Biomedical subjects
T T Yoshikawa
Publications and source records attributed to T T Yoshikawa.
Elimination of tuberculosis from the United States.
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Treatment of nursing home-acquired pneumonia.
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Fever response in elderly nursing home residents: are the older truly colder?
OBJECTIVE: To test the hypothesis that many nursing home residents with an apparently blunted fever response (maximum temperature less than 101 degrees F) may actually have a significant change in temperature (delta T greater than or equal to 2.4 degrees F) which is not recognized because of a low baseline temperature. DESIGN: Retrospective chart review for cases of infection that met specific criteria and for chart-recorded baseline and infection temperatures. Chart-recorded baseline temperatures were prospectively compared with re-measurement of morning temperatures. SETTING: Nursing Home Care Unit of the VAMC West Los Angeles. PATIENTS: Random review of 40 residents' charts resulted in the detection of 69 infections among 26 residents over a 20-month period. Fifty randomly selected residents prospectively underwent comparison of chart-determined and actual re-measurement of baseline temperatures. RESULTS: In 50 randomly selected residents, the mean oral baseline temperature of 97.4 +/- 0.2 (degrees F +/- SEM) closely approximated the mean nurse-recorded measures in the charts (97.6 +/- 0.1). Chart review detected 69 infections among 26 residents, with 53 episodes having a temperature recorded during the infection. The mean maximum temperature (Tmax) during an infection was 101.3 +/- 0.3 (degrees F +/- SEM) but 47% (25/53) of the episodes had a "blunted" fever response (Tmax less than 101 degrees F). Of the 25 "blunted" fevers (Tmax less than 101 degrees F), about one-fourth demonstrated an adequate change in temperature from baseline (delta T greater than or equal to 2.4 degrees F) but failed to reach 101 degrees F because of a low baseline. Most infections (89%) had a Tmax greater than 99 degrees F. CONCLUSION: Establishing a nursing home patient's basal temperature and monitoring for changes in temperature (delta T greater than 2.4 degrees F) and/or lowering the threshold for recognition of fevers (to 99 degrees or 100 degrees F) in nursing home residents with a change in function should assist in early recognition of infections.
Pathogenesis, management, and prevention of infective endocarditis in the elderly dental patient.
Aortic stenosis and mitral valve insufficiency are common precipitating causes of infectious endocarditis in older persons. These degenerative cardiac valvular lesions may result from an exaggerated calcification process seen in association with aging. Mitral valve prolapse, especially when noted in an older man, may predispose the person to infectious endocarditis. Infectious endocarditis is harder to diagnosis and treat in older persons, and about half of patients die of the disease or its complications. Prophylactic antibiotics must be prescribed for patients with degenerative cardiac or atherosclerotic valvular defects having dental procedures likely to produce a bacteremia.
Clinically inapparent (asymptomatic) bacteriuria in ambulatory elderly men: epidemiological, clinical, and microbiological findings.
In a prospective longitudinal study, ambulatory elderly men were followed from 1 to 4.5 years to gain insight into the prevalence rates, clinical characteristics, and patterns of clinically inapparent (asymptomatic) bacteriuria (CIB). The prevalence of CIB was 12% (29/238) and increases with age. Unlike the gram-negative organisms that cause overt urinary tract infection in this age group, gram-positive organisms dominated the CIB group. Both the CIB and abacteriuric patients have multiple chronic medical conditions and are indistinguishable on that basis. Twenty-nine elderly men with bacteriuria and 105 abacteriuric subjects were followed with serial urine cultures. During the study period the bacteriuric subjects exhibited spontaneous temporary or permanent resolution (76%, 22/29), intermittency (21%, 6/29), and probable bacterial persistence (38%, 11/29). No consistent pattern of bacteriuria was evident. Therefore, antimicrobial therapy is not warranted in the treatment of asymptomatic or clinically inapparent bacteriuria in ambulatory elderly men.
Salmonella outbreak in a nursing home.
We performed a retrospective review of an outbreak of Salmonella gastroenteritis that occurred in a community nursing home in 1987. Forty-four of 199 residents had a diarrheal illness; Salmonella heidelberg was isolated from the stool in 19 cases. Although the distribution of cases suggested a common source for the outbreak, no common source of infection could be demonstrated, despite extensive investigation. The clinical presentation of symptomatic individuals ranged from mild diarrhea to a severe gastrointestinal illness, and 26% of symptomatic, culture-positive patients required hospitalization. The median duration of pathogen excretion during convalescence in untreated residents was six weeks, but six patients who were treated with antibiotics shed S. heidelberg for a median duration of 14.5 weeks. We conclude that (1) the clinical spectrum of Salmonella gastroenteritis in nursing-home patients is variable, ranging from mild to severe illness; and (2) nursing-home Salmonella outbreaks impose a high economic burden because of expense of epidemiologic investigation, prolonged isolation measures, hospitalization for severely ill residents, and potential institutional closure.
