Lung Ultrasound in the Evaluation of Pleural Infection

Lung Ultrasound in the Evaluation of Pleural Infection

Resident Clinical Pearl (RCP) July 2019

Yazan Ghanem PGY5 Internal Medicine, Dalhousie University

SJRHEM PoCUS Elective

 

Reviewed and edited by  Dr. David Lewis.

 


CASE: MR. WHITE

 

83 year old male with known past medical history of mild cognitive impairment (lives alone in assisted living). Two weeks prior to current presentation, he was admitted with community acquired pneumonia and discharged after 2 nights of hospital stay on oral antibiotics.

He is now presenting with 5 days history of worsening dyspnea, fever, fatigue and reduced oral intake. Vital signs are: Temperature 38.4 C; heart rate 80/min; Blood pressure 121/67; Respiratory rate 28/ minute; Oxygen saturation 90% on room air. His chest exam showed reduced air entry and dullness to percussion in the right hemithorax.

CXR:

 

Bedside POCUS:

 

Pleural fluid analysis:

•       WBC – 22,000 cells per uL

•       LDH – 1256 Units / L

•       Glc – 2.2 mmol / L

•       pH – 7.18

•       Gram Stain – Neg

 

Next steps in management?

 

A – 14 Fr pleural drain + Start IV Levofloxacin

 

B – 28 Fr pleural drain + Start Ceftriaxone / Azithromycin

 

C – 14 Fr pleural drain + Start Piperacillin – Tazobactam

 

D – Start Ceftriaxone / Azithromycin + Repeat CXR in 1 week

 

 

(See end of page for answer )

 


 

Normal Thoracic Ultrasound:

Thoracic Ultrasound is limited by bony structures (ribs and scapulae) as well as by air within lungs (poor conductor of sound waves).

With the transducer held in the longitudinal plane:

1 –     Ribs are visualized as repeating curvilinear structures with a posterior acoustic shadow.

2 –     Overlying muscle and fascia are seen as linear shadows with soft tissue with soft tissue echogenicity.

3 –     Parietal and visceral pleura is visualized as a single echogenic line no more than 2 mm in width which “slides” or “glides” beneath the ribs with respiration. Two separate lines can be seen with a high frequency transducer.

4 –     Normal aerated lung blocks progression of sound waves and is characterized by haphazard snowstorm appearance caused by reverberation artifact.

5 –     Diaphragms are bright curvilinear structures which move with respiration. Liver and spleen have a characteristic appearance below the right and left hemi diaphragms respectively.

 

 


Pleural Effusion:

Ultrasound has higher sensitivity in detecting pleural effusions than clinical examination and chest X-Ray.

On Ultrasound, pleural effusions appear as an anechoic or hypoechoic area between the visceral and parietal pleura that changes in shape with respiration. Atelectatic lung tissue appear in the far field as flapping or swaying “tongue-like” echodensities.

Ultrasound morphology:

1-     Anechoic Effusion: Totally echo-free (Could be transudative or exudative)

2-     Complex Non-septated: Echogenic appearing densities present (fibrinous debris). Always exudative.

3-     Complex Septated: Septa appear in fluid. Always exudative.

 

 


Parapneumonic Effusions and Empyema:

Ultrasound is superior to CT in demonstrating septae in the pleural space. However, CT is recommended for evaluation of complex pleuro-parenchymal disease and loculated pleural collections if drainage is planned: There is no correlation between ultrasound appearance and the presence of pus or need for surgical drainage; however, the presence of a septated appearing parapneumonic effusion correlate with poorer outcomes (longer hospital stay, longer chest tube drainage, higher likelihood for need for fibrinolytic therapy and surgical intervention.

Parapneumonic effusions appear as hyperechoic (with or without septae) on ultrasound.

 


Pulmonary Consolidation:

Pulmonary consolidation is sonographically visible in the presence of a pleural effusion that acts as an acoustic window or if directly abutting the pleura.

It appears as a wedge-shaped irregular echogenic area with air or fluid bronchograms.

 


 

Back to Mr. White

 

Next steps in management?

 

A – 14 Fr pleural drain + Start IV Levofloxacin

 

B – 28 Fr pleural drain + Start Ceftriaxone / Azithromycin

 

C –14 Fr pleural drain + Start Pipercillin- Tazobactam

 

D – Start Ceftriaxone / Azithromycin + Repeat CXR in 1 week

 

Rationale:

Complicated parapneumonic effusions should be managed with drainage and antibiotics that will treat anaerobic infection. An alternative would be a combination of Ceftriaxone and Metronidazole (No pseudomonas coverage). Levofloxacin alone does not add any anaerobic coverage. Azithromycin has poor penetration into loculated pleural collections.

 


 References

 

British Thoracic Society – Pleural Disease Guideline – 2010

https://thorax.bmj.com/content/65/8/667

 

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ADULT Rapid Sequence Intubation and Post-Intubation Analgesia and Sedation for Major Trauma Patients – NB Trauma

Consensus Statement:

ADULT Rapid Sequence Intubation and Post-Intubation

Analgesia and Sedation for Major Trauma Patients

NB Trauma Program – July 2018

Background:

  • Major trauma patients frequently require advanced airway control.
  • Endotracheal intubation is the preferred advanced airway intervention in major trauma patients.
  • Intubated trauma patients also need significant post-intubation pharmacological support.
  • Specifically, these patients require analgesia and sedation. This is particularly true when transfer to another facility is required, during which ICU level support is not available unless transfer occurs via Air Ambulance.
  • In New Brunswick, there is significant variation in the approach to both advanced airway control and post-intubation analgesia and sedation practices for major trauma patients.
  • Physicians in smaller centres in particular have asked for standardized, evidence-based guidance for both Rapid Sequence Intubation (RSI) and post-intubation pharmacological support in preparation for (and during) ground-based interfacility transfer.
  • Rapid Sequence Intubation (RSI) is a method to achieve airway control that involves rapid administration of sedative and paralytic agents, followed by endotracheal intubation.
  • The purpose of RSI is to affect a state of unconsciousness and neuromuscular blockade, allowing for increased first pass success of endotracheal intubation.
  • Post-intubation analgesia and sedation is a method of controlling pain, agitation and medically induced amnesia for major trauma patients.

