Dog Bite

Also known as: Animal bite

Puncture, laceration or crush injury from a canine bite, causing direct tissue trauma plus a high infection risk from oral flora inoculation; polymicrobial, including Pasteurella multocida, Staphylococcus, Streptococcus, anaerobes, and Capnocytophaga canimorsus (particularly severe in asplenic or immunocompromised patients). Also carries rabies risk in endemic areas, which is a critical consideration in management.

Classified by wound type (puncture: deep, narrow, high infection risk despite small external appearance; laceration; crush; avulsion) and by severity (minor superficial vs. severe: deep, crush, involving face/hands/genitals, joint/tendon/bone involvement, or in a high-risk patient).

Puncture wounds, lacerations, crush injuries, tissue avulsion; commonly hands, face (especially children, given height relative to the dog), and lower limbs
High infection risk features: deep puncture wounds (especially over joints; septic arthritis risk), hand wounds, wounds >8-12 hours old at presentation, immunocompromised host, crush component
Signs of established infection: increasing pain, swelling and erythema beyond the wound margins, purulent discharge, lymphangitis, fever, regional lymphadenopathy; typically 24-72 hours post-bite if untreated
Assess for deep structure involvement: tendon function distal to the wound, joint capsule penetration, neurovascular status, bone involvement (especially skull in young children with deep facial or scalp bites; intracranial penetration risk)
Rabies exposure assessment: unprovoked attack, unknown or unvaccinated animal, endemic area, and type of contact (bite vs. lick on broken skin vs. scratch)

Clinical wound assessment: depth, location, deep structure involvement
X-ray: if bone or joint involvement is suspected, a retained tooth fragment is possible, or for a facial bite in a young child (skull penetration risk)
Wound swab/culture: only if signs of established infection are present, not routinely for fresh wounds
FBC/CRP if systemic infection signs

Differentials: cat bite or scratch (higher infection rate than dog bites due to the puncture mechanism and Pasteurella), other animal bites with region-specific rabies risk.

Wound irrigation: copious saline or water irrigation; the single most important infection-prevention measure
Wound closure: primary closure is generally AVOIDED for puncture wounds and high-risk bites (hand, high-risk sites, >8h old, immunocompromised); leave open or use delayed primary closure. Facial wounds are often closed primarily given cosmetic priority and good vascularity, with prophylactic antibiotics, after thorough irrigation and debridement

Prophylactic antibiotics; recommended for puncture wounds, hand/foot/face/genital bites, wounds requiring closure, immunocompromised patients, crush component, or joint/tendon proximity:

Co-amoxiclav 625mg PO tds for 5-7 days (covers Pasteurella, anaerobes, staph/strep); first-line
Penicillin-allergic: doxycycline + metronidazole, or clindamycin + ciprofloxacin
Established infection: same agents, extended duration (7-14 days), consider IV therapy if systemic signs, urgent surgical review if joint, tendon sheath or deep space infection is suspected

Tetanus prophylaxis per immunization status.

Rabies risk assessment and post-exposure prophylaxis (PEP); critical in endemic areas:

Wound care: immediate thorough washing with soap and water for 15 minutes significantly reduces viral load
PEP per WHO risk categorization: Category I (touching/feeding; no PEP), Category II (minor scratches or abrasions without bleeding; vaccine only), Category III (transdermal bites or scratches, licks on broken skin or mucosa, or any contact with bats; vaccine + rabies immunoglobulin)
Rabies vaccine: intramuscular regimen (days 0, 3, 7, 14, ±28) per WHO Essen or Zagreb schedule, or intradermal dose-sparing regimens where available
Rabies immunoglobulin: infiltrated around and into the wound as far as anatomically feasible, remainder IM at a distant site; for Category III exposures, or Category II in the immunocompromised, given with the first vaccine dose
If the biting animal is available for 10-day observation and remains healthy, PEP can be discontinued per WHO protocol; but do not delay starting PEP while awaiting the observation outcome in a high-risk exposure

Asplenic patients: heightened vigilance for Capnocytophaga sepsis, which can progress to fulminant sepsis and DIC; lower threshold for antibiotics and admission.

Referral: surgery or plastics for deep facial wounds, hand surgery for tendon or joint involvement, urgent surgical review for suspected septic arthritis or deep space infection.

Clinical toolsCalculators

BMI GCS EDD Parkland Formula

Corrected Sodium Corrected Calcium Anion Gap Creatinine Clearance Insulin Calculations qSOFA Wells PE Wells DVT CHA₂DS₂-VASc HAS-BLED CURB-65 Centor/McIsaac

Pelvic Fracture

Pelvic fractures range from stable pubic ramus injuries to complete disruption of the pelvic ring with massive retroperitoneal haemorrhage.

A pelvic ring injury should be approached first as a potential haemorrhagic emergency, not merely an orthopaedic fracture.

Major bleeding sources include:

Presacral and pelvic venous plexus
Exposed cancellous bone
Internal iliac arterial branches

The retroperitoneum can contain several litres of blood.

Associated injuries frequently involve:

Bladder
Urethra
Rectum
Vagina
Abdominal viscera
Spine
Major nerves

Tile classification

Based on mechanical stability.

Type A: Stable

Posterior arch remains stable.

Avulsion or fracture not significantly involving pelvic ring stability.

Stable or minimally displaced pelvic ring fracture.

Transverse sacral fracture.

Type B: Rotationally unstable, vertically stable

Open book injury.

Lateral compression injury.

B2.1 typically involves ipsilateral anterior ring injury.

