A 24-year-old man is brought to the emergency room after being found unresponsive in a city park. Physical examination reveals pinpoint pupils unresponsive to light and a respiratory rate of 7 breaths per minute.
Which one of the following is the most likely cause?
Correct Answer B:
Opiate toxicity should be suspected when the clinical triad of CNS depression, respiratory depression, and pupillary miosis (pupillary constriction) are present. Drowsiness, conjunctival injection, and euphoria are seen frequently. Needle tracks are observed occasionally, depending on the route of abuse. Other important presenting signs are ventricular arrhythmias, acute mental status changes, and seizures. Reliance on pupillary miosis to diagnose opioid intoxication can be misleading. If sufficiently severe, hypertension and pupillary dilation may present because of CNS hypoxia. Morphine, meperidine, pentazocine, diphenoxylate/atropine (Lomotil), and propoxyphene sometimes are associated with mydriasis or midpoint pupils.
What is the earliest side effect of lithium?
Lithium is commonly used to treat mania and bipolar depression (manic-depression or bipolar disorder).
Tremor is the most common neurological side effect. It has been estimated that 53% of patients develop tremor during the first week of lithium therapy, yet tremor is present in only 4% of patients who have taken lithium for one to two years (making it the earliest side effect to present (choice B).) Lithium tremor is an irregular, non-rhythmic twitching of the arms and legs that is variable in both intensity and frequency. The chance of tremor decreases if the dose is reduced. Acute lithium toxicity (poisoning) can result in neurological side effects, ranging from confusion and coordination impairment, to coma, seizures, and death. Other neurological side effects associated with lithium therapy include lethargy, memory impairment, difficulty finding words, and loss of creativity.
→ The role of lithium in the production of acute renal failure (choice A) is well accepted. The cause is generally due to severe dehydration and volume depletion due to the combination of natriuresis and water diuresis accompanied by elevated lithium levels, altered mental status, and subsequent poor oral intake. However, this usually takes weeks and months to develop.
→ Lithium inhibits the synthesis of thyroid hormone (choice C). About 10 to 20% of patients treated with lithium develop some degree of thyroid insufficiency. If the diagnosis of hypothyroidism is established, early initiation of thyroid hormone therapy is indicated, especially when discontinuation of lithium is inadvisable because of the patient's psychiatric status.
→ About 30 to 35% of patients experience excessive thirst and urination, usually due to the inability of the kidneys to retain water and sodium. This is known as nephrogenic diabetes insipidus (choice D) , it usually takes weeks and months to develop.
→ Aplastic anemia (choice E) is rare side effect of lithium that develops months or even years after lithium treatment has been started.
A 52-year-old woman who has had low back pain for several years is admitted to the hospital because the pain has suddenly worsened. Her current medications include oxycodone, amitriptyline, perphenazine, fluoxetine and trazodone. On physical examination, the patient is 10% below her ideal body weight, pupils are constricted and skin turgor is poor. She seems sluggish and her speech is slow. Results of neurologic examination and x-ray films of the lumbosacral spine are normal.
If a medication is responsible for her mental condition, the medication is most likely to be which of the following?
Correct Answer C:
The question gives you the classic sign of opiate use: constricted pupils. Prolonged use of opiates may also induce depression.
→ Amitriptyline can cause weight gain, and does not cause pupil constriction.
→ Fluoxetine may result in mild weight loss of two to five pounds, but does not cause pupil constriction.
→ Neither perphenazine nor trazodone cause pupillary constriction.
A 27-year-old man is brought to the emergency department by his wife because he has been vomiting for the past 24 hours. He has used prochlorperazine suppositories for relief of nausea and vomiting. He now has severe muscle spasms in his neck. On physical examination there is sustained spasm of the sternocleidomastoid and trapezius muscles with twisting of his head to the right.
Which of the following is the most appropriate pharmacotherapy at this time?
Correct Answer D:
Dystonic reactions most often occur shortly after initiation of drug treatment; 50% occur within 48 hours and 90% occur within 5 days of initiation of treatment.
The trick to this question is recognizing that prochlorperazine is classified as an antiemetic and antipsychotic tranquilizer. Prochlorperazine is a phenothiazine derivative. Thus, it is capable of causing similar dystonic reactions, including sustained twisting of the head to the right (torticollis), impaired breathing (laryngospasm), and eyes deviated up, down, or sideways (oculogyric crisis).
Emergency interventions other than pharmacologic treatment rarely are required. The goals of pharmacotherapy are to reduce morbidity and prevent complications. The most commonly used agents are benztropine and diphenhydramine. Both are effective treatments, and data do not support one over the other. IV is the route of choice, with signs and symptoms often resolving within 10 minutes. The medication can be delivered IM if an IV line cannot be established, but medications will take 30 min to be absorbed.
Side effects of methylphenidate (Ritalin) therapy for hyperactivity include each of the following, except:
Correct Answer A:
Ritalin is the most frequently prescribed stimulant drug for Attention Deficit Disorder. Possible side effects of Ritalin include reduced appetite, headache, sleep difficulty, anxiety, increased blood pressure and heart palpitations. Furthermore, growth suppression represents a common long-term side effect of Ritalin use.
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