A 40-year-old man is brought to the emergency department after his wife found him alone in a confused state. He suddenly started accusing his wife of cheating on him and conspiring to send him to jail. En route to the hospital, he was drowsy and ataxic with blurry vision. The patient has a history of insomnia, bipolar disorder, and substance use disorder. Temperature is 37.8 C (100 F), blood pressure is 130/80 mm Hg, pulse is 100/min, and respirations are 22/min. The patient is confused, unable to converse meaningfully, and not oriented to time, place, or person. He picks at imaginary objects. Mucous membranes are dry. There is no neck stiffness. The lungs are clear to auscultation bilaterally. Heart sounds are within normal limits. Lower abdominal fullness is present. A Foley catheter is placed, and 600 mL of urine is collected immediately. Which of the following is the most likely diagnosis?

Question

A 40-year-old man is brought to the emergency department after his wife found him alone in a confused state.  He suddenly started accusing his wife of cheating on him and conspiring to send him to jail.  En route to the hospital, he was drowsy and ataxic with blurry vision.  The patient has a history of insomnia, bipolar disorder, and substance use disorder.  Temperature is 37.8 C (100 F), blood pressure is 130/80 mm Hg, pulse is 100/min, and respirations are 22/min.  The patient is confused, unable to converse meaningfully, and not oriented to time, place, or person.  He picks at imaginary objects.  Mucous membranes are dry.  There is no neck stiffness.  The lungs are clear to auscultation bilaterally.  Heart sounds are within normal limits.  Lower abdominal fullness is present.  A Foley catheter is placed, and 600 mL of urine is collected immediately.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d1cb_bdd1_bc81_9946f73c30f8_MD0003_00 This patient with risk factors for overdose (eg, bipolar disorder, substance use disorder) has symptoms consistent with anticholinergic toxicity, including the following: anticholinergic toxicity Confusion and visual hallucinations (eg, picking at imaginary objects) ("mad as a hatter") Blurry vision, likely due to mydriasis ("blind as a bat") Hyperthermia from impaired heat dissipation ("hot as a hare") Dry mucous membranes ("dry as a bone") Urinary retention ("full as a flask") These symptoms occur due to competitive blockade of muscarinic acetylcholine receptors in the CNS, ciliary body of the eye, salivary glands, and detrusor muscles. Because of similar antagonism of muscarinic receptors in the sweat glands, heart, and intestinal smooth muscle, dry skin, tachycardia, and decreased bowel function (eg, decreased bowel sounds) are also common. muscarinic acetylcholine receptors Toxicity often occurs when anticholinergic medications are taken in excess (eg, overdose) or when multiple anticholinergic medications are combined. Among the many medications with anticholinergic properties, some of the most readily available and commonly used are antihistamines such as diphenhydramine. (Choice A) Severe alcohol withdrawal (eg, delirium tremens) can cause confusion, hallucinations, and autonomic hyperactivity (eg, hyperthermia, tachycardia). However, acute withdrawal does not typically cause blurry vision or urinary retention. (Choice C) Acute toxicity from lithium (used to treat bipolar disorder) can cause neurologic findings, including confusion and ataxia. However, acute toxicity typically also causes gastrointestinal symptoms (eg, nausea/vomiting, diarrhea), and hyperthermia and urinary retention are not expected. (Choice D) Salicylate intoxication can cause hyperthermia, tachypnea, and altered mental status but typically also causes gastrointestinal symptoms (eg, nausea/vomiting) that are absent in this patient. In addition, salicylate toxicity does not typically cause blurred vision or urinary retention. (Choice E) Serotonin syndrome can cause autonomic hyperactivity (eg, hyperthermia, tachycardia), mental status changes, and dilated pupils, leading to blurry vision. However, neuromuscular findings (eg, clonus, tremor, hyperreflexia) are commonly present, and dry mucous membranes and urinary retention are not expected. (Choice F) Wernicke-Korsakoff syndrome (eg, secondary to alcohol use disorder) can cause confusion, visual changes (from ophthalmoplegia), and gait ataxia. However, hyperthermia, dry mucous membranes, and urinary retention are not classically seen. Educational objective: Anticholinergic toxicity can cause confusion, mydriasis (eg, blurry vision), hyperthermia, dry mucous membranes, and urinary retention due to widespread, competitive blockade of muscarinic acetylcholine receptors. This can occur from overdose of common medications (eg, diphenhydramine) that have anticholinergic properties. References: Poisonings with diphenhydramine-a survey of 68 clinical and 55 death cases. (http://www.ncbi.nlm.nih.gov/pubmed/16857332)

A 40-Year-Old Man Is Brought to the Emergency Department After