Antimicrobial therapy for the elderly patient.
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Analysis of cutaneous delayed-type hypersensitivity reaction and T cell proliferative response in elderly nursing home patients: an approach to identifying immunodeficient patients.
Clinical experience suggests the delayed-type hypersensitivity (DTH) skin test lacks sensitivity in assessing the integrity of systemic cell-mediated immunity (CMI) or the status of recent or remote mycobacterial infections in elderly nursing home residents. In an attempt to clarify this issue, DTH reaction to purified protein derivative (PPD), tetanus toxoid and Candida albicans was compared with circulating thymus-derived lymphocyte (T cell) proliferation (TCP) to stimulation with PPD and anti-CD3 antibody in 24 randomly selected nursing home residents. The DTH reaction and the TCP response correlated reasonably well among the DTH reactors but poorly among DTH nonreactors, suggesting there may be age-related immunologic changes in the skin itself. Also, the DTH skin test to PPD alone was found to be a poor index of the integrity of systemic CMI.
Utility of fever, white blood cells, and differential count in predicting bacterial infections in the elderly.
A total of 221 elderly patients between the ages of 70 to 99 years who presented to a community-based teaching hospital emergency room were prospectively evaluated by assessing for fever (greater than or equal to 37.5 degrees C), leukocytosis (greater than or equal to 14,000/mm3) and bandemia (greater than 6%) as a screening method for predicting the presence of bacterial infection. Thirty-three patients had documented bacterial infections. Although with increasing body temperature the percent of patients who were infected increased, 48% of the infected elderly patients had no fever. In patients with fever, 39% had a bacterial infection compared to only 9% in the afebrile group. In patients with fever, leukocytosis, and bandemia, all patients were infected. Conversely, in the absence of fever, leukocytosis, and bandemia, only 6% had bacterial infection. All elderly patients who present with an acute or subacute change in health status or functional capabilities associated with fever, leukocytosis, or bandemia should be carefully assessed for the high probability of a bacterial infection.
Correlation of estimated renal function parameters versus 24-hour creatinine clearance in ambulatory elderly.
This study evaluates the correlation between estimated renal function parameters (ie, creatinine clearance by the Cockcroft-Gault and Lott-Hayton formulas, serum creatinine and blood urea nitrogen) and 24-hour creatinine clearance in 15 young and 15 elderly subjects. Correlation coefficients (r) for the elderly group comparing Cockcroft-Gault and Lott-Hayton against 24-hour creatinine clearance were 0.73 (P less than .005) and 0.60 (P less than .02) respectively, and r for the young subjects were 0.37 (P greater than .05) and 0.57 (P less than .05), respectively. In 13 elderly subjects with creatinine clearance of 60 mL/minute or less, four (31%) had blood urea nitrogen of 20 mg/dL or less and 13 (100%) had serum creatinine between 1.0-1.5 mg/dL. We conclude that the formulas of Cockcroft-Gault and Lott-Hayton are valid in ambulatory elderly patients who are functionally independent without severe underlying disease, have normal body weight and are not on medication affecting renal function. Furthermore, in this select elderly population, an apparently normal serum creatinine (1.0-1.5 mg/dL) and blood urea nitrogen (20 mg/dL or less) may frequently represent a 24-hour creatinine clearance of 60 mL/minute or less.
Pneumonia, UTI, and decubiti in the nursing home: optimal management.
Infections in the nursing home population will increase in importance with the predicted rapid growth of the number of persons age 85 and older in the US. The nursing home population is frail, debilitated, and at high risk for morbidity and mortality due to infections. Coupled with limitations in diagnostic interventions in this population, empiric antibiotic therapy is an important aspect of this management. Pneumonia, catheter-related urinary tract infection, and infected pressure sores comprise the major infections in nursing home patients. This review focuses on the management of these infections.
Fever response in old and young mice after injection of interleukin 1.
