Soft Tissue Abscesses Associated with Parenteral ...

Soft Tissue Abscesses Associated with Parenteral Drug Abuse: Presentation, Microbiology, and Treatment JACK M. BERGSTEIN, M.D., F.A.C.S., E. JACK BAKER IV, M.D., CHARLES APRAHAMIAN, M.D., F.A.C.S., MOSHE SCHEIN, M.D., F.C.S (S.A), D1ETMAR H. WITTMANN, M.D., PH.D., F.A.C.S.

From the Department of Surgery, Section of Trauma and Emergency Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin

Abscess formation at the site of drug injection is the commonest infectious complication in drug addicts. This study characterizes the c1inical presentation of the condition, its current microbiology, and treatment outcome. All patients presenting for treatment of soft tissue abscesses associated with parenteral drug abuse over a 21-month period were studied. Sixty-six patients with 70 subcutaneous abscesses after injection of cocaine (85%), heroin (5%), or unreported drugs (10%) were identified. Only 42% were febrile (T > 37.5°C), 54 percent had leukocytosis, and 47 percent had wound fluctuance. Wound cuHures (243 isolates in 57 patients) grew predominately anaerobes (143 isolates) and faculta­ tive gram-positive cocci (88 isolates). Twenty-six blood cuHures were obtained, and five (19%) were positive, two with the same bacteria isolated from the wound. Of the patients tested, 29 percent were positive for hepatitis B surface antigen and 9 percent for HIV. Simple incision and drainage was effective in all cases. Classical signs and symptoms of infection and abscess formation may be absent in this patient population. Many of these patients carry other blood-borne infections which the health professional must guard against. Cocaine injection, and "mixed" aerobic-anaerobic infections predom­ inated, in contrast to earlier reports, when narcotics and aerobes predominated. Simple incision and drainage is adequate treatment; antibiotics, when given, should cover gram-positive and anaerobic bacteria; gram-negative coverage is unnecessary.

RADITIONALL Y, DRUG ABUSE has been viewed as a social and psychological problem. However, both medical and surgical complications account for an increasing number of hospital admissions. ' It has been estimated that more than 2.5 million people in the United States abu se drugs 2 and that parenteral drug abuse is responsible for significant morbidity and mor­ tality .3.4 In fact, infectious complications of parenteral drug abuse probabJy account for more than one-third of drug-related hospital admissions,3 with abscess for­ mation at the site of injection the most common in­ fection encountered. I. 5. 6 Despite the increased media attention that drug abuse has received, the medical literature has not kept pace with the current and changing trends of drug abuse. Since Hussey and Katz published a comprehen­ sive review in 1950, describing the infectious compli­ cations associated with parenteral drug abuse, 7 the most commonly abused injectable drug has changed from heroin to cocaine. Moreover, bacteriologic data

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Address correspondence and reprint requests to Jack M. Berg­ stein, M.D., Medical College of Wisconsin, 9200 West Wisconsin Avenue, Milwaukee, WI 53226.

from published studies show culture results varying from predominantly Staphylococcus aureus and beta­ hemolytic streptococci7- IO to mixed infections,5. J \-13 containing both aerobic and anaerobic organisms. The present study is an attempt to carefully characterize the current microbial recovery from soft tissue abscesses in substance abuse patients, as weil as the presenting signs and symptoms, and treatment outcome.

Materials and Methods The Department of Surgery computerized database was queried to identify all patients treated for drug­ abuse-related surgical infections at lohn L Doyne Hos­ pital over a 21-month period. Charts were reviewed to determine patient demographics and abused drug, pre­ senting signs and symptoms, and microbiology, as weil as antibiotic and surgical therapy.

Microbiological Procedures Specimens for culture were obtained by needle as­ piration at the site of inflammation or suppuration, or by aspiration of pus at time of surgical drainage. All specimens were processed in an anaerobic chamber

