Scombroid Fish Poisoning

Agents: Toxic decomposition metabolites collectively called scombrotoxins; the scombro-toxins are not bioaccumulated dinoglagellate or diatom exotoxins.

Toxins: Scombrotoxins = histamine and its primary N-methylhistamine metabolite, saurine. LD50: No known human fatalities. Mechanism: Scombrotoxins form during gut bacteria-catalyzed, normothermic decarbox-ylation (Proteus, Klebsiella, Lactobacillus, E. coli, Enterobacter species) of muscle L-histidine in decomposing finfish dangling on commercial long lines or in underrefrigerated ship holes. Vectors: Paradoxically, non-scombroid fish are the most common food vectors of scombroid poisoning (amberjack, bonito, bluefish, mahi mahi, anchovies, sardines, herrings) > scom-broid fish (albacore, cobia, tuna, mackerel, wahoo).

Incubation: Minutes to 3-4 hours. Symptoms: Sudden warm facial flushing and "sunburn-like" rash, metallic-peppery taste, perioral burning and blistering sensations; then urticaria, pruritus, bronchospasm, palpitations, tachycardia, hypotension; fewer gastrointestinal symptoms of abdominal cramps, nausea, vomiting, and diarrhea.

Diagnosis: Histidine-to-histamine spot indicator tests, thin-layer chromatography (TLC), gas chromatography/mass spectrometry, high serum and urine histamine and saurine levels. Treatment: Severe poisoning—gastric emptying, then AC gut decontamination; otherwise, Hj-and H2-blockers, P-agonists for bronchospasm with wheezing, and consider corticosteroids for allergic bronchospasm and urticaria/pruritus. Prognosis: Symptoms resolve in 12-24 hours even without treatment.

Prevention: Patients on isoniazid (INH), a gastrointestinal histaminase inhibitor, are at increased risk; avoid nonrefrigerated and spoiling (pale gills) deep-sea fish; avoid seafood with histamine levels >50 mg/100 mg fish (FDA); regulate long-line fishing; require mandatory cold-chain (0°C) for all seafood from harvest until cooking/consumption.

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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