VOTW: Soft Tissue Foreign Body

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This week’s VOTW is brought to you by Dr. DeStefano and Dr. Wong!

A 3 year old female was brought into the ED a week after a she slid down a wooden pillar and suffered a splinter into her right thigh. A POCUS of the area showed…

Clip 1 is a POCUS of the posterior thigh that shows a small echogenic object with posterior acoustic shadowing. As the they scan through the area, we can tell that the object is linear, about 1cm in length and that its trajectory courses from the dermis to the subcutaneous layer and ends just before entering the muscle. There is no reverbration artifact which is consistent with wood. There is no surrounding signs of abscess of cellulitis.

POCUS for Foreign Bodies

Soft tissue foreign bodies can be imaged by x-ray, CT or ultrasound. Many of us reach for X-rays first but is that really the right move?

X-rays have poor sensitivity for foreign bodies especially for radiolucent objects such as plastic and wood(1). 

Ultrasound on the other hand is highly sensitive for foreign bodies, regardless of what the composition, and has the following advantages over X-rays including:

  1. No radiation

  2. Can map out the shape, trajectory, depth of the object at bedside

  3. Evaluate for involvement of tendons, muscles, joints

  4. Evaluate or complications such as cellulitis or abscess

  5. Guide removal of the object in real time (see videos below)

Characteristics of common foreign bodies on US

Glass: hyperechoic, + shadow, + reverb artifact

Metal: hyperechoic, + shadow, + reverb artifact

Wood: hyperechoic, + shadow, - reverb artifact

Plastic: hyperechoic, + shadow, - reverb artifact

Here is an example of metal which is hyperechoic with reverberation artifact (repeated hyperechoic horizontal lines extending deep to the object)

Metal foreign body with reverberation artifact

Technique

  1. Use a linear probe.

  2. Scan the area of interest in both transverse and sagittal.

  3. Look for a hyperechoic structure with posterior shadowing +/- reverbration artifact.

  4. Identify the shape, length, trajectory and surrounding structures.

  5. For very supericial foregin bodies, try using a water bath to increase the distance between the probe and foreign body (this brings the object closer to the "focal point", the part of image with the best "two-point discrimination" or resolution, which is closer to midway down the screen). Water also provides a great acoustic window.

Foreign body removal using ultrasound-guidance

Check out these great videos on how to use ultrasound to assist w/ foregin body removal

  1. https://www.youtube.com/watch?v=x80NrSUNRrI

  2. https://www.youtube.com/watch?v=OeFDg1hZRDk

  3. https://www.youtube.com/watch?v=h1YQY7guUb0

Back to the patient:

The team identified the splinter in the soft tissue with no evidence of celluitis or abscess. The team approrpiately did not order an x-ray and saved the patient from unecessary radiation! The patient was referred to outpatient general surgery for evaluation for removal of the object.

References:

  1. Pattamapaspong N et al. Accuracy of radiography, computed tomography and magnetic resonance imaging in diagnosing foreign bodies in the foot. Radiol Med. 2013 

  2. https://rebelem.com/pocus-and-soft-tissue-foreign-bodies/

  3. https://sjrhem.ca/detection-of-foreign-bodies-in-soft-tissue-a-pocus-guided-approach/

Physician Mortgage Loans

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What is a physician mortgage loan?

 

A physician loan is a mortgage loan that requires the borrower to have a DM, DO, DPM, DVM, DDS, or DMD degree (there may be more acceptable degrees than that depending on location and bank). Most of these loans typically require you are still in training or within ten years of completing training. This type of loan package enables medical professionals to effectively borrow more money than they otherwise would with a conventional mortgage loan. These loans can be up to $1,000,000! 

What is the benefit of a physician mortgage loan?

One significant benefit of physician mortgage loans is the ability to purchase a home without the requirement of a down payment. This is advantageous for medical professionals who may have substantial student loan debt and limited savings. Additionally, these loans often do not mandate private mortgage insurance (PMI), which is typically required when the down payment is less than 20% on a conventional mortgage. By eliminating the need for PMI, physicians can potentially save on monthly mortgage costs. The calculation of the debt-to-income (DTI) ratio, a crucial factor in mortgage approval, is approached differently for physician mortgage loans. Lenders exclude certain debts, such as student loans, from the DTI calculation, making it easier for doctors to qualify for a larger loan amount.

 

Are there any drawbacks to a physician mortgage loan?

Interest rates on physician mortgage loans may differ from those of standard mortgages or first-time homeowner loans. Often they will be slightly worse than conventional mortgages. The difference is typically not substantial, but often the recommendation may be to refinance the mortgage after a few years to get a better interest rate. This will be situation dependent. Also note, not all banks offer these types of loans.

