Postgraduate Medicine
ISSN: 0032-5481 (Print) 1941-9260 (Online) Journal homepage: http://www.tandfonline.com/loi/ipgm20
Current Concepts in the Treatment of Osteomyelitis Gerald Medoff To cite this article: Gerald Medoff (1975) Current Concepts in the Treatment of Osteomyelitis, Postgraduate Medicine, 58:3, 157-161, DOI: 10.1080/00325481.1975.11714148 To link to this article: http://dx.doi.org/10.1080/00325481.1975.11714148
Published online: 07 Jul 2016.
Submit your article to this journal
View related articles
Citing articles: 2 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ipgm20 Download by: [Australian Catholic University]
Date: 25 July 2017, At: 20:58
co sder • What are the clinical types of osteomyelitis? • What causative organisms are involved? • ln the treatment of osteomyelitis, when is surgery appropriate? When is medical management appropriate?
GERALD MEDOFF, MD Washington University School of Medicine St. Louis
Current Concepts in the Treatrnent of Osteornyelitis Dr. Medoff provides an excellent breakdown of the clinical types of osteomyelitis encountered in practice today. He points out the necessity for long treatment of acute osteomyelitis, that is, four to six weeks of parenteral therapy. He discusses a number of the problems attendant on the chemotherapy of chronic osteomyelitis, painting out the role of surgical débridement in addition to antibiotic therapy.
-HCN
Traditionally, osteomyelitis has been defined as either an acute or a chronic infection, the classifi· cation depending on either the clinical course or the histopathologic findings. In fact, there is probably no abrupt shift from acute to chronic disease, but rather a graduai blending; and distinction between acute and chronic osteomyelitis on clinical or pathologie grounds is sometimes difficult. 1 Thus, patients with apparently acute disease can present with histories suggesting an indolent course, and patients with documented osteomyelitis of many years' duration occasionally present with acute exacerbations characterized by fever and local infiammatory changes. lt is useful to further divide cases of osteomyelitis into three groups: (1) hematogenous oste-
Vol. 58 • No. 3 • September 1975 • POSTGRADUATE MEDICINE
omyelitis, (2) osteomyelitis secondary to a contiguous focus of infection, and (3) osteomyelitis associated with peripheral vascular disease. 1 Because the clinical features of these three groups are different, 1 will describe each separately before . discussing therapy. Hematogenous Osteomyelitis
Hematogenous osteomyelitis is a blood-borne infection which localizes in bone, with primary bacteremia the usual source. lt is much more common in children than in adults. The long bones of the lower extremities, particularly the femoral and tibial metaphyses, are most frequently involved, but the high frequency of vertebral osteomyelitis in adults is striking.2 One suggested explanation is a predilection of osteomyelitis for bones with active red marrow. This explanation, however, is not consonant with the fact that hematogenous osteomyelitis of the skull, ribs, and epiphyses--ali areas with high bone marrow activity-is quite rare in the adult. A more reasonable explanation may be that, because of increased metabolic activity and ingrowth of blood vessels in osteoarthritic vertebral bone and cartilage, this area in adults is equivalent to the metabolically active metaphyseal area of long ~ bones so commonly affected in children.3
157
In acute hematogenous osteomyelitis, most patients are symptomatic, with pain, swelling, chills, fever, and malaise, for less than three weeks before hospital admission. Exceptions are patients with venebral osteomyelitis, which frequently is not heralded by systemic symptoms. Dull continuous back pain may be the only complaint at onset. The associated bone changes are limited to local destruction and new bone formation (involucrum), which are reflected radiologically by lytic lesions and areas of increased density. Frequently, only soft-tissue swelling with minimal periosteal reaction is seen early in the disease. Bone scans have been shown to be abnormal before the disease is
crease in bacteremia due to Gram-negative bacilli has not occurred. The exceptions are Salmonella bone infection, already discussed, and osteomyelitis due to Pseudomonas aeruginosa in drug addias.4 The latter usually involves the spine, symphysis pubis, ribs, ischial tuberosity, or sacroiliac or hip joints. Osteomyelitis Secondary to a Contiguous Focus of Infection
Osteomyelitis secondary to a contiguous focus of infection is defined as an infection of bone arising from an exogenous source or from a progressive, continuous spread of infection.1 Postopera-
