
• Unilateral Leg Swelling: PE
• Bilateral Leg Swelling: CHF, cirrhosis, nephrotic syndrome
• Jugular Venous Distension: CHF

Differential Diagnosis of Pleural Effusions: ^1,2,3,4

References:

1. Light, R. W. (2002). Clinical practice. Pleural effusion. The New England journal of medicine, 346(25), 1971–1977. doi:10.1056/NEJMcp010731
2. McGrath, E. E., & Anderson, P. B. (2011). Diagnosis of pleural effusion: a systematic approach. American journal of critical care : an official publication, American Association of Critical-Care Nurses, 20(2), 119–27– quiz 128. doi:10.4037/ajcc2011685
3. Thomsen, T. W., DeLaPena, J., & Setnik, G. S. (2006). Videos in clinical medicine. Thoracentesis. The New England journal of medicine (Vol. 355, p. e16). doi:10.1056/NEJMvcm053812
4. Wilcox, M. E., Chong, C. A. K. Y., Stanbrook, M. B., Tricco, A. C., Wong, C., & Straus, S. E. (2014). Does this patient have an exudative pleural effusion? The Rational Clinical Examination systematic review. JAMA : the journal of the American Medical Association, 311(23), 2422–2431. doi:10.1001/jama.2014.5552
5. WikEM: Pleural effusion

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Notified by nursing of abnormal vital signs, SpO2 91%. Briefly, this patient is a 52 year-old G1P1 with no prior medical history who is post-operative day three status post total abdominal hysterectomy, bilateral salpingoophorectomy as well as tumor debulking and staging for suspected primary ovarian adenocarcinoma based on peritoneal fluid cyctology.

On evaluation, the patient denied shortness of breath, chest pain, pleuritic chest pain, cough/hemoptysis, or calf/thigh pain. She states that she had been ambulating around the ward prior to having her vital signs assessed.

Physical Exam:

Medications:

• Lovenox 40mg s.q. daily
• Norco 5-325mg p.o. q.4.h. p.r.n. pain
• Morphine 2mg i.v. q.3.h. p.r.n. breakthrough pain
• Colace 100mg p.o. b.i.d. p.r.n. constipation
• Zofran 4mg i.v. q.6.h. p.r.n. nausea/vomiting

Imaging:

CXR

CT Chest

CT Abdomen/Pelvis

Assessment and Plan:

52yo G1P1 with likely primary ovarian adenocarcinoma with extensive peritoneal involvement, complicated by malignant ascites and pleural effusions with hypoxemia. The primary concern in this post-operative patient with a history of malignancy is venous thromboembolism, particularly pulmonary embolism. Aside from hypoxemia, this patient had no symptoms suggestive of pulmonary embolism (denied dyspnea, chest pain, cough, or lower extremity pain). Her examination had some signs infrequently associated with pulmonary embolism which were otherwise adequately explained by known bilateral pleural effusions (including decreased breath sounds, rales, and tachypnea), she was not tachycardic, had no evidence of jugular venous distension, nor a prominent P2. In addition, she was receiving appropriate VTE prophylaxis (both pharmacological and mechanical). The application of the Modified Wells clinical decision rule suggests low likelihood of pulmonary embolism (with 2.5 points assigned for recent surgery and history of malignancy). The patient had a recent CT chest without evidence of pulmonary embolism, and given that an elevated D-dimer was virtually assured which would have necessitated repeat imaging (and the associated risks of radiation exposure and contrast injury), the episode was ascribed to ventilation/perfusion mismatch secondary to large pleural effusions. Hypoxemia resolved after several minutes at rest and no further testing was performed.

