Early complications of human bites to the hand in HIV-positive patients

Human-inflicted bite wounds to the hand are serious injuries that may carry grave consequences. This has been evident in medical literature since the nineteenth century. In 1870 a man’s teeth marks were matched to his dead mistress and in 1894 a dentist died following a bite from a patient. In 1910 a case of a gangrenous paronychia was reported in a seven-year-old girl who had been a habitual nail-biter, and the first case of a clenched fist injury was reported in 1911. Surgical debridement has always formed an essential part of management, even during the earlier days where ‘electrocautery and irrigation with fuming nitric acid’ was a recognised method of treatment. Abstract


Introduction
Human-inflicted bite wounds to the hand are serious injuries that may carry grave consequences.This has been evident in medical literature since the nineteenth century.In 1870 a man's teeth marks were matched to his dead mistress and in 1894 a dentist died following a bite from a patient. 1,2In 1910 a case of a gangrenous paronychia was reported in a seven-year-old girl who had been a habitual nail-biter, and the first case of a clenched fist injury was reported in 1911. 3Surgical debridement has always formed an essential part of management, even during the earlier days where 'electrocautery and irrigation with fuming nitric acid' was a recognised method of treatment. 3uman bite injuries of the hand may be classified as either occlusive or clenched fist (fight bite).Irrespective of the mechanism, they are associated with a high complication rate and this has been attributed to the unique anatomy of the hand and the pathogens involved in human bites. 3,4In addition, wounds are generally small in size resulting in a casual approach to their management.4][5] Complications of a human bite include cellulitis, septic arthritis, tenosynovitis, hand stiffness, lymphangitis and osteomyelitis. 4,6,7ertain developing regions have been experiencing a growing level of social and interpersonal violence. 8As a result, human bites to the hand have also been encountered more frequently.The increasing prevalence of this injury complex exposed the paucity of literature on the topic of human bites to the hand in HIV-positive patients.
0][11] HIV infection is known to compromise the immune system, through immune exhaustion and senescence.This potentially increases the risk of complications following human bites to the hand in HIV-positive patients.
The aim of this study was to determine if HIV infection is associated with an increased risk for the development of early complications following human bites to the hand.

Patients and methods
We retrospectively reviewed the records of a cohort of consecutive patients who were referred to our regional level orthopaedic unit with human bites of the hand between June 2013 and October 2014.Ethical approval was obtained from our institution's ethics review board prior to commencement of the research (BREC Ref: BE 020/15).Approval was also received from the provincial department of health and the hospital where the research was performed (Ref: HRKM 70/15).
All patients over the age of 13 years with human bite injuries to the hand were included.Cases where the human bite injury did not involve the hand or where the bite was not caused by a human were excluded.Patients with hand infection prior to suffering a human bite were also excluded.Patient charts were reviewed and information extracted with regard to demographics, the location of the bite, occurrence of complications, microscopy and culture results, antibiotic sensitivity profiles, HIV status of patients and their CD4 counts, as well as whether patients were on anti-retroviral medication at the time of presentation.The time from injury to presentation was recorded, as well as the time from injury to surgical intervention.Complications were defined as cellulitis, septic arthritis, tenosynovitis, osteomyelitis and surgical amputation.
Statistical analysis was performed using Stata 13.0 (StataCorp.College Station, Texas).Continuous variables were reported as mean (± SD) or median (with interquartile range) and categorical variables as numbers and percentages, unless otherwise stated.Differences in continuous variables were compared with the use of the unpaired t-test or the Mann-Whitney test (depending on the distribution of the data).Categorical data was compared using the Fisher's exact test (if any cell count was below 5) or the chi-squared test (if no cell count below 5).All tests were two-sided and the level of significance was set at p ≤ 0.05.

