An 87-year-old woman with advanced dementia is brought to the emergency department by her son due to 3 days of fever and foul-smelling, productive cough. The patient is bed-bound and requires assistance with all activities of daily living. Her other medical problems include hypertension, hypercholesterolemia, and a hemorrhagic stroke that occurred 8 months ago. She has been admitted to the hospital twice for pneumonia over the past 6 months, most recently 4 months ago. The patient has never smoked cigarettes. Her temperature is 38.3 C (101 F), blood pressure is 100/70 mm Hg, pulse is 105/min, and respirations are 20/min. Pulse oxymetry shows oxygen saturation of 90% on room air. BMI is 20 kg/m². She is not oriented to name, time, or place. Physical examination shows dry mucous membranes and decreased skin turgor. Breath sounds are decreased in the right lung field. Heart sounds are normal. The abdomen is soft, nontender, and nondistended. Chest imaging reveals an infiltrate in the posterior segment of the right upper lobe. Which of the following is the most important predisposing factor for this condition in this patient?

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11ec25c8_d4a6_548a_bc81_97796747afc7_MD0003_00 This patient presents with pneumonia, most likely from aspiration. Impaired swallowing and cough reflex are frequent abnormalities in patients with advanced dementia. Such patients have decreased recognition of food in the oropharynx as well as challenges in forming a food bolus and coordinating the complex action involved in swallowing. This patient's history of stroke places her at even greater risk for impairment of the cough reflex and for dysphagia, further increasing the risk of aspiration. As a result, such patients are also predisposed to aspiration of oropharyngeal secretions and inhalation of colonizing pathogenic bacteria (eg, Peptostreptococcus). Aspiration pneumonia typically develops over the course of days and causes low-grade fever, dyspnea, and a productive, foul-smelling cough. It may be complicated by necrosis and abscess formation. The location of the infiltrate is gravity-dependent and differs according to the patient's position at the time of aspiration. In supine patients, the posterior segments of the upper lobes and superior segments of the lower lobes are most affected. Broad-spectrum antibiotics with good anaerobic coverage (eg, clindamycin, amoxicillin-clavulanate) are a mainstay of treatment. (Choice A) Cell-mediated immunity helps eliminate intracellular pathogens. Patients with depressed cell-mediated immunity present with recurrent infections from ordinarily benign viruses, opportunistic pathogens, or fungi. (Choice B) Although aging is associated with a general decline in immune function, decreased humoral immunity is not specifically associated with an increased risk for aspiration pneumonia. Patients with decreased humoral immunity most commonly present with both recurrent upper and lower respiratory tract infections. (Choice D) Impaired mucociliary clearance occurs in smokers and patients with either cystic fibrosis or Kartagener syndrome. Such conditions are associated with an increased risk for pulmonary infections, but they do not predispose to aspiration pneumonia specifically. (Choices E and G) Stomach acid is protective against pneumonia as the acidic environment sterilizes gastric contents and reduces bacterial colonization of the upper gastrointestinal tract. Although advanced gastroesophageal reflux can cause aspiration of gastric contents, bronchoconstriction, and pneumonia, this patient has no history or evidence of reflux. (Choice F) Increased gastric residual volume is associated with gastroparesis, which is characterized by increased satiety, bloating, and nausea and vomiting, but these symptoms are not present in this patient. Moreover, in patients receiving enteral nutrition in the intensive care unit, residual volume has not been shown to correlate with risk for pneumonia. Educational objective: Patients with impaired consciousness, advanced dementia, and other neurologic disorders are predisposed to aspiration pneumonia due to impaired swallowing and cough reflex. References: Risk factors for aspiration pneumonia in older adults. (http://www.ncbi.nlm.nih.gov/pubmed/26444916) Swallowing difficulties: a prognostic signpost. (http://www.ncbi.nlm.nih.gov/pubmed/22170194)

An 87-Year-Old Woman with Advanced Dementia Is Brought to the Emergency