Signs and Symptoms of Pulmonary Embolism¹

Modified Wells Criteria^1,2

>4.0 Likely
≤4.0 Unlikely

Algorithm for Evaluation of Suspected Pulmonary Embolism²

Utility of D-Dimer:²

Of limited utility in patients with high suspicion for pulmonary embolism

Decreased specificity: malignancy, hospitalized patients, pregnancy, elderly

Efficacy of DVT prophylaxis:³

LMWH prevents approximately ½ of VTE events (including PE, symptomatic and asymptomatic DVT)

References:

• Kruip, M. J. H. A., Söhne, M., Nijkeuter, M., Kwakkel-Van Erp, H. M., Tick, L. W., Halkes, S. J. M., Prins, M. H., et al. (2006). A simple diagnostic strategy in hospitalized patients with clinically suspected pulmonary embolism. Journal of internal medicine, 260(5), 459–466. doi:10.1111/j.1365-2796.2006.01709.x
• Tapson, V. F. (2008). Acute pulmonary embolism. The New England journal of medicine, 358(10), 1037–1052. doi:10.1056/NEJMra072753
• Själander, A., Jansson, J.-H., Bergqvist, D., Eriksson, H., Carlberg, B., & Svensson, P. (2008). Efficacy and safety of anticoagulant prophylaxis to prevent venous thromboembolism in acutely ill medical inpatients: a meta-analysis. Journal of internal medicine, 263(1), 52–60. doi:10.1111/j.1365-2796.2007.01878.x

The post Pulmonary Embolism in Hospitalized Patients appeared first on Differential Diagnosis of.

25M with a history of mild asthma transferred from an outside hospital after 10 days in the intensive care unit for continued management of ARDS.

The patient was well until one week prior to admission when he developed intermittent subjective fevers and general malaise associated with a non-productive cough and nausea/vomiting. He presented to the emergency department of an outside hospital with difficulty breathing and was noted to have respiratory distress and was subsequently admitted. Initial CT at the outside hospital revealed pneumomediastinum but no evidence of pulmonary embolism. Results from the outside hospital reveal a wide array of bacterial/fungal cultures and viral serologies including bronchoscopy but no obvious infectious source. The patient was treated with broad spectrum antibiotics for several days but his condition worsened requiring intubation, mechanical ventilation and transfer to the ICU. Further imaging was suggestive of ARDS, and the patient was transferred for additional management.

The patient was well until one week prior to admission when he reported development of malaise and fatigue. On the day of hospitalization, the patient presented to primary care doctor with complaint of cough and shortness of breath and was found to be in respiratory distress and was admitted. The patient received IV antibiotics (cefepime, vancomycin) and was intubated when respiratory distress worsened. Found to have evidence of ARDS on CXR.

Physical Exam:

Labs/Studies:

• CBC: 25.06/7.0/21.3/426
• BMP: 132/3.3/88/32/18/1.1/103
• ABG: 7.30/97/76/18
• Blood/sputum/urine cultures: Negative
• Aspergillus, crypto, cocci: Negative
• EBV, HIV, influenza, RSV: Negative

Imaging

Assessment/Plan:

25M with ARDS transferred from outside hospital for further management.
# ARDS: Severe (P/F ratio <100). Etiology unclear, thorough infectious workup without obvious source. Consider autoimmune or allergic cause.

• Ventilator: PRVC lung-protective ventilation
• Consider NMB for dyssynchrony despite sedation
• Monitor strict I/O, maintain net negative fluid balance.

# Sepsis: Leukocytosis, tachycardia. Continue broad-spectrum antibiotics and monitor cultures.
# Acidosis: Largely respiratory, place dialysis catheter if acute need arises.
# Pneumomediastinum: Possible Boerhaave syndrome given reports of nausea/vomiting.

Pathophysiology of Acute Respiratory Distress Syndrome (ARDS):¹

ARDS represents a stereotyped response to multiple insults. It is characterized by damaged capillary endothelium and alveolar epithelium resulting in increased permeability and the accumulation of fluid in the alveolar space. This causes diffuse alveolar damage and triggers the release of various cytokines (TNF, IL-1, IL-6) which recruit and activate neutrophils causing oxidative cell damage.

Definition of ARDS (Berlin):^2,3

Causes of ARDS:^2,4

An Introduction to Mechanical Ventilation:^5,6,7

This is a simplification of the general principles underlying the most common ventilator modes. For more detail, see the articles cited in the references.

Breath Sequences:

Continuous Mandatory Ventilation (CMV)

All breaths controlled by ventilator, no triggered breaths.

