Hydrocarbon poisoning

management and diagnosis of hydrocarbon poisoning in pediatrics

1. HYDROCARBON POISONING A.Sasidharan

2. introduction Hydrocarbon (Kerosene) poisoning is one of the most common accidental poisoning in children in developing countries due common use of kerosene in house-hold and unsafe storage practices. Hydrocarbons can cause rapid onset of CNS symptoms including CNS depression and seizures. Volatile hydrocarbons can be aspirated and cause chemical pneumonitis. Cardiac dysrhythmias are less common Poisoning can occur from accidental exposure (often younger children) or deliberate exposure (often from inhalation e.g. from “sniffing” or “chroming ”)

3. Hydrocarbon Compounds Hydrocarbons come in four structural classes. Aromatic  - contain a benzene ring (most toxic) and are used in solvents and glues but also in paint and paint remover.   Aliphatic  - petroleum distillates found in polishes, lamp oils, and lighter fluid. Halogenated  - fluorinated, chlorinated, or brominated, and are used for refrigeration (Freon) and as insecticides and herbicides.  Terpene  - found in turpentine and pine oil. Some of these hydrocarbons may be found in various mixed forms and used as an aerosol spray propellant.

4. Hydrocarbon compounds Petrol Kerosene Lighter Fluid Paraffin Oil 2 Stroke Fuel Diesel Fuel Solvents White Spirit Lubricating Oil Furniture Polishes Essential oils Mineral Turpentine

5. Patient Requiring Assessment All patients with deliberate self-poisoning or significant accidental exposure Any symptomatic patient Any patient whose developmental age is inconsistent with accidental poisoning as non-accidental poisoning should be considered.

6. Risk Assessment History  Was exposure intentional or accidental?   Dose : Type of compound Quantity ingested Duration of exposure in inhalation Co- ingestants (e.g. paracetamol )

7. pathophysiology The toxicity of hydrocarbons is due to their low surface tension and vapour pressure which helps them spread over large surface area of the lungs and cause chemical pneumonitis. While lower surface tension helps in spreading over a large area, lower viscosity enhances penetration into distal airways leading to severe necrotizing pneumonia. Thus compounds like kerosene, gasoline and naphtha with high volatility, low viscosity, and low surface tension are more likely to be aspirated and cause severe lung injury.

8. Pathophysiology Hydrocarbon aspiration inhibit surfactant Alveolar instability early distal airway closure ventilation perfusion mismatch HYPOXIA

9. General Examination / Vitals PR BP SPO2 TEMP Any smell of ingested hydrocarbon

10. Systemic Examination Respiratory Coughing / gagging / choking indicates aspiration Wheeze , tachypnoea, hypoxia, haemoptysis and pulmonary oedema are signs of evolving chemical pneumonitis. Cardiovascular Dysrhythmias occur early in exposure Halogenated hydrocarbon abuse can cause a fatal malignant arrhythmia, termed " sudden sniffing death

11. cont. CNS CNS depression ( Acute exposure leads to an increase in gamma-amino butyric acid (GABA) and glycine function   ), but experimental evidence suggests effects on NMDA, dopamine, and GABA receptors . coma and seizures may occur with large acute exposures. Onset is usually within 2 hours GIT Nausea , vomiting and diarrhoea Excessive burping, heartburn, epigastric pain

12. Conti Renal effects Hydrocarbon toxicity can lead to metabolic acidosis, hypochloremia, and hypokalaemia resulting from distal renal tubular acidosis. Anion gap acidosis occurs as the compounds are metabolized, and sodium and potassium are lost via renal excretion along with these metabolites.

13. INVESTIGATIONS Asymptomatic children with small ingestions do not usually require investigation. For children with more significant ingestions, or who are symptomatic: 12 lead ECG & cardiac monitoring for 4 hours CBC BUSE LFTs VBG

14. INV cont. CXR if respiratory symptoms ( some studies suggest CXR in asymptomatic also) CXR can be taken early or after 6 hrs of observation. For all children with deliberate poisoning, perform further screening for co- ingestants

15. CXR

16. Acute Management 1. Resuscitation Standard procedures and supportive care  Intubate early for progressive CNS depression Ventricular dysrhythmias: Commence advance life support Intubate, hyperventilate, correct hypoxia Correct electrolyte disturbances Withhold catecholamine inotropes if possible 

17. Decontamination Activated charcoal is  specifically contraindicated  in hydrocarbon poisoning as they do not bind hydrocarbons and increase the risk of hydrocarbon aspiration Gastric lavage / emetic is contraindicated as worsens the condition

18. Conti. Seizures – Benzodiazepines remain standard first line treatment . Ongoing care and monitoring Asymptomatic children with normal vital signs should be observed for 6 hours post exposure before discharge Patients with milder respiratory or CNS symptoms should be admitted for a longer period of observation +/- supportive care

19. Chemical Pneumonitis Chemical pneumonitis is managed supportively (Oxygen & bronchodilators – may require non invasive ventilation or intubation if severe).  Corticosteroids and prophylactic antibiotics are not indicated. Fever is common following aspiration with pneumonitis – antibiotics should be withheld until there is objective evidence of bacterial infection

20. Prognosis Prognosis Pulmonary toxicity is the major cause of morbidity and mortality. Aspiration pneumonitis is the most common complication of hydrocarbon ingestion, followed by CNS and cardiovascular complications. The major respiratory complications are aspiration and lung injury secondary to pneumonitis.    Pneumothorax and barotrauma are potential complications of mechanical ventilation. Most patients improve after 24 hours, and symptoms resolve within 1 week.

21. Discharge Criteria Normal GCS   Normal ECG No respiratory symptoms (cough, dyspnoea, wheeze) Normal observations including pulse oximetry Period of observation as above For deliberate ingestion a risk assessment should indicate that the patient is at low risk of further self harm in the discharge setting

22. Prevention Patient Education Patient education is crucial in the prevention of unnecessary or accidental exposure. Most exposures in young children are accidental and can be prevented. Teaching points include the following: Parents should teach young children about the dangers of poisons, beginning at an early age Advise the parents about the proper storage and labelling of harmful chemicals Inform parents about common household products that may be dangerous, and recommend steps that they can take to minimize the possibility of an accidental exposure Educate parents that they need to supervise their children when they are in high-risk areas ( eg , kitchen, garage, laundry room) where toxic substances may be present

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