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As I treat many diabetic patients with foot complications, bone infections are frequently treated in my line of work. Sometimes the treatment is easy and involves wound care and antibiotics. Other times, it can be complex and may require surgery and even loss of toes.
So, what is bone infection and how is it treated?
Osteomyelitis is a serious bone infection that occurs when bacteria, fungus, or another microorganism infects the bone or the bone marrow. The infection can spread to the bone through the bloodstream or through direct contamination from a wound or surgical incision.
To fully understand Bone infection treatment in the feet, we have to consider 4 things: symptoms, diagnosis, and treatment, and rehabilitation
Bone Infection Symptoms
Symptoms of bone infection will depend on the extent and length of the infection process. These symptoms may include fever, chills, fatigue, or localized swelling and pain over infected bone area. There may be redness and warmth to the touch. Pain may cause an individual to have trouble moving the affected limb or joint.
Osteomyelitis can involve cortical (outside of the bone) or intramedullary bone (inside of the bone).
It can be:
– contiguous meaning going from superficial area like skin to deep area of bone. This is the most common type in diabetics with wounds. Surgical wound dehiscence, swelling causing skin cracking, exposed hardware can serve as other sources for this type of bone infection
-hematogenous or spread through blood stream (more common in kids with strep throat for example)
-disseminated (traveling and infecting many different bones in the body due to bacterial growth on heart valve or with bacteria traveling in the blood stream, which spreads the infection).
It can also be chronic or acute
Acute bone infection symptoms: fever, chills, pain, swelling, inflammation, redness purulent drainage, gas gangrene, necrotizing fasciitis.
Chronic osteomyelitis: symptoms may persist for weeks or months. Patients may not be systemically ill meaning no fever, no chills, no nausea, no vomiting, etc.
These chronic bone infections may accompany hardware implantation (screws, plates, implants etc): symptoms include swelling, local pain, warmth, localized redness, hardware loosening, and failure of bones to heal as visualized on the x ray or another imaging modality.
Osteomyelitis can occur in any bone in the body, but it is most common in the long bones of the legs and arms, and in the bones of the spine. It can also occur in the bones of the feet and toes, which can make it difficult for the individual to walk or stand. In the feet, ankles and legs, osteomyelitis usually starts as a skin break or wound over a pressure point like the ball of the foot, tips of toes, bottom or back of heel, sides of the ankle etc.
Left untreated, the wounds deepen and may become infected. Once infection and depth progresses, the infecting organism will reach and infect the bone. This is more common in patients with decreased nerve sensation. This condition is known as neuropathy and is frequent in diabetic patients with persistently high blood glucose. It can also affect patients who develop numbness in their feet because of long standing alcohol abuse.
Patients with spinal, especially low back issues, can develop decreased sensation in their feet. Some nutritional deficiencies like B12 deficiency and certain medications can cause neuropathy as well.
Diagnosis of Bone Infection
Diagnosis of osteomyelitis is typically made through a combination of physical examination, imaging tests, and laboratory tests. X-rays, MRI, and CT scans can be used to identify the location and severity or extent (spread/depth) of the infection. Blood tests, microbiology and pathology tests can be used to identify the specific microorganism and degree of destruction caused by the infection.
Imaging modalities
Modalities like x-rays, bone scans, CT, MRI are very helpful in diagnosis the presence and extent of bone infection.
One should always start with the most basic modality: x – ray
X rays
X rays are inexpensive and relatively safe.
One must remember, however, that bone changes like periostitis (inflammation of tissue on top of bone), corticolysis ( changes in the outer layer of the bone), and osteolysis may not be visible for one to two weeks after the infection started to damage the bone. So, this modality is not great for early diagnosis of bone infection.
In contiguous infection, the infection spreads from superficial to deep, or from wound to bone and so changes to outer layer of the bone are seen first
On the other hand, in hematogenous (blood borne) infection spread, the inside of the bone called medullary bone becomes infected first
In case of chronic bone infection, sclerotic layer of bone (Cloaca) forms around abscess (sequestrum).
Fungal and mycobacterial (tuberculosis) bone infections may present with unusual bone destruction pattern. See examples here:
Tuberculosis: https://radiopaedia.org/articles/tuberculosis-musculoskeletal-manifestations-1
Fungal: https://online.boneandjoint.org.uk/doi/pdf/10.1302/0301-620X.76B1.8300658
When taking an x ray, interpretation of the image may be complicated in patients who have been in the state of prolonged immobilization. In these individuals, the bone appears washed out. This is also a common finding in those who have had casts and offloading fracture boots used for prolonged period of time. With prolonged immobilization, the image appears “washed out”, which may be confused with osteomyelitis.
