Clinical manifestations/diagnosis

Classic symptoms of UTI such as dysuria, urinary frequency and urgency, suprapubic tenderness, and fever are telltale when present. As mentioned previously, however, some or all of these symptoms may be absent despite serious UTI. Atypical presentation of UTI with nausea, vomiting, dehydration, and confusion is common.[26, 27] Urinalysis of a clean catch urine specimen demonstrating pyuria, increased leukocyte esterase, and nitrite is highly suggestive in the setting of the aforementioned clinical presentations. Confirmation of infection with urine culture also permits guidance of antibiotic therapy. Blood culture should be obtained in patients who have more concerning acute illness in order to assess for sepsis.

Quantitative clean catch urine culture revealing 100,000 CFU/mL or greater (for women, confirmed on repeated testing) in persons without symptoms of UTI is considered evidence of asymptomatic bacteriuria. Asymptomatic bacteriuria is common in elderly patients, especially women, and has been linked to institutionalization, bladder-emptying disorders, diabetes, and prior UTI.[28]

Management

Gram-negative organisms are the most commonly cultured UTI pathogens, and empiric therapy should be broadly directed toward these organisms until culture results return.[26, 29] Patients with indwelling urinary catheters are also at increased risk for Enterococcus, and in such patients, coverage of this Gram-positive organism, such as with ampicillin given resistance to cephalosporins, may be prudent. Detection of Staphylococcus aureus in the urine raises concern for endovascular infection, such as endocarditis, because this organism is often spread to the urine hematogenously. Echocardiography and blood cultures are indicated when S. aureus is retrieved from clean catch urine specimen.

Treatment of asymptomatic bacteriuria has not been demonstrated to have an impact on morbidity or mortality and is not recommended.[24] Removal of urinary catheters should be considered and the need for such catheters regularly assessed. Following antibacterial treatment, typically for 7–14 days, repeated urine analysis and culture can be obtained to demonstrate clearing of the organism and resolution of pyuria.

Candida is not infrequently encountered in the urine of elderly hospitalized patients, especially those treated with broad-spectrum antibacterials. In most cases, treatment is unnecessary; however, in patients who are immunocompromised, exhibit symptoms of UTI, or are in need of urological instrumentation, treatment of candiduria should be strongly considered.

Clinical manifestations/diagnosis

As with other infections in the elderly, pneumonia may not be heralded by the usual signs and symptoms. Cough may not be prominent, fever can be absent or mild, and shortness of breath subtle. Nonspecific symptoms of confusion or other mental status change, lethargy, and falling may be the only indications that something is amiss.[32, 33] A high index of suspicion is required, and a chest radiograph should be obtained when the physician is confronted with such changes. X-rays often reveal an infiltrative process, but the absence of an infiltrate on the film does not preclude pneumonia, as dehydration may minimize radiographic evidence of infection.[34] The presence of a cavity suggests anaerobic abscess, TB, or mycotic infection. Sputum analysis, although potentially valuable in the identification of causative organisms, is rarely obtainable, as older individuals may be unable to cooperate with specimen collection or expectorate. When respiratory secretions can be obtained, Gram stain and routine bacterial culture should be performed. Blood cultures may also yield an organism associated with pneumonia. Other non-invasive or minimally invasive studies to be considered include multiplex polymerase chain reaction (PCR) for respiratory viruses on nasopharyngeal cells, obtained by either swabbing the nasopharynx or performing lavage. In addition, urinary antigen testing for Streptococcus pneumoniae is now available. In select cases, testing for Legionella pneumophila and/or Histoplasma capsulatum should be considered by urinary antigen testing. Pulse oximetry and, in some cases, arterial blood gas level should be measured to assess oxygenation status. Viral and other atypical pneumonias, malignancy, and pulmonary embolus should also be considered in the differential diagnosis of the older patient in whom pneumonia is suspected.

