Heal human urine and saliva wounds

Animal and human bite injuries

Background: In Germany there are 30,000–50,000 bite wounds every year. The focus is on dog and cat bites, less often people. Children suffer 25% of all bites < 6 jahren und="" 34 %="" kinder="" im="" alter="" von="" 6–17="">

Method: Selective literature research and own clinical and scientific experience.

Results: In younger children, injuries to the head and neck dominate, in older children to the upper or lower extremity. The spectrum of resulting wounds ranges from minor injuries without a medical consultation to extensive soft tissue defects with loss of functional structures. Unusual pathogens in the saliva that get into the wound with the bite are problematic. The risk of infection after a bite is 10–20%. About 30–60% of infections are of aerobic-anaerobic origin. Prophylactic antibiotic therapy is only recommended for bite injuries with a high risk of infection. This depends on the wound type and
-location, determined by the bite and the patient profile.

Conclusion: Structured surgical management is of the greatest importance for the prevention of infections. High-risk wounds must be differentiated from minor injuries. In the case of injuries to the hands and face, interdisciplinary management should be sought.

Animal bite injuries are common occurrences. About 60–80% of bite injuries are caused by dogs, 20–30% by cats. Bite injuries from other animals (rabbits, guinea pigs, hamsters, rats, mice) are significantly less common (1–3). Children are disproportionately affected.

Human bite injuries can account for up to 20% of bite injuries in cities (4).

The spectrum of injuries is wide (4–6) and infectious complications, mostly due to unusual pathogens, are common (6–10).

learning goals

After reading this article, the reader should know and understand the medical management of bite injuries:

  • in which patients there is an increased risk of infection
  • which infectious agents can be expected
  • how this can be demonstrated and when antibiotics are indicated
  • what surgical measures are urgent.

Epidemiology

The incidence and type of animal and human bite injuries depend on geographical location, industrialization and cultural area.

In the United States, the incidence is estimated at 200 animal bite injuries per 100,000 population per year. With 100 million dogs and cats in US households, around 1-2 million dog bites and 0.4 million cat bites are calculated per year (4, 5).

For the regions of Bologna and South Tyrol, 50–60 injuries per 100,000 inhabitants were determined (1, 2).

The epidemiological data for Germany are imprecise, as there is no obligation to report and no bite statistics are kept for the whole of Germany. Animals are kept in more than a third of all households in Germany. In 2010, a total of 3,610 accidents with bite injuries were reported to the statutory accident insurers, 75% of which were caused by dogs and cats (8). Reports in the media speak of 35,000 dog bites in 3.8 million registered dogs and around 1 million untaxed dogs in Germany (11). A survey by the Allensbach Institute for Demoscopy on animals in German households (2012-2014) showed the following distribution for 2013 as an example: 11.89 million dogs, 12.68 million cats, 2.6 million birds, 3.52 million fish , 4.35 million rodents, 2.53 million other animals (IfD Allensbach de.statistica 2014).

In terms of gender, the male gender dominates in dog bite injuries and the female gender in the ratio of 2: 1. In the age distribution, 2/3 of the victims of cat bite injuries are between 20 and 35 years, and of dog bite injuries 2/3 of the victims are children and adolescents. 25% affect children younger than 6 years, 34% between 6 and 17 years (4, 7, 9, 10). Bite injuries tend to occur in warm seasons. In 90% of cases, one's own dog or a known dog is responsible (1–3, 11, e1, e2). If you look at gender as well as breed, it is noticeable that males have bitten three times more often than females. Mixed breeds and dogs with breed type designations were equally likely to be involved in bite injuries (e2, 5, 11). The animal's bite is usually based on a disturbed interaction. The animal was often frightened, annoyed, or disturbed while eating (e2, e3, 5, 11).

Forensic medical aspects of animal and human bites

Deadly dog ​​attacks

According to the Federal Statistical Office, 1–6 people die each year in Germany as a result of a dog bite (11, 12).

Larger dogs naturally cause more severe bite injuries than smaller dogs. Special dog breeds (Pit Bull, American Staffordshire Terrier, Bull Terrier, Rottweiler, German Shepherd) dominate the statistics of fatal bite attacks, a fact that the dog laws and dog regulations of the individual federal states take into account in very different ways (11, 12). Unobserved attacks usually end fatally (11, 12, e1, e2) and affect victims who are difficult to defend themselves, i.e. mainly older people and small children. Attacks by more than one dog can also lead to extensive injuries (11, 12). Serious injuries to the head, neck, and neck are common in children < 4 jahren am="" häufigsten="" (12).="" aufgrund="" der="" geringen="" größe="" und="" der="" plastizität="" von="" säuglingsschädeln="" ist="" es="" großen="" hunden="" möglich,="" den="" gesamten="" kopf="" in="" die="" schnauze="" zu="" nehmen="" und="" unter="" starkem="" schütteln="" abzubeißen.="" die="" todesursachen="" sind="" in="" den="" meisten="" fällen="" gefäßverletzungen="" mit="" konsekutivem="" verbluten,="" schädel-hirn-trauma,="" dekapitation="" oder="" luftembolie="" (12,="">

Human bites

Human bites in the form of oval or crescent-shaped hematomas and abrasions are seen after sexual offenses, child abuse, physical confrontations ("defense bites"), but also after consensual sexual acts (14, 15). Indirect bite injuries (defensive bites) from striking the closed fist against the teeth represent a separate entity of the injury pattern “fight-bite-clenched-fist injury” (16–19).

