Scombroid poisoning

 A 32 year old woman presents with a severe, sudden onset of throbbing headache, facial flushing and a rash across the upper chest and back. She has also had one episode of loose bowel motion.

When seen she is anxious and tachycardic. She has no past medical history.

30 minutes prior to her symptoms she was eating at a restaurant with her family. She had ordered a tuna sandwich and states that it tasted a little too peppery for her liking but it was otherwise OK and so she continued to eat it. “The minute I had it, I knew something was wrong.”

Well we can go down the road of sudden headaches etc as I was thinking, but what is this diagnosis?

Yes, it’s scombroid.

The disease gets its name from Scombroidea fish – these are large dark fleshed fish such as tuna, however the condition is caused by more types of fish than this.

WHAT ARE THE SYMPTOMS AND SIGNS?

-Flushing of the face, upper chest and back

-Headache

-Anxiety

-Tachycardia

-Hyper/hypotension

-Abdominal pain and diarrhoea

WHAT CAUSES THE SYMPTOMS?

Symptoms are caused by the ingestion of histamine, which is produced by decarboxylation of histadine by bacteria. Cooking does not deactivate this ‘toxin’.

Symtoms occur within 30 minutes of ingestion of fish. Not all individuals will experience the same symptoms. This is related to portion eaten, if from the same fish, and the individual predisposition to histamine related symptomatology.

In very rare cases, there is bronchospasm and even myocardial ischaemia.

Interestingly, the taste may be described as peppery.

INVESTIGATIONS

There are really no investigations needed. Both serum and urinary histamine is elevated in individuals, however this is a clinical diagnosis.

An ECG is helpful especially in the elderly who may be experiencing tachycardia and have ischaemic heart disease.

MANAGEMENT

The disease is usually self limiting. Supportive treatment and the use of antihistamines H1 and H2 blockers.

There may be a place for charcoal early in the presentation and if symptoms are severe and if large quantities of fish have been consumed.

So watch that dark fleshed fish.