Primary Care Coding Alert

Question: Recently, we have had patients present with reactions to red tide. They come in coughing, sneezing and with watery eyes. We have been coding the encounters with E/M office visit codes, but how should we code the diagnoses?

Florida Subscriber

Answer: Red tide is a naturally occurring, higher-than-normal concentration of the microscopic algae Karinia brevis. It produces a toxin that paralyzes fish so they cannot breathe. Red tide occurs mainly in the Gulf of Mexico, and when it blows close to shore, not only are fish affected but humans in coastal towns also breathe in the toxin. People exposed to red tide may develop a variety of upper respiratory problems, such as shortness of breath, coughing, runny nose and watery eyes. When a patient presents with reactions to red tide, you should report the symptoms. For example, if a patient comes in with shortness of breath and eye irritation, use 786.05 (Shortness of breath) and 379.93 (Redness or discharge of eye). In addition, code E905.7 (Poisoning and toxic reactions caused by other plants) to account for the definitive diagnosis.

Patients who have pre-existing conditions, such as asthma or emphysema, are most affected by red tide. Red tide causes swelling in the airways, similar to the effects of tobacco smoke, exacerbating respiratory conditions. For patients whose chronic conditions are aggravated by red tide, use the diagnosis code indicating exacerbation. For example, a patient with asthma who spent a day at the beach during a period of red tide presents wheezing. Code 493.02 (Extrinsic asthma, with acute exacerbation). The fifth-digit classification of 2 represents the exacerbation of the chronic condition. You should also use 786.07 (Wheezing) and E905.7 as secondary diagnosis codes.

Shellfish, such as oysters, clams and mussels, can accumulate red tide toxins in their tissues. People who eat shellfish containing the toxins may become seriously ill with neurotoxic shellfish poisoning, a common reaction even without red tide for some patients. If your family practitioner treats patients with this condition, you should use 988.0 (Toxic effect of noxious substances eaten as food; fish and shellfish). Report the symptoms as secondary, for example 789.00 (Abdominal pain, unspecified site).