Salmonella bacteremia may develop in patients with sickle cell anemia because of defective host resistance and will almost invariably localize in bane because of the bane infarcts which occur commonly in this disease. evident radiologically. Increased uptake of radioactive label has also been seen in a variety of bone tumors, in Paget's disease, and in fractures. Bone scanning, therefore, lacks diagnostic specificity but is helpful in early detection of a bone lesion causing pain. Staphylococcus aureus is the most common etiologie agent in this type of osteomyelitis. Salmonella infections of bone are a relatively common complication of sickle cell anemia. 1 Only three of the many serotypes of Salmonella are u~ually found in association with sickle cell anemia: S choleraesuiJ, S paratyphi, and S typhimurium. Salmonella bacteremia may develop in patients with sickle cell anemia because of defective host resistance and will almost invariably localize in bone because of the bone infarcts which occur commonly in this disease. The long bones are usually involved, but infections of the small bones of the extremities, of the sternoclavicular junction, and of the venebrae have been described; multiple bone involvement also occurs quite frequently. The clinical presentation of Salmonella osteomyelitis cao be a diagnostic challenge in patients with sickle cell disease, because the septic process may mimic intraosseus sickling clinically and radiologically. Surprisingly, an increase in osteomyelitis due to Gram-negative bacteremia paralleling the in-
158
tive infection is an example of the former; sinus disease, felons, and burns are examples of the latter. The highest percentage of patients in this clinical category of osteomyelitis are over 50 years of age. This contrasts with the much younger population seen with hematogenous osteomyelitis. Most cases of osteomyelitis secondary to a contiguous focus of infection occur as a result of postoperative infections. Internai fixation, weil established as a means of treating cenain fracrures of long bones in adults, is an example of a procedure that cao be followed by infection. Indeed, any surgical procedure carries a risk of infection. One of the more complicated problems in osteomyelitis is intra-anicular sepsis after open reduction of a hip fracture. Osteomyelitis of the hip following surgery cao be insidious.5 Quite often there is little or no inflammatory reaction and no wound drainage. Joint pain is sometimes an early sign of sepsis. Infection of an intervenebral disk space cao also be insidious. In most cases, pain is the only symptom and an elevated sedimentation rate the only laboratory abnormality. 6 Another important cause of this type of osteomyelitis is the extension of soft-tissue infection to bone. Infections involving the fingers and toes account for most of these cases.
POSTGRADUATE MEDICINE • September 1975 • Vol, 58 • No. 3
Other Jess common causes are infected teeth, leading co osteomyelitis of the mandible, and sinus disease. Infection of the frontal bone with a cortical breakthrough and a collection of pus under the periosteum may present as a swelling over the frontal sinus (Pott's puffy tumor). In one series, Staph aureus was the most corn· mon infecting organism in osceomyelitis secondary to a contiguous focus of infection, with an incidence similar co chat found in hematogenous osceomyelitis.1 An important difference, however, is that most of these infections were caused by more chan one species of bacteria, and there was a high frequency of Gram-negative bacteria. This presents a problem in evaluating the relative importance of each of severa) baccerial species isolaced on culture. Treacment should be direcced at the organisms infeccing the bone and not necessarily at the flora of the draining sinus tract. Osteomyelitis Associated With Vascular lnsufficiency
The patients who have osteomyelitis associated with vascular insufficiency are almost ali diabetic. The infections involve the toes or the small bones of the feet. lt is frequentl} difficult clinically and pathologically co differentiate this condition from purely occlusive vascular disease (so-called diabetic foot). 7 Most patients with osteomyelitis, however, have frank cellulitis, with deep ulcers in the soft tissue. Most cultures from surgical specimens or from ulcerated lesions show cwo or three organisms, usually including Staphylococcus or Streptococcus and often an enteric organism as weil. Anaerobes, including Clostridium species, also appear often. Treatment of Osteomyelitis
The most important therapeutic measures for osteomyelitis are syscemic administration of antibiotics and surgery co drain abscesses or debride necrotic tissue. The relative importance of these measures in individual cases depends on the location and stage of the disease. In early acute osceomyelitis, conservacive antibiocic creatment is ofcen sufficient. In subacute or more chronic disease, both antibiotics and surgery are necessary. In chronic disease, extensive resection of necrotic bone can result in cure. Acute osteomyelitis-Because of the aforementioned limitations of radiologie studies and the Jack of diagnostic specificiry of laboratory findings, acute hemacogenous osceomyelicis is most fre-
Vol. 58 • No. 3 • September 1975 • POSTQRADUATE MEDICINE
GERALD MEDOFF Dr. Medoff is in the infectious disease division, department of medicine, Washington University School of Medicine, St. Louis.
