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IOTW 12/14/20

65 y/o F p/w fever and hypoxia

  1. Name the structures indicated by labels “A, B, C, D, and E.”
    • A – Diaphragm
    • B – Liver
    • C – Spleen
    • D – Rib with posterior shadowing
    • E – Pleura
  2. What is indicated by label “F”? What type of artifact causes this? What does it signify?
    • B-Lines which are caused by a type of reverberation artifact. This typically signifies thickened or fluid-filled interlobular septa. While occasional B-Lines in the lung bases can sometimes be a normal finding (especially in elderly populations), 3 or more per lung field is usually pathological and consistent with an interstitial syndrome. This can be seen in almost any interstitial process such as pulmonary edema, pneumonia, lung contusions, and masses, for example.
  3. What sign is label “H” and what does it mean?
    • Spine sign. In normal lung, vertebral bodies on ultrasound should terminate at the level of the diaphragm and not be visualized above due to the inability of ultrasound waves to transmit through air. The presence of a fluid collection in the lung, however, will act as an acoustic medium for the transmission of ultrasound waves allowing visualization of the spine above the diaphragm as seen in the images above. This is non-specific for determining the type of fluid collection, as this can be seen with pleural effusions, hemothorax, and even consolidations.
  4. What is indicated by label “G” and what are the two different types?
    • Air bronchograms. They are air-filled areas of the bronchial tree which are visualized in the presence of fluid-filled alveoli which act as an effective acoustic window. There are 2 types of sonographic air bronchograms:
      • Static – These will remain fixed in position during the respiratory cycle. This indicates air trapped in small bronchi caused by complete bronchial obstruction from atelectasis.
      • Dynamic – These will exhibit small movements with respiration indicating partial bronchial obstruction from fluid mixed with air. This finding typically represents pneumonia.
  5. Name four sonographic lung findings that suggest pneumonia as the diagnosis.
    • B-Lines – often seen with small areas of subpleural consolidation. In early stages of pneumonia, only some alveoli will be fluid-filled and can lead to a patch of focal B-Lines.
    • Hepatization – this refers to the solid “liver-like” sonographic appearance of lung as it becomes inflamed and filled with purulent fluid. This can be seen in consolidation or atelectasis.
    • Shred sign – this appears as an irregularity of the pleural interface in the setting of small areas of consolidated lung. These areas abut the pleural surface causing the “shredded” appearance on ultrasound.
    • Dynamic air bronchograms – as discussed in question 4, this finding has been shown to have a 94% specificity and 97% positive predictive value for pneumonia as the cause of the consolidation.
    • Color doppler can also be used which would demonstrate the pulmonary vasculature in areas of consolidation. A concomitant parapneumonic effusion with echogenic debris can suggest empyema.

IOTW 11/30/20

18 y/o M p/w chest and abdominal pain s/p fall from motorcycle the night prior

  1. Which FAST exam view above does NOT contain free fluid?
    • The Subxiphoid view does NOT contain free fluid. All three other views are positive.
  2. The primary survey of ATLS follows the “ABCDE” protocol. Which part of the primary survey does the FAST exam further assess: A, B, C, D, or E?
    • C – Circulation. An Extended-FAST (E-FAST) would also further assess B – Breathing.
  3. Can you accurately name what each arrow is depicting in the images above labeled A-L?
    • A – Liver
    • B – Free fluid in Morrison’s Pouch
    • C – Rib shadow artifact
    • D – Spleen
    • E – Left subdiaphragmatic free fluid
    • F – Left hemidiaphragm
    • G – Urinary bladder in sagittal view
    • H – Pelvic free fluid
    • I – Intestines
    • J – Right ventricle
    • K – Left ventricle
    • L – Pericardium
  4. What is the minimum amount of free fluid that the literature suggests can be detected on a FAST exam?
    • It was suggested that a minimum of 500 mL of free fluid could be detected on a FAST exam. However, as ultrasound imaging technology and operator technique improves, newer literature suggests that as little as 100 mL of free fluid can be detected.
  5. If the patient in the above scenario had unstable vital signs, do ATLS guidelines recommend the next step to obtain a CT scan or to activate the OR? What if the patient had stable vital signs?
    • As per ATLS, an unstable patient with a traumatic mechanism of injury and a positive FAST exam should go directly to the OR for laparotomy. A stable patient with a traumatic mechanism of injury and a positive FAST exam should receive a CT scan.
  6. Does a positive FAST exam differentiate what type of fluid is present?
    • No. Ascites and blood, for example, may have a similar appearance on ultrasound. In certain settings, such as trauma or an unstable patient, the fluid should be assumed to be blood until proven otherwise.
  7. Does a positive FAST exam reliably identify the source of bleeding?
    • No. Free fluid in any quadrant can represent blood that has pooled from a different area.
  8. Where does free fluid tend to initially accumulate in the RUQ view? What about in the LUQ view?
    • In the RUQ view, free fluid most often will be initially visible in the paracolic gutter (liver tip and inferior pole of kidney). In the LUQ view, free fluid most often will be initially visible in the subdiaphragmatic space above the spleen. Be sure to include everywhere from diaphragm to paracolic gutter in both views because free fluid can hide in variable locations.