 

Consensus Statements:

 

  • A provincially standardized, evidence-based guideline for Rapid Sequence Intubation should be available in all NB Trauma Centres (Appendix A).
  • Similarly, a provincially standardized, evidence-based guideline for Post-Intubation Analgesia and Sedation should be available in the Emergency Department of all NB Trauma Centres (Appendix B).
  • In addition to standardized, evidence-based guidelines, a provincially standardized equipment layout is recommended to optimize the preparation for RSI (Appendix C).
  • Ambulance New Brunswick should ensure consistency with the provincially standardized guidelines for RSI and Post-Intubation Sedation and Analgesia in procedures for Ambulance New Brunswick’s Air Medical Crew.
  • RSI should not be considered or applied for trauma patients who are in cardiac arrest or who are apneic.
  • RSI should not be considered in patients with a predicted difficult airway.
  • RSI should be considered for all trauma patients meeting the following:
    • GCS < 8, quickly deteriorating GCS or loss of airway protection
    • Facial trauma with poor airway control
    • Burns with suspected inhalation injury
    • Respiratory failure
    • Hypoxia
    • Persistent or uncompensated shock (reduction of respiratory efforts)
    • Agitation with possible injury to self or others
    • Potential for eventual respiratory compromise
    • Possible respiratory and/or neurological deterioration during prolonged transport
    • Transport in a confined space with limited resources
  • In addition to the above, RSI Guidelines should include
    • Assessment of the possibility of a difficult intubation
    • Troubleshooting
    • Immediate reference to post-intubation analgesia and sedation
  • In addition to standardized, evidence-based guidelines, a provincially standardized pre-induction checklist is recommended to optimize the preparation for RSI (Appendix D)

 


 

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EM Reflections – June 2019 – Part 2

Thanks to Dr. Joanna Middleton for leading the discussions this month

Edited by Dr David Lewis 


Discussion Topics

  1. When is a pregnancy not a pregnancy? (see part 1)
  2. Caustic Ingestions (see part 1)
  3. Transient Ischemic Attack – ED Questions

 

Transient Ischemic Attack – ED Questions

 

Transient Ischemic Attack (TIA): A brief episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischemia, with clinical symptoms and without imaging evidence of acute infarction. Transient ischemic attack and minor stroke are the mildest form of acute ischemic stroke in a continuum that cannot be differentiated by symptom duration alone, but the former typically resolves within one hour.

https://www.strokebestpractices.ca/

 

Dual Anti-Platelet Therapy (DAPT)?

Patients who present within 48 hours of a suspected transient ischemic attack are at the highest risk for recurrent stroke

Uptodate – DAPT for high-risk TIA, defined as an ABCD2 score of ≥4

For CVA – ASA only unless already on ASA, then DAPT.  For minor CVA/TIA – DAPT


Hold Birth Control?


 

Admission?

Of all ischemic strokes during the 30 days after a first TIA, 42 percent occurred within the first 24 hours.

 


Stroke Assessment Pocket Cards

Saskatchewan TIA Referral Pathway

Saskatchewan TIA Patient Information Leaflet

 

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EM Reflections – June 2019 – Part 1

Thanks to Dr. Joanna Middleton for leading the discussions this month

Edited by Dr David Lewis 


Discussion Topics

  1. When is a pregnancy not a pregnancy?
  2. Caustic Ingestions
  3. Transient Ischemic Attack – Emergency Medicine (see part 2)

When is a pregnancy not a pregnancy?

Molar Pregnancy

Hydatidiform mole (molar pregnancy) is a relatively rare complication of fertilization with an incidence in the United States of 0.63 to 1.1 per 1000 pregnancies, although rates vary geographically. It is included in the spectrum of gestational trophoblastic diseases and is comprised of both complete molar pregnancies (CM) and partial molar pregnancies (PM).

The most well characterized risk factor for CM is extreme of maternal age. Maternal ages less than 20 or greater than 40 years have been associated with relative risks for CM as high as 10- and 11-fold greater respectively. Other potential risk factors include oral contraceptive use, maternal type A or AB blood groups, maternal smoking, and maternal alcohol abuse.

Molar pregnancy typically presents in the first trimester and may be associated with a wide array of findings, including vaginal bleeding (most common), uterine size larger than expected according to pregnancy date (CM), uterine size smaller than expected according to pregnancy date (PM), excessive beta-human chorionic gonadotropin (β-hcg) levels, anemia, hyperemesis gravidum, theca lutein cysts, pre-eclampsia, and respiratory distress.Studies comparing modern clinical presentations of CM with historical presentations have demonstrated a significant reduction in many of the classic presenting signs and symptoms such as vaginal bleeding and excessive uterine size. This reduction is attributed to early detection by transvaginal ultrasound and increasingly sensitive β-hcg assays. Numerous studies evaluating the efficacy of ultrasound in detecting molar pregnancy demonstrate a 57–95 percent sensitivity for the detection of CM compared to only 18–49 percent sensitivity for PM.

