CME INDIA Presentation by Dr. Ashu Rastogi, MD, DM(Endocrinology), FACE, FRCP (Edin), Faculty, Dept. Of Endocrinology, PGIMER, Chandigarh, India.
Based on a presentation at Diabetica, RSSDI-Gujrat, Ahmedabad on 20-05-2023.

What could be the possible etiology?


Addressing the pathophysiology of Charcot

53-yr-old gentleman, type-2 diabetes for 9 years came with swelling of right foot for 12 weeks.

What is the possible diagnosis?
- Cellulitis.
- Osteomyelitis.
- Gouty arthritis.
- Charcot’s foot.
- Traumatic fracture.
Is it Vanishing Bone Disease?
Lesson No 1 – Unilateral foot oedema and warmth in diabetic patient is strong predictor of early acute Charcot foot. |
Lesson No 2 – Every Diabetic Foot Swelling isn’t Infection! |

Outcome

Another case
- 43-yr-old lady.
- T2DM for 6 yrs., on OADs.
- Swelling and progressive deformity of left foot for 1 year.
- History of swelling and redness of same foot 1 year prior.
- Had been treated with varying course of antibiotics.

Mid-foot involvement Sequelae of Charcot foot.
Pes planus.


Here is Concurrent Wrist and Mid foot Charcot Neuroarthropathy

Why Imaging is required?
- Active Charcot is essentially a Clinical Diagnosis.
Temperature difference between feet (>2C) is sine-quo-non
- Varied presentation.
- Non-specific symptoms.
- Clinically Innocuous and Surprise on radiograph.
- Common Differentials:
- Cellulitis.
- Gout.
- Deep Vein Thrombosis.
- Tubercular Rheumatism.
- Osteomyelitis.
Imaging: Conventional Radiography

- Bilateral Foot Radiograph Weight Bearing.
- Views:
- Dorsoplantar.
- Lateral.
- Pronated oblique views.
- Can be normal in early stages
- Anatomical classifications:
- Eichenholtz (Fragmentation, Coalescence, Reconstruction).
- Sanders & Frykberg (5 types).
- Brodsky (5 types).
Anatomical classification

Plane Radiography
Acute CN:
- Flattening of the metatarsal head is 1st sign.
- Also, early finding is focal demineralization.
- Strong indicators of neuroarthropathy on radiograph:
- Absence of soft tissue involvement.
- Polyarticular distribution.
- Subchondral or periarticular changes in the midfoot.
- Involvement of the IP joints and ankle less common.
- Chronic CN: Rule of ‘‘6 D’s’’
- Distension of joints.
- Destruction.
- Dislocation.
- Disorganization.
- Debris.
- Density increase (sclerosis).
- Midfoot or tarsometatarsal (Lisfranc) typically affected.
- Collapse of the longitudinal arch.
- Increased load on cuboid, causing a rocker bottom deformity.

Limitations of Plane Radiographs
- Subtle changes such as occult fractures, bone marrow oedema not detected.
- Low sensitivity and specificity rates (< 50%) in detection of early findings of CN.
- May be normal in early CN.
Do all patients require MRI scan?
- If Plain X-ray is normal and strong suspicion of active Charcot.
- Overlying ulcer for better soft tissue details.
- Differentiate DFO with Charcot.
- Follow-up for remission.
Osteomyelitis: |
Low focal signal intensity on T1- weighted images |
High focal signal on T2-weighted images |
High bone marrow signal in short tau inversion Recovery (STIR) sequences |
Less specific or secondary changes: Cortical disruption adjacent cutaneous ulcerSoft-tissue massSinus tract formationAdjacent soft- tissue inflammation or oedema |
Charcot neuro-osteoarthropathy |
Altered bone marrow signal manifested by low signal intensity in the subchondral bone on both T1 and T2 weighted images. |
Signal intensity abnormalities demonstrated by osteosclerosis and cyst like lesion. |
Cortical fragmentation. |
Joint deformity or subluxation. |
Bone marrow oedema pattern: Tends to be periarticular and subchondral. |
Predominant midfoot involvement. |
Overlying skin is usually intact but may be oedematous. |
MRI Characteristics

- Acute CN:
- Soft tissue edema.
- Joint effusions.
- Subchondral bone marrow edema.
- Disruption of Lisfranc ligament.
- Malalignment and collapse of the longitudinal arch.
- Bone marrow edema: Low signal intensity on T1W and high signal intensity on T2W images.
- Bone-marrow enhancement predominantly in the subchondral region on Gd -enhanced studies.
When do we need nuclear scans?
Not Required Routinely
- Skin is ulcerated as a result of Charcot deformity.
- Secondary osteomyelitis is a possible complication.
- Follow-up for quiescence of Active CN.
- What kind of nuclear scan are useful?
- Tc99m-MDP three phase bone scans.
- WBC labelled bone scan.
- F18 PET/CT.
- F18 WBC- PET/CT.
- Labelled WBC scan to differentiate DFO and CN.
What to inform the radiologist?
- Use a fluid sensitive sequence (e.g., STIR) for assessing edema in the bone marrow and soft tissue.
- A classic T1 TSE (turbo spin-echo) sequence for:
- Anatomy.
- Fat signal of the bone marrow.
- T2-weighted sequences can demonstrate:
- Subchondral cysts.
- Fluid collections.
- Sinus tracts.
How to Stop Acute Charcot?

