Chronicity of neurological features in ciguatera fish poisoning

A 43-year-old woman complained of colicky abdominal pain, followed by numbness, myalgias, and muscle weakness in the four limbs after eating a grouper (Epinepheius spp.). She presented to our hospital 36 hours later with increased myalgias, muscle weakness, and malaise. On examination, the muscle power and sensation in her four limbs appeared to be normal. She was given an intravenous infusion of mannitol 20% (200 ml over 1 hour) and an intramuscular injection of diclofenac (75 mg). Her myalgias then improved and she was discharged. She presented to our hospital again 1 week later with poor appetite, malaise, numbness of the four limbs, and increased muscle weakness. On examination, the muscle weakness was more marked in the lower limbs (4(+)/5) than in the upper limbs (5(-) /5) and proximally than distally. She also had some difficulty in getting up from a squatting position. She was given another intravenous infusion of mannitol 20% (200 ml over 1 hour), following which there was subjectively slight improvement in her muscle weakness. Her plasma creatine phosphokinase level was normal. Electromyography performed 4 weeks later revealed no abnormalities. When she was reviewed 45 days after the consumption of the grouper, her muscle weakness and malaise had improved considerably. She could then stand up from a squatting position. However, mild impairment of finger grip was still present. Chronicity of neurological features in other reported cases (e.g., chronic fatigue, relapse of symptoms after exposure to ciguateric fish or alcohol, and peripheral neuropathy) may also indicate a lengthy persistence of ciguatoxins in the body.