Management

Treatment of bacterial pneumonia should be guided by sputum Gram stain and culture. Given the difficulty of establishing a specific bacterial cause of pneumonia via sputum analysis and the seriousness of such infections in elderly patients, empiric therapy directed at the likely culprits is prudent and recommended.[35] Delay in the initiation of therapy risks progression of disease; therefore, treatment should begin within hours of presentation.[36] In community-acquired pneumonia, Streptococcus pneumoniae, Hemophilus influenza, enteric Gram-negative bacilli, influenza, and other respiratory viruses are most common; however, S. aureus and atypical organisms such as Mycoplasma, Legionella, and Chlamydia also occur.[37] Patients residing in nursing homes more commonly experience pneumonia caused by the enteric Gram-negative organisms, oral aerobes and anaerobes, and S. aureus.[16] These organisms (see Table 23.2) are responsible for the lion’s share of pneumonia in the hospitalized patient, but more unusual organisms (including Acinetobacter and Pseudomonas) may also cause disease. Obviously, those patients who are more ill and those unable to tolerate oral intake require inpatient care and intravenous administration of antibiotics. Treatment of most bacterial pneumonia lasts for 7–14 days.

Antibiotic choice must be guided by host and environmental factors such as concomitant illnesses, risk of aspiration, and the setting in which the patient resides.[35] Broader coverage – taking into account drug-resistant organisms and anaerobes – is typically indicated in institutionalized patients compared with those who live at home who may be able to be treated initially with an antipneumococcal fluoroquinolone, third-generation cephalosporin, or macrolide, depending on local drug susceptibility patterns. There is likely a spectrum of risk for drug-resistant bacterial infection spanning from living at home to assisted-living facilities to nursing homes and skilled nursing facilities, and the attendant risk with each setting may influence selection of treatment. In general, the level of independence for activities of daily living as well as the exposures to the healthcare system and specifically antibiotic exposure will determine the risk for multidrug resistance.

Detection of a specific organism can lead to the narrowing of antibiotic therapy. Failure to detect improvement during therapy may indicate that the selected therapy is suboptimal and that a change in antibiotics is required. In such cases, the presence of underlying immunodeficiency, such as that from HIV infection, and atypical infections caused by fungi or P. jiroveci (formerly carinii), should be considered.

Patients with pneumonia who are moderately to severely ill should be hospitalized. Findings associated with poor prognosis in elderly patients with community-acquired pneumonia include PaO2 <60 mm Hg, O₂ saturation <90%, altered mental status, heart rate higher than 125 beats/minute, respiratory rate higher than 30/min, hypo- or hyperthermia, leukocytosis or leukopenia, anemia, hyponatremia, hyperglycemia, multilobar infiltrates, and pleural effusion.[20] In addition, older patients with pneumonia and significant comorbid diseases such as malignancy, immunodeficiency, renal or hepatic insufficiency, or cardiovascular disease may also require inpatient monitoring.

The risk of pneumococcal pneumonia can be reduced by vaccination. Patients who are naïve to the pneumococcal conjugate 13-valent (PCV13) should receive a single dose of PCV13. For those who received pneumococcal polysaccharide vaccine-23 (PPSV23), PCV13 should be administered at least one year after the last PPSV23 dose.[38]

Clinical manifestations/diagnosis

As in bacterial pneumonia, elderly patients with influenza may present atypically, with the triad of cough, fever, and acute onset less evident than mental status alteration, generalized malaise, and other nonspecific complaints.[40] Among patients living in confined settings, the report of a similar illness or actual influenza among other residents or staff is an important epidemiological clue. Secondary bacterial infection with streptococci or staphylococci occurs and typically manifests as a period of worsening of disease after an initial improvement. The chest radiograph may demonstrate bilateral infiltrates – suggestive of a viral pneumonia. Definitive diagnosis is made on nasopharyngeal samples through rapid antigen testing or through PCR testing. The benefit of point-of-care rapid antigen testing must be seriously weighed against a decreased sensitivity.[41]

In travelers returning from Asia or the Middle East, it is important to assess for infection with more virulent strains of influenza or with coronaviruses such as severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS).

Management

Antiviral drugs active against influenza include the adamantine derivatives, amantadine and rimantadine, and neuraminidase inhibitors such as oseltamivir and zanamivir.[42, 43] The adamantine derivatives are only active against influenza A and do not cover influenza B strains. Currently, adamantine derivatives are of very limited use, given the widespread resistance found in circulating strains of the most recent influenza seasons. Also, they are associated with reversible adverse effects involving the central nervous system, such as anxiety, concentration issues, nervousness, and insomnia.