Results
A total of 39 patients were included in the study and there were no exclusions.The mean age of patients was 31.5 years (range 14-60 years; standard deviation [SD] = 11.4 years), with an approximately equal distribution between males (n=20) and females (n=19).There was no significant difference in the age of patients by gender (p=0.48).The type of injuries were occlusional bites (64%), fight bites (15%), traumatic amputation (18%) and one self-inflicted occlusion bite (3%).The most commonly injured digit(s) were the thumb and ring finger (26% each), followed by the middle finger (18%), with the remaining digits affected equally.Forty-three per cent of middle finger injuries were the result of a fight bite.In 8% of cases the anatomical location of the bite injury was not specified in the records.A total of 16 patients (41%) in our study cohort were found to be HIVpositive, 15 patients were HIV-negative (38%), and in eight cases (21%) the HIV status was unknown.Of the HIV-positive patients, 44% had a CD4 counts below 350 cells/mm 3 but only four (25%) were on ART (antiretroviral therapy) at the time of injury.
The mean time to presentation, time from injury to initial debridement and duration of hospital stay is given in Table I.The duration of hospital stay was found to be independent of the time to presentation (p < 0.01) (Figure 1).The duration of hospital stay was significantly longer in the HIV-positive group (9.9 vs 4.7 days; p < 0.01).None of the patients in our study group required admission to a critical care unit.
Complications occurred in 77% (30/39) of cases and the development of a complication was associated with an increased duration of hospital stay (p=0.05)These included cellulitis (n=17), soft tissue loss requiring split skin graft (n=2), septic arthritis (n=6), osteomyelitis (n=3), tenosynovitis (n=1) and surgical amputation (n=5).There was no significant difference in the time to presentation (median = 3 days, interquartile range [IQR] = 6) of the group of patients who did develop complications in comparison to the group without complications (median = 1 day, IQR = 2) (p=0.07).We did, however, observe an increased time to presentation (median = 7 days, IQR = 27) in the subset of patients who required amputation (p=0.05).
HIV-positive and -negative patients (p=0.65).HIV-positive status was however associated with an increased duration of hospital stay (p=0.05).
The cases in our cohort were somewhat older (mean 31.5 years) than those in previous studies and we found an equal distribution of males and females, in comparison to other studies where mostly males were affected with an average age of 24 years. 3,7,84][5] This was not our experience as 67% of cases involved the occlusive type of bite injuries.Delay in presentation has been documented extensively in the literature as the single most important determinant of morbidity following human bites to the hand. 3,6,7,12,15,16In our series, the association between time to presentation and the development of complications did not reach statistical significance (p=0.07).There was however an increased risk of surgical amputation in cases with a delay in presentation (p=0.05).
There have been several recent clinical studies in orthopaedics that have shown that the HIV-positive population is not at an increased risk of infection or fracture non-union when compared to the HIV-negative population.Ferreira and Marais investigated the rate and severity of pin track sepsis in HIV-positive and HIV-negative patients treated with circular external fixators.In their retrospective analysis of 229 patients they found no statistically significant difference in the incidence of pin track sepsis (p=0.94) and no statistically significant difference in the severity of pin track sepsis (p=0.9) between the two groups.They also found that the CD4 count had no influence on either the incidence (p=0.57) or the severity (p= 0.21) of pin track sepsis. 10raham et al., in their prospective single blinded controlled study, presented 91 HIV-positive patients who underwent 103 procedures which involved the insertion of 111 implants.They followed up this group for a mean of 27 months, and found no association between the HIV status and developing late implant sepsis following internal fixation in acute trauma.They also found that if the HIV-positive patient develops early (< 6 weeks) infection and they receive appropriate management it is unlikely that they will develop late implant sepsis. 17Gardner et al. looked at fracture union following internal fixation in the HIV-positive population, in the largest study to date investigating fracture union in the HIV-positive population.Of 506 consecutive patients they had 96 HIV-positive patients with 107 factures that required internal fixation, with an average age of 37.8 years.They observed a non-union rate of 7.7% in femur fractures (the most frequent injury in their study) which was comparable to that found in series involving seronegative patients, whose non-union rate ranged from 0-10% in the femur. 1814][15]19 Our data suggests that an HIV-positive patient is not necessarily at increased risk for the development of early complications, irrespective of anti-retroviral therapy or the patient's CD4 count.HIV-positive status was however associated with an increased duration of hospital stay (p < 0.01).Our data on the microbiology of infections was insufficient to draw any definitive conclusions in this regard.Previous studies identified Streptococcus spp and Staphylococcus spp, followed by Eikenella corrodens and anaerobes, as the most common organisms involved in human bites of the hand. 5,7,20We observed a similar trend, except we did not identify Eikenella corrodens in any of our specimens.Screening for exposure to hepatitis B virus was not performed in any of our patients.This is of concern as hepatitis B virus is 20-100 times more likely to be transmitted from a human bite than HIV. 7,14e recognise the fact that this study has various limitations.The retrospective nature creates a problem in terms of the completeness of the data.This was illustrated by the fact that microscopy and culture results were only recorded in a small number of cases.A longer follow-up is required in order to assess the impact of HIV infection on a wider range of complications and permanent impairment.In addition the small difference in the frequency of complications in HIV-positive and -negative patients necessitates a much larger sample size.We propose that a larger prospective study is undertaken in order to determine the association of HIV infection and infectious complications as a result of human bites to the hand.

Conclusion
Patients with human bite injuries to the hand are at a high risk of developing complications.As such, they require urgent surgical debridement and administration of broad spectrum empiric antibiotic therapy that should be tailored to the suspected organism and adjusted according to the culture results and clinical response.In this series, HIV infection was not associated with an increased risk of developing complications following human bites to the hand.An increase in the time from injury to presentation was however associated with an increased risk of amputation.

Compliance with ethics guidelines
Drs Duma and Marais have no financial or personal relationships with any individual and/or organisation that has or could have influenced their work.This article is the sole work of the authors and no benefits have been received from a commercial entity related directly or indirectly to the subject of this article.
• Conflict of interest • Ethics statementThis article was not submitted to an ethical committee for approval.Ethical approval was obtained from our institution's ethics review board prior to commencement of the research (BREC Ref: BE 020/15).Approval was also received from the provincial department of health and the hospital where the research was performed (Ref: HRKM 70/15).