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(Cox, Ann Arbor, Mich.) within 30 minutes of collec­ tion. The sampies were plated on the following media: trypticase soy blood agar (BBL, Cockeysville, Md.) Columbia CNA (colistin-nalidixic acid) blood agar, Macconkey agar (Difco, Detroit, Mich.), cocanaerobic blood agar, phenylethyl alcohol anaerobe blood agar, and kanamycin-vancomycin anaerobe blood agar (Re­ mel, Lenexa, Kan.). Media for anaerobic recovery were stored in the chamber for at least 48 hours before use. In addition, a thioglycollate (supplemented with vitamin K and hemin) and a chopped meat carbohy­ drate (CMC) broth were inoculated and incubated at 35°C. All plate media were incubated at 35°C. The aerobic plates were inspected at 24 hours and 48 hours, and any isolates were characterized by stan­ dard means. 14 The anaerobic plates were visually in­ spected at 48 hours, and individual isolates were ini­ tially characterized by colonial morphology and Gram's stain. After oxygen tolerance testing, obligate microbial isolates were identified by conventional bio­ chemical methodology using PRAS II tubed media (Scott laboratories, Fiskeville, R.I.).IS. 16 Volatile and nonvolatile microbial metabolic byproducts were an­ alyzed by gas liquids chromatography (Model 5804A, Hewlett Packard, Rolling Meadows, lll.) with flame ionization detectof. The CMC broth was subcultured daily after 96 hours until Day 14; isolates were char­ acterized as above. Results

Patient Population A total of 66 patients with 70 soft tissue abscesses associated with parenteral drug abuse were treated during the study period. Four patients had two ab­ scesses each. These patients were either treated as outpatients or admitted for in-patient care. Forty-seven were men and 19 women. The average age was 35 years, ranging from 21 to 77 years. The abused drug consisted of cocaine in 56 (85%) patients, heroin in 3 (5%), and remained unreported in 7 (10%) patients. The upper extremity was the predominant site of drug-re1ated abscess. Only three patients used alterna­ tive sites; two injected the anterior thigh and one used both breasts. The abscesses in the upper extremity were equally distributed between the left and right sides, with the forearms invo1ved seven times more commonly than the hand. The presenting signs and symptoms of the soft tissue infections varied widely among these patients (Table 1), with the exception of pain and tenderness at the site of injection, wh ich were present in all patients. Although there was no policy requiring serologic testing, several patients in this se­ ries were tested for hepatitis Band human immuno­ deficiency virus (HIV). Of the patients tested, 29 per-

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I. Signs and Symptoms in 66 Patients with 70 Subcutaneous Abscesses Associated with Parenteral Drug Abuse

TABLE

Sign/Symptom

Percentage

Number

PainlTenderness Erythema Fluctuance LeukocYLOSis Lymphadenopathy Febrile (T > 37.5" C)

100% 93% 74% 54% 48% 42%

(70170) (65170) (52170) (35/55) (12/25) (28/66)

cent (217) were positive for the hepatitis B surface antigen, and 9 percent (3/41) were reactive for HIV.

Microbiology Routine wound cultures were obtained from 57 pa­ tients. They grew 243 isolates, predominantly anaer­ obes (143 isolates) and non-obligate gram-positive cocci (88 isolates). Table 2 shows a list of isolates. Of the soft tissue abscesses, 61 percent (35/57) repre­ sented 'mixed' infections, containing both anaerobic and aerobic bacteria; 35 percent (20/57) contained only aerobic organisms; and 2 percent (1/57) only an anaerobe. No growth was observed in one cuhure. Blood cultures were obtained in 26 patients; five cul­ tures (19%) were positive, two with the same bacteria isolated from the wound (a Staphy/ococcus coagulase­ positive and a Streptococcus group A). 2. Microbial Recovery from 57 Patients with Soft Tissue Abscesses Associated with Parenteral Drug Abuse

TABLE

Bacteria

Patients

Isolates

Swphylococcus aureus Swphylococcus coagulase negative Streptococcus species Bacillus cereus Escherichia coU Enterobacter cloacae Hemophilus species Pseudomonas aeruginosa Eikenella corrodens Total aerobic isolates ANAEROBES

20 6 42 1 I I 2 2 5

21 6 61

PeplOstreptococcus anaerobius PeplOstreplOcoccus magnus PeplOstreplOcoccUS micros PeptostreplOcoccuS species Propionibacteria Eubacteria Fusobacterium Veillonellae Bacteroides Clostridium Actinomyces species Total anaerobic isoJates

18 6 25 13 26 2 14 4 16 4 3

AEROBES

I I I 2 2 5 100

18 6 25 13 26 2 16 4 26 4 3 143

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DRUG IN..IECTION ABSCESSES

Management

All abscesses were incised and drained under local or regional anesthesia. There were no cases of associ­ ated septic thrombophlebitis, and no patient required a second procedure. A majority of the patients (57/66) received perioperative antibiotics. A wide variety of antibiotics were administered: ampicillin-sulbactam in 21 patients, cephalosporins in 17, and nafcillin in 13 patients. Ciprofloxacin and vancomycin were each used twice, and clindamycin and ticarcillin-clavu­ lanate once each. Discussion