Direct occlusal bites show more or less clearly the denture imprint of the causer, which, for example, usually allows a reliable distinction to be made between childish (smaller radius, imprint of individual teeth, deciduous teeth) and adult teeth if child abuse is suspected. A distance of over 3 cm between the canines suggests a bite injury caused by an adult.

Bites by children before changing teeth show the distance between the deciduous molars, which is usually less than 2.5 cm (20, e4, e5). In addition to dental impressions, hematomas or petechiae can be observed due to suction.

A detailed photographic documentation with a scale for later assignment to suspects is crucial for the later forensic evidence (21). In the case of fresh bite injuries, DNA abrasion should be attempted for a later genetic examination and, if necessary, assignment of the DNA profile to the causer (14, 22, e6). Here, the skin area that came into contact with the culprit's saliva is rubbed with specially designed self-drying DNA swabs (commercially available or available in larger primary care clinics in gynecology for victims of sexual offenses), which are then used for DNA analysis be given to the laboratory.

Clinical symptoms and findings

The local force exerted by the animal's teeth leads to tissue crushing with variable areas of non-vital tissue (19). The injury patterns range from superficial abrasions, tears and bruises to peeling with considerable loss of substance, including bone involvement. In addition to perforating skull injuries, avulsion injuries have also been described (23–27). Cats mostly cause puncture-shaped injuries with deep inoculation of animal saliva. The real depth of the injury can be underestimated due to a backdrop phenomenon in which the various anatomical layers slide over one another. Penetration of the periosteum and joints can occur in the hands in particular (4, 7, 25, 26, e7).

Indirect injuries from punching the teeth typically lead to injuries to the joint capsule of the long finger metatarsophalangeal joints and metacarpals (16, 18). Classification systems for assessing the severity of bite injuries in literature (28, 29) are based on the involvement of deeper tissue structures as well as vascular and nerve injuries (Box 1, Table 1).

In 70–80% of cases the bite wounds are on the hands, arms and legs, in 10–30% in the area of ​​the head, neck and neck (especially in children aged < 10 jahren). bei="" kindern="">< 5="" jahren="" dominieren="" bis="" zu="" 90 %="" verletzungen="" im="" gesicht="" und="" halsbereich="" (10,="" 15,="" 23,="">

Infections from bite wounds

Box 2 demonstrates the infection rates reported in the literature. In general, infections occur in 10–20% of bite injuries, in cats in 30–50%, in dogs in 5–25% (30–33) and after human bites in 20–25% of cases (4, 14, 19 , 30). The risk of infection is determined on the one hand by the type and location of the wound and on the other hand by the individual patient profile and the causer (Box 3). Bite wounds with an increased risk of infection are deep wounds (cats), soiled wounds, wounds with severe tissue destruction, edema, poor circulation as well as wounds on hands, feet, face, genitals and in the area of ​​bones, joints and tendons (3, 4, 6-9).

Newborns and infants are more susceptible to infection, but above all if the immune system is impaired: AIDS, hepatopathies (alcohol abuse), asplenia, malignancies and neutropenia, diabetes mellitus, therapy with corticosteroids or immunosuppressants (26, 31–33). But people without disposition factors can also develop severe, potentially fatal infections (34, e8 – e10).

Bacterial pathogens from infected bite wounds

30–60% of the cases are aerobic-anaerobic mixed infections (30, 33, 35) caused by representatives of the oral bacterial flora of the biting animals, less often by representatives of the skin flora of the bitten person or environmental bacteria (25, 30, 32). In cat and dog bites, an average of 2–5 bacterial species can be detected per wound (32, 35, 36). There is a connection between the number of pathogen species detected and the wound (median 7.5 for abscesses, 5 for purulent wound secretion, 2 for non-purulent wounds) (36). Together with Staphylococcus ssp. (including MRSA) and Streptococcus ssp.(including Streptococcus pyogenes) are the most commonly isolated pathogens in many studies Pasteurella spp. (P. multocida, P. canis, P. dogmatis), Capnocytophaga (C.) canimorsus and various anaerobes (Fusobacterium spp., Prevotella spp., Bacteroides spp., Porphyromonas spp.) And other species (e11, e12) (Table 2).

Streptococci can be isolated from human bite wounds in 50% of cases, Staphylococcus (S.) aureus in 40% and Eikenella (E.) corrodens in 30% of cases. It is generally assumed that E. corrodens, a gram-negative microaerophilic rod-shaped bacterium, is the most common pathogen leading to infection (30, 32). In the case of human-made bite wounds, the possibility of transmission of HBV, HCV and HIV as well as the corresponding post-exposure prophylaxis must always be considered (16). Rodent bites rarely cause infection. Mostly P. multocida is then responsible. Other rare diseases caused by rodent bites are rabies, tularemia (Francisella tularensis), and rat bite fever (Streptobacillus moniliformis or Spirillum minus) (e13, e14). In addition to pathogens causing wound infections, pathogens of systemic bacterial infections can also be transmitted through bite injuries. Contaminated urine or stool as well as skin and mucous membrane contact with contaminated water should also be taken into account (e15) (Table 3).