IOTW 11/23/20

67 y/o F p/w RUQ pain

  1. What are the three structures that compose the portal triad?
    • Portal vein, hepatic artery, and common bile duct. The common bile duct will not exhibit flow when evaluated with color doppler.
  2. Which structure is indicated by label “A”?
    • The common bile duct. Note the absence of flow with color doppler.
  3. What is the name of the artifact indicated by label “B”?
    • Acoustic shadowing. Ultrasound waves are absorbed by a solid structure or reflected off of air, causing “clean” or “dirty” shadowing, respectively.
  4. What is the normal diameter of structure “A”? What about if the patient is post-cholecystectomy?
    • The CBD should measure <6 mm in diameter and the upper limit increases by 1 mm per decade after age 60. Post-cholecystectomy CBD may measure up to 10 mm (1 cm) in diameter. Be sure to measure from inner wall to opposing inner wall in a perpendicular fashion.
  5. What is the diagnosis hinted at by label “C”?
    • Choledocholithiasis. The CBD is grossly enlarged and measures about 9-10 mm in diameter when compared with the scale on the right-hand side of the screen. Label “C” indicates a visualized stone within the CBD distally which appears as an echogenic rounded focus with shadowing.
  6. Do these images suggest the presence of concomitant acute cholecystitis?
    • No. Sonographic evidence of cholecystitis includes stone in neck (SIN sign), anterior gallbladder wall thickening, pericholecystic fluid, gallbladder hydrops, and sonographic Murphy’s sign, none of which are present. There are numerous small gallstones within the gallbladder, however, which should at least raise suspicion for other biliary tract obstruction.
  7. Which diagnosis would you be most concerned about if the patient exhibited signs of infection?
    • Ascending cholangitis. The classic Charcot’s Triad (fever + jaundice + RUQ pain) only occurs in ~50% of patients and the classic Reynold’s Pentad (triad + altered mental status + hypotension) only occurs in <5%. In elderly patients, hypotension may sometimes be the only presenting sign, so a high index of suspicion must be maintained. If the diagnosis is likely, patients should be treated aggressively for sepsis with fluid resuscitation and antibiotics targeted at organisms such as E. coli, Enterococcus, Bacteroides, Clostridium, and even MRSA in severe cases. The case should be coordinated with gastroenterology and general surgery for ERCP and cholecystectomy to achieve source control and biliary decompression.

IOTW 11/10/20

28M p/w biliary colic however reports PMHx of “dilated heart”. Bedside ECHO was performed…

