1) MILD TO MODERATE TOXICITY: Possible estuary-associated syndrome (PEAS) has been used to describe persons with any of the following symptoms within 2 weeks of exposure to estuarine water: intense memory loss, confusion, disorientation, limited ability to learn new information following exposure, peripheral neuropathy, headaches, acute skin burning, skin rash, eye irritation, upper respiratory irritation, muscle cramps, and gastrointestinal complaints (eg, nausea, vomiting, abdominal pain, or diarrhea). There appears to be dose-response relationship between exposure and neuropsychological clinical events. Acute effects of exposure appear to resolve within a few days to a week.
2) SEVERE TOXICITY: To date, no deaths have been associated with PEAS. The most severe effects include profound memory loss, confusion, difficulty learning new information and disorientation. These effects resolve spontaneously in 1 to 6 months.

1) Treatment is symptomatic and supportive.

1) Treatment is symptomatic and supportive. In an uncontrolled case series, cholestyramine plus sorbitol appeared to have beneficial effects in patients exposed to Pfiesteria toxin. The proposed mechanism of action was binding of the toxin in the small intestine with subsequent excretion. Neuropsychological tests may be indicated in symptomatic individuals.

1) PREHOSPITAL: Prehospital gastrointestinal decontamination is generally not recommended.
2) HOSPITAL: Consider activated charcoal if the exposure is recent, the patient is not vomiting, and is able to maintain airway. However, the utility of gastric decontamination after ingestion of contaminated material is unknown.

1) Airway management is very unlikely to be necessary.

1) None.

1) It is unknown if hemodialysis would be effective.

1) HOME CRITERIA: Most patients with mild symptoms can be managed at home.
2) OBSERVATION CRITERIA: Patients with severe gastrointestinal symptoms may need to be monitored for several hours to assess electrolyte and fluid balance. There is no evidence to suggest that asymptomatic patients are likely to develop symptoms and would benefit from observation.
3) ADMISSION CRITERIA: Patients should be admitted for severe vomiting, profuse diarrhea, severe abdominal pain, dehydration, and electrolyte abnormalities. A patient with comorbidities that put them at risk for decompensation from the symptoms of PEAS may benefit from admission for IV hydration and further support.
4) CONSULT CRITERIA: Consult a regional poison center or medical toxicologist for assistance in managing patients with severe toxicity or in whom the diagnosis is not clear.

1) Symptoms are self-limited. Missing an ingestion of a chemical (eg, heavy metal toxicity) or other possible etiologies for a patient’s symptoms. Failure to obtain adequate history of exposure.

1) In patients in whom a source of exposure can be identified, consider heavy metal toxicity. Carbon monoxide poisoning may also present with similar acute symptoms.

1) WITH POISONING/EXPOSURE

1) Upper respiratory tract irritation, including coughing and wheezing, has been reported following Pfiesteria contact (CDC, 1997; Matuszak et al, 1998; Shoemaker, 1998; Morris, 1999). Pneumonia has been reported infrequently (Samet et al, 2001).