How to recognize remission in active CN?


How long to continue offloading with TCC?
- Till remission of active phase of Charcot.
- Shift the patient from non-walking TCC to CROW boot or modified footwear.
How to recognize remission?
- Temperature difference between two foot is <20C for 4 weeks.
- Other markers.
- Bone turnover markers.
- MRI signal intensity changes.
- PET CT SUV.
What happens after remission of Charcot?
Effect on BMD as per Sinacore DR et al. Phys Ther 2008
- BMD was 13% greater in controls than diabetes with neuropathy.
- BMD was 16% lower in the charcot foot.

Survival in People with Charcot Foot
- (Chaudhary S, Rastogi A. Acta Diabetologica 2019)
- 15.0% with CN and 9.8% (p=0.03) individuals without CN died.
- Mean survival in CN was 4.49 years compared to 4.78 years (p<0.01) without CN.
- Unadjusted OR=1.62 (CI, 1.03-2.5; p=0.03).
- Adjusted OR=2.72 (CI, 1.4-5.2; p=0.003).
- CN is associated with a higher mortality compared to people with diabetes without CN.
- Despite being younger, CN patients have a higher prevalence of microvascular complications.
Other Considerations
- Teriparatide increases foot bone remodelling by an osteoanabolic action in people with CN.
- Data are too weak to support the use of bisphosphonates as a routine treatment for acute Charcot neuroarthropathy.
Quick Take-Aways
TCC is the gold standard for acute CN. |
Bisphosphonates increase BMD but effect on clinical resolution? |
Danosumab is another option for acute CN (CKD). |
Chronic CN is associated with decreased BMD of foot. |
Teriparatide may be useful for chronic CN. |
CN patients need close follow up in view of higher mortality. |
- Offloading is the gold standard strategy that could arrest the progression of deformity.
- Data are too weak to support the use of bisphosphonates as a routine treatment for acute Charcot neuroarthropathy.
CME INDIA Learning Points (By Dr. Ashu Rastogi)
- Charcot Foot is essentially a clinical diagnosis.
- Radiology supports the diagnosis when strong index of suspicion.
- Plane radiograph may be normal in acute CN.
- Anatomical classification
- MRI useful for:
- Early detection of acute CN.
- Better soft tissue details.
- Differentiating osteomyelitis.
- Follow up for Quiescence.
- PET scan (Limited Role):
- Differentiate OM in complicated cases.
- Better marker of remission.
CME INDIA Tail-Piece
- The Charcot foot has been first described in 1868 by Jean-Martin Charcot.
- His early investigations into the tabetic arthropathies (1868) led to brilliant presentation, Demonstration of Arthropathic Affections of Locomotor Ataxy, at the 7th International Medical Congress (1881).
- He established this disease as a distinct pathological entity.
- Charcot and Féré published the first observations of the tabetic foot (Pied tabétique) in the Archives de Neurologie in 1883.
- It was not until 1936, however, that W. R. Jordan established the association between neurogenic arthropathy of the foot/ankle and diabetes mellitus.
- The detailed pathomechanisms of this disease still remain unclear.
- It is said that the cause is multifactorial and that polyneuropathy (reduced pain sensation and proprioception) is the underlying basic condition of this disease.
- Diabetes mellitus is the main cause of polyneuropathy in the lower limb much more common than other causes like alcohol abuse or malnutrition.
References:
- Vanishing Bone Disease.Rastogi A, Bhansali A.Post Graduate Med Journal 2016; doi: 10.1136/postgradmedj-2016-134183
- Rastogi, Ashu & Prakash, Mahesh & Bhansali, Anil. (2018). Varied presentations and outcomes of Charcot neuroarthropathy in patients with diabetes mellitus. International Journal of Diabetes in Developing Countries. 39. 10.1007/s13410-018-0700-8.
- Rastogi A, Hajela A, Prakash M, Khandelwal N, Kumar R, Bhattacharya A, Mittal BR, Bhansali A, Armstrong DG. Teriparatide (recombinant human parathyroid hormone [1-34]) increases foot bone remodeling in diabetic chronic Charcot neuroarthropathy: a randomized double-blind placebo-controlled study. J Diabetes. 2019 Sep;11(9):703-710. doi: 10.1111/1753-0407.12902. Epub 2019 Feb 13. PMID: 30632290.
- Sanders LJ. The Charcot foot: historical perspective 1827-2003. Diabetes Metab Res Rev. 2004 May-Jun;20 Suppl 1:S4-8. doi: 10.1002/dmrr.451. PMID: 15150805.
- Rosskopf, A.B., Loupatatzis, C., Pfirrmann, C.W.A. et al. The Charcot foot: a pictorial review. Insights Imaging 10, 77 (2019). https://doi.org/10.1186/s13244-019-0768-9

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Excellent presentation, very informative & practical tips…. Heart full Thanks to Dr Ashu Rastogi for such a wonderful presentation on forgotten & not so well understood topic
Very well presented. Thanks for giving these details.