More here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2791738/

PoCUS – Normal Early Pregnancy

Arrow = Yolk sac (YS) within Gestational sac (GS), note the hyperechoic decidual reaction surrounding GS, Arrow head = Fetal Pole

PoCUS – Molar Pregnancy

 

PoCUS SIgns:

  • enlarged uterus
  • may be seen as an intrauterine mass with cystic spaces without any associated fetal parts
    • the multiple cystic structures classically give a “snow storm” or “bunch of grapes” type appearance.
  • may be difficult to diagnose in the first trimester 6
    • may appear similar to a normal pregnancy or as an empty gestational sac
    • <50% are diagnosed in the first trimester
  • More on Radiopedia.org

Useful post from County EM blog- click here

 


Caustic Ingestions

 

 

Hydrochloric Acid – pH 1-2

Dangerous if pH <2 or >11.5-12

For alkaline – higher percent, shorter time to burn – 10%NaOH – 1 min of contact to produce deep burn, 30% within seconds

 

Acid – painful to swallow so usually less volume, bad taste so more gagging/laryngeal injury, more aqueous so less esophageal injury, pylorospasm prevents entry into duodenum producing stagnation and prominent antrum injury.  Food is protective.  Acid ingestion typically produces a superficial coagulation necrosis that thromboses the underlying mucosal blood vessels and consolidates the connective tissue, thereby forming a protective eschar.  In enough amount – perforation.

Alkali – burns esophagus more, neutralized in stomach.  Liquefaction necrosis.

Management

Decontamination: Activated charcoal / GI decontamination / neutralisation procedures are contraindicated

Obtaining meaningful info from endoscopy after treatment with charcoal is very difficult

If asymptomatic – observe, trial of oral intake at 4 hours after exposure, earlier if low suspicion or likely benign ingestion after discussion with Poisons Centre

Symptomatic patients or those with a significant ingestion

(high-concentration acid or alkali or high volume [>200 ml] of a low-concentration acid or alkali)

Upper GI endoscopy should be performed early (3 to 48 hrs) and preferably during the first 24 hrs after ingestion to evaluate extent of esophageal and gastric damage and guide management.  Endoscopy is contraindicated in patients who have evidence of GI perforation. (Ingestion of >60 mL of concentrated HCl leads to severe injury to the GI tract with necrosis and perforation, rapid onset of MODS and is usually fatal – endoscopy within 24 hours (unless asymptomatic at 4 hours)

Complications – 1/3 develop strictures – directly related to depth/severity of injury, years later

 


 

TAKE HOME POINTS

  1. PV Bleed, Hyperemesis, PoCUS = bunch Grapes or Snowstorm – consider Molar Pregnancy
  2. Don’t use Activated Charcoal for Caustic Ingestions
  3. Discuss Caustic Ingestions with Poisons Centre
  4. Consider early endoscopy
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Trauma Reflections – February 2019

Thanks to Dr. Andrew Lohoar and Sue Benjamin for leading the discussions this month

 

Another highly informative and brilliantly written summary by Dr. Lohoar:


 

Major points of interest:

A) Are we still calling ‘Trauma Codes’ in post TTL era?

Yes. Call away. Activation rates for cases that qualify continue to hover around 80%. Patient care is always improved with a coordinated team approach – triggered by calling a trauma code overhead. Activation criteria are as follows:

B) Should RN Trauma notes continue to be used?

Yes. Folder box on counter in room #19 has trauma activation packages – one stop shopping for all documents needed. “SJRH ED Trauma Process Checklist” is in package and is a very useful prompt (see below). Put on a sticker, get into character.

C) Are you feeling lucky?

Symptomatic head injured patients seen in peripheral centers, with concern enough for an emergent CT head request should come by ambulance not car.

 

D)  What did this guy eat for supper?

Pizza and beer, and lots of it.

Ducanto suction catheters are available on all airway carts. They are much more efficient at decontaminating airways soiled with semi-solid material when compared to Yankauer suction catheters

 

E) Boom, ET tube is in – high five – I am going for coffee..

Not so fast Slick, there is more work to be done.

 

1/ Check for ET tube placement, check for cuff leaks

2/ Post intubation sedation and analgesia can be challenging. Key is to avoid starting medications that could potentially drop blood pressure at very high infusion rates, but we need sedation and analgesia promptly.

Consider bolus of sedatives and analgesics prior to initiating infusions and prn boluses afterwards. Reassess frequently. Inadequate analgesia is often the cause of continued agitation. See attached guidelines from NB trauma – page 5 in particular

3/ NG or OG tubes should be placed and position checked as well

F)   Transfers “just for imaging”

Calls from other facilities for imaging should be screened for potential trauma patients. Care is often substandard if we are not aware of these patients, and they are being managed remotely by MDs in other facilities (playing phone tag with a radiologist).

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EM Reflections – May 2019

Thanks to Dr Paul Page for leading the discussions this month

Edited by Dr David Lewis 


 

Discussion Topics

  1. Measles – Refresher
  2. Posterior Stroke – Beware of Mimics
  3. Missed Fracture – Distracting Injuries

 

Measles – Refresher

Measles has for many years been an infrequent diagnosis in our population. However falling herd immunity is resulting in cases presenting to Canadian ED’s.

Measles signs and symptoms appear around 10 to 14 days after exposure to the virus.

  • Fever
  • Dry cough
  • Runny nose
  • Sore throat
  • Conjunctivitis

 

Measles causes a red, blotchy (erythematous maculopapular) rash that usually appears first on the face and behind the ears, then spreads downward to the chest and back and finally to the feet. Koplick’s spots can appear 1-2 days before the rash. The rash appearance can be variable, discrete maculopapular or merging erythematous.

