This transcript has been edited for clarity.
As we head into late summer, the weather is a frequent topic of concern, especially with heat and humidity (and in many parts of the country, extra water). Climate change is often thought to play a role in some of the diseases we're seeing. The reality is, when faced with a patient who has a fever and nonspecific symptoms, it can be quite challenging to determine what's going on.
Until recently, it was all COVID all the time. Of course, that has not been the case now for some time. Although COVID is increasing a bit, with some statistics in July of 2023 pointing toward increased hospitalizations, death rates [from COVID] have remained stable.
So what do I think about when I see a patient with a relatively undifferentiated fever, meaning no particular focus for their symptoms such as the lungs, the urinary tract, or the skin? Some patients present with fever, just feeling awful and run down, and there isn't much else to say about their symptoms. It can be quite perplexing. Some patients are labeled as having a summertime flu or virus. In past years, that wasn't an unreasonable consideration.
For example, enteroviruses are famous for appearing more in later summer months or in early fall. They can cause a febrile illness with pulmonary or gastrointestinal symptoms. But what I'd like to focus on are some of the other diseases that when first encountered, present an opportunity to have an impact on the patient's health.
The first thing to think about is where the patient has been in the past 2-4 weeks. The reason for this is tickborne diseases. Lyme disease is the most common vector-borne illness in the United States transmitted by the Ixodes black-legged tick, and it can be acquired up to 30 days after a tick bite, which many people don't even notice. But there is a whole host of other tickborne diseases, so it's important to take a bit of a history as to where the patient has been in the past 30 days and to have some knowledge of common tickborne illnesses in your area.
Lyme disease is famous for being most common in the mid-Atlantic, New England, and upper Midwest states. Rocky Mountain Spotted Fever (RMSF) or human monocytic ehrlichiosis (HME) tend to occur more often in the Southern and South-Central states. But HME can occur in an increasing number of states, and RMSF can occur in any of the lower 48 states.
The importance here is that you'd like to give doxycycline before you even have a diagnosis, when someone lacks a characteristic rash (such as erythema migrans) or a petechial rash that can take 3-5 days to develop in the case of RMSF.
Other conditions could be mosquito borne, which most commonly include West Nile virus infection. The risk is highest in people over age 50 years or in immunocompromised patients. This can present with just flu-like symptoms with a headache. But in about 1 in 150 people, West Nile virus can cause neuroinvasive disease, meningoencephalitis, and more rarely, a flaccid myelitis infection. Much less common arboviruses include Eastern or Western equine encephalitis virus, Powassan, and others.
You can get some hint about what might be going on with a patient by checking the CDC's ArboNET to find out which tickborne illnesses are most common in your area or, for example, whether West Nile virus has been increasingly reported in your area. There are often hotspots for the arbovirus infections. ArboNET is a surveillance entity that I use. They provide references that you can check to read about diseases of concern and determine whether you want to order testing or just proceed to lumbar puncture.
With the warm weather, not everyone is taking care with proper refrigeration and hygiene techniques, and there are often more foodborne infections, including salmonella and toxin-based infections such as Staphylococcus aureus. In warmer water, patients can acquire a Vibrio infection. If they present with a severe cellulitis, often with bullae or other skin changes that are a bit beyond a typical cellulitis, and they have been exposed to brackish water, then think about a Vibrio species (Vibrio vulnificus and others). Patients with iron overload or liver disease may have ingested Vibrio with insufficiently cooked oysters or seafood.
These are some infectious diseases I mention when speaking with infectious disease fellows here at the medical school or when we are seeing patients during the summertime. It's worth running through this list when dealing with an acute fever but little else at hand. It's by no means a comprehensive list, but I hope it provides some help and some references that might be helpful for you if you need to take a closer look at what might be going on in your region.
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Cite this: Late Summer Fevers: History Is Paramount - Medscape - Aug 14, 2023.
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