Internal Medicine Coding Alert

Question: The internist diagnosed an elderly patient with "Charcot foot" that requires treatment. The main cause of this condition is uncontrolled type 2 diabetes mellitus (DM), so I should code 250.00 for the diagnosis, correct?

Oregon Subscriber

Answer: To code correctly for Charcot foot, work from the bottom up. Start with the secondary diagnosis code, which would be 713.5 (Arthropathy associated with neurological disorders).

Both Charcot's arthropathy associated with diseases classifiable elsewhere and neuropathic arthritis associated with diseases classifiable elsewhere fall under code 713.5, according to the brackets following the code's description.

Then tackle the underlying disease as the primary diagnosis. Under 713.5, ICD-9 includes these three possibilities:

• tabetic [syphilitic] (094.0)

• diabetic (249.6, 250.6)

• syringomyelic (336.0).

Tip: Ask your provider to document the etiology.That way, you will avoid labeling a patient with a diagnosis like neurosyphilis if he or she does not have it.

Important: While diabetes is the most common cause [of Charcot arthropathy], there are others. Therefore, 250.00 should not be an automatic coding choice. If the diagnosis is in fact Charcot foot due to diabetes, then code 250.6x (Diabetes with neurological manifestations) before 713.5. When in doubt, ask the provider to document.

Despite an improvement in the understanding of the cause and development of diabetic foot problems in the last two decades, the current epidemic of type 2 diabetes ensures that the incidence of foot problems will continue to increase in the diabetic population.

One such problem is Charcot foot -- also known as Charcot's joint or neuropathic arthropathy -- which occurs when a joint deteriorates because of nerve damage, a common complication of diabetes.

Charcot's joint primarily affects the feet, hence the term "Charcot foot."