Once the doctor completes the x rays and has high suspicion for bone infection, the next step would be to do a bone biopsy or collecting a small segment of bone to send to microbiology lab for analysis and identification of infecting organism
If the x ray is not conclusive, then the doctor may order a bone scan.
Bone Scans
There are several bone scans available that use different chemical elements (isotopes) that help with differentiation of chronic vs acute infection and also help to visualize the spread of the infection. Some examples of these isotopes include Technetium 99, Gallium 67, Indium 111
These tests are used in combination to properly diagnose the type and extent of bone vs soft tissue infection.
CT/MRI
CT/MRI imaging is better for special distribution and visualization of bone and soft tissue infection.
CT: good for early erosion visualization, sequestrum foreign body, emphysema (gas producing bacteria in the tissue)
MRI: study can be with or without contrast as contrast may be damaging in patients with kidney disease. Even though MRI probably has the highest sensitivity and specificity, it has limitations. Body weight limited (MRI tubes can only fit people up to a specific weight), hardware may obstruct view due to visual artifact formation. As MRI works like a magnet and magnets turn off pacemakers, MRI is frequently contraindicated in patients with pacemakers.
Laboratory findings:
White blood cell count, ESR, CRP and Procalcitonin are some of the labs that may be ordered to help with diagnosis of infection.
Diabetics with chronically elevated blood sugar and other immunocompromised individual may not generate leukocytosis or white blood cell count increase ( body’s immune fight response to infection). Therefore, laboratory findings in this patient group may not be a reliable indicator as to the degree of the infection.
ESR and CRP tests must be interpreted in light of imaging modalities and clinical exam and are better for tracking response to therapy.
Certain levels of ESR and CRP correlated with chronic vs acute bone infection vs soft tissue infection.
Procalcitonin level measurement can be useful in distinguishing osteomyelitis from cellulitis. This is not a commonly ordered test.
Management of bone infection
Treatment for osteomyelitis typically involves a combination of antibiotics to kill the infection-causing microorganisms and surgery to remove any dead or infected bone tissue. In some cases, the individual may need to spend several weeks in the hospital to receive treatment and to prevent the infection from spreading.
Physical therapy and rehabilitation exercises are also an important part of recovery from osteomyelitis. These exercises can help to strengthen the muscles and improve range of motion in the affected limb or joint.
Prevention of osteomyelitis includes taking care of any wounds or injuries promptly, avoiding contact with individuals who have active infections, and practicing good hygiene, such as washing your hands frequently.
In summary, Osteomyelitis is a serious bone infection caused by bacteria, viruses, or other microorganisms. Symptoms include fever, chills, fatigue, and localized pain and swelling in the affected area. Treatment typically involves a combination of antibiotics and surgery. Physical therapy and rehabilitation exercises are also important for recovery, and prevention includes taking care of any wounds or injuries promptly, practicing good hygiene and avoiding contact with individuals who have active infections.
Most common organism
Most common organism in bone infection is Gram positive bacteria in adults with Staph aureus being most common. Streptococcus beta bacterial is the most common organism that causes bone infection in children.
E coli, Pseudomonas, Klebsiella, Aerobacter are more common organisms causing bone infection in immunocompromised (alcoholism, diabetes, sickle cell) individuals.
Fungal bone infection should be considered in patient with severe immune compromise and those on chronic steroid therapy.
Pathology report is a more accurate diagnostic modality. Bone culture can produce false negative results, especially in individuals who have been on repeat or long-term antibiotic therapy.
Sometimes, when hardware (screws, plates, anchors) cannot be safely removed, suppressive lifelong antibiotics can be used to control bone infection. However, potential complications like antibiotic resistance, nephrotoxicity (kidney injury), ototoxicity (hearing injury) may occur.
Surgical Approaches
Goal of surgery is to remove infection and produce functional foot fit for ambulation.
Surgery reduces need for long term antibiotics.
Some researchers and clinicians believe that surgery that removes bones but preserves appendages/toes has similar re-ulceration outcomes.
Infections of bone involving hardware removal and bone tissue deficits are particularly challenging because require multiple procedures, likely at different times, with high failure rate. Also, therapy including external fixators, antibiotic infused bone cement and bone cement spacers frequently need to be used to achieve limb stability and salvage.
