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Patient A, a man 58 years of age, presents to the walk-in clinic complaining of a 24-hour history of fever and chills, with an episode of rigors last night. He has previous history that is significant for COPD, diabetes, and a 2 pack per day smoking habit and a lifetime pack year history greater than 75 years. His medications include a combination steroid/long-acting beta agonist inhaler, tiotropium bromide and albuterol, as needed. He complains of increased dyspnea and has been using his inhaler almost constantly. He admits to a productive cough but is not sure if it is much different than his normal "smoker's cough," as he calls it. The office medical technologist obtains vital signs, and Patient A has a blood pressure of 168/92 mm Hg, a pulse of 128 beats per minute, a respiratory rate of 32 breaths per minute, and a pulse oximetry on room air of 87%. His temperature (taken with a forehead "tape" thermometer) is 97.5°F. The patient is placed on 4 liters O2 and given an albuterol solution via small volume nebulizer. His O2 saturation increases to 94%, his respiratory rate decreases to 24 breaths per minute, and his pulse decreased to 112 beats per minute.
Comments and rationale : At this point, the differential includes exacerbation of COPD, acute viral syndrome, viral pneumonia, and bacterial pneumonia. A few actions can help quickly limit the differential. The first is to determine if Patient A is sweaty. A very recent defervescence could cause a wide discrepancy between rectal and tympanic temperatures versus methods that measure skin temperature. The cooling effect of sweat will cause an underestimation of the patient's true body temperature. The patient's tympanic temperature would likely be more accurate in this situation.
Next, lung sounds should be assessed, with percussion and full examination for egophony and fremitus performed. The presence of abnormal sounds would alert the clinician to do a more thorough exam. Finally, if the clinician is convinced that the patient likely has CAP, the decision whether or not to hospitalize must be made.
A tympanic probe displays a temperature of 101.3°F. Auscultation of lung sounds reveals fremitus as well as expiratory wheezes and rhonchi. As Patient A is still mildly hypoxic (as well as tachypneic and tachycardic) and requiring supplemental oxygen, the decision is made to transport to the local hospital via emergency medical services. There, a chest x-ray reveals a right lower lobe infiltrate and a white blood cell count of 17,000/mm3. Sputum culture reveals S. pneumoniae. The patient is placed on moxifloxacin 400 mg daily for 7 days and is started on prednisone and albuterol via small-volume nebulizer. Patient A rapidly improves and is discharged 3 days later with instructions to finish his antibiotics and steroids and to follow-up with his primary care practitioner.
Comments and rationale : Patient A represents a typical case of CAP, with relatively common underlying risk factors (COPD, smoking, and diabetes). While his hospitalization was short due to rapid identification of his pneumonia, he now requires outpatient follow-up to avoid relapse and to decrease his risk for recurrence. Intensive treatment for smoking cessation is warranted, and he may need adjustment of his insulin regimen while on steroids. Another factor to consider is how long to follow his chest x-ray. Many clinicians advocate serial x-rays until the pneumonia is completely resolved, to eliminate the possibility of an underlying carcinoma causing a chronic infiltrate. As this patient is very high risk for lung cancer, this may be a reasonable strategy. A persistent infiltrate would require further work-up.
Patient B is a man, 82 years of age, living in a nursing home. He has COPD, a history of smoking, mild dementia, and hypertension. One morning, his caregivers note that he has a temperature of 101°F and is mildly obtunded and confused. His oxygen saturation as obtained by pulse oximetry is 88%. His primary care practitioner is called and an order is obtained to transfer him to an acute care facility. While in the emergency department, sputum for culture, sensitivity, and Gram stain is obtained. Lab work including a white blood cell count is sent, and a chest x-ray is obtained.
Comments and rationale : Healthcare-associated pneumonia can be caused by a wide variety of pathogens, including multidrug-resistant, aerobic, gram-negative bacteria such as P. aeruginosa, E. coli, K. pneumoniae, and Acinetobacter spp. Potential gram-positive causative organisms include S. aureus, and the potential for a methicillin-resistant strain is significant. While it should not delay care, all patients with suspected pneumonia should have a lower respiratory tract sample sent for culture and microscopic evaluation. Diagnostic testing is ordered both to determine if the patient's symptoms are the result of pneumonia and to determine the causative pathogen.
Patient B's chest x-ray reveals a new right lower lobe infiltrate, and his white blood cell count is 18,000/mm3. His temperature is 101°F, and he is noted to have purulent sputum. A diagnosis of healthcare-associated pneumonia is made, and the patient is started on moxifloxacin 400 mg per day. He is placed on supplemental oxygen via nasal cannula to maintain an oxygen saturation of 90% or greater.
Comments and rationale : The clinical diagnosis of pneumonia is generally defined as the presence of a new infiltrate on chest x-ray and at least two or three clinical symptoms (in Patient B's case, fever, leukocytosis, and purulent secretions). The selection of appropriate initial antibiotic therapy is key in reducing morbidity and mortality.
The patient's fever increases to 102°F, and he now requires 40% ventilation mask to maintain adequate oxygenation. He is moved to the ICU, and the hospital laboratory reports initial findings on the patient's sputum culture. The sputum is found to contain a predominant strain of gram-positive organism. Due to the patient's failure to improve on a quinolone and the presence of gram-positive bacteria, the decision is made to change the patient's antibiotic regimen to a broad-spectrum regimen designed to cover multidrug-resistant organisms. Patient B is placed on vancomycin 1 gram IV every 12 hours, with orders to check a trough level one hour after the third dose. He is also placed on piperacillin and tazobactam and intravenous levofloxacin, in accordance with the American Thoracic Society's guidelines for the treatment of patients with healthcare-associated pneumonia with risk factors for multidrug-resistant pathogens .