TLDR: You can qualify for a $1,000,000 mortgage loan with no down payment, and no PMI, if you are in medical training or within ten years of completing training. 

Spider Bites

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The brown recluse spider, scientifically known as Loxosceles reclusa, is known for its venomous bite. This spider is found in southern US states.

  1. Mechanism of Toxin: Sphingomyelinase D causes hemolysis and complement mediated erythrocyte destruction. There are multiple proteases that break down collagen, elastin, fibrinogen, etc and act synergistically with sphingomyelinase D to cause local tissue destruction

  2. Clinical Features of Bites:

    • Course of bite: The bite is often painless or with minimal pain. There will be two small puncture wounds. This will become pale with the edges becoming red. Over the next few days, this turns into a blister with a central ulcer, followed by skin sloughing. Can take weeks for wound to heal.

    • Early Symptoms (2-8 hours):

      • Redness and swelling around the bite site

      • Mild to moderate pain and itching

    • Delayed Symptoms (12-36 hours):

      • Necrotic (dead) tissue formation, leading to an ulcer

      • Systemic symptoms like fever, chills, malaise, headache, nausea

    • Worsening complications:

      • DIC

      • Rhabdo

      • Kidney Failure

  3. Evaluation: Lab tests should only be ordered in patients with systemic symptoms and fear of worsening complications. Should order CBC, CMP, CK, retic count, haptoglobin, LDH, PT/INR, D-dimer, fibrinogen.

  4. Medical Management:

    • Local Wound Care: Primary management is local wound care. Clean the site with soap and water, apply a cold compress to reduce swelling, and elevated the affected site. Sphingomyelinase D also has reduced activity in lower temp, so ice packs are important! Patient should also receive tetanus prophylaxis!

    • Pain Management: NSAIDs

    • Wound Care for Necrotic Tissue: If wound is severe enough, may require eval for debridement and potential skin grafting (this is usually weeks later). Hyperbaric oxygen therapy can also be considered for severe cases.

    • Antibiotics: Only if concern for local cellulitis.

    • Systemic Treatments: Weak evidence for use of dapsone. There is slightly more evidence behind the use of corticosteroids for reducing the risk of AKI and rhabdo.

It's crucial to note that brown recluse spider bites are rare, and most cases resolve with local wound care.

 

Black widow spiders, known as Lactrodectus spp, are venomous arachnids found in various regions around the world. The venom they produce contains neurotoxins, primarily alpha-latrotoxin, which affects the nervous system. These spiders classically have the “red hourglass” marking on them.

1.       Mechanism of Toxin: The primary toxin in black widow spider venom is alpha-latrotoxin. It works by binding presynaptic neurons, creating calcium permeable channels in the lipid layers, causing an influx of calcium into the presynaptic cells. This leads to an excessive release of neurotransmitters. Primarily concerned with release of acetylcholine.

 

2.       Clinical Features of Bites:

  • Course of bite: Bites are often initially characterized by severe local pain at the bite site. Very quickly patients will develop erythema and edema at site of bite

  • Systemic Symptoms: As the venom spreads, systemic symptoms may develop, including muscle pain and cramps, abdominal pain, weakness, sweating, and nausea. Patients may experience autonomic nervous system effects such as increased blood pressure and heart rate.

  • Worsening complications

    • Rhabdo

    • Myocarditis

    • A-fib

3.     Laboratory Tests: Lab values are generally nonspecific for black widow bites. Patients will tend to have elevated WBC, hematuria, and elevated liver enzymes. There are documented cases of rhabo and myocarditis from black widow bites, and there for kidney function and troponins can be checked if patients complain of systemic symptoms.

4.       Medical Management:

  • Local Wound Care: Clean the site with soap and water. Patient should also receive tetanus prophylaxis!

  • Pain Control: Analgesics, such as opioids or muscle relaxants, may be used to manage pain.

  • Antivenom: In severe cases or when systemic symptoms are significant, antivenom may be administered. This can rapidly reverse the effects of the venom. It is horse derived, and may cause anaphylaxis.

  • Observation: Patients may be observed for several hours to ensure symptoms do not worsen and to monitor for potential complications. Consider admission in children, patients with preexisting cardiac conditions, pregnant women, or for severe symptoms.

    It's important to note that while black widow spider bites can be painful and cause distressing symptoms, fatalities are rare.

     

    Anoka IA, Robb EL, Baker MB. Brown Recluse Spider Toxicity. [Updated 2023 Aug 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537045/

    Williams M, Sehgal N, Nappe TM. Black Widow Spider Toxicity. [Updated 2023 Aug 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499987/