Neuraminidase inhibitors are the drug of choice to treat influenza. Starting treatment early after the onset of symptoms is key to maximum efficacy. However, in elderly patients who are ill or need to be hospitalized, treatment should not be withheld even if several days have passed since symptom onset.

Both oseltamivir and zanamivir can be used as prophylaxis in institutionalized elderly patients in outbreak situations. Per guidelines from the Infectious Disease Society of America, when more than two institutional residents manifest signs and symptoms of influenza-like illness within 72 hours of each other, testing for influenza should occur. When influenza viruses are circulating in the community, even one positive laboratory result in conjunction with other compatible illnesses on the unit indicates that an outbreak of influenza is occurring. In these outbreaks, all residents – not just those on the floor or ward where the first cases have occurred – should receive chemoprophylaxis, regardless of vaccination status. Quarantining of cases does not appear to be a useful strategy.

The most effective method of preventing influenza and reducing its impact on morbidity and mortality of older adults is vaccination. The multi-valent inactivated influenza vaccine is recommended annually for those 65 years and older and younger individuals with chronic medical conditions or who reside in confined settings.[44, 45] The vaccine contains killed virus and cannot cause influenza. Unfortunately, the influence of aging on the immune system is associated with a decreased vaccine response to influenza.[8, 46, 47] Therefore, individuals such as health-care workers who have frequent contact with high-risk older adults should also be vaccinated annually.

Clinical manifestations/diagnosis

Pulmonary TB presents generally as a nonacute illness characterized by weight loss, fever, night sweats, and cough. Some patients may have hemoptysis. Nonspecific constitutional complaints may mask the more classic symptoms, and the diagnosis of TB should be considered in elderly persons with “failure to thrive.” Chest radiographs, tuberculin skin testing and sputum stain, and culture are the foundations of the diagnostic workup for pulmonary TB. Chest films may reveal an area of infiltration – often in the upper lobes – or a cavitary lesion, but patterns similar to bacterial pneumonia can also be seen.[50] The diagnosis is made microbiologically with the culture of sputum for Mycobacterium tuberculosis. The specimen should undergo an acid-fast stain and be plated on specialized media. Unfortunately, sputum may be difficult to collect, and it may take six weeks for the culture to grow sufficiently. In some cases, bronchoscopy may be required to obtain specimens for stain and culture. Given the difficulty of establishing a quick diagnosis, empiric therapy is a consideration when suspicion of TB is high, such as in a patient with a classic chest film and a positive tuberculin skin test. Rapid tests for TB are now available; these molecular assays may be of use in some patients.[51] They are generally used to confirm the presence of TB in respiratory specimens that reveal acid-fast bacilli (AFB). The use of these assays in AFB-negative smears, although not approved for such use by the US Food and Drug Administration (FDA), is tempting in cases in which TB is suspected despite the smear result, and a positive result would be considered strong evidence of the infection.

Tuberculin skin testing is useful for determining prior exposure to TB. As the test relies on cellular immune responses, the false-negative rate of the test increases during advanced age. In some individuals, skin testing itself can boost immune responses to tuberculin such that repeated testing will become positive, giving the appearance of a conversion in the test from initially negative to positive.[52] In settings where skin testing for TB is performed on a regular basis, a two-step procedure at initial intake is advisable. If the initial reaction is negative, a repeated skin test is done two to three weeks later, and the second result is considered final. Bacillus-Calmette-Guérin vaccination may produce skin reactions to tuberculin. For those who received the vaccine as a child, the cross-reactivity to the skin testing should wane by adulthood and not be a significant factor in elderly individuals. Those who receive Bacillus-Calmette-Guérin vaccination as adults should have skin testing done several months after vaccination to establish a baseline test reaction size. Subsequent skin testing can be compared with this baseline result, and increases of more than 15 mm should be considered positive in persons older than 35 years of age.

Gamma-interferon assays of blood are also used to detect latent TB and are now available through commercial laboratories.[53, 54] There are limited data on the accuracy of this assay in the elderly, but a positive result indicates prior exposure. The Centers for Disease Control and Prevention have published recommendations regarding the use of the interferon-γ assay QuantiFeron-TB Gold. They state that the test can be used in all circumstances in which tuberculin skin testing is performed.[55]

All patients with either latent or active TB, regardless of age, should be tested for HIV infection.