Poisoning in Childhood

Very common problem in pediatrics and most encounters are via the telephone. It is important to have a good understanding of basic principles of taking care of common ingestions and knowing when you need to intervene and treat.

With introduction of public and physician awareness, there has been a decrease in the incidence of death secondary to poisonings. The introduction of childproof caps and other mechanisms has probably added to the decline of deaths. Between 1988 and 1992 there were 152 reported deaths in children less than 5 years old and there were 221 deaths in 6-17 year olds, the majority which were suicides. 

The common things ingested are medications, household cleaners, personal care items, and plants. Most common ingestion associated with death is Iron containing drugs. Parents should be instructed to have a general idea of what to do in case of an ingestion and should try to fix their homes so that drugs and chemicals are not easily accessible. They should also have Ipecac at home and the number of the local poison control center availabel and easily accessible.

During the first encounter it is important to get a good history. The name and brand name of the material ingested should be ascertained and be very specific about the ingredients and concentration. It is also important to ask the caller what are the directions on the label. You should try to quantify the amount ingested, the time the suspected ingestion took place, are there any other medical problems and whether any other individuals may have ingested something.  You must get the child's age and weight and ask if they are on any medications on a regular basis.  The time of onset of symptoms is very important. 

POISON CONTROL 1 800 942-5969

Initially should decontaminate

  1. Ipecac- causes vomiting within about 30 minutes and empties about 1/3 of ingested contents. For liquids give within 30 minutes and for solids within 2 hours. Contraindicated when the patient has decreased conciousness and has ingested caustics or hydrocarbons. The dose is one tsp if <1 year old, 3tsp for <12 year olds and 6tsp for >12. Ipecac may cause protracted vomiting, diarrhea, and lethargy. An alternative if the patient doesn't have ipecac is 3 tbs of liquid soap and 8 oz water.
  2. Activated charcoal. May give po but usually given by lavage. It is often combined with sorbitol that is a cathartic. You may geve 10-30 grams to small children and 50-100 grams to older children. Some will follow with a cathartic. Not effective with most heavy metal ingestions like iron.

Your first contact is usually over the telephone so it is important to calm the family and administer good advice. Most calls do not necessitate doing anything and it is important to have a good knowledge of common non-toxic ingestions. It is important to take down the family’s phone number so that you can check back with them after calling the Poison Control Center or looking up information. It is also a good time to instruct parents about making sure that drugs and chemicals are out of the way. Do not make the parents feel anymore guilty than they already do.

In the ER or office setting, it is important to get an excellent history and it may be necessary to ask the same question over and over before you get the answers. Make sure that other involved are also questioned. Timing is important and you must suspect poisoning when a patient presents with unusual symptoms and signs.

The physical exam may be helpful. Vital signs, pupil size, skin temperature and color, body temperature, hydration, breath, stool with blood, mental status, coordination, ataxia.

Laboratory evaluation- PO2 saturation, carboxy Hb, anion gap (MUDPILES), Electrolytes  If you have a history of specific ingestiion, you may get levels or do toxic screens of the urine and blood. Different labs measure different toxins in their "screening" so know what the test is screening for. 

  • Iron.


Must calculate the elemental amount of iron in the ingested compound ( sulfate 20%, fumurate 33%, and gluconate 12% ).

Greater than 20mg/kg has GI symptoms, greater than 60mg/kg considered toxic and greater than 200/kg possibly lethal. Most common form is ferrous sulfate tab (65mg of elemental iron).

Initially may have some vomiting, diarrhea, and abdominal pain. After about 6-12 hours symptoms may improve and begin to feel that the child is okay. This is followed by metabolic acidosis and decreased cardiac output, failure, coma, shock and acute renal failure and hepatic injury. 
Initially must induce vomiting and gavage stomach. Charcoal is not iffective. Lavage with sodium bicarbonate may change the ferrous salt to insoluble compound. Blood level at 4-6 hours after ingestion of 350-500 is considered moderate ingestion. Greater than 500 should chelate with desforoximine regardless of symptoms and levels greater than 1000ug may be associated with death.
 

  • Acetaminophen


Considered to have toxic ingestion if greater than 150 mg/kg and 7.5 grams for children over 12 years old. Dropper has 80mg/.8cc, liquid has 160mg./5cc, and chewables are 80 or 160 mg / tab. Adult acetaminophen contains either 325 or 500 mg. Acetaminophen is often associatied with teen suicide attempts. Ingestions in older individuals are more toxic than in younger aged children because younger ages have greater turnover of glutathione. Hepatic damage is secondary to metabolites of acetaminophen binding to liver cells and causing damage. 

Stage I- first 24 hours: the child may be nauseous, vomiting and feeling lousy. Lab reports at this time are normal. The drug is being absorbed and metabolized and glutathione stores are being called into action. During this phase, treatment will lessen the toxic effects. May initially be asymptomatic.

Stage II- 24-48 hours: SGOT and SGPT and bilirubin and prothrombin time are abnormal. Patient may be feeling better now. Plasma levels of drug may be normal. 

Stage III- 48-96 hours: icteric, hypoglycemia, encephalopathy, renal changes.

Stage IV- Labs return to normal and process is resolved. If there has been severe toxicity, a liver transplant may be indicated.