B2.2 may produce a contralateral bucket handle pattern.

Bilateral rotational instability.

Type C: Rotationally and vertically unstable

Unilateral complete instability.

Subclassified according to posterior lesion through:

Ilium
SI joint
Sacrum

Bilateral injury with one side type C and the opposite side type B.

Bilateral complete instability.

Young Burgess classification

Based on force direction.

Anterior posterior compression

APC I

Symphyseal widening below approximately 2.5 cm
Posterior SI ligaments intact
Usually mechanically stable or minimally unstable

APC II

Symphyseal widening greater than approximately 2.5 cm
Anterior SI joint opening
Sacrospinous and sacrotuberous ligament disruption
Posterior SI ligaments intact

Rotationally unstable but vertically stable.

APC III

Complete anterior and posterior SI ligament disruption
Complete hemipelvic instability
High haemorrhage risk

Lateral compression

LC I

Pubic ramus fracture
Ipsilateral sacral compression fracture

Most common pelvic ring pattern.

LC II

Rami injury plus posterior iliac crescent fracture through the SI complex

LC III

Ipsilateral lateral compression with contralateral external rotation injury

Called a windswept pelvis.

Vertical shear

Vertical displacement of one hemipelvis with complete posterior ligament disruption.

Severely unstable and associated with major bleeding and neurological injury.

Denis sacral zones

Useful when the posterior injury passes through the sacrum.

Zone I

Lateral to neural foramina.

Lowest neurological risk.

Zone II

Through neural foramina.

Risk of radicular injury.

Zone III

Central sacral canal.

Highest risk of cauda equina, bowel and bladder dysfunction.

Follow major trauma resuscitation principles.

Inspect for:

Pelvic deformity
Perineal bruising
Scrotal or labial haematoma
Rectal bleeding
Vaginal bleeding
Open wounds
Leg length discrepancy
Neurological deficit

Do not repeatedly spring or compress the pelvis after an unstable injury has been identified because repeated manipulation can disrupt clot.

Look for urethral injury:

Blood at urethral meatus
Inability to void
Perineal haematoma
High risk pelvic ring pattern

Perform retrograde urethrography before blind catheterisation when urethral disruption is suspected.

Open pelvic fractures involving rectum or perineum have extremely high septic and haemorrhagic morbidity.

Haemorrhage control

In an unstable pelvic ring injury, apply a pelvic binder over the greater trochanters, not around the iliac crests.

The binder:

Reduces pelvic volume in APC injury
Improves tamponade
Stabilises fracture surfaces

Initiate balanced haemostatic resuscitation when major bleeding is present.

A practical massive transfusion strategy uses approximately:

Packed red cells : plasma : platelets in a 1 : 1 : 1 ratio during active uncontrolled haemorrhage.

Correct:

Hypothermia
Acidosis
Hypocalcaemia
Coagulopathy

Persistent haemodynamic instability requires rapid haemorrhage control.

Options include:

Preperitoneal pelvic packing
External pelvic fixation or pelvic C clamp where appropriate
Angiography with arterial embolisation

These are complementary rather than competing techniques.

Angioembolisation is particularly effective when CT or ongoing physiology suggests arterial bleeding.

Preperitoneal packing rapidly controls predominantly venous and cancellous bleeding and is valuable in an unstable patient requiring immediate operative control.

Temporary mechanical stabilisation

APC injuries can be stabilised using:

Binder
Anterior external fixator
Pelvic C clamp in selected posterior instability

Vertical shear may require:

Skeletal traction
Temporary external fixation
Definitive posterior fixation

Stable pelvic fracture

Tile A and many LC I injuries can be managed nonoperatively.

Provide analgesia and mobilise early with protected weight bearing according to pain and stability.

Prolonged bed rest should be avoided.

Operative indications

Fixation is appropriate for:

APC II and III instability
Vertical shear
Tile C fracture
Displaced crescent fracture
Symptomatic unstable posterior ring injury
Progressive displacement
Open unstable pelvic fracture
Selected LC injuries demonstrating instability under stress

Posterior ring

Posterior stability is critical.

Options include:

Percutaneous iliosacral screws
Transsacral screws
Posterior plating
Lumbopelvic fixation for severe spinopelvic dissociation

Careful preoperative CT assessment is mandatory because sacral dysmorphism alters safe screw corridors.

Anterior ring

Options include:

Symphyseal plate
Ramus screw
External fixation

In vertically unstable injuries, anterior fixation alone is inadequate. The posterior ring must also be stabilised.

Open pelvic fracture

Urgently address:

Haemorrhage
Faecal contamination
Urinary injury
Devitalised perineal tissue
Unstable bone

Broad antimicrobial coverage is required when rectal or gross perineal contamination exists, for example:

Piperacillin tazobactam 4.5 g IV every 8 hours by extended infusion, renal adjusted.

Perform repeated debridement as necessary.

Faecal diversion is considered with:

Rectal injury
Massive perineal contamination
Destructive anorectal injury

It is not mandatory for every open pelvic wound.

VTE prophylaxis

Pelvic fracture carries high venous thromboembolism risk.

Begin pharmacological prophylaxis once haemostasis is secure and bleeding risk is acceptable.

A commonly used regimen is:

Enoxaparin 40 mg subcutaneously once daily, with adjustment for renal function, body weight and local trauma protocol.

Major complications include:

Fatal haemorrhage
DVT or pulmonary embolism
Pelvic sepsis
Neurological injury
Chronic pelvic pain
Sexual dysfunction
Urological dysfunction
Malunion
Leg length discrepancy

Dog Bite

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management