The incidence of infectious complications of paren­ teral drug abuse continues to increase.I.3-7 Abscess formation at the site of injection is by far the most common infection encountered.1.6 7However, only oc­ casional clinical reports have been published that offer data to help guide the antibiotic treatment of these common infectious complications. This is particularly true with regard to cocaine abuse. Previous investiga­ tors have published studies relating to heroin abuse,s-Io yet cocaine has replaced heroin as the most commonly abused injectable drug. Cocaine is a powerful vaso­ constrictor; when applied topically to experimental contaminated subcutaneous incisions as a component of the topical anesthetic solution TAC (tetracaine, 0.5%, epinephrine, 1:2000, and cocaine, I 1.8%), it has increased the incidence of wound infections. 17 The use of a vasoconstrictor in wounds decreases the oxygen tension of the surrounding tissues, and thus inhibits the bacterial killing ability of the polymorphonuclear leu­ kocytes. Knighton and Hunt demonstrated an increas­ ing incidence of infection with decreasing oxygen tension in a guinea pig model. IS The decreased oxygen tension also favors the proliferation of anaerobic pathogens and may account for the increased inci­ dence of "mixed" infections as opposed to those of single aerobic organisms. 7­ 10 The abscesses are usually located on the antecubital area and the dorsum of the hand. However, as the veins in these areas sclerose after repeated injection, those of the fingers, groin, leg, neck, and even the breasts are used. Eventually, the drug addict exhausts nearly all vascu lar access routes, and as the veins sclerose, extravasation of the injected substance oc­ curs easily with subsequent infection of the subcuta­ neous tissues.1.6 Consequently, a large number of ad­ dicts increasingly rely on subcutaneous injection ("skin-popping") as the preferred method of adminis­ tration. This method also results in the formation of soft tissue abscesses, as both bacteria and irritants are injected into the subcutaneous issues. In our current study, only pain and tenderness at the

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site of injection were present in all patients. Erythema was common; however, fluctuance was absent in 25 percent of the patients. Thus, if the physician relies on the presence of f1uctuance to diagnose an abscess, this complication may be overlooked in many substance abusers. Moreover, other systemic signs of infection, in particular fever, Iymphadenopathy, and leukocyto­ sis were absent in half of the patients. It has been suggested also by others 5. 12 that the classical signs and symptoms of an abscess may be absent, and the phy­ sician should presume that any soft tissue infection in a parenteral drug abuser is likely to harbor an abscess. This population of patients is also at high risk for other infectious diseases. Of the tested patients, 29 percent were positi ve for the hepatitis B surface anti­ gen, and an additional 9 percent were HIV-reacti ve. These rates are high enough to warrant routine screen­ ing for hepatitis and HIV infections, in this population. Barrier precautions, including double-gloving, rein­ forced gowns, and eye protection, should be used consistently in order to decrease the risk of exposure during blood drawing, invasive procedures, or dress­ ing changes. Perhaps the most controversial issue with regard to soft tissue infections in drug addicts relates to the bacteriology. Initially, soft tissue infections were thought to be caused by S. aureus and beta-hemolytic streplOcocci. 6 - 11 . 19.20 Studies have shown S. aureus to be present in 19 percent to 71 percent of subcutaneous abscesses. 5. s. 10. 11. 13 However, using proper anaerobic culture-techniques many investigators have isolated peptostreptococci and other anaerobes, and reported that many of these subcutaneous abscesses are caused by anaerobic or "mixed" infections. 5 . 8.10-13 Moreover, it appears that abuse of different substances may pre­ dispose to infections by different organisms. lt is also likely that infections will vary from one institution to another, suggesting that ongoing bacteriologic surveil­ lance may be a useful guide to initial antibiotic ther­ apy.8 The infecting organisms of the soft tissue abscesses associated with parenteral drug abuse in our study appeal' to be those that predominate in the flora of the skin and oropharynx. S. aureus was isolated in 36 percent of the cultured abscesses, whereas anaerobes accounted for 59 percent of the total isolates. The high incidence of staphylococcal infections may result from the prevalence of staphylococcal carriage in the drug addict population, which was reported in 70 percent of the infected drug abusers and 38 percent of the unin­ fected ones. 8 Furthermore, the occurrence of oropha­ ryngeal bacteria in the abscesses probably results from the common practice of blowing clots from the injec­ tion paraphernalia, or using saliva to either lubricate

