Problems for Discussion - 4 - Marine Creatures

• Understand how marine envenomation occurs.
• Detail how nematocysts discharge.
• Compare the toxicity of organisms in the phylum Cnidaria.
• Detail the toxicity of marine organisms.
• Understand the first aid required for marine envenomation and the current controversy over the approach to jellyfish stings.
• Detail the management of marine envenomation including the indication for antivenom, where available.

A 35-year-old, previously well, male was scuba-diving on a coral reef with a companion. He knelt on large piece of coral to take a photograph when he felt a scratch on his knee. Ten minutes later he surfaced and complained of feeling strange and said his tongue and mouth felt ‘frozen’. He found it difficult to focus on objects and felt weak in the legs. He and his companion went to a beach-side hotel and starting drinking a beer. He found he was unable to swallow and then collapsed to the floor unable to move his legs. An ambulance was called.

1. What is the differential diagnosis?
2. What is the likely progression?
3. What assessment is required?
4. What treatment is required?
5. What is the potential prognosis?

A 13-year-old boy was swimming at a closed beach near Cairns in January when he suddenly screamed and ran from the water. He collapsed on the beach. His legs and lower abdomen were covered in multiple brown lines with sounding erythema. What appeared to be jellyfish tentacles were adherent to his legs. He is unresponsive, has shallow breathing and a weak rapid pulse.

1. What marine organisms could be responsible for this envenomation?
2. What first aid is required?
3. How should the tentacles be removed? Is vinegar indicated; if so where could it be obtained?
   An ambulance arrives as the boy stops breathing. No pulse is palpable.
4. What treatment is indicated?
5. The ambulance is a paramedic car. What medication should be administered and by what route?
   The patient arrives at the local hospital. He is being ventilated and has a pulse of 120/min. and a BP of 80/50.
6. What further management is required?

A 53-year-old male is stung on the index finger by his pet lionfish while cleaning its aquarium. He presents to the Emergency Department 30 minutes later. He is greatly distressed with severe pain and is vomiting. There is a puncture wound on his index finger which is surrounded by a bluish discoloration and swelling. The axillary lymph nodes of that limb are swollen and tender.

1. What treatment is indicated?
2. What options are there for controlling the patient’s severe pain?
3. What is the likely time course of this envenomation?
4. This is the second time the patient has been stung by his pet lionfish. What advice do you give him?

A 67-year-old male was fishing in the shallow of a sheltered beach when he trod on what he presumed to be a stingray. He felt an impact to the right lower leg. Looking down he saw the ray swim away and bleeding from a wound on his leg. Immediately, he felt a searing pain in his leg. He stumbled to shore, the wound still bleeding profusely.

1. What first aid is indicated?
2. Should the patient go to hospital? Why?
   Over the next 20 minutes the pain extended up to the hip. The pain was made worse by any movement. >He presents to hospital requesting analgaesia. He appears pale. His pulse rate is 50/min and BP 120/70. A ragged puncture wound on the lower leg is noted. It continues to bleed profusely. Muscle belly is exposed.
3. What do you recommend for pain relief?
4. How should the wound be managed?
5. What complications may occur?

• To be able to differentiate between the common seafood poisonings: Ciguatera, Paralytic shellfish poisoning, Tetrodotoxin and Scombroid.
• Explain the basis of ‘temperature inversion’ reported for Ciguatera poisoning.
• Detail the first aid and management for common seafood poisons.
• Critique the specific therapies and recommendation for Ciguatera poisoning.
• Outline the steps that should be undertaken to avoid seafood poisoning.

A 50-year-old Fijian man presented to the Emergency Department (ED) two days after ingestion of prawns, oysters and ‘bati’ or red bass (Lutjanus bohar). He developed symptoms within 24 hours of ingestion and complained of lethargy, generalised myalgia, and a burning sensation when he washed his hands in cold water. He had no gastrointestinal symptoms. Physical exam was normal with no focal neurological signs. Heart rate was 66/min and blood pressure 130/90. On diagnosing fish poisoning, he was given 40g (200mL of 20%) mannitol as a slow intravenous infusion over 30 minutes. All his symptoms disappeared, except for slight tingling when washing his hands.

On subsequent review 3 days later, the patient described ongoing paraesthesia of lips tongue, hands and feet, lower back pain, headache, and lumbar pruritus. At this stage a further dose of intravenous mannitol of 50 gm was given over half an hour. During the subsequent hour, the patient declared that his pain and neurosensory symptoms were completely relieved. He was reviewed in the ED two days later and complained of a return of his symptoms 6 hours following mannitol administration. Although ibuprofen was giving him adequate temporary relief of pain, he described persistent lethargy and pruritus.

1. What is the possible diagnosis?
2. What treatment should the patient get?
3. What advice should he be given?
4. Which seafood is the likely culprit and where could it have come from?
5. What are the possible mechanisms for the response to mannitol?

A 51-year-old female with a history of migraine headaches but no known food allergies ate a tuna salad and drank bottled orange juice, both purchased at a coffee shop, after an exercise session. Within 30 minutes a ‘throbbing’ headache, more severe than her usual migraines, developed along with nausea, palpitations and a feeling of impending doom. No vomiting, diarrhea or abdominal pain occurred. Her only medication was paracetamol for migraines. Over the next 30 minutes her symptoms intensified and her face became flushed: both cheeks, as well as her forehead, chin and neck were erythaematous. Her pulse rate was 90 (usually 50) beats/min and her blood pressure 190/105 (usually 125/85) mm Hg.

She was transferred to a local emergency department, where her pulse rate was 100 beats/min and her blood pressure 200/120 mm Hg. The emergency physician initially looked to rule out neurologic problems and intracranial bleeding: the results of neurologic examination and computed tomography (CT) of the head were normal. A CT scan of the abdomen, ordered to rule out an adrenal mass, was also normal. A complete blood count and serum electrolyte levels were within normal limits, as were serum creatinine and calcium levels.

(Predy G, Honish L, Hohn W, Jones S. Was it something she ate? Can Med Assoc J, 2003; 168: 587)

1. What is the likely diagnosis?
2. How can this diagnosis be confirmed?
3. What treatment should be administered?
4. What are the criteria for discharging this patient?
5. What other action is required?

An immigrant family of 5 adults present to the local Emergency Department. They fell sick after consuming a fish stew made with fish they had caught themselves. Thirty (30) minutes after ingestion they all experienced peri-oral parasthaesias and nausea. Three people then vomited. Four of the five experienced peripheral parasthaesias and unsteadiness on walking. One of these was unable to walk, complaining of weakness in the legs. This patient had consumed the largest serve of the fish stew. On examination she had 2/5 weakness in the legs and 4/5 weakness in the arms. Cranial nerves were normal to examine.

1. What should be done for further assessment of these patients?
2. What is the likely diagnosis?
3. What is the potential clinical course?
4. What treatment should be administered?
5. What are the criteria for discharging these patients?