Assist-Control Ventilation (AC)

Every patient-triggered breath is fully supported, a backup rate is set. In the absence of patient-triggered breaths, AC acts like CMV.

Synchronized Intermittent Mandatory Ventilation (SIMV)

Preset minimum mandatory breaths are “synchronized” to patient’s efforts. The patient is allowed to breathe spontaneously between supported breaths.

Pressure Support (PS)

All breaths are triggered by the patient and each is supported by preset pressure.

Continuous Positive Airway Pressure (CPAP)

Spontaneous breathing at elevated baseline pressure.

Control Variables:

Volume Control (VC)

Volume Control (VC)

Volume is set, pressure is variable. With a drop in compliance, the preset minimum volume is maintained with an increase in pressure.

Pressure Control (PC)

Pressure Control (PC)

Pressure is set, volume is variable. With a drop in compliance, a smaller volume is delivered to maintain pressures at the preset limit.

Pressure-Regulated Volume Control (PRVC)

Pressure-Regulated Volume Control (PRVC)

Pressure is targeted with a set minimum volume. The ventilator makes breath-to-breath adjustments of pressure to maintain minimum volumes. Breath mechanics are therefore comparable to pressure-control as a defined pressure is delivered based on prior breath’s respiratory mechanics (note pressure and flow tracings for PRVC/PC vs. VC)

References:

1. Pierrakos C, Karanikolas M, Scolletta S, Karamouzos V, Velissaris D. Acute respiratory distress syndrome: pathophysiology and therapeutic options. J Clin Med Res. 2012;4(1):7–16. doi:10.4021/jocmr761w.
2. Fanelli V, Vlachou A, Ghannadian S, Simonetti U, Slutsky AS, Zhang H. Acute respiratory distress syndrome: new definition, current and future therapeutic options. J Thorac Dis. 2013;5(3):326–334. doi:10.3978/j.issn.2072-1439.2013.04.05.
3. ARDS Definition Task Force, Ranieri VM, Rubenfeld GD, et al. Acute respiratory distress syndrome: the Berlin Definition. In: Vol 307. 2012:2526–2533. doi:10.1001/jama.2012.5669.
4. Ware LB, Matthay MA. The acute respiratory distress syndrome. N. Engl. J. Med. 2000;342(18):1334–1349. doi:10.1056/NEJM200005043421806.
5. Deng, J. (10/20/13). Principles of Mechanical Ventilation. Medical Intensive Care Unit Lecture. Los Angeles, CA.
6. Singer BD, Corbridge TC. Basic invasive mechanical ventilation. South. Med. J. 2009;102(12):1238–1245. doi:10.1097/SMJ.0b013e3181bfac4f.
7. Hamed HMF, Ibrahim HG, Khater YH, Aziz ES. Ventilation and ventilators in the ICU: What every intensivist must know. Current Anaesthesia & Critical Care. 2006;17(1-2):77–83. doi:10.1016/j.cacc.2006.07.008.

The post Acute Respiratory Distress Syndrome appeared first on Differential Diagnosis of.

Linear IgG deposits consistent with anti-GBM disease.

CC:

“bad cough”

HPI:

61yo African American female w/hx of HTN presenting with 1mo of persistent cough productive of green-yellow sputum, noticed streaks of blood for the past 5 days. She came to the ED today because she has been feeling increasingly fatigued. She reports subjective fevers at the onset of symptoms which has resolved. She denies shortness of breath, chest pain, chills, night sweats. She sought medical care for this problem 2wk ago and was treated with amoxicillin and a cough suppressant. She recalls a coworker was ill one month ago. She is US-born, had a negative PPD in the past and has no known exposures to tuberculosis.

Of note, the patient reports her urine had a foamy appearance and has been darker in color beginning 3 weeks ago, but this had resolved. She denied dysuria, or frank hematuria.

Physical Exam:

Labs:

• CBC: 12.3/6.7/19.8/52.3 (S: 94, B: 1, L: 4, M: 1, MCV: 92.3); baseline Hb/Hct (1/11/2012) 13.4
• BMP: 136/3.6/101/25/46/3.43/126; baseline creatinine (1/11/2012) 1.18
• UA: brown, trace LE, – nitrites, 2+ protein, 81 RBC

Imaging:

• Right mid-lung zone consolidation is present, suggests pneumonia if acute.
• Mild asymmetric right parenchymal increased density is seen diffusely as well.