quendy a clinical diagnosis. Once the diagnosis is made, antibiotic therapy should be instituted immediately. If an appropriate antibiocic is used, cure rates in excess of 90% can be expected, even without surgical drainage. Selection of antibiocic is dependent on identification of the causative organism. An adequate culture ideally should be obtained before therapy is begun. Because blood cultures are positive in 25% co 50% of patients with acute hematogenous osceomyelitis, a blood culture is frequently ali chat is needed. If the disease is uncomplicated (ie, involves a long bone in a patient without underlying medical problems), chen in my opinion therapy for Staph aureus infection can be started empirically. If the disease is arypical (eg, vertebral osceomyelitis in an addict), bone aspiration or biopsy should be done. By definition, hematogenous osteomyelitis must be considered a "mecastasis" of a septic process. Antibiocics must therefore be given in high dosage (12 co 20 million unies of penicillin or 8 co 10 gm oxacillin each day). A patient with staphylococcal infection musc also be treated empirically for endocarditis (four co six weeks of parenteral therapy). Surgery in acuce osteomyelicis should be limited co biopsy for diagnosis (in arypical or nonresponsive cases) and to drainage of suppurative collections and débridement of necrocic bone (sequestrum). The development of neurologie abnormalities in vertebral or cranial osteomyelicis, or infection spreading ro the hip joint in a child, is also indication for surgical drainage. Such surgery (with adequate antibiocic coverage) usually is weil tolerated. As is crue in acute hemacogenous osteomyelitis, early antibiocic creacment is effective in curing most osteomyelitis secondary co contiguous infection. However, because so many cases are not
159
secondary to Staph aureus infection or because other organisms are frequently present as weil, exact etiologie diagnosis is essential. · Careful bacteriologie examination of drainage or aspirate from the operative wound should be done, followed if necessary by biopsy or aspiration of bone for culture. lntra-articular and bone sepsis after nailing or the introduction of an endoprosthesis presents a difficult problem. Recent evidence8 suggests that prophylactic use of antibiotic just before and during surgery greatly lowers the incidence of infection. More extensive studies are needed to confirm this impression. In most patients with this kind of infection, the prosthesis or naïl bas to be removed to control the sepsis. Management should be in the bands of physicians familiar with this type of infection. Intensive parenteral antibiotic therapy for six weeks, with operative resection of infected and compromised tissue at the time of removal of the prosthesis, is the most effective combination. lntramedullary fixation is a well-established treatment for midshaft femoral fractures without extensive comminution. Here, as in the insertion of intra-articular deviees, postoperative infection is a serious complication. In contrast to the approach to sepsis about an intra-articular deviee, it is generally held that an intramedullary naïl must remain in place, in spite of sepsis, until union bas taken place.9 If the naïl is removed too soon, instability at the fracture site can lead to persistence and spread of sepsis. The infection is treated vigorously with high dosages of antibiotic and locally with drainage and sequestrectomy when required. In MacAusland's9 series, union was obtained in the majority of cases so treated. The only indication for removal of the naïl was loss of rigid immobilization because of loosening of the naïl; after removal, the naïl was replaced by a larger one. After union was evident, the naïl could be removed and any remaining sepsis treated by local débridement and antibiotics given systemically. Many patients with osteomyelitis associated with vascular insufficiency are initially given conservacive treatment aimed at salvaging the limb. This approach is almost uniformly unsuccessful in patients with polyneuropathy, retinopathy, or nephropathy-three hallmarks of advanced diabetes. 1 More radical surgical approaches such as transmetatarsal amputation and below- and above-knee amputations are associated with a high cure rate.
