During a night shift, a ward nurse urgently pages the orthopedic resident regarding a pati… — USMLE Step 2 CK

During a night shift, a ward nurse urgently pages the orthopedic resident regarding a patient with uncontrolled pain. The patient is a $34$ -year-old right-hand-dominant carpenter who sustained a closed, displaced fracture of the right distal radius $8$ hours ago. He was treated with closed reduction and application of a circumferential fiberglass cast. He has received $2$ doses of intravenous morphine over the past hour but continues to writhe in bed, describing a severe, burning pain in his forearm. Vital signs are temperature $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), blood pressure $142/88\text{ mmHg}$ , and heart rate $112\text{/min}$ . Examination of the right upper extremity shows a rigid, intact cast. The exposed digits are mildly swollen but pink, and capillary refill is $< 2\text{ seconds}$ . The radial pulse is palpable. Passive extension of the digits by the examiner elicits agonizing pain that causes the patient to withdraw the arm immediately. Which of the following is the most appropriate next step in management?

Bivalve the cast and divide all underlying circumferential dressingsAnswer
B
Measure tissue pressures using a handheld compartment monitor
C
Administer additional intravenous analgesia and reassess in $1$ hour
D
Transport the patient immediately to the operating room for a fasciotomy
E
Elevate the right arm above the level of the heart

Answer

Bivalve the cast and divide all underlying circumferential dressings

The patient presents with classic signs of acute compartment syndrome (ACS): pain out of proportion to the injury, increasing analgesic requirements, and excruciating pain with passive stretch of the involved muscles. In any patient with suspected ACS who has a cast, splint, or tight dressing, the immediate most appropriate next step is to relieve the external constriction. This is achieved by bivalving the cast (cutting it on two sides) and completely dividing all underlying webril or padding down to the skin. This simple maneuver can reduce intracompartmental pressure by up to

85\%

and may restore adequate perfusion, potentially averting the need for surgical fasciotomy. Pulses are typically preserved in ACS until very late in the course, so the presence of a palpable radial pulse does not rule out the diagnosis.

Step-by-Step Solution

Identify the clinical syndrome based on the patient's presentation.

The patient exhibits pain out of proportion to the injury, pain with passive stretch, and a tense compartment, which are classic signs of acute compartment syndrome (ACS).

Recognizing ACS is a clinical emergency necessary to prevent irreversible muscle and nerve necrosis.

Determine the first therapeutic intervention for ACS in a patient with a circumferential cast.

The immediate action is to remove all external constricting materials by bivalving the cast and cutting the padding down to the skin.

Releasing external compression can significantly lower intracompartmental pressure and may resolve the syndrome without the need for surgical fasciotomy.

Key Concept

The immediate management of acute compartment syndrome in a casted extremity is the complete removal of all external constrictive dressings (bivalving the cast and cutting all padding to the skin).

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic