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Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018
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Image courtesy of Jerome JTJ. Foot Ankle Online J. 2008;1(6):3.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
The above radiograph demonstrates a divergent Lisfranc dislocation of the first metatarsal in a diabetic male with Charcot neuroarthropathy; associated lesser metatarsal fractures are revealed as well.
Charcot neuroarthropathy is a destructive process that can lead to deformities that result in instability, ulceration, or even amputation. Diagnosis of this condition is challenging and relies primarily on the clinical presentation. Charcot neuroarthropathy has been associated with many diseases, including leprosy, poliomyelitis, syringomyelia, multiple sclerosis, and neuropathy; however, the most common etiology is diabetes mellitus. All patients who develop Charcot neuroarthropathy have peripheral neuropathy. Peripheral neuropathy and sensory deficits usually precede the diagnosis. Charcot neuroarthropathy is common in the foot and ankle but can occur in other joints as well.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
A 46-year-old Hispanic woman with a history of poorly controlled diabetes presents to the emergency department (ED) with a red, hot, and swollen right foot and ankle that started 10 days previously. She is not experiencing pain. The patient has no history of prior foot problems or of similar symptoms or pain in other joints. She does not recall any history of significant trauma but says that she may have injured her foot when stepping off a curb about 2 weeks ago.
On the basis of this clinical presentation, which of the following should be considered in the differential diagnosis?
Infection
Deep vein thrombosis (DVT)
Inflammatory/gouty arthritis
Charcot neuroarthropathy
All of the above
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Answer: E. All of the above.
Infection may present with edema, cellulitis, abscess, or ulceration with regional lymphadenopathy. Leukocytosis and an elevated erythrocyte sedimentation rate (ESR) may be seen with an infectious process. DVT is common in patients with a history of stasis/immobilization or cancer and can present with edema, erythema, and pain in the extremity. Inflammatory arthritis should also be considered. Hand joints are usually involved; however, early rheumatoid arthritis (RA) can present in the lower extremity. Swelling and painful metatarsophalangeal (MTP) joints can be present.
Image from Wikimedia Commons | Hellerhoff.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Acute gouty flare is another possibility. This condition usually peaks within 24-48 hours and resolves by itself within 1 week or less. The first metatarsophalangeal joint is commonly affected (arrow), but insteps, heels, and ankles may also be involved. The skin overlying the affected joint is exquisitely sensitive. There is usually a history of prior attacks. Hyperuricemia (>6.8 mg/dL) is common; however, the uric acid level can be normal during an acute gouty attack.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
The patient is afebrile, and her vital signs are stable. She has significant peripheral neuropathy that extends up to the midleg bilaterally. Her pedal pulses are strong bilaterally, and increased warmth is noted in her right foot, ankle, and lower leg. There are no open lesions, puncture wounds, or ulcerations, and no interdigital maceration or fissuring is apparent. Erythema and edema are localized to the right lower extremity from the shin down. The Homans sign is absent, with no palpable cords noted. No pain is elicited with palpation or range-of-motion exercise of joints in either the upper or the lower extremities. No popliteal or inguinal lymphadenopathy is appreciated.
Which of the following imaging modalities would help establish the diagnosis?
Ultrasonography
Radiography
Computed tomography (CT) scanning
Magnetic resonance imaging (MRI)
Nuclear bone scanning
All of the above
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Answer: F. All of the above.
Ultrasonography can help to rule out DVT (arrow), which usually involves swelling of the calf area in addition to the foot. It can detect blocked venous blood flow to the extremity from above the knee and can also detect pockets of fluid collection (eg, abscesses).
Image from Medscape.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
In early Charcot neuroarthropathy, radiographs are usually normal. Common late-stage Charcot radiologic findings include subchondral sclerosis (arrow) and subluxation. Plain radiography can be used to help diagnose osteomyelitis (OM) in addition to fractures. Radiologic findings of OM can be delayed for as long as 2 weeks and are only about 50% specific in detecting OM.[1] Periosteal reaction or lifting can be seen early on. In gout, subcortical cysts without erosion can be seen on plain films. In inflammatory arthritis (eg, RA), bony erosions, periarticular osteopenia, and loss of joint space can be seen in the metatarsophalangeal joints.
Image from Medscape.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
This radiograph is of a patient with diabetes mellitus who presented with both Charcot neuroarthropathy and OM. Note the lateral disruption of the base of the metatarsal in relation to the tarsals, which represents a Lisfranc fracture-dislocation due to Charcot neuroarthropathy. Also, note the soft-tissue gas and OM of the second and third metatarsal heads (arrow).
Image from Medscape.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
In this CT scan of the ankle of a patient with neuroarthropathy, note the destruction of the articular surface, the disorganization of the joint, and the fragmentation.
