Clinical Update on the Management of Common Infectious Diseases

In her talk “Infectious Diseases Update 2013” at the 2013 Southern Hospital Medicine Conference in New Orleans, Julia Garcia-Diaz, MD, internist at Ochsner Medical Center, discussed the spread of hepatitis C, HIV, and Clostridium difficile infections and related problems.

Garcia-Diaz observed that there are 180 million people worldwide infected with hepatitis C (HCV); it is the most common chronic blood-borne in the United States, with more than 5.2 million infected people and rising. Chronic HCV infection reduces life expectancy as much as smoking, and mortality associated with the condition now exceeds that of HIV. Typically patients develop chronic HCV after contracting acute HCV. Some people recover completely, but 70-80% become chronic. If this occurs, cirrhosis results, with some patients progressing to liver cancer. Chronic HCV patients may benefit from antiviral therapy to reduce their overall mortality.

HCV infection also results in increased mortality from extrahepatic diseases, including circulatory diseases and renal diseases. It may stimulate atherothrombosis by triggering a cascade of immune and inflammatory responses, either locally within vascular tissue or systematically through inflammatory mediators.

There are many risk factors for developing HCV. They include receiving blood products or solid organ transplants before 1992; taking recreational drugs by injection or intranasally; long-term kidney dialysis; regular contact with blood on the job or sustaining needle injuries; unprotected sexual contact with an HCV-infected person; infected mother; receiving tattoo or acupuncture with contaminated needles; sharing personal items with infected person; HIV infection; having a birth date between 1945-1965. Baby boomers have a rate of infection five times higher than other cohorts. Garcia-Diaz noted that 75% of infected people are unaware of their status; about one-third of HCV patients report no risk factors. With such a high rate of undiagnosed HCV, there is an obvious need for improved screening guidelines.

The CDC recommends that everyone born from 1945-1965 be tested, that those infected be referred for treatment, and that they be screened for alcohol use and receive intervention if clinically indicated. The US Preventive Services Task Force recommends that people aged 15-65 years, younger adolescents and older adults at increased risk, and pregnant women be tested.

As to HIV, she noted that 49% of worldwide cases reported in 2013 are women, 7.5% are children, most of whom become infected by their mothers. The CDC reported in 2009 that of the 1,148,200 HIV-infected persons in the US, 18% are unaware of their infection; 85% of females were diagnosed, 81% of males; 36% and 32% were prescribed antiretroviral therapy (ART), respectively; 26% and 25% were in viral suppression.

The US Public Health Service recommends postexposure prophylaxis (PEP) when report of exposure is delayed by over 72 hours; infection is from an unknown source; in a pregnant woman; woman is breast-feeding; source person is resistant to ART; initial PEP is toxic (medicate symptoms); patient is seriously ill.

The preferred PEP regimen consists of raltegravir 400 mg PO twice a day plus one Truvada (tenofovir 300 mg + emtricitabine 200 mg) once a day.

Garcia-Diaz also discussed several issues related to the management of C. difficile infections (CDI). She said CDI is mostly associated with severe diarrhea from antibiotic therapy. Infection rates tripled in the US from 2000-2005, with overall mortality now reported at 7.1%.

Initial episodes that are mild to moderate are usually treated with metronidazole. Severe infections are typically treated with vancomycin. Doses below 500 mg/day may be just as effective as higher doses. Fidaxomicin, a newer antibiotic that is less disruptive to normal gut flora, can be more effective than vancomycin in curing CDI and preventing recurrence.

Donor feces transplant is a relatively new strategy for treating recurrent CDI that supplies gut flora from healthy donors to CDI patients. The donor fecal matter is processed and given by infusion. The treatment has proven to be highly effective, with more than 90% of patients reported cured, with no relapse, compared to about 31% treated with vancomycin.

Finally, Garcia-Diaz said that the widespread use of antibiotics has led to the growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections worldwide. Other commonly used antibiotics also have adverse effects. Some of the more serious include azithromycin-related mortality in patients with underlying heart disease, and severe dysglycemia from levofloxacin, ciproflxacin, and moxifloxacin in diabetic patients.