160
This does not mean that small-bone osteomyelitis of the lower extremities in diabetic patients with severe arteriosclerosis and other complications should be treated primarily by amputation. However, it is my belief that after an unsuccessful course of amibiotics, performing surgery is preferable to prolonging questionably effective medical management. When surgery is considered, the blood supply at the anticipated line of amputation should be checked to assure that it is adequate to permit satisfactory healing. Chronic osteomyelitis--Generally, in ali three clinical types of osteomyelitis, the number of treatment failures is highest in the chronic form of the disease. There are no exact criteria as to when acute osteomyelitis becomes chronic, but generally the earlier in the course of acute disease that appropriate antibiotic treatment is initiated, the becter is the cure rate. lt bas been stressed that adequate antibiotic levels are difficult to achieve within a focus of chronic osteomyelitis. The bone levels obtained with lincomycin or clindamycin reportedly are particularly high,10 and it bas been suggested that these may be the antibiotics of choice in the treatment of osteomyelitis. 11 However, the evidence for high bone levels is based on a report that did not define the status of bone being assayed and that also did not include comparative data for other antibiotics. Because it bas been shown that even tetracycline, which is readily bound to bone,12 cannot penetrate the ischemie or dead bone (sequestrum) of chronic osteomyelitis, it is hard to see how lincomycin or clindamycin could be effective. Among other forms of therapy recommended for chronic osteomyelitis are closed irrigation of lesions with antibiotic or antibiotic-detergent (Alevaire) mixtures, regional perfusion of antibiotics intra-arterially, or use of hyperbaric oxygen.1 1 have bad little practical experience with these forms of therapy, but it is clear from an evaluation of the experiences of others that the recurrence rate of chronic osteomyelitis is still disturbingly high. In fact, in those series in which these forms of therapy were successful, they were used in conjunction with extensive surgery and débridement, and the latter may have contributed greatly to the success. Recently, success bas been obtained with carefully monitored antibiotic treatment of chronic osteomyelitis given over a period of six months
POSTGRADUATE MEDICINE • September 1975 • Vol. 58 • No. 3
to a yearY1 This suggests that intensive prolonged antibiotic therapy should be employed in conjunction with excision of necrotic bone and scar tissue. In my experience, chronic osteomyelitis is rarely cured without the combination of careful, complete surgical débridement and prolonged antibiotic therapy.
Conclusion The clinical picture of osteomyelitis is influenced by many different factors, including the source of the infection, the point in the course of disease when the diagnosis is made, and previous
treatment with antibiotics or surgery or both. Successful therapy frequently requires close collaboration and consultation among severa! medical and surgical disciplines. Address reprint requests to Gerald Medoff, MD, Infectious Disease Division, Depanment of Medicine, Washington University School of Medicine, St. louis, MO 63110. For ReadySource on infection control, see page 225. Surnmary self-test on infection control begins on page 217.
REFERENCES 1. Waldvogel FA, Medoff G, Swartz MN: Osteomyelitis: A review of clinical features, therapeutic considerations and unusual aspects. N Engl J Med 282: 198:206; 260-266; 316-322, 1970 2. Wiley AM, Trueta J: The vascular anatomy of the spine and its relationship to pyogenic vertebral osteomyelitis. J Bone Joint Surg 41B:796-809, 1959 3. Mankin HJ: The reaction of articular cartilage to injury and osteoarthritis. N Engl J Med 291:13351340, 1974 4. Lewis R, Gorbach S, .Altner P: Spinal Pseudomonas chondro-osteomyelitis in heroin users. N Engl J Med 286:1303, 1972 5. Harris WH: Sinking prostheses. Surg Gynecol Obstet 123:1297-1302, 1966 6. Thibodeau AA: Closed space infection following removal of lumbar intervertebral dise. Clin Neurosurg 14:337-360, 1966 7. Kulowski J, Perlman R: Skeletal changes in malum perforans. Pedis Arch Surg 32:1-21, 1936
8. Boyd RJ, Burke JF, Colton T: A double-blind clinical trial of prophylactic antibiotics in hip fractures. J Bone Joint Surg 55A:1251-1258, 1973 9. MacAusland WR Jr: Treatment of sepsis after intramedullary nailing of fractures of femur. Clin Orthop 60:87-94, 1968 10. Holloway WJ, Kahlbough RA, Scott EG: Lincomycin: A clinical study. Proceedings of the Third Interscience Conference on Antimicrobial Agents and Chemotherapy, pp 200-203, 1963 11. McMillan NL, McRae RK, McDougall A: Lincomycin in the treatment of osteomyelitis. Practitioner 198:390-395, 1967 12. Frost HM, Villanueva AR, Roth H: Pyogenic osteomyelitis: Diffusion in live and dead bone with particular reference to the tetracycline antibiotics. Henry Ford Hosp Med Bull 8:255-262, 1960 13. Hedstrom SA: The prognosis of chronic staphylococcal osteomyelitis after long-term antibiotic treatment. Scand J Infect Dis 6:33-38, 1974
~,o_n________,,-----_a_nsw_e--'r The most common causative organism of hematogenous osteomyelitis is a. Salmonella b. Streptococcus c. Staphy/ococcus au reus d. Pseudomonas aeruginosa A 27-year-old heroin addict is hospitalized because of increasingly sharp interscapular pain. X-ray films disclose a destructive process involving 06-7, with narrowing of the intervertebral disk space. a. What is the most likely diagnosis?
c
Vertebral osteomyelitis
b. What is the likely causative organism?
Pseudomonas aeruginosa
c. What diagnostic procedures should be performed?
