Emergency Medicine
Board Review

Educational Objective:

Discuss advanced life support in a hypothermic drowning victim in cardiac arrest.

Key Point:

For hypothermic drowning victims, leaders in the fields of wilderness and emergency medicine recommend providing full regular resuscitation while simultaneously rewarming the patient.

Explanation:

The American Heart Association guidelines only briefly address the topics of drowning and accidental hypothermia, leaving the details to experts in these fields.

Clinical management does not differ between fresh and salt water drowning. Isotonic crystalloid is the preferred resuscitation fluid for all drowning victims.

Pearls: If it appears that the patient may later benefit from therapeutic hypothermia, then the body should not be rewarmed beyond 32°C to 34°C (90°F to 93°F), which is the goal temperature of therapeutic hypothermia.

References:

Sempsrott J, et al. Drowning and Submersion Injuries (Chapter 69). Auerbach's Wilderness Medicine 7^th ed. 2017. Part 10 1-28.

Richards DB. Drowning. (Chapter 137) In: Walls R, et al. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th ed., 2018: 1801-1804e.

Educational Objective:

Define the categories of open fractures.

Key Point:

Open fractures are divided into 3 types. Type 3 open fractures have a wound size of ≥10 cm.

Explanation:

Type 1 open fracture is a fracture with a minimal wound (< 1 cm) and minimal soft-tissue damage in the vicinity of the fracture. Type 2 open fractures have a 1- to 10-cm wound and moderate soft tissue damage without compromise of neurovascular structures or periosteal stripping. Type 3 fractures are associated with an >10 cm wound and/or extensive soft-tissue damage that may include neurovascular injury and periosteal stripping. The mechanism of injury for a type 3 open fracture often is a motorcycle collision, high-energy shotgun blast, or any type of high velocity gunshots.

In patients with fractures, it is worth noting that any nearby break in the skin must initially be assumed to communicate with the fracture.

References:

Hoff WS, Bonadies JA, Cachecho R, Dorlac WC; East Practice Management Guidelines Work Group. Update to practice management guidelines for prophylactic antibiotic use in open fractures. J Trauma. 2011;70:751-754.

Walls R, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed., 2017.

As can be seen on the patient’s CT-scan (see image), this patient had an inferior orbital wall fracture (classic blowout fracture of the orbital floor) with blood in the maxillary sinus and some extrusion of orbital contents through the orbital floor. Blowout fractures of the orbital floor can create anesthesia over the branch of the infraorbital nerve (a branch of the trigeminal nerve or CN V, NOT the facial nerve), which runs along the orbital floor. The anesthesia is due to the nerve being stretched and contused, which will lead to anesthesia over the anteromedial cheek and the upper lip. The diplopia is due to entrapment of the inferior rectus muscle (not due to nerve entrapment). Both the anesthesia and the diplopia might resolve on their own as the edema and contusion resolves. Close follow-up is required, but urgent repair is usually not necessary.

Orbital floor blowout fractures can be complicated by a retro-orbital hematoma, but this would present with exophthalmos rather than ecchymosis on the affected side.

About 53% of orbital wall fractures involve one wall only, which means that 47% involve more than one wall. A 2003 study found that the presence of diplopia (or exophthalmos) RAISED the likelihood that the patient had an orbital fracture with a medial wall component. The presence of diplopia in the context of one orbital wall fracture should therefore lead to a search for fractures in the other three orbital walls. The patient’s x-ray is essentially non-contributory except for showing blood in the maxillary sinus. It definitely does not rule out a medial orbital wall fracture.

Often, patients with isolated trauma to the inferior orbital floor can be discharged with close follow-up. The eye can be taped shut for comfort until the diplopia has resolved. The patient should be advised to not drive.

Reference:
Marx: Rosen’s Emergency Medicine, Concepts and Clinical Practice, 6th ed., 2006

Educational Objective:

Discuss why certain lip lacerations may benefit from specialty consultation (when available).

Key Point:

Initial surgical consultation is considered reasonable (not mandatory) for lip lacerations involving more than 25% of the lip (horizontally speaking), lacerations directly through the commissure of the mouth, or deep lacerations in the upper lip vermillion border (as in the above patient).

