Infectious Disease Alert Updates
By Carol A. Kemper, MD, FACP
TB Screening for High-Tech Workers
SOURCE: ProMED-mail post. Tuberculosis – India (03): National TB control program assessed. July 11, 2015. www.promedmail.org.
We’re seeing only the tip of the iceberg in Silicon Valley. In my infectious disease practice in Mountain View, CA, we’ve seen nine new cases of M. tuberculosis infection (MTb) in the past few months. Two cases were clearly reactivation TB in older Filipinos who have been in the United States for many years. But seven cases are young Asian Indians, all in their 20s or early 30s, working or going to school in the Silicon Valley. Six were male. At least four of these individuals are here on a student or work visa — which requires no TB screening for entry into the United States. Six had pulmonary involvement, and two were sputum smear-positive, including one patient with drug resistance. The other smear-positive case was a young graduate student at one of the state schools in San Jose who was ill, with 35 pounds of weight loss, hoarseness, and cough for four months before presenting for care and being diagnosed with pulmonary and laryngeal MTb — the most highly contagious form for the disease. His smears were 4+ smear-positive on presentation and remained positive for weeks on therapy. He had declined to pay for student health insurance, and had been reluctant to seek medical care.
It is no surprise we are seeing these kinds of cases in Silicon Valley, especially after reviewing recent reports from India. A draft Indian public health report for the “Revised National TB Control Program” (or what is referred to as RNTC), leaked by authorities in India, suggests that MTb may be close to out of control in some parts of India. While the WHO global TB report suggests that cases of TB in India have steadily declined during the previous 10 years, other data suggest this is the result of under-diagnosis and under-reporting.
Approximately two million cases of MTb were diagnosed in India in 2013, representing one-fourth of the world’s cases, and resulting in approximately 270,000 deaths. The recent draft report states that perhaps as many as 1,000,000 additional cases are undetected or unreported. The RNTC program is overwhelmed and underfunded. Delays in procurement of medications are frequent, and sufficient laboratory facilities and technology are lacking. Most importantly, many labs are not able to perform necessary screening tests for susceptibility, and therefore cases of drug resistance may be missed or mistreated. One-third of cases are empirically treated without microbiologic diagnosis. And private hospitals have no obligation to participate in the care of these patients.
In addition, MDR- and XDR-TB is emerging as a major threat in India. Officially 2.2% of new MTb cases in India are MDR. This is considered an underestimate, since many cases have no susceptibility testing performed. And the RNTC program lacks adequate resources and facilities to manage these more complex cases.
I make an argument that immigration reform measures and H-IB visa policy, currently being pushed by the high-tech industry, need to incorporate adequate screening measures for MTb. In their push for adequate skilled workers, tech companies are overlooking an important contagious disease and neglecting the health of their future workforce.
Cellulitis or Pseudocellulitis?
SOURCE: Strazzula L, et al. Inpatient dermatology consultation aids diagnosis of cellulitis among hospital patients: A multi-institutional analysis. J Am Acad Dermatol 2015;73:70-75.
Cellulitis remains a leading cause of hospitalization, and data suggest, with our increasingly obese, diabetic population, the incidence is increasing. Mean hospital stays are estimated at seven days. However, accurate diagnosis of cellulitis can be a challenge — and studies have suggested that up to 28% of hospital cases of cellulitis may be misdiagnosed. Pseudocellulitis, which is a non-infectious, non-necrotizing condition, can mimic cellulitis in many ways, also presenting with warmth, redness, swelling, pain, and even fever and leukocytosis. Distinguishing the two conditions is an important challenge to physicians and infectious disease specialists caring for these patients in the hospital. Over-diagnosis and over-treatment of cellulitis in the outpatient setting may also be common: A recent British study found that 100% of patients referred to a primary care doctor for evaluation of cellulitis were diagnosed with cellulitis, compared with only 10% of those referred to dermatology.
A retrospective review of 1430 inpatient dermatology consults performed at several major medical centers throughout the United States found that 74 (5.1%) were requested for evaluation of cellulitis. Presenting signs and symptoms, risk factors, and outcomes were reviewed and compared for diagnosis of cellulitis vs. pseudocellulitis. Nearly three-fourths (74.3%) of the possible cellulitis cases evaluated were found to have alternate conditions. The most common diagnosis was stasis dermatitis (31%), followed by contact dermatitis (14.5%) and inflammatory tinea (9%). Other diagnoses included drug eruption, erythema chronicum migrans, psoriasis, vasculitis, and lymphedema. One-third were found to have more than one of these diagnoses. Skin biopsies were performed in only one-third of the patients, and the rest were diagnosed based on dermatologic expertise.
Risk factors and presenting signs and symptoms for patients with cellulitis and pseudocellulitis were similar — and, therefore, may not be reliable diagnostic cues. Interestingly, only 5% of those with cellulitis presented with leukocytosis, compared with 16% of those with pseudocellulitis.
These dermatologists argue that clinicians would be wise to consider alternate diagnoses when evaluating patients with cellulitis, and inpatient dermatology consultation may be helpful in distinguishing infectious cellulitis from non-infectious cases. As someone who sees an awful lot of cellulitis, I’d like to know what the dermatologists seem to know — especially since the patients presented similarly, and most did not have skin biopsies performed.
Screening for Creutzfeldt-Jakob Disease Before Invasive Procedures
SOURCE: Brown P, Farrell M. A practical approach to avoiding iatrogenic Creutzfeldt-Jakob disease (CJD) from invasive instruments. Infect Control Hosp Epidemiol 2015;36(7):844-848.
The use of dedicated equipment and surgical instruments for patients with proven Creutzfeldt-Jakob disease (CJD) is standard practice, with incineration of all materials with body fluid or tissue contamination. But problems arise when patients with unproven or unsuspected disease undergo invasive procedures. What about those who have not yet been diagnosed?
These authors suggest a relatively low-cost pre-emptive screening approach may be helpful. Any patient with dementia or cerebellar signs (even if another diagnosis seems likely) being considered for any invasive procedure should have routine screening of spinal fluid for 14-3-3 protein. Based on reports of the specificity (> 90%) and sensitivity of the test, this simple screening tool could significantly reduce iatrogenic risk in hospitals. Alternatively, a test detecting aberrant prior protein in nasal washings may prove useful.
A recent 10-year longitudinal study of neurologic patients in Europe examined the utility of the 14-3-3 protein and other dementia markers in patients with neurologic disease.1 A huge number of cerebrospinal fluid samples were analyzed (n= 29,022). The 14-3-3 proved to be a useful biomarker, with an overall specificity of 90%. In patients with neurodegenerative disease, the specificity of the 14-3-3 prion screening test was 95-97%, compared to that found for other acute neurologic diseases (82-85%).
Hospital infection control programs will have to consider alternate scenarios for risk as well, such as those patients with characteristic symptoms with a negative screening test but nonetheless suspected of having CJD; asymptomatic persons who carry the PrP(sc) gene mutation; and/or asymptomatic individuals who have received potentially contaminated human growth hormone, dural grafts, or blood products.
RESOURCE
- Stoeck K, Sanchez-Juan P, Gawinecka J, et al. Cerebrospinal fluid biomarker supported diagnosis of Creutzfeldt-Jakob disease and rapid dementias: A longitudinal multicentre study over 10 years. Brain 2012;135(Pt 10):3051-3061.
TB Screening for High-Tech Workers
Cellulitis or Pseudocellulitis?
Screening for Creutzfeldt-Jakob Disease Before Invasive Procedures
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