Biopsy and culture
Vol. 58 • No. 3 • September 1975 • POSTGIRADUATE MEDICINE
161
ISSN: 0032-5481 (Print) 1941-9260 (Online) Journal homepage: http://www.tandfonline.com/loi/ipgm20
Current Concepts in the Treatment of Osteomyelitis Gerald Medoff To cite this article: Gerald Medoff (1975) Current Concepts in the Treatment of Osteomyelitis, Postgraduate Medicine, 58:3, 157-161, DOI: 10.1080/00325481.1975.11714148 To link to this article: http://dx.doi.org/10.1080/00325481.1975.11714148
Published online: 07 Jul 2016.
Submit your article to this journal
View related articles
Citing articles: 2 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ipgm20 Download by: [Australian Catholic University]
Date: 25 July 2017, At: 20:58
co sder • What are the clinical types of osteomyelitis? • What causative organisms are involved? • ln the treatment of osteomyelitis, when is surgery appropriate? When is medical management appropriate?
GERALD MEDOFF, MD Washington University School of Medicine St. Louis
Current Concepts in the Treatrnent of Osteornyelitis Dr. Medoff provides an excellent breakdown of the clinical types of osteomyelitis encountered in practice today. He points out the necessity for long treatment of acute osteomyelitis, that is, four to six weeks of parenteral therapy. He discusses a number of the problems attendant on the chemotherapy of chronic osteomyelitis, painting out the role of surgical débridement in addition to antibiotic therapy.
-HCN
Traditionally, osteomyelitis has been defined as either an acute or a chronic infection, the classifi· cation depending on either the clinical course or the histopathologic findings. In fact, there is probably no abrupt shift from acute to chronic disease, but rather a graduai blending; and distinction between acute and chronic osteomyelitis on clinical or pathologie grounds is sometimes difficult. 1 Thus, patients with apparently acute disease can present with histories suggesting an indolent course, and patients with documented osteomyelitis of many years' duration occasionally present with acute exacerbations characterized by fever and local infiammatory changes. lt is useful to further divide cases of osteomyelitis into three groups: (1) hematogenous oste-
Vol. 58 • No. 3 • September 1975 • POSTGRADUATE MEDICINE
omyelitis, (2) osteomyelitis secondary to a contiguous focus of infection, and (3) osteomyelitis associated with peripheral vascular disease. 1 Because the clinical features of these three groups are different, 1 will describe each separately before . discussing therapy. Hematogenous Osteomyelitis
Hematogenous osteomyelitis is a blood-borne infection which localizes in bone, with primary bacteremia the usual source. lt is much more common in children than in adults. The long bones of the lower extremities, particularly the femoral and tibial metaphyses, are most frequently involved, but the high frequency of vertebral osteomyelitis in adults is striking.2 One suggested explanation is a predilection of osteomyelitis for bones with active red marrow. This explanation, however, is not consonant with the fact that hematogenous osteomyelitis of the skull, ribs, and epiphyses--ali areas with high bone marrow activity-is quite rare in the adult. A more reasonable explanation may be that, because of increased metabolic activity and ingrowth of blood vessels in osteoarthritic vertebral bone and cartilage, this area in adults is equivalent to the metabolically active metaphyseal area of long ~ bones so commonly affected in children.3
157
In acute hematogenous osteomyelitis, most patients are symptomatic, with pain, swelling, chills, fever, and malaise, for less than three weeks before hospital admission. Exceptions are patients with venebral osteomyelitis, which frequently is not heralded by systemic symptoms. Dull continuous back pain may be the only complaint at onset. The associated bone changes are limited to local destruction and new bone formation (involucrum), which are reflected radiologically by lytic lesions and areas of increased density. Frequently, only soft-tissue swelling with minimal periosteal reaction is seen early in the disease. Bone scans have been shown to be abnormal before the disease is
crease in bacteremia due to Gram-negative bacilli has not occurred. The exceptions are Salmonella bone infection, already discussed, and osteomyelitis due to Pseudomonas aeruginosa in drug addias.4 The latter usually involves the spine, symphysis pubis, ribs, ischial tuberosity, or sacroiliac or hip joints. Osteomyelitis Secondary to a Contiguous Focus of Infection
Osteomyelitis secondary to a contiguous focus of infection is defined as an infection of bone arising from an exogenous source or from a progressive, continuous spread of infection.1 Postopera-
