Limited evidence for diagnosing bacterial skin infections in older adults in primary care: systematic review

Skin and soft tissue infections in the elderly

PURPOSE OF REVIEW

To highlight the peculiarity of skin and soft tissue infections (SSTIs) in elderly patients and to provide useful elements for their optimal management.

RECENT FINDINGS

In the COVID-19 era, early discharge from the hospital and implementation of outpatient management is of key importance.

SUMMARY

Elderly patients are at high risk of SSTIs due to several factors, including presence of multiple comorbidities and skin factors predisposing to infections. Clinical presentation may be atypical and some signs of severity, such as fever and increase in C-reactive protein, may be absent or aspecific in this patients population. An appropriate diagnosis of SSTIs in the elderly is crucial to avoid antibiotic overtreatment. Further studies should explore factors associated with bacterial superinfections in patients with pressure ulcers or lower limb erythema. Since several risk factors for methicillin-resistant Staphylococcus aureus (MRSA) may coexist in elderly patients, these subjects should be carefully screened for MRSA risk factors and those with high risk of resistant etiology should receive early antibiotic therapy active against MRSA. Physicians should aim to several objectives, including clinical cure, patient safety, early discharge and return to community. SSTIs in the elderly may be managed using long-acting antibiotics, but clinical follow-up is needed.

Skin infections in older adults

Skin infections are extremely common throughout the community in older people. Cellulitis and infected ulcers are the most common cutaneous skin infections in older adults, but various other aetiologies can be identified by community nurses and healthcare staff throughout their area's patient population. Staphylococcus aureus is common and increases morbidity so prompt identification is required. Assessment of the skin and appropriate swabbing is necessary and crucial in order to be proficient when looking after people with skin conditions and infections in the community. This article will cover the basic principles of assessment, investigation and treatment, as well as encouraging an awareness of risk, touching on the common predictors of skin infections in older people.

Biomarkers for diagnosing serious bacterial infections in older outpatients: a systematic review

Background

The value of biomarkers for diagnosing bacterial infections in older outpatients is uncertain and limited official guidance exists for clinicians in this area. The aim of this review is to critically appraise and evaluate biomarkers for diagnosing bacterial infections in older adults (aged 65 years and above).

Methods

We searched Medline, Embase, Web of Science and the Cochrane Library, from inception to January 2018. We included studies assessing the diagnostic accuracy of blood, urinary, and salivary biomarkers in diagnosing bacterial infections in older adults. The QUADAS-2 tool was used to assess study quality.

Results

We identified 11 eligible studies of moderate quality (11,034 participants) including 51 biomarkers at varying thresholds for diagnosing bacterial infections. An elevated Procalcitonin (≥ 0.2 ng/mL) may help diagnose bacteraemia in older adults [+ve LR range 1.50 to 2.60]. A CRP ≥ 50 mg/L only raises the probability of bacteraemia by 5%. A positive urine dipstick aids diagnosis of UTI (+ve LR range 1.23 to 54.90), and absence helps rule out UTI (−ve LR range 0.06 to 0.46). An elevated white blood cell count is unhelpful in diagnosing intra-abdominal infections (+ve LR range 0.75 to 2.62), but may aid differentiation of bacterial infection from other acute illness (+ve LR range 2.14 to 7.12).

Conclusions

The limited available evidence suggests that many diagnostic tests useful in younger patients, do not help to diagnose bacterial infections in older adults. Further evidence from high quality studies is urgently needed to guide clinical practice. Until then, symptoms and signs remain the mainstay of diagnosis in community based populations.

Electronic supplementary material

The online version of this article (10.1186/s12877-019-1205-0) contains supplementary material, which is available to authorized users.