Treatment- emesis and charcoal. Get level after 4 hours of ingestion and refer to nomogram and may start acetylcysteine (Mucomyst) within 16 hours after ingestion by gavage and continue q 4 hours for 17 doses. Starting after 32 hours may not prevent hepatic damage. Glutathione depletion allows the accumulation of intermediate metabolites that cause the liver damage. There is no need to repeat acetaminophen levels after starting treatment and Mucomyst should be continued for 17 doses.
 

  • Salicylates


 

 

Respiratory stimulant, uncouples oxidative phosphorylation, affects platelet function, decreases production of factor VII, and causes gastric irritation.

Reference level is about 150mg/kg for an acute ingestion. Adult aspirin has 325 mg and baby aspirin has 81mg. Bottle contains total of 36 aspirins. Pepto Bismol has 9mg/ml. One teaspspoon of oil of wintergreen has 1.4 grams of ASA.

Initially have hyperpnea and respiratory alkalosis. Loose K, Na, and HCO3 in the urine. Develop fever, lethargy, vomiting, dehydration, metabolic acidosis and coma. May develop tinnatus and delirium and hallucinations. Death from electrolyte inbalance, bleeding, CV collapse or cerebral edema. 

Treatment consists of emptying the stomach, charcoal and monitor serum level of ASA and look at the Done nomogram. Nomogram not applicable in chromic ingestions. Level after about six hours. If less than 35 mg usually asymptomatic and 35-70 usually mild symptoms. Greater than 150 may be lethal. Monitor lytes, pH, Ca, and PT and PTT and glucose. Treat dehydration, give vitamin K if coagulation studies are off, and watch electrolytes. If unable to correct acidosis or renal failure and seizures unable to be controlled, may need to hemodialyze. Alkalinization of the urine greatly enhances excretion of ASA.

Nomogram does not apply to chronic ingestion and equal levels in chronic ingestion usually associated with more symptoms.
 

  • Caustics-Acids and Alkalis


Alkali and acids can cause damage to the pharynx and esophagus. Usually give water or milk following ingestion and should avoid neutralizing solutions, emesis, or NG tubes. Then keep NPO. Drooling, bloody secretions or vomitus, and retrosternal pain may be indicative of esophageal damage and will give the best indication of damage even in the absence of mouth findings. Should have esophagoscopy to determine the extent of damage and dictate followup care. If no symptoms, may watch carefully. Use of steroids controversial.

Common products include lye, automatic dishwasher soap, toilet bowl cleaners, concentrated acid, disc batteries, oven cleaners, industrial strength bleach. Often see when chemicals placed in different containers than they came in.
 

  • Hydrocarbons


All are lipophilic and will accumulate in fatty tissue like the brain.

High blood levels will cause CNS depression and other major organ toxicities. The volatility of these compounds will often lead to aspiration pneumonitis and this is the usual acute manifestation. Even small amounts swallowed will often lead to small amounts in the pulmonary tree and their low viscosity allows spread to the entire respiratory tree. 

Clinically the child may be fine initially and then develops a cough and the signs and symptoms of aspiration pneumonia. The course may be benign or go on to respiratory failure with the development of chronic lung changes. Treatment is supportive and emesis and steroid use are contraindicated. Some toxic ones with additives like pesticides may necessitate careful, controlled gastric lavage.
 

  • Carbon Monoxide


CO has a great affinity for Hemoglobin and will replace O2. The symptoms include dizziness, cyanosis, confusion, SOB, and coma. Immediate treatment with 100% oxygen important to decrease the 1/2 life of the CarboxyHb. If carboxyhbemoglobin level is above 40%, consider hyberbaric oxygen therapy.

 

 

  • Methanol and Ethylene Glycol


Small amounts can cause serious toxicity, especially in young children.  Ingestion of 10-15ml in small children can be fatal.  Methanol is a component of windshield washer fluid, toxic in 0.1ml/kg.  Initial presentation is often delayed, with high anion gap metabolic acidosis and visual disturbances/blindness.  Ethylene glycol is in radiator antifreeze, deicers, engine coolants, toxic at 0.2 ml/kg.  Presentation is CNS depression and high anion gap metabolic acidosis.  Late effects include renal and cardiac failure.

Traditional therapy of both was continuous IV ethanol, which is complicated.  It requires large infusion and it causes metabolic derangements and CNS depression.  Fomepizole (4-methylpyrazole, 4-MP) is indicated for treatment of these ingestions.  It is a competitive inhibitor of alcohol dehydrogenase and prevents metabolism of methanol and ethylene glycol into their toxic metabolites.  It is safe and has very few side effects, making it a better therapy than ethanol.  Therapy may also include hemodialysis, though early administration of fomepizole may avoid the need.  Adequate urine output should be maintained to enhance excretion of unmetabolized poison.  Additional therapies to consider: sodium bicarb (for acidosis), correction of hypocalcemia, administration of cofactors (thiamine and pyridoxine for ethylene glycol, folate for methanol).

 

References

1.     Woolf, Alan D. Poisoning by Unknown Agents. Pediatrics in Review. May 1999

2.     McGuigan Michael.  Poisoning Potpourri  Pediatrics in Review September 2001

3.     Committee on Drugs Acetaminophen Toxicity in Children Pediatrics Oct. 2001

4.     Heard, K.  Acetylcysteine for Acetaminophen Poisoning. NEJM July 17, 2008

5.     White ML and Liebelt EL. Update on Antedotes for Pediatric Poisoning. Pediatric Emergency Care, November 2006.