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the needle or to moisten the "straining cotton." From our bacteriologic results, it is apparent that initial antibiotic therapy for subcutaneous abscesses should be directed primarily against anaerobe and non-obligate gram-positive cocci. The first generation cephalosporins Ce.g., Cefazolin) or alternatively Clindamycin would seem to be reasonable as antimicrobials of first choice. We conclude that given the dramatic increase in parenteral drllg abuse and the magnitude of the infectious complications associated with this addiction, health care professionals must recognize the varied presentation of these patients. By far the most common complication will be soft tissue infections; however, classical signs and symptoms of an abscess may be absent. Associated with the subcutaneous abscesses, many patients carry viral agents of potentially life-threatening infections such as hepatitis B, hepatitis C, and HIV, which the health professional mllst screen for and guard against. The bacteriologic data suggest that these abscesses represent "mixed" infections, and broad-spectrum antibiotic coverage may be useful in controlling the infection when used in conjunction with simple incision and drainage. REFERENCES

I. Butlerfield wc. Surgical complications of narcotic addiction. Surg Gynecol Obstet 1972: 134:237-40. 1. Adams EH. Gfroerer Je. Rouse BA. Epidemiology of substance abuse including alcohol and cigarette smoking. Ann NY Acad Sci 1989:562: 14-20. 3. White AG. Medical disorders in drug addicts: 100 consecutive admissions. JAMA 1973:123:1469-71. 4. Ouvall HJ. Locke BZ. Brill L. Follow-up study of narcotic drug addicts five ycars after hospitalization. Pub Health Rep 1963; 78: 185-93. 5. Webb O. Thadepalli H. Skin and soft tissue polymicrobial infections from parenteral abuse of drugs. West J Med 1979; 130: 200-4.

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6. Geelhoed ON, Joseph WL. Surgical sequelae of drug abuse. Surg Gynecol Obstet 1974;139:749-56. 7. Hussey HH, Katz S. Infections resulting from narcotic addiction. Areport of 102 cases. Am J Med 1950;9:686-93. 8. Orangio GR. Pitlick SO. Oella Lalla P. et al. Soft tissue infections in parenteral drug abusers. Ann Surg 1984; 199: 97-100. 9. Fullarton GM. Softtissue infections in drug abusers presenting 10 an accident and emergency department. Health Bull 1983; 41:296-9. 10. Wallace JR, Lucas CE. Ledgerwood AM. Social. economic. and surgical anatomy of a drug-related abscess. Am Surg 1986. 52:398-40 I. 11. Tuazon CU. Hili R. Sheagren JN. Microbiologic study of street heroin and injection paraphernalia. J Infect Dis 1974; 129: 327-9. 12. Meislin HW, Lerner SA. Graves MH. et al. Cutaneous abscesses. Anaerobic and aerobic bacteriology and outpatient management. Ann Int Med 1977;87: 145-9. 13. Smith OS. Busuito MJ. Orug injection injuries of the upper extremity. Ann Plast Surg 1989;22: 19-24 14. Lennelle EH. Balows A. Hausler WJ Jr, Shadomy HJ. eds: Manual of clinical microbiology. 4th ed. Washington OC: American Society for Microbiology. 1985. 15. Hood RS, Bundred NJ. Jeffery RJ, et al. The role of Robertson's meat broth in the bacteriological evaluation of surgical specimens. J Med Microbiol 1985;20:373-8. 16. Brook I. Microbiology of non-puerperal breast abscesses. J Infect Dis 1988;157:377-9. 17. Barker W. Rodeheaver G. Edgerton M, et al. Oarnage to tissue defenses by a topical anesthetic agent. Ann Emerg Med 1983;11:307-10. 18. Knighton DR. Halliday B. Hunt TK. Oxygen as an antibiotic. A comparison of the effects of inspired oxygen concentration and antibiotic administration on in l'i\'o bacterial c1earance. Arch Surg 1986:121:191-5. 19. Louria OB, Hensle T. Rose J. The major medical complications of heroin addicts. Ann Int Med 1967;67: 1-22. 20. Lerner AM. Oerther FJ. Characteristics and sequelae of paregoric abuse. Ann Int Med 1966:65:1019-30.