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612 S P E C I A LT Y P R A C T I C E I N C R I T I C A L C A R E

TABLE 22.12 Symptoms of Ciguatera 174

Gastrointestinal Neurological Cardiovascular Other symptoms
Abdominal pain Paraesthesias in extremities and around Bradycardia Dermatitis, rash, arthralgia and myalgia,
Nausea the mouth, tingling, burning, and pain Tachycardia general weakness, salivation, dyspnoea,
Vomiting Painful extremities Hypotension neck stiffness, headache, ataxia,
Diarrhoea Paradoxical temperature reversal where Hypertension sweating, metallic taste in the mouth
hot feels cold and cold feels hot Arrhythmia
Temperature sensitivity
Vertigo
Dental pain where teeth feel loose
Blurred vision
Tremor

NEAR-DROWNING medical conditions predispose a person to drowning and
DESCRIPTION AND INCIDENCE should be considered during management, including sei-
zures, arrhythmia (especially torsades de pointes associ-
Submersion incidents are frequent preventable events ated with long Q–T interval), coronary artery disease,
associated with significant mortality and morbidity, often depression, cardiomyopathy (dilated or hypertrophic
necessitating an ED presentation and subsequent hospi- obstructive), hypoglycaemia, hypothermia, intoxication
tal admission. In Australia, drowning is a relatively or trauma. 190
uncommon death (<1% of all reported deaths), but this Pulmonary manifestations after aspiration of fresh or salt
is significantly higher for children under 5 years (4.6 per water differ, as fresh water is hypotonic and when aspi-
100,000 population); 22% of all drowning deaths (over rated moves quickly into the microcirculation across
three times the adult rate). A higher incidence is seen in the alveolar–capillary membrane. With fresh water
males compared to females and a bimodal distribution aspiration, surfactant is destroyed, producing alveolar
of deaths is seen, with a peak in the toddler age group instability, atelectasis and decreased lung compliance
(0–4 years) and a second peak in young adolescent males and resulting in marked V/Q mismatching 185,186,190 (see
(15–19 years). 185-189 Chapter 13). In contrast, salt water has 3–4 times the
When near-drowning rates are added to drowning deaths, osmolality of blood, and when aspirated draws damaging
190
the incidence climbs to 24.5 per 100,000 population. protein-rich fluid from the plasma into the alveoli, result-
It is estimated that for every drowning death there are ing in both interstitial and alveoli oedema, with associ-
4–5 near-drowning hospital admissions and 14 ED ated bronchospasm and subsequent shunting and V/Q
presentations. 185-187 Near-drowning is also associated with mismatch. 185,186,190
high-impact injuries, especially boating or personal Despite these different physiological effects from aspi-
watercraft incidents and shallow-diving-related injuries. rated fresh and salt water, the resulting clinical manifesta-
Associated cervical spine injury is seen in 0.5% of near- tion is the same: profound hypoxaemia secondary to V/Q
drowning cases. 185 mismatch with intrapulmonary shunting (see Figure
CLINICAL MANIFESTATIONS 22.2). 185,186,190 Patients with evidence of fluid aspiration
The sequence of events in drowning has been identified often progress to develop severe ARDS within a very short
185
primarily by animal studies, highlighting an initial phase time. No significant effects on electrolytes are noted in
of panic struggling, some swimming movements and humans, as rarely more than 10 mL/kg and commonly
sometimes a surprise inhalation. There may be aspiration no more than 4 mL/kg of water is aspirated, while clini-
of small amounts of water at this time that produces cally significant electrolyte disturbances occur when over
185,186,190
laryngospasm for a short period. Apnoea and breath- 22 mL/kg has been aspirated.
holding occur during submersion and are often followed Cardiovascular effects are influenced by the extent and
by swallowing large amounts of water with subsequent duration of hypoxia, derangement of acid–base status,
vomiting, gasping and fluid aspiration. This leads to the magnitude of the stress response and hypothermia. 185
severe hypoxia, loss of consciousness and disappearance Ventricular arrhythmias and asystole may result from
of airway reflexes, resulting in further water moving into hypoxaemia and metabolic acidosis. Acute hypoxia results
the lungs prior to death. 185,186,190 in release of pulmonary inflammatory mediators, which
increase right ventricular afterload and decrease contrac-
Approximately 80–90% of submersion victims suffer ‘wet tility. 185,186,190 Hypotension is commonly seen due to
drowning’ as described above, with aspiration of water volume depletion secondary to pulmonary oedema,
into the lungs resulting from loss of airway reflexes and intracompartmental fluid shifts and myocardial
laryngospasm. Approximately 10–15% of victims have dysfunction. 185
sustained laryngospasm, and no detectable amount of
water will be aspirated (known as ‘dry drowning’), with Severe hypoxic and ischaemic injury is the most impor-
the resulting injury secondary to anoxia. 185,186 Preexisting tant factor related to outcome and subsequent quality of