1) WITH POISONING/EXPOSURE

1) Various neuropsychological symptoms, including confusion, disorientation, memory problems, and headache have been reported following Pfiesteria exposure. Cognitive disturbances appear to be temporary and do not last more than 2 to 3 weeks. There appears to be a dose-response relationship between exposure and neuropsychological clinical effects (Grattan et al, 2001).
2) In a retrospective study of 24 people who had contact with the Pocomoke river and other waters of the Chesapeake Bay during periods with high numbers of fish killed with Pfiesteria-like lesions, people with high exposure were significantly more likely to have neuropsychological symptoms compared to controls. These symptoms included confusion, disorientation, new or increasing forgetfulness, or difficulty concentrating (Grattan, 1998).
3) Tracy et al (1998) studied the psychological health of symptomatic fishermen exposed to Pfiesteria piscicida and unexposed matched fishermen to determine if an underlying disorder played a role in the symptomatic fishermen's complaints. The exposed fishermen had problems with memory, attention, and psychomotor speed. The study found that both groups scored similarly on a Profile of Mood States (POMS) test, indicating that there was not a preexisting, unusual incidence of mood or personality disorders in the affected fishermen.
4) In a study of 18 people with documented exposure to estuary waters with Pfiesteria or related organisms who had abnormal performances on standardized neurological tests not explained by any other cause, concentration problems, forgetfulness, prospective memory, and information overload were the most common subjective memory complaints. Exposed cases also reported feeling uneasy and confused more than controls (Grattan et al, 1998a).
5) In a review of Pfiesteria and related dinoflagellates, the authors noted design flaws in some of the Maryland studies, including non-blinding of examiners, case detection depending on neuropsychological tests alone, and no proper control group. The authors suggested that at least 1 other dinoflagellate, Cryptoperidiniopsis, may have played a role in patient symptoms (Smith & Music, 1998).
6) In a review of the events surrounding the outbreak of symptoms in Maryland in the summer of 1997, Greenberg et al (1998) concluded that the symptoms were not consistent with that of a mass psychogenic illness.
7) CASE SERIES - Glasgow et al (1995) presented 3 cases in which scientists working with cultures of Pfiesteria or handling fish exposed to Pfiesteria developed neuropsychological symptoms. Symptoms included difficulty concentrating, disorientation, poor memory, depersonalization, irritability, loss of judgment, and personality changes (Glasgow et al, 1995).
8) Based upon case reports of neurologic deficits from fishermen in Maryland, 3 case reports of scientists exposed to Pfiesteria, and preliminary results of PET scans of a group of symptomatic Maryland cases, Bever et al (1998) suggested that the symptoms were consistent with a limited encephalopathy, possibly involving the inferior frontal and temporal cerebral regions.
9) In a review of symptomatic persons calling the Maryland Pfiesteria Hotline, low Rey Auditory Verbal Learning Test (RAVLT) scores were correlated with Pfiesteria associated illness. This test is a standardized word list learning task (Golub et al, 1998).
10) DURATION - In a review of Pfiesteria-associated illness, Grattan (1998) stated that memory and cognitive disturbances seemed to improve gradually over 3 to 6 months (Grattan, 1998).

1) In a retrospective study of 24 people who had contact with the Pocomoke river and other waters of the Chesapeake Bay during periods with high numbers of fish killed with Pfiesteria-like lesions, people with high exposure were significantly more likely to have headache compared to controls (Grattan, 1998).

1) CASE REPORT - A laboratory worker experienced acute onset of numbness and tingling of the hands and feet and difficulty walking after working with dilute cultures of Pfiesteria piscicida. The symptoms resolved over a 1 to 2 year period (Glasgow et al, 1995).

1) MENTAL STATUS CHANGES

1) Nausea, vomiting, and abdominal cramps have been reported following exposure to Pfiesteria (Samet et al, 2001; CDC, 1997; Matuszak et al, 1998; Glasgow et al, 1995).
2) CASE REPORTS - A 23-year-old man and a 30-year old woman who were in the water 500 yards downstream of a Pfiesteria fish kill experienced abrupt onset headache and nausea. The woman also had diarrhea and cramping abdominal pain (Shoemaker, 1997).

1) WITH POISONING/EXPOSURE

1) Skin rashes or skin lesions have been observed with Pfiesteria contact (Samet et al, 2001; CDC, 1997; Shoemaker, 1997; Morris, 1999).