Assessment/Plan:

65AAF w/hx HTN presents with persistent productive cough, recently with hemoptysis.

# Cough: Symptoms and physical findings of abnormal breath sounds (crackles, though no strict consolidation) concerning for community-acquired pneumonia. Addition of hemoptysis raises concern for TB, particularly when taking into consideration the duration of cough and presence of constitutional symptoms. CBC shows leukocytosis with left shift, CXR with right mid/lower lob infiltrates consistent with pneumonia. Recommend admission and isolation to rule out TB, start empiric therapy for community acquired pneumonia with ceftriaxone, azithromycin. Obtain induced sputum samples for culture, AFB smear and culture.

# Abnormal urine: Patient describes changes in urine suggestive of proteinuria and hematuria. Acuity of onset and apparent spontaneous resolution suggests a chronic kidney injury 2/2 hypertension is unlikely. Absence of dysuria, or tenderness (suprapubic, costovertebral) suggests complicated UTI unlikely. Urinalysis notable for 2+ protein and significant RBC’s, possible nephritic syndrome. In the setting of hemoptysis, this raises concern for anti-GBM disease vs. vasculitis.

# Anemia: Normocytic anemia. No evidence of acute, life-threatening hemorrhage as patient is currently hemodynamically stable. Possible sites of blood loss include alveoli, glomeruli. Given that patient sought care today for worsening fatigue, will monitor hemoglobin closely and consider transfusion. Obtain iron studies.

# HTN: BP stable, hold home medications.

Interval History:

The patient was admitted for management of community-acquired pneumonia and isolation to rule out TB. Empiric therapy with CTX + azithromycin was continued. On HOD1, the patient was transfused two units of PRBC’s. On HOD2, the patient underwent CT chest/abdomen/pelvis due to worsening respiratory status despite antimicrobial therapy. On HOD3, the patient went into atrial fibrillation with RVR which was converted to sinus rhythm with metoprolol 5mg IV x3. On HOD5, nephrology consult recommended starting steroid therapy, plasmapheresis and obtaining a renal biopsy, however the biopsy was delayed due to worsening respiratory status.

Interval Labs:

• Iron studies: Fe 8, TIBC 203, Ferritin 468, haptoglobin 333, retics 2.7
• Inflammatory markers: ESR 120, CRP 34
• Micro: BCx NGTD, RCx moderate Candida, sputum AFB smear negative x3
• LFT: AST 34, ALT 29, ALP 52, protein 6.3, albumin 2.4, T.bil 0.8, D.bil 0.2
• Quant-gold: negative
• Anti-GBM 1.2 (nl <1.0)
• p-ANCA: positive 1:640, [ELISA pending]
• ANA: positive 1:320, speckled
• HIV: negative

Interval Imaging:

CT Chest

• Diffuse right lung, tree and bud opacities, ground-glass opacities and areas of confluence with scattered air bronchograms. Less severe similar pattern in the left lung as well particular at the base.
• Right paratracheal, subcarinal and perihilar LAD.
• Findings concerning for primary TB in the right clinical setting. DDx nonspecific bacterial PNA and fungal PNA.

CT Abdomen/Pelvis

• Mild nonspecific R > L perinephric stranding.
  

