T61.11XD Scombroid fish poisoning, accidental (unintentional), subsequent encounter

Name of the Condition

• Common Name(s): Scombroid Fish Poisoning, Histamine Fish Poisoning
• Technical Terms: Scombroid Fish Poisoning, Accidental (Unintentional), Subsequent Encounter

Summary

Scombroid fish poisoning is a foodborne illness resulting from consuming fish with elevated histamine levels. This condition typically arises from improper handling or storage of certain fish species, leading to bacterial growth and histamine production. Symptoms usually appear within minutes to hours after ingestion and may mimic allergic reactions. The "subsequent encounter" designation indicates this is a follow-up visit for a previously diagnosed case.

Causes

The primary cause is consuming fish that has not been properly refrigerated or stored, allowing bacteria to convert histidine into histamine. Fish species prone to this include tuna, mackerel, mahi-mahi, and other dark-meat fish. Cooking or freezing does not reduce histamine levels, so contamination persists even after preparation.

Risk Factors

• Eating fish from unrefrigerated or poorly stored sources.
• Consumption of fish with high histidine content (e.g., tuna, mackerel).
• Inadequate food safety practices during handling or storage.
• Purchasing fish from unregulated or unverified suppliers.

Symptoms

• Gastrointestinal: Nausea, vomiting, diarrhea, abdominal cramps.
• Neurological: Headache, flushing, dizziness, palpitations.
• Dermatological: Urticaria (hives), itching, facial swelling.
• Respiratory: Wheezing or difficulty breathing (rare).

Diagnosis

Diagnosis is primarily clinical, based on a history of fish consumption and characteristic symptoms. Laboratory tests may confirm elevated histamine levels in leftover fish or patient samples, though this is not always necessary. Differentiation from allergic reactions or other foodborne illnesses may be required.

Treatment Options

Treatment focuses on symptom management, including antihistamines for mild cases. Severe symptoms may require supportive care, such as intravenous fluids or medications for respiratory distress. Most cases resolve within 24 hours with appropriate care.

Prognosis and Follow-Up

Prognosis is generally good, with most patients recovering fully within a day or two. Follow-up care may be needed for persistent symptoms or complications. Subsequent encounters (as indicated by the "subsequent encounter" code) suggest ongoing monitoring or management of residual effects.

Complications

Rare complications include severe respiratory distress, hypotension, or prolonged neurological symptoms. These are more likely in individuals with pre-existing conditions or severe exposure.

Lifestyle & Prevention

• Ensure proper refrigeration and storage of fish (below 40°F or 4°C).
• Consume fish promptly after purchase or preparation.
• Avoid fish with a strong, peppery, or "off" odor, which may indicate histamine formation.
• Practice good food safety hygiene during handling and cooking.

When to Seek Professional Help

Seek medical attention if symptoms are severe (e.g., difficulty breathing, dizziness, or widespread hives) or if they persist beyond 24 hours. Immediate care is recommended for signs of anaphylaxis or respiratory distress.

Tips for Medical Coders

Use T61.11XD for subsequent encounters of accidental (unintentional) scombroid fish poisoning. Document the encounter type (subsequent) and confirm the condition was previously diagnosed. Ensure clinical notes support the follow-up nature of the visit and any ongoing management of symptoms.