Hand infections are important to recognize in the emergency setting. Prompt recognition and initiation of treatment are necessary to prevent loss of hand function. In the EMS setting, most infections will be seen in the context of traumatic injury.

Location:
The most common hand infections involve the distal tip of the fingers. These include nail fold infections known as paranechiae and eponechiae and deep pulp infections of the finger tip. These infections are considered relatively minor. However they often require incision and drainage to remove pus and relieve pressure. These infections can also spread to the hand if not recognized and treated.

Distal finger infections may move into the tendonous sheath of the fingers and palm on the palmar side of the hand. This is known as flexor tenosynovitis. This condition is important to recognize as a pre-hospital care provider, as it is a surgical emergency and requires immediate treatment by a plastic surgeon. Patients with flexor tenosynovitis present with globally swollen fingers which are held in a semi-flexed position. Patients will not allow the examiner to extend their fingers straight due to pain. They will also be tender along the affected tendon.

“Fight bite” is a potentially serious infection which may be seen by EMS providers. In this situation, an individual punches another person impacting one of their knuckles on the victim’s teeth. Although this may appear as a simple laceration on the individual’s knuckle, it is important to suspect more serious injury. Due to the location, it is common for teeth to violate the joint capsule or injure the extensor tendon to the finger. Human saliva has especially virulent organisms which spread quickly and destroy tissue when a wound is inoculated. When assessing a patient who may have suffered a fight bite injury, it is important to assess the wound with the patient’s hand held in a fist to look for foreign bodies (i.e. toot fragments) and to irrigate the wound thoroughly in this position. Loose dressings should be applied and the hand should be splinted for comfort.

The hand has a number of potential spaces deep in the palm which may develop collections of pus. Again, the most common mechanism of infection is secondary to trauma. In this situation, the affected area is generally swollen and red and the patient has limited hand function. When comparing the affected hand to the unaffected hand, the examiner will note a loss of the normal concavity of the palm secondary to a collection of pus in the palm.

Animal Bites:
Animal bites are a common cause of hand trauma and infection. By far the most common are from dogs and largely affect children. Cats are also commonly implicated and generally these injuries are worse than those produced by dogs because of the depth that cat teeth pierce. Wild animals are also implicated. Animal saliva contains a variety of virulent organisms which often require prophylactic antibiotics. Additionally, rabies must be considered with animal bites. As an EMS provider, priorities include copious irrigation, loose dressing application, splinting of the hand and a detailed history of the circumstances of the animal bite. Animal control should be involved immediately. If possible, the animal should be captured for assessment as a potential carrier of rabies. If the animal is domesticated, it should be quarantined and observed for any symptoms of rabies.

Necrotizing fasciitis:
Necrotizing fasciitis (aka “flesh eating” disease) is a rapidly progressing, life threatening infection that can affect any area of the body. Prompt recognition by the EMS provider is potentially life-saving. Certain bacteria spread quickly through the planes of a patient’s tissue and progress to systemic illness and cardiovascular collapse. Clinical features that should prompt considering necrotizing fasciitis include rapidly progressing infection over hours, pain out of proportion to the size of the infection, presence of crepitations (crunching) because of gas in the tissues and black, necrotic looking tissue. This represents a patient who should be triaged for immediate treatment in the emergency department. Long off-load delay because of an underestimation of the severity of the infection may be life-threatening.

Infectious source:
An important component of the EMS provider’s assessment of hand infections involves determining the history of infectious exposure. This should include questions about nail biting, exposure to dirt/soil, impaled or embedded objects, fecal contamination or other bacterial exposures. This history can help the emergency physician in selecting an appropriate antibiotic for treatment.

Summary:
Hand infections can be minor and self-limited or potentially life or limb threatening. The pre-hospital care provider should obtain a detailed history to determine potential sources of infection. Additionally, treatment should include copious irrigation as soon as possible with normal saline. Lacerations and lesions should be loosely dressed to allow for continued drainage. Also, hand infections should be splinted and elevated for comfort and to prevent spread of infection during transport to hospital. If EMS providers suspect infections such as flexor tenosynovitis or necrotizing fasciitis, these concerns should be communicated to the triage nurse immediately and should prompt rapid assessment by the emergency physician.

Dr. Morgan Hillier is an emergency medicine resident with the division of Emergency Medicine, faculty of Medicine at the University of Toronto. Dr. Hillier has a research interest in pre-hospital care and holds and EMR Instructor Trainer status with the Canadian Red Cross.