Dog bites are common injuries, and they frequently cause damage extending beyond the skin. The immense force and sharp puncture wounds inflicted by a dog’s teeth can injure the body’s communication network. A bite has the potential to compromise the delicate structures that control both sensation and movement. This article explains the mechanisms of nerve injury, the symptoms to watch for, and the medical steps necessary for diagnosis and recovery.
How Dog Bites Cause Nerve Injury
Nerve damage from a dog bite generally results from two mechanisms: crushing and laceration. A dog’s jaw can exert several hundred pounds of pressure per square inch. This blunt force is enough to severely compress or stretch nerve fibers, even without breaking the skin. This compression injury, known as neurapraxia, temporarily blocks the nerve’s ability to transmit signals and often resolves as swelling subsides.
The second mechanism involves the sharp teeth of the animal causing a direct cut or laceration to the nerve. If the nerve is partially or completely severed, this more severe injury is termed axonotmesis or neurotmesis. In these cases, the physical continuity of the axon is disrupted, leading to a much more complex healing process.
Certain body parts are at greater risk because the nerves are close to the surface. Areas like the hands, wrists, feet, face, and neck have less protective muscle and tissue. The nerves in these locations are easily compromised by sharp puncture wounds or powerful crushing force.
Swelling and infection developing hours or days after the bite can also lead to secondary nerve compression. As inflammatory fluid accumulates around the wound, it puts pressure on nearby nerves. This delayed compression can cause new or worsening symptoms, even if the nerve was not directly hit during the attack.
Identifying Symptoms of Nerve Damage
Symptoms of nerve damage can manifest immediately after the bite or develop later as swelling increases. Recognizing these signs helps in promptly seeking medical attention. Symptoms depend on whether sensory nerves (which transmit feeling) or motor nerves (which control muscle movement) have been affected.
A common sign of sensory nerve involvement is a loss of feeling or numbness in the affected area. Patients may also experience paresthesia, including tingling, prickling, or the sensation of “pins and needles.” Individuals sometimes report a burning sensation or shooting pain radiating from the injury site.
When motor nerves are injured, symptoms relate to a loss of function in the controlled muscles. This presents as muscle weakness, making it difficult to grip objects or move fingers and toes. Severe motor nerve damage may result in a partial or complete inability to move the limb, known as paralysis.
A person may be able to move a limb but cannot feel it, indicating isolated sensory nerve damage. Conversely, normal sensation with difficulty moving points toward motor nerve damage. Any noticeable change in sensation, strength, or coordination following a dog bite warrants a thorough medical evaluation.
Diagnosis and Treatment Options
The initial medical response focuses on meticulous wound cleaning and infection control, as bacteria from the animal’s mouth pose a significant risk. Once the wound is stabilized, medical professionals assess the extent of underlying soft tissue damage, including potential nerve injury. A physical examination testing sensation and motor function helps determine the likelihood of nerve involvement.
If nerve damage is suspected, specialized tests may be ordered to confirm the diagnosis and determine severity. These diagnostic tools include nerve conduction studies (NCS) and electromyography (EMG), which measure how electrical signals travel through the nerve and how muscles respond. Imaging tests like ultrasound or MRI can also provide a visual assessment of the nerve’s structure.
Treatment depends on the type and extent of the damage. For mild compression injuries (neurapraxia), a conservative approach is taken, involving rest, splinting, and observation, as the nerve may heal spontaneously. Medications manage pain and reduce inflammation that contributes to compression.
If a nerve is completely severed, surgical intervention is necessary to reconnect the ends of the nerve. This procedure, known as nerve repair or grafting, aims to provide a pathway for nerve fibers to regenerate. Recovery is slow, as nerve cells regenerate at approximately one inch per month.
Physical and occupational therapy are important for maximizing functional recovery. These therapies help maintain muscle strength and joint flexibility while waiting for nerve regeneration. While some patients achieve a full recovery, severe nerve damage may result in a permanent reduction in sensation or function.