Poisoning

Poisoning

Millions of poisoning exposures occur each year in the United States, resulting in nearly 900,000 visits to emergency departments. About 90% of poisonings happen in the home, and more than half of them involve children under age six. Many poisonings can be prevented if safety precautions are taken around the home. If a poisoning occurs, calling a poison control center can help ensure rapid, appropriate treatment.
History
The history obtained from a poisoned patient is often inaccurate or incomplete, but the following information should still be sought from any source available.
(a) Name of substance ingested.
(b) Time of exposure or ingestion.
(c) Amount ingested - this usually ends up as an estimate. It is best to have both a 'maximum possible ingestion' based on the premise that the bottle, prescription, or container was completely full, as well as a 'probable amount ingested' based on available information. When in doubt, base your actions on the maximum possible ingestion.
(d) A calculation of the mg dosage ingested.
(e) Interventions (i.e., Ipecac, etc.) before to presentation.
(f) Past history of poisoning, overdose, or psychiatric history.

Physical Exam
(a) Complete vital signs noting any trends.
(b) Mental status.
(c) Focused exam: pulmonary, cardiovascular, abdomen, neurological systems as well as evidence of trauma and abdominal exam, (useful in identifying toxidromes).

Diagnostic Studies
Request an electrocardiogram (ECG) for patients with an abnormal or irregular pulse or who have ingested a cardiotoxic drug. A flat plate and upright abdominal x-ray (KUB) may be helpful in identifying radiopaque substances such as heavy metals or enteric coated tablets.

Laboratory Studies
(a) Electrolytes, glucose, BUN/creatinine.
(b) Arterial blood gas (ABG).
(c) Aspirin, acetaminophen, ETOH levels.
(d) CBC.
(e) Qualitative urine or serum drug screens seldom alter treatment or immediate disposition, but may be useful for later documentation of psychiatric evaluation.
(f) Qualitative levels of specific drug toxins are useful in the following limited number of agents: acetaminophen, aspirin, ethanol, methanol, ethylene glycol, iron, digoxin, theophylline, lithium, and anticonvulsants.


Principles of treatment
Five principles of treatment should be considered in the management of every poisoned patient. They may need to occur simultaneously in some patients while in other patients some of them may be inappropriate or even dangerous and have no role.

(a) ABC's (Airway-Breathing-Circulation).
Ensuring and protecting an adequate airway and maintaining effective ventilation are paramount in managing the poisoned patient. Many agents produce sedation, leading to loss of airway protection and the risk of vomiting and aspiration. Maintaining adequate perfusion of the brain, heart, and kidneys can usually be accomplished with intravenous fluids and pressors such as dopamine. In the patient with altered mental status, the following drugs are given.
Oxygen
Narcan (naloxone) 2mg 1V push
Thiamine 100mg IV push
D50 1 AMP IV push (or check dextrostick to R/O hypoglycemia)

(b) Decontamination.
The first goal in managing the adequately resuscitated poisoned patient is minimizing further exposure to the toxin by decontamination. For dermal exposures, decontamination of the skin should be accomplished quickly by removing all contaminated clothing and washing the skin thoroughly with soap and water while protecting care providers from secondary exposure. Ocular decontamination is accomplished by copious irrigation using tap water or normal saline. Gastrointestinal decontamination may be accomplished by the following methods
Note: The single most effective method to decontaminate the GI tract is with the use of activated charcoal.
Emesis
Syrup of ipecac has a very limited role currently because of the risk of aspiration in the patient whose mental status may decline, and because it is less effective than activated charcoal alone. It is contraindicated in caustic ingestions or in patients with an altered mental status or in the ingestion of any agent which may lead to seizures or coma. Complications include aspiration, Mallory Weiss tear, esophageal tears, and electrolyte imbalance.
Gastric Lavage
May be more effective than emesis, but is of limited use if more than an hour has passed from the ingestion. Lavage is performed using a large (36F) orogastric tube with the patient in the left lateral decubitus position. Use saline in small aliquots of 100-200cc lavage with a total of 2 liters or until the return is clear.
Adsorbent (activated charcoal
Administration of 1 to 2 gm/kg of activated charcoal orally (PO) or via a nasogastric (NG) tube is adequate gut decontamination for the majority of patients. Activated charcoal does not bind iron, heavy metals, hydrocarbons, or alcohols well, but should be given in the event other co-ingestants are present.
Whole-bowel Irrigation.
Using Go-Lytely, 2L/hour PO or via a nasogastric tube for 5-6 hours. This may be indicated after ingestion of substances poorly bound to charcoal (iron, lithium), extended-release preparations (Theodur, calcium channel blockers), foreign bodies (button batteries), and drug packets (heroin, cocaine, condoms).

(c) Aggressive Supportive Care.
When combined with resuscitation and decontamination, aggressive supportive care to prevent and manage complication is key to the successful management of the vast majority of poisoning exposures. Therefore, early consultation and possible transfer is generally indicated due to limited resources available to most GMOs.

(d) Enhanced Elimination
Techniques for removing toxins after they have already been absorbed into the systemic circulation are seldom indicated or applicable, but at times they may be central to the management of certain toxins.
Alkaline diuresis (salicylates): alkalinize the urine to a pH of 8.0 by administering normal saline with 1-2amps of bicarbonate per liter and adequate potassium replacement.
Repeat-dose activated charcoal (theophylline, phenobarbital, carbamazepine): 0.5gm/kg PO or NG every 4 hours to produce gut dialysis and interrupt enterohepatic recirculation.
Hemodialysis (salicylates, methanol, ethylene glycol, lithium): consult with a toxicologist or nephrologist for recommendations.