Salmonella bacteremia may develop in patients with sickle cell anemia because of defective host resistance and will almost invariably localize in bane because of the bane infarcts which occur commonly in this disease. evident radiologically. Increased uptake of radioactive label has also been seen in a variety of bone tumors, in Paget's disease, and in fractures. Bone scanning, therefore, lacks diagnostic specificity but is helpful in early detection of a bone lesion causing pain. Staphylococcus aureus is the most common etiologie agent in this type of osteomyelitis. Salmonella infections of bone are a relatively common complication of sickle cell anemia. 1 Only three of the many serotypes of Salmonella are u~ually found in association with sickle cell anemia: S choleraesuiJ, S paratyphi, and S typhimurium. Salmonella bacteremia may develop in patients with sickle cell anemia because of defective host resistance and will almost invariably localize in bone because of the bone infarcts which occur commonly in this disease. The long bones are usually involved, but infections of the small bones of the extremities, of the sternoclavicular junction, and of the venebrae have been described; multiple bone involvement also occurs quite frequently. The clinical presentation of Salmonella osteomyelitis cao be a diagnostic challenge in patients with sickle cell disease, because the septic process may mimic intraosseus sickling clinically and radiologically. Surprisingly, an increase in osteomyelitis due to Gram-negative bacteremia paralleling the in-
158
tive infection is an example of the former; sinus disease, felons, and burns are examples of the latter. The highest percentage of patients in this clinical category of osteomyelitis are over 50 years of age. This contrasts with the much younger population seen with hematogenous osteomyelitis. Most cases of osteomyelitis secondary to a contiguous focus of infection occur as a result of postoperative infections. Internai fixation, weil established as a means of treating cenain fracrures of long bones in adults, is an example of a procedure that cao be followed by infection. Indeed, any surgical procedure carries a risk of infection. One of the more complicated problems in osteomyelitis is intra-anicular sepsis after open reduction of a hip fracture. Osteomyelitis of the hip following surgery cao be insidious.5 Quite often there is little or no inflammatory reaction and no wound drainage. Joint pain is sometimes an early sign of sepsis. Infection of an intervenebral disk space cao also be insidious. In most cases, pain is the only symptom and an elevated sedimentation rate the only laboratory abnormality. 6 Another important cause of this type of osteomyelitis is the extension of soft-tissue infection to bone. Infections involving the fingers and toes account for most of these cases.
POSTGRADUATE MEDICINE • September 1975 • Vol, 58 • No. 3
Other Jess common causes are infected teeth, leading co osteomyelitis of the mandible, and sinus disease. Infection of the frontal bone with a cortical breakthrough and a collection of pus under the periosteum may present as a swelling over the frontal sinus (Pott's puffy tumor). In one series, Staph aureus was the most corn· mon infecting organism in osceomyelitis secondary to a contiguous focus of infection, with an incidence similar co chat found in hematogenous osceomyelitis.1 An important difference, however, is that most of these infections were caused by more chan one species of bacteria, and there was a high frequency of Gram-negative bacteria. This presents a problem in evaluating the relative importance of each of severa) baccerial species isolaced on culture. Treacment should be direcced at the organisms infeccing the bone and not necessarily at the flora of the draining sinus tract. Osteomyelitis Associated With Vascular lnsufficiency
The patients who have osteomyelitis associated with vascular insufficiency are almost ali diabetic. The infections involve the toes or the small bones of the feet. lt is frequentl} difficult clinically and pathologically co differentiate this condition from purely occlusive vascular disease (so-called diabetic foot). 7 Most patients with osteomyelitis, however, have frank cellulitis, with deep ulcers in the soft tissue. Most cultures from surgical specimens or from ulcerated lesions show cwo or three organisms, usually including Staphylococcus or Streptococcus and often an enteric organism as weil. Anaerobes, including Clostridium species, also appear often. Treatment of Osteomyelitis
The most important therapeutic measures for osteomyelitis are syscemic administration of antibiotics and surgery co drain abscesses or debride necrotic tissue. The relative importance of these measures in individual cases depends on the location and stage of the disease. In early acute osceomyelitis, conservacive antibiocic creatment is ofcen sufficient. In subacute or more chronic disease, both antibiotics and surgery are necessary. In chronic disease, extensive resection of necrotic bone can result in cure. Acute osteomyelitis-Because of the aforementioned limitations of radiologie studies and the Jack of diagnostic specificiry of laboratory findings, acute hemacogenous osceomyelicis is most fre-
Vol. 58 • No. 3 • September 1975 • POSTQRADUATE MEDICINE
GERALD MEDOFF Dr. Medoff is in the infectious disease division, department of medicine, Washington University School of Medicine, St. Louis.