 

Visit emDocs.net for this great refresher on EMin5 – Measles

EM in 5: Measles


 

Posterior Stroke – Beware of Mimics

Stroke Mimics

  • Acute peripheral vestibular dysfunction (Don’t forget the HINTS exam)
  • Basilar migraine
  • Intracranial hemorrhage
  • SAH
  • Brain Tumour
  • Toxic or metabolic disturbances
  • Neuroinflammatory or chronic infectious disorders

Note that it is possible to be influenced by past experience with mimics, resulting in falsely diagnosing a mimic in the presence of a stroke.

Stroke Chameleons

Stroke chameleons are disorders that look like other disorders but are actually stroke syndromes

  • Bilateral thalamic ischaemia is such a disorder and may cause reduced consciousness level or a global amnesic syndrome
  • Bilateral occipital stroke may present as confusion or delirium
  • Infarcts limited to the medial vermis in medial posterior inferior cerebellar artery (PICA) territory usually cause a vertiginous syndrome that resembles peripheral vestibulopathy

A very useful BMJ review article on Posterior Stroke can be accessed here.

Be cautious of migraine diagnosis with history that is different to typical migraine presentation. Multiple visits should raise concerns. Importance of thorough neuro exam to find possible deficits that would raise suspicion for more serious pathology. In posterior stroke, special attention should be given to examining the visual fields.

 

Imaging in Stroke and TIA

See Rounds Presentation by Dr. Dylan Blacquiere (Neurologist)

Imaging Recommendations. Dr Jake Swan (Radiologist)

After meeting with Dr. Blacquiere and the ER Department regarding stroke management and SAH management, I’m recommending the following based on new literature and evolving management in “high risk” patients.

1) High risk TIA patients, such as those who had a profound motor / speech deficit that is resolving should have a CTA carotid / COW as well as their standard CT head.

2) SAH patients should have CT done prior to LP due to false positive LP rates.  If there is any question about vascular malformation / aneurysm, follow with a CTA. The CTA isn’t necessary for every headache patient, etc, just those with a positive bleed on the unenhanced CT.

 

The evidence is summarised in this recent paper – Imaging Recommendations for Acute Stroke and Transient Ischemic Attack Patients: A Joint Statement by the American Society of Neuroradiology, the American College of Radiology and the Society of NeuroInterventional Surgery


 

Missed Fracture – Distracting Injuries

Standard ATLS teaching, but this error still occurs……

Ensure a complete secondary survey is completed in all patients presenting with history of trauma.

Read the StatPearl Article and then do the MCQ test here

 

Trauma! Initial Assessment and Management

 

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PoCUS – Dilated Aortic Root

Medical Student Clinical Pearl

James Kiberd

Class 2019 Dalhousie Medicine

Reviewed and Edited by Dr. David Lewis


Case:

A 66 year-old female presented to the Emergency Department with shortness of breath and back pain. She had a known dilated aortic root, which was being followed with repeat CT scans. Given the nature of her presenting complaint, a PoCUS was performed to assess her aorta.

 

 

 

Long Axis Parasternal View:

PoCUS for Cardiac imaging has been studied in the acute care setting; focusing on the assessment for pericardial effusion, chamber size, global cardiac function, and volume status, and cardiac arrest.1

In the setting of acute aortic dissection, further evaluation is often recommended depending on the practitioner’s skill level.2 There have been case reports where ultrasound has been used to assess both Type A and Type B aortic dissections.3–5

In order to assess the aortic root, have the patient in a supine position. Either the phased array or the curvilinear probe can be used depending on examiner’s preference. The probe should be positioned with the marker towards the patient’s right shoulder on the anterior chest to the left of the patient’s lower left sternal border. By tilting the transducer between the left shoulder and right hip, long axis views are obtained at different levels with the goal of identifying four main structures; the aorta, the left atrium, and the right and left ventricles. The parasternal long axis view of our patient is shown in Figure 1, where her aortic root measured 3.83cm.

 

Figure 1: Parasternal Long Axis View of Heart: Patient’s root diameter was found to be 3.83cm.

More generally, this view can be used to assess left ventricular contractility and the presence of pericardial effusion, which were not present in this patient. She went on to have a confirmatory CT scan where her aortic root was found to be unchanged from her last scan and was 3.8 cm in diameter as assessed by PoCUS.

In Summary:

Although not rigorously studied to assess aortic root dilatation at the bedside, we present a case where PoCUS was reliable in the assessment of the aortic root. There have been other cases of aortic dissection identified by ultrasound in the emergency department setting, however confirmatory studies (either CT scan or formal echocardiography) are still recommended.


References:

  1. Labovitz AJ, Noble VE, Bierig M, et al. Focused cardiac ultrasound in the emergent setting: A consensus statement of the American society of Echocardiography and American College of Emergency Physicians. J Am Soc Echocardiogr. 2010;23(12):1225-1230. doi:10.1016/j.echo.2010.10.005.
  2. Andrus P, Dean A. Focused cardiac ultrasound. Glob Heart. 2013;8(4):299-303. doi:10.1016/j.gheart.2013.12.003.
  3. Perkins AM, Liteplo A, Noble VE. Ultrasound Diagnosis of Type A Aortic Dissection. J Emerg Med. 2010;38(4):490-493. doi:10.1016/j.jemermed.2008.05.013.
  4. Bernett J, Strony R. Diagnosing acute aortic dissection with aneurysmal degeneration with point of care ultrasound. Am J Emerg Med. 2017;35(9):1384.e3-1384.e4. doi:10.1016/j.ajem.2017.05.052.
  5. Kaban J, Raio C. Emergency department diagnosis of aortic dissection by bedside transabdominal ultrasound. Acad Emerg Med. 2009;16(8):809-810. doi:10.1111/j.1553-2712.2009.00448.x.
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Abdominal ACNES: anterior cutaneous nerve entrapment syndrome and trigger point injections in the ED

Abdominal ACNES: anterior cutaneous nerve entrapment syndrome and trigger point injections in the ED

Resident Clinical Pearl (RCP) March 2019

Devon Webster – PGY1 FMEM Dalhousie University, Saint John NB

Reviewed and edited by Renee Amiro and  Dr. David Lewis.