Comments and rationale : Only vancomycin and linezolid are currently approved for use in the United States to treat MRSA pneumonia . Although TMP-SMX often has significant activity against MRSA, its use should be limited to mild disease, such as urinary tract infection not causing sepsis. As the causative agent is rarely identified prior to initial antibiotic dosing, the type of pneumonia and the patient's known risk factors are used to guide antibiotic selection.
In this case, the patient is failing to improve, and the Gram stain is able to provide guidance regarding tailoring the individual antibiotic regimen. After the patient has been identified as having healthcare-associated pneumonia, likely due to a drug-resistant organism, the decision must be made whether and how to use broad-spectrum antibiotics. Although all clinicians should strive to avoid inappropriate initial selection when ordering antibiotic therapy, this case presents the dilemma faced in treating a patient whose only known initial risk factor was residing in a nursing home. The American Thoracic Society guidelines state that initial empiric antibiotic therapy for these patients can be ceftriaxone or a respiratory quinolone, or ampicillin/sulbactam or ertapenem . The patient was initially treated with a respiratory quinolone, and therefore, his initial treatment was appropriate. However, after information was obtained that the causative organism was likely a gram-positive organism and the patient was noted to be deteriorating, his antibiotic regimen was broadened to include protection against multidrug-resistant organisms, especially MRSA. Length of therapy can vary depending on the rate of improvement, but generally the patient should be on the appropriate antibiotic for 7 days.
Patient B gradually improves, and after 72 hours, the cultures are found to be positive for MRSA. His antibiotic regimen is tailored to these findings, and he is placed solely on IV vancomycin.
Patient C is a community-dwelling woman, 58 years of age, with a history of asthma and diabetes. She presents to an urgent care facility with a 48-hour history of cough, fever, and wheezing. On exam, her vital signs are: blood pressure 154/78 mm Hg; pulse 94 beats per minute; respirations 24 breaths per minute; and temperature 99.4°F. Her oxygen saturation is 93% on room air. Her usual medications are fluticasone/salmeterol, metformin, lisinopril, and albuterol (as needed). A chest x-ray reveals a small infiltrate in the right lower lobe, and a diagnosis of CAP is made. Patient C is given a prescription for levofloxacin 500 mg twice daily, prednisone 40 mg with a tapering schedule calling for a decrease in dosage by 5 mg every other day, and instructions to take acetaminophen for fever and guaifenesin for cough. She is instructed to follow up with her primary care clinician in 24 to 48 hours and to seek immediate emergency treatment for worsening of symptoms.
Comments and rationale : Given this patient's comorbidities, an initial choice of a respiratory fluoroquinolone is a good one. The patient has several pre-existing conditions that could complicate her care, and antibiotic failure would leave her susceptible for a poor clinical outcome. It is unclear if the clinician checked the patient's renal status via a blood test for BUN and serum creatinine. Levofloxacin is excreted via the kidney, and diabetic patients like Patient C are at increased risk for developing chronic kidney disease, which could lead to acute renal failure in the presence of dehydration. Further complicating Patient C's care is the fact that steroid therapy often results in worsening glycemic control, which can lead to polyuria and further exacerbate dehydration.
Patient C continues to have wheezing despite the use of her albuterol inhaler. Her condition worsens until she contacts emergency medical services and is transported via ambulance to a local hospital. Her vital signs in the emergency department are: blood pressure 104/53 mm Hg; pulse 115 beats per minute; respirations 28 breaths per minute; temperature 99.3°F; and oxygen saturation 89%. Auscultation of her lungs reveals inspiratory and expiratory wheezing with diminished air flow as well as decreased breath sounds at the right base. Patient C is placed on supplemental oxygen and given hydrocortisone sodium succinate 150 mg IV. Laboratory studies are sent and reveal an arterial blood gas of pH 7.41, arterial carbon dioxide tension of 45 mm Hg, and pulmonary arterial oxygen tension of 55 mm Hg. Her serum glucose is 235 mg/dL, BUN 53 mg/dL, and serum creatinine of 2.8 mg/dL. She is placed on IV fluid of D5 ½ at 150 mL per hour. The patient's lisinopril and metformin are placed on hold, and an insulin sliding scale is ordered. A chest x-ray again reveals a right lower lobe infiltrate. She is continued on oral levofloxacin, but the dose is decreased based on her renal function, and sputum for Gram stain as well as culture and sensitivity is sent. Patient C also has blood cultures drawn. She is admitted with diagnosis of CAP, exacerbation of asthma, diabetes, dehydration, and mild acute renal failure. She is placed on albuterol nebulizer treatments every 4 hours or more often as needed, and she is given heparin 5000 Units subcutaneously for deep vein thrombosis prophylaxis.
Comments and rationale : Patient C represents a case in which the initial antibiotic therapy was correct, but the patient's pre-existing conditions and severity of illness made continued outpatient therapy unwise. Physician consultation is always recommended for patients with oxygen saturations of less than 90% on room air, rigors, changes in mental status, abnormal vital signs, or comorbid disease (e.g., diabetes, HIV, cancer, or COPD).