quendy a clinical diagnosis. Once the diagnosis is made, antibiotic therapy should be instituted immediately. If an appropriate antibiocic is used, cure rates in excess of 90% can be expected, even without surgical drainage. Selection of antibiocic is dependent on identification of the causative organism. An adequate culture ideally should be obtained before therapy is begun. Because blood cultures are positive in 25% co 50% of patients with acute hematogenous osceomyelitis, a blood culture is frequently ali chat is needed. If the disease is uncomplicated (ie, involves a long bone in a patient without underlying medical problems), chen in my opinion therapy for Staph aureus infection can be started empirically. If the disease is arypical (eg, vertebral osceomyelitis in an addict), bone aspiration or biopsy should be done. By definition, hematogenous osteomyelitis must be considered a "mecastasis" of a septic process. Antibiocics must therefore be given in high dosage (12 co 20 million unies of penicillin or 8 co 10 gm oxacillin each day). A patient with staphylococcal infection musc also be treated empirically for endocarditis (four co six weeks of parenteral therapy). Surgery in acuce osteomyelicis should be limited co biopsy for diagnosis (in arypical or nonresponsive cases) and to drainage of suppurative collections and débridement of necrocic bone (sequestrum). The development of neurologie abnormalities in vertebral or cranial osteomyelicis, or infection spreading ro the hip joint in a child, is also indication for surgical drainage. Such surgery (with adequate antibiocic coverage) usually is weil tolerated. As is crue in acute hemacogenous osteomyelitis, early antibiocic creacment is effective in curing most osteomyelitis secondary co contiguous infection. However, because so many cases are not
159
secondary to Staph aureus infection or because other organisms are frequently present as weil, exact etiologie diagnosis is essential. · Careful bacteriologie examination of drainage or aspirate from the operative wound should be done, followed if necessary by biopsy or aspiration of bone for culture. lntra-articular and bone sepsis after nailing or the introduction of an endoprosthesis presents a difficult problem. Recent evidence8 suggests that prophylactic use of antibiotic just before and during surgery greatly lowers the incidence of infection. More extensive studies are needed to confirm this impression. In most patients with this kind of infection, the prosthesis or naïl bas to be removed to control the sepsis. Management should be in the bands of physicians familiar with this type of infection. Intensive parenteral antibiotic therapy for six weeks, with operative resection of infected and compromised tissue at the time of removal of the prosthesis, is the most effective combination. lntramedullary fixation is a well-established treatment for midshaft femoral fractures without extensive comminution. Here, as in the insertion of intra-articular deviees, postoperative infection is a serious complication. In contrast to the approach to sepsis about an intra-articular deviee, it is generally held that an intramedullary naïl must remain in place, in spite of sepsis, until union bas taken place.9 If the naïl is removed too soon, instability at the fracture site can lead to persistence and spread of sepsis. The infection is treated vigorously with high dosages of antibiotic and locally with drainage and sequestrectomy when required. In MacAusland's9 series, union was obtained in the majority of cases so treated. The only indication for removal of the naïl was loss of rigid immobilization because of loosening of the naïl; after removal, the naïl was replaced by a larger one. After union was evident, the naïl could be removed and any remaining sepsis treated by local débridement and antibiotics given systemically. Many patients with osteomyelitis associated with vascular insufficiency are initially given conservacive treatment aimed at salvaging the limb. This approach is almost uniformly unsuccessful in patients with polyneuropathy, retinopathy, or nephropathy-three hallmarks of advanced diabetes. 1 More radical surgical approaches such as transmetatarsal amputation and below- and above-knee amputations are associated with a high cure rate.
