Acute Compartment Syndrome

Acute compartment syndrome is when the pressure in a muscle compartment increases, compromising circulation and function. This occurs because the compartment is surrounded by a fascial membrane that restricts further expansion. It typically occurs after trauma, crush injury, or burns. Signs include severe pain (earliest sign), pallor, paresthesia, paresis, and pulse deficit. To measure compartments, you take your measurement device and insert it into the compartment of interest. 

How to set up your measurement device: 

• Your materials include a sterile 3cc saline syringe, chamber, and needle. The needle has a side port (hole) for measuring pressure.

• Connect the syringe, chamber, and needle

• Flush the chamber and needle with saline to get rid of the air; do this by holding the entire device at a 45-degree angle.

• Load into the monitoring unit and press zero, you should see 00

• Insert the needle into the compartment of choice and hold it for reading

There are two ways to assess for compartment syndrome. You can use the absolute or delta pressure (normal: 0-8). Suspect compartment syndrome if:

• the absolute pressure is > 30 mmHg

                                   OR

• The delta pressure is < 30 mmHg

  • Delta pressure = diastolic pressure - compartment pressure. This means that the pressure in your compartment is so high that it is close to your diastolic blood pressure

Tip: remember the number 30 

These patients require a fasciotomy so call ortho ASAP. Meanwhile, you should level their affected limb and support BP if hypotensive to help maintain perfusion. 

Thanks for reading!

-Ariella

References: 

https://www.emrap.org/episode/trauma1/compartment

https://www.emrap.org/episode/measuring/measuring

POTD: Listen, Frank, let's talk about Lisfranc Injuries

Background

Lisfranc ligament attaches 2nd metatarsal to medial cuneiform

2nd metatarsal is held in mortice created by the three cuneiform bones

Injury to 2nd metatarsal often results in dislocation of the other MTs

Dorsalis pedis may be injured in severe dislocation

Lisfranc Injury = any fracture or dislocation of the tarsal-metatarsal joint

Mechanism of Injury

MVAs, falls from height, and athletic injuries

Indirect rotational forces and axial load through hyper-plantarflexed forefoot

hyperflexion/compression/abduction moment exerted on forefoot and transmitted to the TMT articulation

metatarsals displaced in dorsal/lateral direction

Clinical Features

Inability to bear weight (especially on tiptoe)

Tenderness over tarsometatarsal region

Pain with pronation and passive abduction of the midfoot

Ecchymosis of plantar section of midfoot is highly suggestive

Imaging

Obtain radiographs, which include AP, lateral, oblique, and weight bearing views.

AP: Medial margin of 2nd metatarsal base does not align with medial margin of 2nd cuneiform. Bony displacement 1mm or greater between bases of first and second metatarsals is considered unstable.

Oblique: Medial margin of 3rd metatarsal does not align with medial margin of 3rd cuneiform.

Lateral: 2nd metatarsal is higher than middle cuneiform (step-off).

If suspicion is high based on history and physical, you may want to consider obtaining further imaging in conjunction with your ortho consultants.

Treatment and Dispo

Sprains and non-displaced fractures:

Non-weightbearing splint with ortho follow up (most managed with cast x 6 weeks)

Posterior Ankle Splint

Displaced fractures:

Emergent ortho consult

When diagnosed appropriately, patients who undergo open reduction and internal fixation of fractures have superior outcomes to those with purely ligamentous injury

20% are missed on first presentation to ED, so keep this in mind the next time you see a patient with the chief complaint of foot pain!

References:

https://www.orthobullets.com/foot-and-ankle/7030/lisfranc-injury

Sherief, T et al. Lisfranc injury: How frequently does it get missed? And how can we improve? Injury: International Journal of the Care of the Injured 2007: 34; 856-860. PMID: 17214988

POTD: Trigger Point Injections

Today, I wanted to write about the first bedside procedure I learned how to perform as an intern: the trigger point injection. I’ve heard that many residents have never done one of these, so I wanted to share that they have worked very well for me.

Musculoskeletal pain is a very common complaint in the ED and many of us have a special cocktail we refer to when treating it, usually involving a combination of topical analgesics, NSAIDs, and muscle relaxants. However, there is a time when these oral medications aren’t enough in the ED, or the patient has already failed outpatient management, and that is when the pain involves a trigger point.

A trigger point is a palpable area of muscle spasm that feels extra taut, which many of us commonly call a “knot.” While a patient will commonly complain of a broad region of pain, the pain is typically originating from the trigger point and the remainder is referred pain. Trigger points are significantly more tender than the surrounding region and pain is easily reproducible on palpation. There is no imaging to identify a trigger point (not even ultrasound); you have to feel it.

You can find everything you need easily: an alcohol swab, 1-2 mL local anesthetic (1-2% lidocaine without epinephrine, 0.25-0.5% bupivacaine, OR a 50-50 combination of the two), a 22 to 25 gauge needle, and a band-aid.

The procedure is fast and easy, and relief is nearly instantaneous when done correctly.

Steps:

1. Identify the trigger point and clean the area around it with the alcohol swab.

2. Insert the needle at a 30-degree angle, deep enough to penetrate the point (make sure your needle is long enough for deeper muscles!) When you hit the knot, you may elicit a “twitch” response, which is pathognomonic for a trigger point. Inject some anesthetic.

3. Pull out almost to the surface of the skin and redirect to deliver a small amount of anesthetic to each of the 4 quadrants of the trigger point. It is important to pull out almost all the way to avoid hematoma.

4. Apply a band-aid when complete.

Contraindications:

1. Overlying cellulitis

2. Nearby critical anatomical structure

3. Allergy to local anesthetic

4. Coagulopathy or bleeding disorder

5. Can’t feel a trigger point, or can't find a maximal point of tenderness – not a contraindication… but wouldn’t recommend, mainly because you and the patient are unlikely to be satisfied. And you’re more likely to become one of those people who say that trigger point injections don’t work!

Be well,

Maisa Siddique, PGY3

Sources

https://www.aliem.com/trigger-point-injection-musculoskeletal-pain/

https://www.acep.org/patient-care/map/map-trigger-point-injection-tool/