Explanation:

The reason for considering a consultation for deep upper vermilion border lacerations is not the difficulty of the initial repair (the average emergency physician is fully trained for such a repair), but the fact that even with good initial alignment, these lacerations tend to heal with redundant scar tissue and require later revision. Alternately, if an emergency physician completes the repair, the patient should be sent for follow-up with a reconstructive surgeon, ideally with written instructions that repairs of deep upper vermillion border lacerations often heal with excess scar tissue and require later revision even if the initial repair was “perfect”.

Figure: hypertrophic scar of deep upper lip laceration through vermilion border.

The surface of the lip consists of 3 distinct regions: the skin, vermillion mucosa (which already is oral mucosa, but different in that it is exposed to the outside), and the inner oral mucosa (anatomically similar to the vermillion, but not exposed to the outside). The vermillion-cutaneous junction (which is a mucosal-epidermal junction) is a critical landmark that needs to be well aligned to prevent permanent disfigurement, as even a 1 mm step off of mucosal dermis sutured to cutaneous epidermis can be cosmetically unappealing. Thus, it is important that the first external suture approximate the vermillion border to align mucosal and epidermal regions. 

In addition to thorough irrigation, lip lacerations should be explored for foreign bodies such as tooth fragments. The tongue, oral mucosa, and teeth should also be examined for injury. The search for an embedded tooth fragment should be heightened if a tooth avulsion exists or if the patient presents at a follow-up visit with a wound infection. If strong suspicion exists for a foreign body, but one is not identified with wound exploration, then obtaining X-rays may assist in such identification.

To avoid anatomic distortion and obscuration of the vermillion border, a regional block is preferred to local anesthetic injection. The infraorbital nerve supplies the upper lip, and the mental nerve supplies the lower lip.

Large through and through lip lacerations should be repaired in 3 layers. The muscle layer and the inner oral mucosa are each closed with a 4.0 or 5.0 absorbable suture. The first external suture should be placed to approximate the vermillion border. The vermillion itself (visible part of oral mucosa) may then be closed with either an absorbable or nonabsorbable suture. Finally, the skin is closed with a 6.0 nonabsorbable suture.

Small (< 1 cm) inner oral lacerations may be left open. Oral mucosal lacerations should mostly be closed if the laceration is extensive enough to trap food (> 2-3 cm) or if it interferes with chewing. Larger tissue bites with each suture involving the muscle layer are discouraged due to the risk of bunched mucosa and outside skin puckering. At least 4 square knots should be placed for inner oral sutures because the sutures can be easily untied by constant tongue motion.

Evidence does not support the use of postrepair prophylactic antibiotics. Patients should practice good oral hygiene and be advised to use mouth rinses frequently.

References:

Lammers RL. Methods of Wound Closure (Chapter 35). In: Roberts JR. Roberts and Hedges’ Clinical procedures in Emergency Medicine 7th ed., 2019:655 - 707.e3

Educational Objective:

Appropriately treat encephalitis caused by type 1 herpes simplex virus.

Key Point:

In HSV-1 encephalitis, CSF findings do not correlate with outcome.

Explanation:

The patient history and presentation are concerning for HSV-1 encephalitis, which characteristically presents with fever, altered mental status, and focal deficits. Electroencephalography or neuroimaging will suggest abnormalities in the frontotemporal area. Even patients appropriately treated may be left with severe neurologic deficits.

Good prognostic factors include younger age, lesser compromise of the mental status at baseline, and the prompt initiation of antiviral therapy. CSF findings do not correlate with the prognosis.

References:

Raschilas F, Wolff M, Delatour F, et al. Outcome of and prognostic factors for herpes simplex encephalitis in adult patients: results of a multicenter study. Clin Infect Dis. 2002;35(3):254-260.

Somand DM, Meurer WJ. Central nervous system infections (chapter 99). In: Walls R, et al. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed., 2018: 1328-1340.

Tyler KL. Herpes simplex virus infections of the central nervous system: encephalitis and meningitis, including Mollaret's. Herpes. 2004;11(suppl 2):57A-64A.