 

Case:

A 32 year old woman with a history of chronic abdominal pain has been sitting in RAZ, presenting with, predictably, lower abdominal pain. She has been investigated multiple times over, with comprehensive labs, ultrasounds, pelvic exams and a previous CT, all of which have been normal. She carries with her a myriad of diagnoses; chronic abdominal and pelvic pain, IBS, fibromyalgia, depression and anxiety.

On history she reports near constant, left lower quadrant pain over the past 4 months. It is worse when sitting up and lying on her left side. The pain is sharp and she is able to localize the pain with a single fingertip. On history, you elicit no red flags for an intra-abdominal source of her pain. You ask her to lay down on the examination bed and hold your finger over the area of maximal pain. You feel no mass or abdominal wall defects. You apply light pressure, which triggers the pain, and ask her to lift her legs up. She yelps in pain, noting significant worsening to the site after tensing her abdominal muscles.

While you think of your differential for abdominal wall pain, you are highly suspicious of anterior cutaneous nerve entrapment syndrome (ACNES)…

What is ACNES?

  • Anterior cutaneous nerve entrapment syndrome (ACNES) is one of the most frequent causes of chronic abdominal wall pain and often goes undiagnosed. It is caused by entrapment of the anterior cutaneous abdominal nerves as they pass through the fibrous abdominal fascia.
  • This common condition can be treated rapidly and effectively by local trigger point injection of lidocaine and long acting steroid in the emergency department.

Pathophysiology:

  • The cutaneous branches of the sensory nerves arising from T7-T12 must make two 90* turns, traversing through channels within the abdominal fascia at the linea semilunaris (lateral border of the rectus muscles) in order to innervate the cutaneous surface of the abdomen.
  • While the neurovascular bundle should be protected from impingement by fat, it is susceptible to entrapment due to the tight passageway through the fibrous channels and sharp angulation.

Risk factors:

  • There are multiple risk factors for entrapment, and subsequent pain: tight clothing or belts, intra or extra-abdominal pressure, scarring and obesity. Pregnant women and those taking OCPs may also be at higher risk.
  • 4x more common in women, particularly those between ages 30-50 years of age.

 

 Clinical features on history:

  • Patients may describe chronic abdominal pain with maximal tenderness over a small area of the abdomen, typically <2cm
  • Pain is typically at the lateral edge of the rectus abdominis muscles and has a predilection for the right side although, the pain may be anywhere over the abdomen and may be in multiple locations.
  • Pain tends to be sharp in nature, positional and aggravated by activities that tense the abdominal muscles. Pain is generally better supine and worse when sitting or lying on the side.
  • There should be no red flags associated with the history suggestive of a more nefarious source of pain (e.g. GI bleeding, change in bowel function).

 

Physical exam:

  • Use a Q-tip to apply pressure as you move along the abdomen and try to locate the area of maximal tenderness. In most ACNES patients, you will find an area of allodynia or hyperalgesia corresponding to the area of nerve entrapment.
  • Look for a positive Carnett’s sign:
    • Ask the patient to either lift the head and shoulders or alternatively, lift their legs off of the bed while lying flat while you apply pressure over the area of pain on the abdomen.
    • Tightening of the rectus muscles should protect intra-abdominal pathology and pain will be reduced. In the case of abdominal wall pathology, including ACNES, pain will remain the same or be increased.
  • Understanding extra vs intra-abdominal pain:
    • There are 2 types of pain receptors: A-delta and C fibers.
      • A-delta: These fibers mediate sharp, sudden pain and innervate skin and muscles. Patient’s can localize this pain with a fingertip and this corresponds well with extra-abdominal wall pain, such as in ACNES
      • C fibers: Mediate dull ‘visceral’ pain that is often difficult to localize and results in pain over larger areas of the abdomen. These fibers innervate the viscera and parietal peritoneum.

 


Approach and Differential Diagnosis for Abdominal Wall Pain:

  • Look for ‘red flags’ (e.g. GI bleeding, abnormal labs, malnourished appearance) and rule out intra-abdominal sources of pain.
  • Once this has been ruled out, consider your differential for extra-abdominal wall pain which may include the following…

 

 

Diagnosis:

  • ACNES can be diagnosed on the basis of 3 criteria:

 1) Well localized abdominal pain

 2) Positive Carnett’s sign

 3) Response to trigger point injection of local anesthetic and steroid

 

 Treatment

  • Trigger point injections:
    • Act as both a source of treatment and diagnosis.
    • Provides immediate relief of symptoms to 83-91% of patients.
    • Injections can be repeated q-monthly.
    • Works through immediate anesthetization of the nerve, steroidal thinning of surrounding connective tissue and hydrodissection.
  • If the pain returns after trigger point injections, after considering other diagnoses, patient’s can be referred for chemical neurolysis (alcohol injections) or in some instances, surgical neurectomy.
  • Conservative treatment may include activity modification (e.g. avoid stomach crunches) and physical therapy

 

Technique for trigger point injections:

  1. Mark the site of maximal tenderness
  2. Inject 1-3 mL of 1% lidocaine and 1 mL of a long acting steroid using a 1.5 inch 26 gauge needle. Insert the needle until the tender area is reached (pt will let you know)
  3. Pain should resolve within 5 minutes.