Image courtesy of Poll LW, Weber P, Böhm HJ, Ghassem-Zadeh N, Chantelau EA. Diabetol Metab Syndr. 2010 Oct 5;2:60. PMID: 20923545. PMCID: PMC2958966.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
MRI gives a better view of bone, soft-tissue, and joint abnormalities. It has a high sensitivity and specificity in the detection of OM.[2] MRI can detect early signs of Charcot neuroarthropathy, such as joint and ligamentous abnormality, bony stress injury, and surrounding soft-tissue, joint, and bone-marrow edema.[2,3]
In contrast to Charcot neuroarthropathy, OM usually shows focal activities in joints on MRI with contrast.[4] In general, however, there is no single imaging modality that can clearly differentiate Charcot neuroarthropathy from OM.[4]
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
A three-phase bone scan with technetium-99m (99mTc) is highly sensitive for diagnosing bony abnormalities; however, it is not very specific for differentiating OM from Charcot neuroarthropathy. Bone scanning (shown) is best used to diagnose early Charcot neuroarthropathy when there is a low suspicion of OM or no bony pathology. Indium-111 (111In)-labeled leukocyte scintigraphy can be used along with the three-phase bone scan to increase the sensitivity and specificity of bone scanning for diagnosing Charcot neuroarthropathy (93-100% and 80%, respectively).[1] Positron emission tomography (PET) scanning with fluorine-18 (18F) fluorodeoxyglucose (FDG) in combination with CT scanning can be useful in diagnosing OM and Charcot neuroarthropathy, though it has some limitations.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
A diabetic man with a history of peripheral neuropathy presents to the ED with a nonpainful, red, hot, and swollen right foot, which he has had for the past 3 days. He denies sustaining any recent trauma, and he reports no recent history of fever, chills, nausea, or vomiting. The physical examination is significant for edema, erythema, and increased warmth in the entire right foot and ankle. There are no open lesions. Regional lymphadenopathy, the Homans sign, and streaking are all absent. Laboratory test results include the following:
White blood cell (WBC) count 8000/µL (normal, 4500-10,000/µL)
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Foot radiographs (shown) are negative for fracture, erosions, or periosteal elevation.
On the basis of the clinical findings of diabetic peripheral neuropathy, the normal physical examination, and the normal laboratory values, which of the following is the most likely diagnosis for this patient?
Infection
Gout
RA
Charcot foot
None of the above
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Answer: D. Charcot foot.
In this scenario, Charcot neuroarthropathy is the most likely diagnosis. (Remember that radiographic findings in the early stages may be normal.)
Image from Medscape.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
The above radiograph shows Lisfranc fracture-dislocation in a patient with diabetes and neuropathic arthropathy. Note the soft-tissue swelling, fragmentation, sclerosis, and periostitis.
Diabetic peripheral neuropathy is thought to be the sine qua non for the presence of Charcot foot. Accordingly, patients with type 2 diabetes usually present with Charcot foot at a much later age than those with type 1 diabetes do. The incidence of Charcot foot is estimated to be in the range of 0.1-5.0% in patients with diabetic neuropathy but could be greater in high-risk patients. This type of complication associated with diabetes is increased in those who have had their disease for a longer period of time. The mean age of presentation is in the 50s, with occurrence equally in males and females.[5]
Although Charcot is most frequently unilateral, it can also be bilateral, though in such cases there is usually a lag time between the presentations of the two feet.[1]
Image courtesy of Jerome JTJ. Foot Ankle Online J. 2008;1(6):3.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Only about 50% of patients with Charcot foot experience pain, and the pain often subsides as the disease progresses.[1] Examination reveals increased warmth of the involved skin, diffuse erythema and edema of the extremity, and a normal distal pedal pulse. Decreased response to protective sensation (using a monofilament), light touch, and pinprick is noted in the distal extremities, in a stocking-glove distribution. In the early stages, patients with Charcot foot typically lack ulcerations, abrasions, or an open or tracking wound. They present with red, hot, and swollen joints in the feet (shown). There may or may not be a history of trauma. By use of an infrared cutaneous temperature monitor, detection of a temperature difference of 4° F (2° C) or greater between the affected foot and the contralateral foot would help to support a diagnosis of active Charcot neuropathy, especially when the white blood cell count is normal.[5]
Image from Medscape.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
The above radiographic image depicts osteolysis of the distal metatarsals and phalanges with tapering, which results in a pencil-like appearance in the late stage of diabetic neuropathy.
Although the etiology of Charcot neuroarthropathy remains unknown, several theories have been advanced, including the neurotraumatic, neurovascular, and unregulated inflammatory process theories. According to the neurotraumatic theory, patients with neuropathy would have repetitive joint trauma as a result of their inability to sense pain, and this repetitive trauma would then lead to bone deformity and joint dysfunction. According to the neurovascular theory, alterations in the autonomic system would result in increased blood flow to the area of injury, which would then give rise to increased osteoclastic activity and bone resorption.[1] However, neither the neurotraumatic nor neurovascular theory alone can explain the pathogenesis. The unregulated inflammatory theory suggests that proinflammatory cytokines, mainly the receptor activator of the nuclear factor-kappa B ligand (RANKL), causes an increase in osteoclastogenesis;[6,7] there is an imbalance of bone turnover in this process.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
A patient with poorly controlled diabetes and peripheral neuropathy presents to the clinic with a red, hot, and swollen left foot. She reports no recent fever, chills, nausea, vomiting, or trauma. Radiography of the left foot is ordered.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
On this radiograph of the patient's foot, fragmentation (arrow) is noted at the talonavicular joint.