  1. What are some EKG findings associated with the suspected diagnosis?
    • In the setting of hypertrophic cardiomyopathy, EKGs may often be nonspecific or normal. However, you may see a high voltage or LVH pattern and deep narrow “needle-like” Q waves in the inferolateral leads. There may also be deep T-wave inversions in the anterolateral leads.
  2. What LV wall thickness supports the diagnosis?
    • Unexplained wall thickness >1.5 cm in any myocardial segment. A septal:posterior wall thickness ratio can be measured. An abnormal ratio is >1.3 in normotensive patients and >1.5 in hypertensive patients. The ratio in the image above comes out to (3.1 cm/1.8 cm=) ~1.7 which is abnormal and should prompt further evaluation. Asymmetric septal hypertrophy may be present. In addition, the LV outflow tract diameter can be measured in the parasternal long view just proximal to the aortic valve to assess for obstruction. The LVOT normally measures 1.6 – 2.4 cm.
  3. What features of the mitral valve are associated with this?
    • Mitral regurgitation is sometimes present. You may also assess for systolic anterior motion (SAM) of the mitral valve to help assess for obstruction. To do this you would obtain an M-Mode waveform through the anterior mitral valve leaflet in parasternal long view similar to how you would assess for EPSS. The mitral valve would exhibit anterior excursion toward the interventricular septum during systole if this was present.
  4. If this patient presents in decompensated CHF, what are some considerations in the management in regards to…
    • Administering IV fluids?
      • Volume loading is essential to increase preload and you should be sure to adequately fluid resuscitate prior to considering pressors in order to avoid worsening of the LV outflow tract obstruction. Monitor carefully for signs of fluid overload.
    • Intubation?
      • If it is absolutely necessary and cannot be avoided, you want to take all precautions to maintain preload. Push dose phenylephrine should be mixed and readily available (1 mL of 10 mg/mL phenylephrine in 100 mL NS = 100 mcg/mL; may use 1-2 mL (100-200 mcg) q2-5 min). BVM ventilations should not be aggressively performed. Avoid high airway pressures.
    • Managing tachycardia?
      • Beta blockers are the mainstay especially if angina or dyspnea present. You can titrate to a resting heart rate of 60 bpm. Use with caution if there is sinus bradycardia or conduction abnormality. Verapamil is another option. You must avoid vasodilators such as nitrates and dihydropyridine CCBs such as nifedipine. Do not give digitalis. Have a low threshold to cardiovert if needed to maintain sinus rhythm, for example if there is atrial fibrillation.
    • Choice of vasopressors?
      • If hypotensive and decision is made to initiate pressors, goal is to increase afterload. Phenylephrine is probably the best pressor to start with and consider vasopressin if it is maxed and a second pressor is needed. To increase efficacy of your pressors, attempt to fix any acidosis if present. AVOID positive intotropes such as dobutamine, norepinephrine, epinephrine, and dopamine.
  5. What is the definitive treatment of this condition?
    • While an ICD +/- AV sequential pacing may be used to treat ventricular dysrhythmias, the definitive treatment of LV outflow tract obstruction is myomectomy or resection of outflow tract.
  6. If the patient cannot be admitted, what discharge instructions should be provided?
    • Important to avoid exertion. May be started on beta-blocker from ED while pending cardiology appointment and follow-up comprehensive echo.

IOTW 11/02/20

38 y/o F p/w RUQ pain

  1. Does this gallbladder contain gallstones?
    • Yes. Although gallstones are not seen on this CT, they are easily visualized on the ultrasound (see image below answers) Only 74-79% of stones are identified on CT scan. Typically they are only seen on CT if they are calcified, whereas cholesterol stones and others may be hypoattenuating or isodense to bile, rendering them non-distinguishable. Ultrasound is considered the gold standard for detecting gallstones which can identify stones as small as 2 mm with a sensitivity of greater than 95%.
  2. Which label (A, B, or C) is the most accurate GB wall measurement and is it abnormal?
    • A is the most accurate measurement in this image corresponding to a wall thickness of approximately 1.8 cm. Wall >4 mm (with some sources even stating 3 mm) is considered abnormal. Label B may be tempting to select, however this only measures from the inner wall to a region of wall edema, which would lead to a greatly under-measured wall. Label C measures the posterior wall, which would falsely enhance the measurement due to the artifact posterior acoustic enhancement. Due to this artifact, only the anterior gallbladder wall should ever be measured when performing biliary ultrasound.
  3. Is this a contracted gallbladder or is there wall edema? How does the sonographic appearance of these differ?
    • This is gallbladder wall edema. Note the irregular anechoic and hypoechoic areas within the wall. A contracted gallbladder will show pseudothickening which tends to form a more symmetric and diffuse pattern. Wall edema may be focal or more diffuse with irregular areas demonstrating various echogenicities. (See images below answers)
  4. What is represented by label D?
    • Pericholecystic fluid. It can often be subtle, so be sure to have a keen eye.
  5. Are these images overall consistent with cholecystitis?
    • Yes. Gallbladder wall thickening and pericholecystic fluid are secondary findings of cholecystitis and have a low specificity alone. The presence of gallstones with wall thickening, however, has been shown to have a positive predictive value of >95% for cholecystitis.
Gallstones. Note the hyperechoic rims with shadowing posteriorly
Contracted gallbladder on left exhibiting pseudothickening. Gallbladder wall edema on right.