A 50-year-old man with insulin dependent diabetes presents

A 50-year-old man with insulin dependent diabetes presents with a two week history of an acutely
painful, erythematosus, swollen left mid-foot for the last two weeks. He does not drink alcohol, and
has had no recent injuries to the foot.
On examination, the mid-foot is warm. Pedal pulses are intact. There is sensory loss in a glove and
stocking distribution bilaterally. Recent blood tests show a normal FBC, CRP, urea, and electrolytes
and creatinine.
Which of the following is the most likely diagnosis?

Charcot joint  This is the correct answer
Deep venous thrombosis
Fragility fracture

In patients with longstanding diabetes and peripheral neuropathy, a red hot swollen foot should raise
suspicion of Charcot neuroarthropathy.
Charcot neuropathy presents as a warm, swollen, erythematous foot and ankle, and infection is
important to exclude. The majority of patients are in their 50-60s, and they often present in the latter
stages of the disease.
It can occur in association with a variety of conditions, including leprosy, poliomyelitis, and
rheumatoid arthritis, although today the most common cause is diabetes mellitus.
The pathophysiology of Charcot neuroarthropathy is not completely understood, but is thought to start
with peripheral neuropathy. The lack of pain sensation may mean that patients subject the foot joints
(commonly the midfoot) to stress injuries that lead to the Charcot process. It is important to note
however that about half of patients present with pain.
Four stages of Charcot neuropathy are recognised:
Stage 0 (inflammation) - characterised by erythema and oedema, but no structural changes
Stage 1 (development) - bone resorption, fragmentation and joint dislocation. Swelling, warmth
and erythema persist but there are also radiographic changes such as debris formation at the
articular margins, osseous fragmentation, and joint disruption
Stage 2 (coalescence) - bony consolidation, osteosclerosis, and fusion are all seen on plain
Stage 3 (reconstruction) - osteogenesis, decreased osteosclerosis, progressive fusion. Healing
and new bone formation occur, and the deformity becomes permanent.
Radiographs are an important part of investigating a patient with possible Charcot arthropathy. All
radiographs should be taken in the weight-bearing position.
MRI can demonstrate changes in the earlier stages of the condition, and is therefore important in
allowing treatment to be instigated earlier.
In stages 0 and 1, the treatment is immediate immobilisation and avoidance of weight bearing. A
total-contact cast is worn until the redness, swelling and heat subside (generally 8-12 weeks,
changed every 1-2 weeks to minimise skin damage). After this, the patient should use a removable
brace for a total of four to six months.
Bisphosphonates can be used, but evidence of clinical benefit is lacking. Surgery is reserved for
severe deformities that are susceptible to ulceration, and where braces and orthotic devices are
difficult to use.
A normal FBC and CRP in this case make cellulitis unlikely. There is no swelling of the calf to suggest
a deep vein thrombosis.
Fragility fractures are those which are caused by a force equivalent to a fall from the height of a chair
or less. They are typically seen on a background of osteoporosis and there is usually a history of
Gout classically causes an acute monoarthritis and the presentation is typically more acute than
described here.
Botek G, et al. Charcot neuroarthropathy: An often overlooked complication of diabetes. Cleve Clin J