If you suspect Charcot neuroarthropathy, what stage would it be?
Stage 0
Stage I
Stage II
Stage III
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Answer: B. Stage I.
The above table shows the stages for Charcot neuroarthropathy according to the modified Eichenholtz classification. Most current theories of the pathogenesis of this condition involve a triggering event that releases inflammatory cytokines (eg, tumor necrosis factor [TNF] and interleukin [IL]-1β). This cytokine release promotes production of RANKL, which stimulates maturation of osteoclasts, leading to increased bone resorption. Patients with neuropathy lack the ability to sense trauma and protect the extremity, and this allows continual expression of the RANKL cytokine and continual destruction.[6.7]
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
A patient with poorly controlled diabetes and peripheral neuropathy presents to your office with a red, hot, and swollen left foot. No fever, chills, nausea, or vomiting is reported, and there is no recent history of trauma.
Which of the following is the most appropriate initial treatment measure?
Colchicine
Anticoagulation
Surgery
Offloading
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Answer: D. Offloading.
Unfortunately, the patient is initially sent home on antibiotics alone for suspected foot cellulitis and is allowed full weight bearing. Two months later, the patient returns to the ED with residual edema and a foot deformity. Radiographs of the same patient reveal significant fractures and deformity of the midfoot (shown).
In up to 25% of patients with Charcot foot, diagnosis will be missed or delayed at first presentation. Disease prevalence ranges from 0.8-13% in persons with diabetes and could be as high as 29% in diabetic individuals with neuropathy.[8]
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
The keys to treatment of Charcot neuroarthropathy are early detection and prompt intervention. Early institution of therapy substantially reduces fractures and deformity. Accordingly, the primary initial treatment measure for Charcot foot is offloading, which removes the task of weight bearing from the affected joint(s). The patient is placed in a below-the-knee controlled ankle movement (CAM) walker (left) or a total contact cast (right) for as long as several months. Frequent cast changes are required to avoid an ill-fitting cast that can lead to abrasion and ulcerations. Once the diagnosis of Charcot foot is made, it is also important to refer the patient to a specialist, such as a podiatric or orthopedic surgeon.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
After a period of offloading, a stage II patient may be graduated to a molded total-contact polypropylene-type ankle-foot orthosis or a bivalve ankle-foot orthosis.[1] A stage III patient may be allowed weight bearing with a custom-made orthosis and shoe. A Charcot Restraint Orthotic Walker (CROW) can also be utilized. In later stages of Charcot foot with bony deformity and protuberance, exostectomy may be needed to prevent ulcerations with footwear. Reconstructive surgery with arthrodesis for stabilization may also be necessary (shown). Finally, some patients who still have recurrent ulcers and infection may eventually require surgical amputation.
Image courtesy of Aksone Nouvong, DPM.
Red, Hot, and Swollen Foot in Diabetes: Charcot or No?
Dieu-Thu Nguyen-Khoa, MD; Aksone Nouvong, DPM | March 30, 2018 | Contributor Information
Other medical therapies have been used for early Charcot neuroarthropathy, including bisphosphonates[9] (pamidronate, ibandronate, zoledronate), calcitonin, and TNF-α antagonist. However, only limited data are available on the long-term efficacy and benefits of these therapies.[10] Radiotherapy and bone stimulation have also been employed, with the same caveats as the aforementioned medical therapies. The above radiograph reveals significant fractures and deformity of the midfoot in a patient with Charcot foot.
In 1703, William Musgrave first described a neuropathic joint as an arthralgia caused by venereal disease. In 1868, Jean-Martin Charcot gave the first detailed description of the neuropathic aspect of this disease; hence, the condition is named after him.Diseases/Conditions, Procedures, July 2017
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Contributor Information
Authors
Dieu-Thu Nguyen-Khoa, MD
Associate Clinical Professor
Department of Medicine
David Geffen School of Medicine at UCLA
Los Angeles, CA
Disclosure: Dieu-Thu Nguyen-Khoa, MD, has disclosed no relevant financial relationships.
Aksone Nouvong, DPM
Clinical Professor
Department of Vascular Surgery
David Geffen School of Medicine at UCLA
Los Angeles, CA
Disclosure: Aksone Nouvong, DPM, has disclosed no relevant financial relationships.
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References
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Jude EB, Selby PL, Burgess J, et al. Bisphosphonates in the treatment of Charcot neuroarthropathy: a double-blind randomised controlled trial. Diabetologia. 2001 Nov;44(11):2032-7. PMID: 11719835 [Full text].
Jostel A, Jude EB. Medical treatment of Charcot neuroosteoarthropathy. Clin Podiatr Med Surg. 2008 Jan;25(1):63-9, vi-vii. PMID: 18165112
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