In an attempt to determine why certain elderly humans show a blunted febrile response to infection, a mouse model was developed. Interleukin 1 (IL1), previously called endogenous pyrogen (EP), the predominantly macrophage-derived mediator of fever, was obtained from supernatants that were generated by stimulating macrophages obtained from young and old mice. The dose versus febrile response curves were generated by injecting crude or partially purified supernatants that contained IL1 into the tail veins of young and old mice. Old mice responded with less fever than young mice to both crude and partially purified supernatants, suggesting that one mechanism for the blunted fever response observed with aging may be an altered response to EP.
The aching head. Intracranial suppuration due to head and neck infections.
Many infections of the head and neck may progress to cause more serious suppurative complications that involve the brain and its associated structures. Because many, if not all, of these infectious diseases present as headache, it would be appropriate to discuss all these clinical entities, but because of space limitations, this article focuses on brain abscess, subdural empyema, and cranial epidural abscess. These three pyogenic infections are reviewed in relation to their causal relationship to common and important pericranial infections.
Fever and aging: central nervous system prostaglandin E2 in response to endotoxin.
The pathophysiology of the blunted febrile response often seen in elderly individuals with infection is not well understood. In this study, we attempted to determine the impact of aging on prostaglandin E2 release from the brain in response to endotoxin (LPS) stimulation. Eight young (4-6 month) and eight old (24-28 month) BALB/c mice were studied. Right and left half brains from old and young mice were either stimulated with LPS or control solution. Each mouse provided a stimulated and a control value. Results were reported for each mouse as the difference (stimulated minus control) in picograms of PGE2 released per milligram tissue and as the percent of baseline (control). Significant stimulation was demonstrated in the young mice, mean difference being +3.7 pg/mg, SD = 2.2 (Student's paired t, p less than 0.01) or +44% of control. In the old mice the mean difference was +2.9 pg/ml, SD = 6.7, or +22%, which was not statistically significant. Moreover, in three of eight old mice, there was a lack of PGE2 stimulation. The authors conclude that in a select group of old mice ("nonresponders"), the failure to mount a febrile response to an infection may be related to diminished release of PGE2 from the brain.
Prevalence of thyroid disease and abnormal thyroid tests in older hospitalized and ambulatory persons.
To determine the utility of laboratory tests for diagnosing thyroid disease in the hospitalized elderly, we measured serum thyroid-stimulating hormone (TSH), thyroxine (T4), free thyroxine index (FT4I), triiodothyronine (T3), and free triiodothyronine index (FT3I) in 125 geriatric inpatients, mostly men, and compared the results to those in elderly ambulatory patients. Hypothyroidism (TSH greater than 10 microU/mL with a low T4 and FT4I or clinical findings) was present in 7.8% (nine of 116) of male inpatients compared to only 0.7% of male ambulatory controls (P less than 0.01). Only a few women were studied but 17% (two of 12) were hypothyroid compared to 2.4% of ambulatory elderly women. Three of the hypothyroid inpatients had no clinical clue to their hypothyroidism. Further, decreased thyroid reserve or subclinical hypothyroidism (TSH greater than 10 microU/mL with a normal T4 and FT4I and no overt clinical findings), a condition which may lead to overt hypothyroidism, was more common in male inpatients (4.3%) than in male ambulatory controls (1.8% [P less than 0.01]). Thus, a clearly elevated serum TSH (greater than 10 microU/mL) was more common in inpatient (12.1%) than in ambulatory (2.4%) elderly men (P less than 0.01). Four inpatients and nine ambulatory controls had an elevated T4 and FT4I, but in only one (0.8%) inpatient and one (0.6%) control was a final diagnosis of hyperthyroidism made; the others had no clinical findings and a normal or low T3 and FT3I.(ABSTRACT TRUNCATED AT 250 WORDS)
Pyuria: its predictive value of asymptomatic bacteriuria in ambulatory elderly men.
A total of 664 urine samples collected from 254 asymptomatic, ambulatory, elderly men was examined for pyuria with a standardized glass slide microscopy method. The presence or absence of more than 10 polymorphonuclear leukocytes per high power field was highly predictive of the presence or absence of significant bacteriuria, respectively. The determination of pyuria in this select population may be a useful and inexpensive test to screen for bacteriuria.
Fever and aging.
The pathogenesis and clinical relevance of fever is reviewed. The interrelationship between fever and other biologic responses to infection is summarized. A blunted or absent fever response to infections observed in some elderly patients may be due to defects in thermoregulation. These abnormalities in thermoregulation may include impairment of both behavioral and physiologic responses.