Use of local antibiotics (infused into bone cement or creams) can reduce need for systemic antibiotic need and duration. This method could be helpful in delivering antibiotics to poorly vascularized bone in patients with poor circulation in lower limbs, as well as patients with kidney problems. Patients with kidney problems who are close to dialysis therapy may end up having to start dialysis because of antibiotic toxicity.
This is a list of some pharmaceutical agents that can be used to treat infection locally: colistin, meropenem, vancomycin, gentamycin, tobramycin, amphotericin B, and daptomycin with calcium sulfate base.
Hyperbaric oxygen (HBO) therapy can be used as adjunct therapy
Hyperbaric oxygen therapy (HBO) is a treatment that involves breathing pure oxygen in a pressurized chamber. This chamber can be as big as a room and as small as a full body capsule. In the treatment of bone infections, HBO works by increasing the oxygen concentration in the bloodstream, which allows the infected area to receive more oxygen. This is known as aerobic respiration.
Aerobic respiration, which is promoted by hyperbaric oxygen therapy, can enhance bacteriocidic properties of beta lactam, aminoglycosides, and fluroquinolone antibiotics by exposing oxygen poor biofilms with HBO treatment.
Aerobic respiration allows for stimulation of angiogenesis (new blood vessel growth), decreases soft tissue edema (swelling), and helps to reduce inflammation. Hyperbaric oxygen therapy is not a cure for bone infections, it can be an effective adjunctive therapy when used in conjunction with other treatments, such as antibiotics and surgery.
Emotional Toll of Losing a Part of Your Body
In addition to understanding physical aspects of bone infections and frequently resulting body part loss or even limb loss, one must consider emotional aspects of such a surgery.
Losing a limb can be a traumatic and life-altering experience that not only affects an individual physically, but also emotionally.
The emotional toll of limb loss can be just as devastating as the physical challenges, and it is important to address these emotional struggles in order to facilitate the healing process. These struggles affect not only the person losing a body part but also family members and friends of that person.
One of the most common emotional reactions to limb loss is depression.
This is understandable, given the profound impact that the loss of a limb can have on an individual’s life. The loss of a limb can lead to feelings of sadness, frustration, and helplessness, and these feelings can become overwhelming. It is important for individuals who are experiencing depression after limb loss to seek help from a mental health professional. I encourage you to discuss a referral to a mental health professional and/or amputee support group prior to undergoing limb amputation. Joining an amputee group will empower you with coping skills and will allow you to see what is available in terms of recovery and resources.
Another emotional challenge that individuals may face after limb loss is a sense of loss of identity.
The loss of a limb can make an individual feel like they are no longer who they were before, and this can be a difficult adjustment. This is particularly true if one relied on their limb to provide for themselves and their family. In cases of lower limb amputations, it would be virtually impossible to return to a job requiring extensive standing, walking, climbing etc. Thus, a chance in vocation and life style will likely be required. It is important for individuals to recognize that it is normal to feel this way, and that it is a part of the healing process. Your surgery team should have case manager or social worker available to help you find resources to address transition to a new way of living. Many of my patients go to a nursing home as require intensive physical therapy, occupational therapy, and prosthetic limb fitting before they can return to independent life.
Grief, Fear and Anxiety are also common emotional reactions to limb loss.
Fear of the unknown can be especially challenging, and it is not uncommon for individuals to feel anxious about how they will manage their daily activities without their limb. It is important to understand that these fears are normal. Losing a limb can be a grieving process, and it is important to allow individuals to express their emotions and to support them in their healing.
In conclusion, the emotional toll of limb loss can be just as devastating as the physical challenges, both challenges must be addressed simultaneously to ensure successful recovery and return to independent living!
With the right support, individuals can and do recover from the emotional toll of limb loss and reclaim their sense of self and their place in the world.
Author bio:
My name is Dr. Marat Kazak. I have been working as a professional Podiatrist serving Northern California community since 2014. My extensive medical and surgical knowledge combined with an ongoing curiosity to learn about the latest trends define my success in the field of foot, ankle and leg medical and surgical care.
The goal of this website is to give you the tools to better care for yourself, to dispel medical myths, and to empower you with information to save time and money! If you are looking for an answer on foot and ankle pain, this is the place to find it. If you do not see your topic of interest covered, please send me a message and I will do my best to discuss it thoroughly in my next upcoming post.
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