A 35 year old, somewhat rough looking, man arrives in your emergency room around midnight under his own power. He is complaining of 10/10 severe left arm pain. He says the pain started 5 hours earlier and has gotten worse every hour. The pain is mainly about the elbow and forearm. There pain began around 19:00 while he was watching TV. There is no history of trauma or injury. The pain does not radiate. there is no chest pain or shortness of breath. The patient is right handed.
The patient has no past medical history. He works as a roofer, and he drinks 6 beers per day and smokes a pack a day, he denies drug use.
On exam the patient is screaming and rolling around the stretcher, examination is difficult because every time you touch his arm he begins screaming and swearing. His arms are both heavily muscled, and his left forearm is slightly larger in girth than the right. The patient refuses to move the wrist. The pulses are present at the wrist, and sensation over the hand is intact.
The patient receives 10mg of IV morphine but his pain is unchanged. After a further 10 mg of morphine the patient is somewhat sleepy but says his pain is unchanged.
The nurse taking care of the patient asks you ‘Come on, are you buying this?’ and rolls her eyes.
The primary job of the emergency doctor is to consider the possibility of serious and dangerous diagnoses. Judging patients who present with disproportionate pain to be symptom magnifiers, malingerers, or drug seekers is a pitfall to be avoided.
Severe pain in the absence of compelling physical findings has a number of serious life and limb threatening causes. Premature closure, or mislabelling of the patient in these cases can have dire consequences. When confronted with disproportionate pain in a limb I like to consider if the patient could have:
- Vascular catastrophe
- Compartment syndrome
- Necrotizing soft tissue infection
With the patient now in a near somnolent state you re-examine the arm. The area of maximal tenderness seems to be the proximal volar forearm, and there are perhaps some subtle parasthesias over the palm. The patient wakes with agonized screams with passive ranging of the wrist or elbow.
Getting a surgeon to attend the patient without ancillary testing is another matter…
If you have the equipment available a measured compartment pressure is the best test in this case to help differentiate among possible causes. An excellent review of the use of the Stryker pressure monitor can be found at emedicine.com
Blood tests are unlikely to be useful in this case. The white blood cell count will likely be elevated regardless of cause, the CK may be elevated in either necrotizing myofasciitis or compartment syndrome. Serum lactate may be elevated but is non-specific.
A CT scan of the arm may be useful. Contrast enhanced images including aortic imaging should be obtained if vascular catastrophe is suspected. An edematous compartment may be visible, and signs of necrotizing infection may be apparent.
A pressure of > 30 mmHg is considered diagnostic of compartment syndrome. However, it is probably more useful to consider the issue of compartment perfusion pressure (in the same way we think about cerebral perfusion pressure). Patients with low perfusion states, such as the trauma patient with hypovolemic shock, are at risk of compartment syndrome at lower absolute compartment pressures.
In this case a Stryker monitor was not available. The patient’s bloodwork was notable for an elevated CK at 13,000, and a WBC of 18 (worthless) and a lactate was normal. A CT scan showed edema of the volar compartment of the forearm.
The patient was taken to the OR for fasciotomy of the volar forearm, and made a good recovery. In retrospect the patient had been using a heavy impact drill in the left hand the previous day and this was thought to have precipitated the compartment syndrome.
- Pain out of proportion to physical findings should make the emergency physician very wary.
- Be reluctant to define a patient as a symptom magnifier, malingerer or a drug seeker.
- Vascular catastrophe, compartment syndrome and necrotizing skin infection can all present with disproportionate pain and subtle or no physical findings.
- A swollen painful limb with any neurovascular findings represents a surgical emergency.