 

  • US guidance may be useful for increasing the precision of the injection and can be used to visualize the passage of the nerve through the abdominal fascia.

Video guided review of ACNES:

https://www.youtube.com/watch?v=bDyX3myA0Gw&t=163s

 


References:

  1. Meyer, G, et al. “Anterior cutaneous nerve entrapment syndrome.” Uptodate. Accessed March 8, 2019. URL: https://www.uptodate.com/contents/anterior-cutaneous-nerve-entrapment-syndrome
  2. Suleiman, S, Johnston, D. “The Abdominal Wall: An Overlooked Source of Pain” American Family Physician. August 2001.
  3. Kanakarajan, S., et al. “Chronic Abdominal Wall Pain and Ultrasound-Guided Abdominal Cutaneous Nerve Infiltration: A Case Series.” Pain Medicine, volume 12, Issue 3, 1 March 2011, Pages 382-386.
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A Crushing Case – Compartment Syndrome

A Crushing Case – Compartment Syndrome

Resident Clinical Pearl (RCP) March 2019

Mark McGraw– PGY1 FMEM Dalhousie University, Saint John NB

Reviewed and edited by Renee Amiro and Dr. David Lewis.


Case Part 1

Its early afternoon during your ortho call shift and you get a call from emerge staff saying that they have two patients coming with potentially significant injuries when a piece of equipment rolled over during transport. EMS has informed them that one has a broken ankle. When you arrive to the ED he tells you they are just getting the patient’s pain under control and ordering x-rays.

You head to the room to see the patient, a large burly 35 y/o with an obviously deformed R ankle. His exam is otherwise unremarkable at this time, he has good cap refill to the toes, sensation to the web space, dorsum/plantar and medial/lateral surfaces of the foot is intact and he is able to move his toes. On palpation his lower leg compartments are firm but not hard. An x-ray is done at bedside and shows a Weber Type B fracture of the fibula. His pain seems to be increasing as you speak with him and he has no significant past medical history. He tells you he was loading a piece of equipment when it got away from them and rolled over his leg pinning him momentarily, so he was hanging off a piece of equipment by the leg. Your exam is limited by pain and you ask the nurse if she can give the patient some more pain medication and you’ll return as soon as you see the other patient.


Clinical Pearl: Compartment Syndrome

Compartment Syndrome occurs when the pressure within a muscle compartment exceeds the pressure needed to adequately perfuse tissue. It is considered a true orthopedic emergency and delays in diagnosis and treatment can result in the loss of a patient’s life or limb

Anatomy/Pathophysiology

-Muscle compartments are bound by bone or fascia, two restrictive tissues that create a relatively fixed volume compartment with a very limited ability to compensate for any increase in fluid volume.

-When a traumatic or pathological process results in increased fluid within a muscle compartment the pressure within the compartment increases. This increase in pressure results in reduced arteriovenous pressure gradient (reduced arterial pressure and increased venous pressure) that impairs tissue perfusion within the compartment.

  • As the pressure rises within the compartment capillary flow declines resulting in an enhanced local blood vessel permeability which further increases compartment pressures. If pressures continue to rise tissue ischemia and necrosis will develop.
  • Time for tissue necrosis to occur will vary from patient to patient it can occur in as little as 3 hours and most literature suggests that a fasciotomy must be performed within 4 hours of the onset of ACS to prevent irreversible damage.2

 

 

Signs and Symptoms

Compartment syndrome is a true orthopedic emergency and early recognition of its clinical signs is critical in preventing irreversible tissue damage, rhabdomyolysis, and limb loss.

  1. Pain out of proportion
  2. Pain with passive stretch
  3. Paresthesia
  4. Pain at rest
  5. Paresis

 

  • Severe pain out of proportion to the examination and pain with passive stretching are the first symptoms of ACS to occur. While the early signs are 97% specific for ACS they are only 19% sensitive in the absence of other findings.

  • The combination of pain with passive stretch, paresthesia, and pain with rest has been reported to be 93% sensitive and if paresis is present the sensitivity increases to 98%1. Unfortunately, paraesthesia and paresis are late findings of ACS and delaying the diagnosis until they are present can result in unacceptable delays in treatment. Once a motor nerve deficit has occurred patients will rarely recover function after fasciotomy.

Diagnosis 1

  • Normal compartment pressures are between 8 and 10mmHg in adults and 10-15mmHg in children.
  • 30mmHg is diagnostic for compartment syndrome and should prompt an orthopedic referral when combined with clinical symptoms of compartment syndrome.
  • An alternative is to calculate a differential compartment pressure for an individual patient as factors such as hypertension, peripheral vascular disease and patient medication can cause a large variance in individuals compartment pressures.
  • Differential compartment pressure is calculated by the diastolic blood pressure minus the intra-compartmental pressure if this is under 20mHg then fasciotomy is indicated.
  • If the patient is alert and able to elevate the affected limb, serial examinations over a two-hour period may prevent unnecessary fasciotomies. This should be done in consultation with your orthopedic colleagues.

 

Measuring compartment pressures

Devise: dedicated compartment manometer (Stryker Intra-Compartmental Pressure Monitor) or by using IV tubing and an ART line transducer attached to a long needle.

Who is most at risk of developing compartment syndrome?

  1. Fractures represent 70% of all cases5.
  2. Fractures of the tibial diaphysis account for 40% of all cases in North America.
  3. Open fractures of the tibia are still high risk for compartment syndrome because the opening is insufficient to relieve the compartment pressure associated with the fracture.6

Management of potential compartment syndrome in the ED

  1. Supplemental oxygen if indicated
  2. Remove all cast material, clothing or wraps around the limb
  3. Elevate the limb to the level of the hear
  4. Apply ice to the affected limb if the compartment syndrome is secondary to trauma.
  5. Definitive treatment is a surgical fasciotomy.

 

Case Part 2

You return to see the patient and nursing staff tell you they are unable to get the patients pain under control despite significant amounts of narcotics.

The examination of the lower leg is repeated and the compartments of the leg feel the same however the patient is unable to move his toe. He reports significant pain on passive flexion and extension of the great toe. You call your staff to inform her of the change in the patient and that you are concerned about compartment syndrome and she requests compartment pressure measurements using the Stryker Kit. The senior resident performs the compartment pressure measurements with you and you record pressures of 14, 14 and 25mmHg.

In discussion with the staff you decide to leave the leg on a posterior slab unwrapped, at the level of the heart, and with ice applied 20 on 20 off and perform serial examinations. The serial examinations are unremarkable and the patients pain becomes manageable. The patient is brought to the OR approximately 5 hours later for ORIF of his distal fibula. Compartment pressures are repeated in the OR and were 12, 10, 32 mmHg. An ORIF is performed and you perform serially examinations on the patient q1h overnight. The patient is discharged the following day


Case Follow Up

The patient had significant leg pain on discharge and subsequently presented to the ED on POD#7 for significant leg swelling. Ultrasound was performed to rule out DVT and the patient was discharged for follow up in clinic. He did not go on to develop any further complications.


 

Bottom Line

Compartment syndrome is an important not to miss diagnosis. It should be considered in any hard to control limb pain, especially when associated with fracture.


 

References

  1. 1.Duckworth, A. D., & McQueen, M. M. (2017). The Diagnosis of Acute Compartment Syndrome: A Critical Analysis Review. JBJS Reviews, 5(12), e1. https://doi.org/10.2106/JBJS.RVW.17.00016
  2. Long, B., Koyfman, A., & Rdms, M. G. (2019). Clinical Review. Journal of Emergency Medicine, (December 2018), 1–12. https://doi.org/10.1016/j.jemermed.2018.12.021
  3. McQueen, M. M., & Court-Brown, C. M. (1996). Compartment monitoring in tibial fractures. The pressure threshold for decompression. The Journal of Bone and Joint Surgery. British Volume, 78(1), 99–104.
  4. McQueen, M. M., Duckworth, A. D., Aitken, S. A., Sharma, R. A., & Court-Brown, C. M. (2015). Predictors of Compartment Syndrome After Tibial Fracture. Journal of Orthopaedic Trauma, 29(10), 451–455. https://doi.org/10.1097/BOT.0000000000000347
  5. Stella, M., Santolini, E., Sanguineti, F., Felli, L., Vicenti, G., Bizzoca, D., & Santolini, F. (2019). Aetiology of trauma-related acute compartment syndrome of the leg : A systematic review. Injury, (2018). https://doi.org/10.1016/j.injury.2019.01.047
  6. Strohm, P. C., & Su, N. P. (2004). Acute compartment syndrome of the limb, 1221–1227. https://doi.org/10.1016/j.injury.2004.04.009
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Shoulder Dislocation – The Cunningham Technique

The Cunningham Technique for massaging a shoulder dislocation back into place

Resident Clinical Pearl (RCP) February 2019

Renee Amiro – PGY2 FMEM Dalhousie University, Saint John NB

Reviewed and edited by Dr. David Lewis


Case

A 53-year-old man comes in to the emergency department after having fallen at work and “hurt his shoulder”. Clinically, it is assessed as an anterior shoulder dislocation and he is sent to x-ray which confirms your diagnosis.

Traditionally, the way to reduce a dislocated shoulder involves procedural sedation and some pulling on the arm. While it may save the patient some pain, procedural sedation is not without its risks to the patient and has high staffing needs. Learning some less risky techniques for shoulder reduction can make it safer for your patient and less time intensive for you and your staff!

Anatomy

The shoulder is an inherently unstable joint. The glenoid is shallow and only a small portion of the humeral head is articulating with the glenoid in any position. The rotator cuff provides additional support to the shoulder joint.

Mechanism of Injury for an Anterior Shoulder Dislocation

Most commonly it is a blow to the abducted, externally rotated, and extended arm.

Less commonly a blow to the posterior humerus or fall on an outstretched arm.

Clinical Exam

The arm will be slightly abducted and externally rotated. It will be lost of the normal rounded appearance of the shoulder.

Examination of the axillary nerve and peripheral pulses are essential when examining a patient with an anterior shoulder dislocation before and after reduction.

Imaging

On AP radiograph  the head of the humerus will appear medial to the glenoid. On a lateral radiograph it will appear anteriorly displaced. Take care with posterior dislocations as these can appear in joint on the AP, and may only be apparent on the lateral Y view.

 

Figure 2. radiograph of an anterior shoulder dislocation.2

Don’t forget you can use PoCUS to triage shoulder injuries too:

Resident Clinical Pearl – PoCUS Triage Shoulder Dislocation

 

Based on your clinical examination and imaging, you have determined that this patient indeed has an anterior shoulder dislocation. You have decided to avoid procedural sedation if you can and attempt reduction with the Cunningham technique!