Clinical symptoms and findings in infections

Symptoms suggestive of infection appear after 12–24 hours with P. multocida infection, somewhat later with infections caused by other pathogens, and with C. canimorsus infection may not appear until after 5–8 days (32, 33).

Local redness, swelling, purulent secretion and pain, general malaise and fever indicate an infection. In most cases it is a soft tissue infection (especially on the hands, in smaller children often in the head and neck area), i.e. cellulitis, possibly phlegmon with abscesses and swelling of the lymph nodes. Tenosynovitis or joint empyema are more common in the hands (4, 7, 18, 19, 24–26).

Sepsis rarely develops from the local infection. Osteomyelitis, arthritis, meningitis, endocarditis, endophthalmitis, and organ abscesses (brain, liver, lungs) have been reported in isolated cases (4, 31, 33, e12, e16). Above all, a Capnocytophaga canimorsus infection, especially in predisposed patients, can progress as acute sepsis (with disseminated intravascular coagulopathy, gangrene, kidney failure) and end fatally (e8, e9, e16).

Diagnosis

The diagnostic algorithm (Box 4) includes the targeted collection of the medical history, including the vaccination status, the assessment of risk factors, the recording of the general condition and the wound inspection with assessment of muscle, joint, vascular and nerve involvement as well as the search for signs of inflammation. If a fracture or foreign body is suspected, imaging procedures such as X-rays, CT or MRT are indicated, and if there is fluid accumulation in the soft tissue structures or an abscess is suspected, sonography.

If a bacterial infection is suspected, laboratory diagnostics include examinations of the patient's blood (blood count, CRP / PCT, serology, coagulation values, blood cultures), liquor, punctures, smears and stool (microscopy, culture, PCR). In addition, the animal must be examined (swabs, stool).

Advance information to the laboratory is of crucial importance because any special methods (culture medium, anaerobic technique), fast transport times and longer incubation times (7–10 d) are indicated, and mixed cultures and unusual pathogens are to be expected (34, 38). Transport media for anaerobes must be given special attention.

therapy

Despite the general acceptance of a division into risk groups according to cause and type of injury, localization and patient profile, there are no evidence-based guidelines. However, the quality of the first aid is of decisive importance for the functional and aesthetic later results.

The fact is that minor injuries are underestimated by patients and doctors, as it is precisely the punctiform lesions of the skin that conceal the extent of the depth of the injury. Necrosectomy, mechanical reduction of the number of germs and optimization of the microcirculation in the wound area form the basis of surgical therapy. In general, treatment under analgesic sedation / general anesthesia is recommended for children and adults, depending on the findings and the expected duration of the operation. Depending on the location and extent of a bite injury, an interdisciplinary, interdisciplinary collaboration should be sought.

Surgical therapy includes general measures of local treatment and infection prophylaxis. The S1 guideline of the AWMF was updated for childhood in 2014 (006/129) (Box 5).

Wound irrigation

Infusion catheters or button cannulas are used, which are inserted into the depth of the bite canal to flush foreign bodies and inoculated material out of the wound. Rinsing under pressure can only be recommended cautiously, because uncontrolled spread of the bacteria into deeper tissue layers is possible or, as has been observed with rinsing with Octenisept, aseptic necrosis can result (e17, e18).

Usually physiological saline solution is used. Some authors recommend antiseptic solutions (19, e19, e20).

Debridement

Necrosectomy with the removal of torn, crushed and devitalized tissue is superior to irrigation treatment, but is limited by anatomical conditions.

More extensive surgical debridement is possible on the extremities than in the face and head area thanks to the effective methods of repairing tissue defects that arise (19, 23). If the joint is involved, irrigation with antiseptics and drainage are useful if the cartilage is still flat. In the case of tooth bite (“fight-bite-clenched-fist”) injuries, extensive debridement of the affected joint with synovectomy and irrigation, the insertion of drainage material and daily hand baths are recommended. Postoperative immobilization and early functional physiotherapy are mandatory (18, 19, 23). An infected joint requires a planned revision after about 48 hours in order to avoid the dreaded joint destruction and stiffening. In general, if there is extensive necrosis, a planned revision (“second-look” operation) should be carried out after 1–2 days (18).

Wound closure

There is agreement on primary wound closure for facial injuries (37). Primary replantations and surgical plastic reconstructions with auricular cartilage transplants are also successfully performed here today (6, 27, e17, e21 – e24). The recommendations for the extremities are still inconsistent (27, e19, e20). Generally accepted is the postponement of the 6–8 hour limit after injury for a primary suture to> 12 hours. In recent years, various studies have shown that wound infections do not occur more frequently with primarily sutured bite wounds than with secondary healing (e22,