- Differential Diagnosis:
- vascular lesions:
- location of ulcerations/lesions may be helpful in determining etiology of the lesions;
- gangrene secondary to ischemia/arterial insufficiency will usually start at the most distal part of the extremity;
- neuropathic lesions tend to occur on wt bearing areas and rarely become gangrenous unless there is associated infection or arterial insufficiency;
- osteomyelitis
- neuropathic ulcerations may resemble the lesions found in osteomyelitis in that foot appears swollen with overlying erythema and warmth;
- history, exam, laboratory data, and radiographs can all help to distinguish between Charcot joint and infection;
- exam:
- w/ neuropathic foot, pt may present with a hot swollen erythematous, but painless foot;
- pt w/ dense neuropathy will have marked muscle wasting which should not be confused with ischemia;
- if ulceration is present, it will be of the mal perforant type vs the ischemic type;
- an ulcer that leads directly down to bone (along w/ radiographic osteolytic changes) is more indicative of infection;
- labs: w/ Charcot foot
- glucose under control and the HA1c is normal;
- normal ESR
- radiographs:
- bone/gallium scan or indium scan may help to r/o osteomyelitis, but these are usually not necessary;
- plain radiographs should be scrutinized for osteolysis which is usually not present in Charcot joints (and is more indicative of osteomyelitis);
- syphilis:
- neuropathetic phase of diabetes is a specific degeneration closely resembling neuropathic changes of late syphilis, & like diabetic gangrene, it has a prediliction for the foot;
- changes are essentially caused by the destruction of the posterior horn of the spinal cord;
- most drastic results of the trophic changes are complete collapse and distortion of the tarsometatarsal articulation;
- this may occur as a Charcot type of destruction