160
This does not mean that small-bone osteomyelitis of the lower extremities in diabetic patients with severe arteriosclerosis and other complications should be treated primarily by amputation. However, it is my belief that after an unsuccessful course of amibiotics, performing surgery is preferable to prolonging questionably effective medical management. When surgery is considered, the blood supply at the anticipated line of amputation should be checked to assure that it is adequate to permit satisfactory healing. Chronic osteomyelitis--Generally, in ali three clinical types of osteomyelitis, the number of treatment failures is highest in the chronic form of the disease. There are no exact criteria as to when acute osteomyelitis becomes chronic, but generally the earlier in the course of acute disease that appropriate antibiotic treatment is initiated, the becter is the cure rate. lt bas been stressed that adequate antibiotic levels are difficult to achieve within a focus of chronic osteomyelitis. The bone levels obtained with lincomycin or clindamycin reportedly are particularly high,10 and it bas been suggested that these may be the antibiotics of choice in the treatment of osteomyelitis. 11 However, the evidence for high bone levels is based on a report that did not define the status of bone being assayed and that also did not include comparative data for other antibiotics. Because it bas been shown that even tetracycline, which is readily bound to bone,12 cannot penetrate the ischemie or dead bone (sequestrum) of chronic osteomyelitis, it is hard to see how lincomycin or clindamycin could be effective. Among other forms of therapy recommended for chronic osteomyelitis are closed irrigation of lesions with antibiotic or antibiotic-detergent (Alevaire) mixtures, regional perfusion of antibiotics intra-arterially, or use of hyperbaric oxygen.1 1 have bad little practical experience with these forms of therapy, but it is clear from an evaluation of the experiences of others that the recurrence rate of chronic osteomyelitis is still disturbingly high. In fact, in those series in which these forms of therapy were successful, they were used in conjunction with extensive surgery and débridement, and the latter may have contributed greatly to the success. Recently, success bas been obtained with carefully monitored antibiotic treatment of chronic osteomyelitis given over a period of six months
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to a yearY1 This suggests that intensive prolonged antibiotic therapy should be employed in conjunction with excision of necrotic bone and scar tissue. In my experience, chronic osteomyelitis is rarely cured without the combination of careful, complete surgical débridement and prolonged antibiotic therapy.
Conclusion The clinical picture of osteomyelitis is influenced by many different factors, including the source of the infection, the point in the course of disease when the diagnosis is made, and previous
treatment with antibiotics or surgery or both. Successful therapy frequently requires close collaboration and consultation among severa! medical and surgical disciplines. Address reprint requests to Gerald Medoff, MD, Infectious Disease Division, Depanment of Medicine, Washington University School of Medicine, St. louis, MO 63110. For ReadySource on infection control, see page 225. Surnmary self-test on infection control begins on page 217.
REFERENCES 1. Waldvogel FA, Medoff G, Swartz MN: Osteomyelitis: A review of clinical features, therapeutic considerations and unusual aspects. N Engl J Med 282: 198:206; 260-266; 316-322, 1970 2. Wiley AM, Trueta J: The vascular anatomy of the spine and its relationship to pyogenic vertebral osteomyelitis. J Bone Joint Surg 41B:796-809, 1959 3. Mankin HJ: The reaction of articular cartilage to injury and osteoarthritis. N Engl J Med 291:13351340, 1974 4. Lewis R, Gorbach S, .Altner P: Spinal Pseudomonas chondro-osteomyelitis in heroin users. N Engl J Med 286:1303, 1972 5. Harris WH: Sinking prostheses. Surg Gynecol Obstet 123:1297-1302, 1966 6. Thibodeau AA: Closed space infection following removal of lumbar intervertebral dise. Clin Neurosurg 14:337-360, 1966 7. Kulowski J, Perlman R: Skeletal changes in malum perforans. Pedis Arch Surg 32:1-21, 1936
8. Boyd RJ, Burke JF, Colton T: A double-blind clinical trial of prophylactic antibiotics in hip fractures. J Bone Joint Surg 55A:1251-1258, 1973 9. MacAusland WR Jr: Treatment of sepsis after intramedullary nailing of fractures of femur. Clin Orthop 60:87-94, 1968 10. Holloway WJ, Kahlbough RA, Scott EG: Lincomycin: A clinical study. Proceedings of the Third Interscience Conference on Antimicrobial Agents and Chemotherapy, pp 200-203, 1963 11. McMillan NL, McRae RK, McDougall A: Lincomycin in the treatment of osteomyelitis. Practitioner 198:390-395, 1967 12. Frost HM, Villanueva AR, Roth H: Pyogenic osteomyelitis: Diffusion in live and dead bone with particular reference to the tetracycline antibiotics. Henry Ford Hosp Med Bull 8:255-262, 1960 13. Hedstrom SA: The prognosis of chronic staphylococcal osteomyelitis after long-term antibiotic treatment. Scand J Infect Dis 6:33-38, 1974
~,o_n________,,-----_a_nsw_e--'r The most common causative organism of hematogenous osteomyelitis is a. Salmonella b. Streptococcus c. Staphy/ococcus au reus d. Pseudomonas aeruginosa A 27-year-old heroin addict is hospitalized because of increasingly sharp interscapular pain. X-ray films disclose a destructive process involving 06-7, with narrowing of the intervertebral disk space. a. What is the most likely diagnosis?
c
Vertebral osteomyelitis
b. What is the likely causative organism?
Pseudomonas aeruginosa
c. What diagnostic procedures should be performed?
Biopsy and culture
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