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Content 9

 

Naloxone (Narcan)

Dose: Adults. 0.4–2.0 mg IV or IM, repeat as needed. Note: If you suspect the patient is addicted to narcotics, give 0.4 mg and repeat PRN to avoid severe withdrawal. Peds.0.01–0.02 mg/kg IV or IM, repeat PRN.

  • 1. Observe patient for at least 6 h after treatment.
  • 2. Manage airway by intubation if airway failure not immediately responsive to naloxone. (See Coma.)

 

 

Complications of Injecting Drug Use

  • Local problems—Abscess (Figures 240-2 
    Image not available.

    A 32-year-old woman with type 1 diabetes developed large abscesses all over her body secondary to injection of cocaine and heroin. Her back shows the large scars remaining after the healing of these abscesses. (Courtesy of ­Richard P. Usatine, MD.)

    and 240-3; Abscess), cellulitis, septic thrombophlebitis, local induration, necrotizing fasciitis, gas gangrene, pyomyositis, mycotic aneurysm, compartmental syndromes, and foreign bodies (e.g., broken needle parts) in local areas.2
    • IDUs are at higher risk of getting methicillin-resistant Staphylococcus aureus(MRSA) skin infections that the patient may think are spider bites (Figure 240-4).
    • Some IDUs give up trying to inject into their veins and put the cocaine directly into the skin. This causes local skin necrosis that produces round atrophic scars (Figure 240-5).
  • IDUs are at risk for contracting systemic infections, including HIV and hepatitis B or hepatitis C.
    • Injecting drug users are at risk of endocarditis, osteomyelitis (Figures 240-6and 240-7), and an abscess of the epidural region. These infections can lead to long hospitalizations for intravenous antibiotics. The endocarditis that occurs in IDUs involves the right-sided heart valves (see Chapter 50, Bacterial Endocarditis).2 They are also at risk of septic emboli to the lungs, group A β-hemolytic streptococcal septicemia, septic arthritis, and candidal and other fungal infections.

 

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A 38-year-old woman is brought to the emergency department by her spouse because of decreased mental status. She had knee surgery 2 days ago and was prescribed oral oxycodone for pain. Her spouse notes that she finished the entire 7-day supply during that day. He denies any seizure activity. They have no other drugs or medications in the house. She is afebrile with blood pressure of 130/75 mmHg, heart rate of 70 bpm, respiratory rate of 4 breaths/min, and SaO2 of 85% on room air. She barely responds to painful stimuli but moves all four extremities equally. Which of the following medications is most likely to improve her mental status?

Answer

The answer is E. Opioids, such as oxycodone, work centrally and may cause significant respiratory depression and sedation. Because of the hypoventilation, hypoxemia is common although easily treated with supplemental oxygen. Naloxone is an opioid antagonist that may rapidly reverse the respiratory depression and sedation. Alvimopan is an oral opioid antagonist that is confined to the gut. It may be useful to counteract peripheral opioid side effects, such as constipation, but has no central actions. Albuterol is a β-agonist that may increase respiratory rate but will not reverse the opioid sedation. Flumazenil is a γ-aminobutyric acid (GABA) receptor antagonist that can be used for benzodiazepine overdose. N-Acetylcysteine is used for acetaminophen overdose. Many forms of oxycodone also include acetaminophen, so the clinician should be careful to elicit an accurate medication history because of the possibility of concurrent acetaminophen-induced liver toxicity.

 

A 75-year-old triathlete complains of gradually worsening vision over the past year. It seems to be involving near and far vision. The patient has never required corrective lenses and has no significant medical history other than diet-controlled hypertension. He takes no regular medications. Physical examination is normal except for bilateral visual acuity of 20/100. There are no focal visual field defects and no redness of the eyes or eyelids. Which of the following is the most likely diagnosis?

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The correct answer is A. You answered A.

Age-related macular degeneration is a major cause of painless, gradual bilateral central visual loss. It occurs as nonexudative (dry) or exudative (wet) forms. Recent genetic data have shown an association with the alternative complement pathway gene for complement factor H. The mechanism link for that association is unknown. The nonexudative form is associated with retinal drusen that leads to retinal atrophy. Treatment with vitamin C, vitamin E, beta-carotene, and zinc may retard the visual loss. Exudative macular degeneration, which is less common, is caused by neovascular proliferation and leakage of choroidal blood vessels. Acute visual loss may occur because of bleeding. Exudative macular degeneration may be treated with intraocular injection of a vascular endothelial growth factor antagonist (bevacizumab or ranibizumab). Blepharitis is inflammation of the eyelids usually related to acne rosacea, seborrheic dermatitis, or staphylococcal infection. Diabetic retinopathy, now a leading cause of blindness in the United States, causes gradual bilateral visual loss in patients with long-standing diabetes. Retinal detachment is usually unilateral and causes visual loss and an afferent pupillary defect.

 

Mr. Jenson is a 40-year-old man with a congenital bicuspid aortic valve who you have been seeing for more than a decade. You obtain an echocardiogram every other year to follow the progression of his disease knowing that bicuspid valves often develop stenosis or regurgitation requiring replacement in middle age. Given his specific congenital abnormality, what other anatomic structure is important to follow on his biannual echocardiograms?

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The correct answer is A. You answered A.

The answer is A. (Chap. 282) Bicuspid aortic valve is among the most common of congenital heart cardiac abnormalities. Valvular function is often normal in early life and thus may escape detection. Due to abnormal flow dynamics through the bicuspid aortic valve, the valve leaflets can become rigid and fibrosed, leading to either stenosis or regurgitation. However, pathology in patients with bicuspid aortic valve is not limited to the valve alone. The ascending aorta is often dilated, misnamed “poststenotic” dilatation; this is due to histologic abnormalities of the aortic media and may result in aortic dissection. It is important to screen specifically for aortopathy because dissection is a common cause of sudden death in these patients.

 


 

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