The Cunningham Technique

Step 1
  • Inform the patient of what you are going to attempt. Tell them that their cooperation is necessary for success. Try and relax the patient by getting them to do deep, slow breathing.
Step 2
  • Sit the patient up with the back straight and shoulder blades pulled back. You can use a bed or a chair, whatever is easiest and most comfortable for both you and the patient.
Step 3
  • Get the patient to support the arm and bring it in to the best position to facilitate reduction. That location is typically with the arm abducted and pointing down with the elbow flexed at 90 degrees with the forearm pointing horizontally and anteriorly.
Step 4
  • Sit opposite the patient and place your hand on their elbow in between their body and their arm. Rest their forearm and hand on your arm.
Step 5
  • Apply steady downward traction with the weight of your forearm. Keep the gentle weight on the arm through out. Should now be causing pain as this will cause the muscles to spasm.
Step 6
  • Massage the trapezius, deltoid, and biceps muscles in sequential order. Repeat this process over and over. Your thumb should be anterior with four fingers posterior as your massaging these muscles. Most times you will not get the traditional “clunk” sound so frequent reassessments are necessary to see if the shoulder has been relocated.

YouTube Video Link of Cunningham Technique

The Bottom Line

The Cunningham technique can be used as a safe, successful and less resource intensive procedure to relocate an anterior shoulder dislocation. Patient engagement and cooperation is essential in its success.


Similar Alternative to the Cunningham Technique (The Sool’s Method):


References

  1. Cunningham N. A new drug free technique for reducing anterior shoulder dislocations. Emerg Med (Fremantle). 2003 Oct-Dec;15(5-6):521-4. PMID: 14992071.

 

  1. Sherman, S. (2018, August). Shoulder dislocation. Retrieved March 01, 2019, from UTD
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PoCUS – Pleural Effusion

Medical Student Clinical Pearl

James Kiberd

Class 2019 Dalhousie Medicine

Reviewed and Edited by Dr. David Lewis


Case: 

A 90 year-old male presented with worsening shortness of breath on exertion, crackles bilaterally at the bases on auscultation with known history of congestive heart failure. Bedside ultrasound was performed to assess for pleural effusion

Lung Views:

In order to perform ultrasound of the lungs, there are four views that are obtained (see Figure 1). Place the patient supine. The high frequency linear array transducer is often used, but either the phased array or curvilinear transducers can be used. The first views are taken at both right and left mid-clavicular lines of the anterior chest. With the marker of the transducer pointed toward the patient’s head, a minimum of 3-4 rib spaces should be identified. The next views are of the posterior-lateral chest. The patient can be supine or in the sitting position. It is these views where a pleural effusion can be identified.

Figure 1: Chest views with ultrasound. ‘A’ are anterior chest view positions and ‘B’ are posterolateral view positions

Pleural Effusion

Pleural effusion is assessed by ultrasound placing the transducer in the midaxillary line with the marker oriented toward the patient’s head. On the patient’s right side the diaphragm, the liver, and the vertebral line can be seen. On the left, the diaphragm, spleen, and vertebral line should be in view. In a patient without pleural effusion, one should not be able to visualize the lung as it is mostly air and scatters the sound produced by the transducer. However, in the presence of pleural effusion, the area above the diaphragm is filled with fluid and therefore will appear anechoic. In addition, the vertebral line will be present past the diaphragm as the fluid allows the sound waves to propagate and not scatter. This is known as the ‘spine sign’ (also known as the ‘V-line’). Finally, one is often able to see the atelectatic lung float and move with respirations in the fluid, this is known as the ‘sinusoid sign.’ These are the three criteria outlined by consensus statements in the identification of pleural effusions.1 Occasionally, the area above the diaphragm may look like spleen or liver, but this is known as ‘mirror image’ artifact and is normal.2 Figure 2 shows both the right and left views of our patient.

Figure 2: Pleural effusion showing anechoic pleural fluid, atelectatic lung, and ‘spine sign

Accuracy with Ultrasound

Ultrasound is more accurate than either chest x-ray or physical exam in the identification of small pleural effusions.3 For a chest x-ray to identify fluid there usually needs to be more than 200cc present.2 A meta-analysis found that ultrasound had a mean sensitivity of 93% (95%CI: 89-96%) and specificity of 96% (95%CI: 95-98%).4

 

Our patient went on to have a chest x-ray where he was found to have bilateral pleural effusions (see Figure 3).

Figure 3: Bilateral pleural effusions seen on chest radiography in our patient.

In Summary

Three criteria are used to identify pleural effusion on ultrasound; anechoic fluid above the diaphragm, the ability to visualize the spine above the diaphragm (‘spine sign’), and atelectatic lung moving with respirations (‘sinusoid sign’). Lung ultrasound for the detection of pleural effusion is more reliable to identify small effusions in comparison to both radiography and physical exam.


References:

  1. Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591. doi:10.1007/s00134-012-2513-4.
  2. Liu RB, Donroe JH, McNamara RL, Forman HP, Moore CL. The practice and implications of finding fluid during point-of-care ultrasonography: A review. JAMA Intern Med. 2017;177(12):1818-1825. doi:10.1001/jamainternmed.2017.5048.
  3. Wong CL, Holroyd-leduc J, Straus SE. CLINICIAN ’ S CORNER Does This Patient Have a Pleural Effusion ? PATIENT SCENARIO. Jama. 2010;301(3):309-317. doi:10.1001/jama.2008.937.
  4. Grimberg AI, Carlos Shigueoka DI, Nagib Atallah III Á, et al. Diagnostic accuracy of sonography for pleural effusion: systematic review Acurácia diagnóstica da ultrassonografia nos derrames pleurais: revisão sistemática
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