1) Skin complaints are relatively common following exposure and may include itching, red bumps or sores, and scaling flat regions (Grattan et al, 2001; Samet et al, 2001).
2) A scientist developed skin lesions on the hands and arms, with pustular blisters, after handling dilute concentrations of Pfiesteria (Glasgow et al, 1995).
3) In a retrospective study of 24 people who had contact with the Pocomoke river and other waters of the Chesapeake Bay during periods with high numbers of fish killed with Pfiesteria-like lesions, people with high exposure reported significantly more skin lesions and a burning sensation on the skin compared to controls (Grattan, 1998).
4) In 13 patients exposed to Pfiesteria on the Pocomoke river during 1997, 9 reported an intense cutaneous burning sensation on contact with the water, with 7 patients developing skin lesions. The authors suggested that many of the skin findings were unrelated to Pfiesteria. However, unexplained skin reactions possibly related to Pfiesteria included edematous, erythematous, or skin-colored papules on the trunk or extremities. Histopathologic examination indicated an inflammatory, toxic, or allergic process. The skin reactions improved within 2 to 4 weeks (Grattan, 1998).
5) In a review of Pfiesteria, the authors suggested that many of the reported skin lesions may have been attributable to bacteria and other organisms known to cause human skin problems. Further studies were suggested to validate claims of human cell necrosis due to Pfiesteria (Smith & Music, 1998).
6) In a North Carolina study, 252 crabbers working in waterways affected by Pfiesteria or related organisms were compared to 114 crabbers working in a non-affected area and 125 controls (non-fishermen in the community). The 3 groups were similar except for an increased incidence of skin disorders among crabbers in both Pfiesteria-affected and non-affected waterways, indicating a possible occupational hazard of crab fishing rather than Pfiesteria exposure (Rullan & Jenkins, 1998).

1) Muscle and leg cramping have been observed following exposure to Pfiesteria (Samet et al, 2001; CDC, 1997; Matuszak et al, 1998)

1) WITH POISONING/EXPOSURE

1) NEUROPSYCHOLOGICAL ASSESSMENT
2) VISUAL CONTRAST SENSITIVITY TESTS

A) Patients should be admitted for severe vomiting, profuse diarrhea, severe abdominal pain, dehydration, and electrolyte abnormalities. A patient with comorbidities that put them at risk for decompensation from the symptoms of PEAS may benefit from admission for IV hydration and further support.

A) Most patients with mild symptoms can be managed at home.

A) Consult a regional poison center or medical toxicologist for assistance in managing patients with severe toxicity or in whom the diagnosis is not clear.

A) Patients with severe gastrointestinal symptoms may need to be monitored for several hours to assess electrolyte and fluid balance. There is no evidence to suggest that asymptomatic patients are likely to develop symptoms and would benefit from observation.

1) The portal of entry of Pfiesteria piscicida or related dinoflagellates is unknown. Consider activated charcoal if the exposure is recent, the patient is not vomiting, and is able to maintain airway. However, the utility of gastric decontamination after ingestion of contaminated material is unknown.

1) CHARCOAL ADMINISTRATION
2) CHARCOAL DOSE

1) MANAGEMENT OF MILD TO MODERATE TOXICITY
2) MANAGEMENT OF SEVERE TOXICITY

1) No specific laboratory tests are necessary unless otherwise clinically indicated.
2) Monitor serum electrolytes in patients with significant vomiting and/or diarrhea.
3) Monitor mental status in symptomatic patients. Neuropsychological tests may be indicated in symptomatic individuals exposed to Pfiesteria toxin.
4) Exposure criteria and clinical criteria for evaluating adverse events associated with Pfiesteria piscicida and related organisms have been defined by a multistate CDC sponsored workshop (CDC, 1997; Matuszak et al, 1998).
5) Exposure criteria are defined as exposure to estuarine water characterized by any of the following:
6) The clinical criteria defining Estuary Associated Syndrome include any of the following (CDC, 1997):

1) In an uncontrolled case series, cholestyramine plus sorbitol appeared to have beneficial effects in patients exposed to Pfiesteria toxin. The proposed mechanism of action was binding of the toxin in the small intestine with subsequent excretion (Shoemaker, 1998). Further studies are necessary to determine the role of cholestyramine in treatment of Pfiesteria-related illness.