Interval Assessment/Plan:

# Acute respiratory failure: Unlikely simple CA-PNA given worsening status while on appropriate antibiotic therapy. Active tuberculosis possible given history of chronic productive cough with hemoptysis, constitutional symptoms and imaging findings. IGRA’s of limited utility in diagnosis of active disease, further, while three negative sputum AFB smears decreases the likelihood of TB, additional testing with NAAT and culture is required. Another possibility is a vasculitic process given concomitant hematuria and acute renal failure, with respiratory symptoms now 2/2 alveolar hemorrhage. This was evaluated with ANCA assay which was positive for p-ANCA with high titer. This is often suggestive of primary vasculitis (in this case likely microscopic polyangiitis vs. Churg-Strauss), however ELISA for target antigen is of particular importance as p-ANCA with specificity for antigens other than MPO can be associated with another condition on the differential: Goodpasture’s syndrome. This patient was found to have elevated anti-GBM antibodies which are highly suggestive of Goodpasture’s syndrome, and can be associated with ANCA-positivity (often suggesting a poorer prognosis with decreased likelihood of recovery of renal function).¹

# Acute kidney injury: The patient had significant elevation of serum creatinine compared to last-recorded baseline. She also described darkening and foamy appearance of urine 3 weeks prior to admission, suggestive of proteinuria/hematuria of relatively acute onset. This was supported by urinalysis findings of protein and RBC’s (with casts). Given presence of anti-GBM antibodies, high specificity of such findings, and correlation with glomerulonephritis with evidence of pulmonary alveolar hemorrhage, this appears to be the most likely cause at this time. Definitive diagnosis with renal biopsy to be obtained following stabilization of respiratory status. Patient will be started on plasmapheresis and immunosuppressive therapy (corticosteroids, cyclophosphamide).

# Normocytic Anemia: Likely combination of acute blood loss (2/2 hematuria, pulmonary alveolar hemorrhage) and chronic disease. Normocytic anemia with some reticulocytosis suggestive of acute blood loss, however iron studies with low Fe, TIBC and elevated ferritin suggest chronic disease as an associated factor.

Differential Diagnosis of Hemoptysis: ^{2, 3}

A System for the Diagnosis of Tuberculosis: ^{4, 5}

A System for Vasculitides: ^{8, 9}

Vasculitis Mimics: ⁹

Interpretation of antineutrophil cytoplasmic autoantibodies (ANCA): ¹⁰

Differential Diagnosis of Anemias: ¹¹

References:

1. Levy, J. B., Hammad, T., Coulthart, A., Dougan, T., & Pusey, C. D. (2004). Clinical features and outcome of patients with both ANCA and anti-GBM antibodies. Kidney international, 66(4), 1535–1540. doi:10.1111/j.1523-1755.2004.00917.x
2. Bidwell, J. L., & Pachner, R. W. (2005). Hemoptysis: diagnosis and management. American family physician, 72(7), 1253–1260.
3. Hirshberg, B., Biran, I., Glazer, M., & Kramer, M. R. (1997). Hemoptysis: etiology, evaluation, and outcome in a tertiary referral hospital. Chest, 112(2), 440–444. doi:10.1378/chest.112.2.440
4. Campbell, I. A., & Bah-Sow, O. (2006). Pulmonary tuberculosis: diagnosis and treatment. BMJ (Clinical research ed.), 332(7551), 1194–1197. doi:10.1136/bmj.332.7551.1194
5. Zumla, A., Raviglione, M., Hafner, R., & Reyn, von, C. F. (2013). Tuberculosis. The New England journal of medicine, 368(8), 745–755. doi:10.1056/NEJMra1200894
6. Diagnostic Standards and Classification of Tuberculosis in Adults and Children. American journal of respiratory and critical care medicine. doi:10.1164/ajrccm.161.4.16141
7. Laraque, F., Griggs, A., Slopen, M., & Munsiff, S. S. (2009). Performance of nucleic acid amplification tests for diagnosis of tuberculosis in a large urban setting. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 49(1), 46–54. doi:10.1086/599037
8. Gross, W. L., Trabandt, A., & Reinhold-Keller, E. (2000). Diagnosis and evaluation of vasculitis. Rheumatology (Oxford, England), 39(3), 245–252.
9. Suresh, E. (2006). Diagnostic approach to patients with suspected vasculitis. Postgraduate medical journal, 82(970), 483–488. doi:10.1136/pgmj.2005.042648
10. Rus, V., & Handwerger, B. S. (2000). Clinical value of antineutrophil cytoplasmic antibodies. Current rheumatology reports, 2(5), 383–389.
11. Goljan, E. (2011). Pathology. Philadelphia, PA: Mosby/Elsevier.

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