(e) Specific Antidotes
Appropriately administered antidotes may prevent further complications, morbidity and mortality, but most antidotes have potential adverse effects and may not be indicated in a given patient. Seek advice when considering the use of an antidote. The following list includes some of the more useful antidotes.

(1) Acetaminophen
Mucomyst 140mg/kg 1st dose, then 70mg/kg every 4 hours for 17 additional doses.

(2) Tricyclic antidepressants
Sodium bicarbonate 1 to 2 amps IV push, then infusion of bicarbonate in D5W to keep the arterial pH 7.50.

(3) Isoniazid (INH)
Pyridoxine (vitamin B6) same amount as INH ingested if known; if unknown, give 5gm IV.

(4) Narcotics
Naloxone (Narcan) 2mg IV push (some narcotics may require larger doses or continuous infusions).

(5) Cyanide
Lilly Cyanide Antidote Kit (amyl nitrate pearls, sodium nitrite, sodium thiosulfate vials-see insert for directions).

(6) Carbon Monoxide
100 percent oxygen followed by hyperbaric oxygen.

(7) Iron
Deferoxamine 10 to 15mg/kg/hr.

(8) Beta blockers
Glucagon 1 to 5mg IV push, repeat as necessary.

(9) Anticholinegics
Physostigmine 1 to 2mg IV push - (use only for dysrhythmias with hypotension, intractable seizures, or coma with respiratory compromise; intubation should be performed first; contraindicated in TCA overdose).

(10) Insecticides/organophosphates
Atropine IV (may require large doses), followed by Pralidoxime (2- PAM )

(11) Benzodiazepines
Flumazenil (Romazicon) 0.5 to1mg increments IV, total dose rarely to exceed 3mg (do not use if coingestion of an epileptogenic drug).

(12) Oral hypoglycemics
For intractable hypoglycemia, not responsive to IV glucose, use diazoxide 300mg IVPB over 30 minutes.

(13) Calcium Channel Blockers:
Calcium chloride, 1 to 2amps (100 to 200mg) over 2 to 5 minutes. May repeat to effect, and may need continuous infusion. Consider atropine 1 to 2 mg or glucagon 3 to 10mg for A-V block or profound bradycardia. May require pressors and pacing.

(14) Cocaine
Control seizures with benzodiazepines, control hypertension with lopressor and nitroprusside. Caution: the use of beta blockade alone increases mortality due to unopposed alpha effects.

Which one of the following statements is true regarding tuberculosis testing and evaluation?



a.The CDC recommends two-step screening of new employees of long-term care facilities using a booster dose of Mantoux followed by repeat testing in 1-2 weeks
b.BCG vaccine should be considered for TB prevention in HIV-positive patients
c.A positive Mantoux test is defined as erythema greater than 10 mm in diameter at 48-72 hours, or greater than 5 mm in patients who are HIV positive, who have recent documented TB contact, or who have radiologic evidence of old TB
d.Tuberculin testing should not be given on the same day as live virus vaccines
e.Patients who report a positive skin test many years ago but cannot recall any details should be retested and the induration measured and documented

A

Mantoux testing of high-risk patients is becoming more important with the reemergence of tuberculosis and the emergence of HIV disease. A patient who reports a positive test in the past should not be retested, as no further information would be obtained and adverse reactions could occur. TB testing can be done at the same time as live virus vaccines are given but should not be done within 4 to 6 weeks afterward due to the possibility of interference and a false reaction. A Mantoux is measured by the amount of induration only, and erythema should be ignored. BCG is contraindicated in an HIV-infected patient. The booster method is recommended for testing high-risk elderly patients and employees and residents of long-term care institutions.

A 22-year-old sexually active white female comes to your office for a pelvic examination. She has no complaints, but you find a flat wart on her cervix.

The most appropriate management is



a.explaining to her that warts are harmless, although contagious, and giving her the option of having it treated or left alone
b.reassuring her of the benign nature of these lesions and offering her treatment with either podophyllin or liquid nitrogen
c.reassuring her if her Papanicolaou test is negative, and scheduling a return visit in 3 months
d.performing a colposcopically directed biopsy of the lesion to rule out cervical neoplasia
e.freezing the lesion at this visit to help prevent spread to her sexual partner

D

A flat wart should be biopsied to exclude cervical neoplasia. Treatment should be delayed until the biopsy results are known. Basing the decision on the results of a Papanicolaou test is inappropriate because of the possibility of false-negative results, which occur 10% to 30% of the time.

A 23-year-old man presents for a persistent, slowly worsening rash to the face. He states that it first occurred in January; it is now March. He denies any pruritus. He has experienced some relief with over-the-counter 0.5% topical hydrocortisone. The patient has tried changing soaps and shampoos without effect. He notes a fair amount of cosmetically unacceptable scale, including the scalp area, which he has been attempting to wash off. Past medical history and review of systems are unremarkable, and the patient is using no medications. What is most likely diagnosis?

A seborrheic dermatitis
B acne
C psoriasis
D keratosis pilaris
E hidradenitis suppurativa

Answer is A. The correct diagnosis is seborrheic dermatitis. This very common disorder pre- dominantly affects the scalp and face, although there is generally more involvement of the forehead and eyebrows and less chin involvement than seen in this patient. Seborrheic dermatitis can also affect the upper chest and groin area. The typical eruption involves a greasy appearance (which patients may interpret as a hygiene issue) and scale, which may be yellow in appearance. With scalp involvement, dandruff is the result; in many patients, this is the complete manifestation of the disorder. Seborrheic dermatitis patients tend to have had their symptoms for some time before coming in; symptoms are likely to be more pronounced in late fall and winter.