Doxycyline Deficiency State – Diagnostic Schema From The Clinical Problem Solvers

Return to page 1 of this post.

Transcript of the video:

High clinical problem solvers. My name is Stephanie and I’m a third year internal medicine resident at the University of California, San Francisco Today, I’m excited to review with you, the doxycycline deficient state in a schema for doxycycline responsive zoonotic infections.

What is doxycycline deficiency? Doxycycline deficiency is a favorite term among many infectious disease doctors and infectious disease wantabees like me to bring attention to many types of illnesses that can be hard to diagnose but that are doxycycline responsive. A classic case of this might be a patient with fever of unknown origin where the patient seems to improve from a course of doxycycline.

So if there’s a history of animal exposure or outdoor activity in the summer, you will hopefully consider these doxycycline responsive zoonotic infections.

Okay, let’s start with the clinical syndrome.

While there are unique presentations of these infections most doxycycline deficiency syndromes carry a common clinical syndrome: Fever, headache, and myalgia. More succinctly, this is what you might consider a viral or influenza-like illness, remember that patients can also have nausea and GI distress, as well. And since there are so many different animal and geographic exposure details to remember, it’s helpful to use all the characteristic clues we can to arrive at the correct diagnosis.

If you see a characteristic rash like the central clearing of erathema migrans with the bulls-eye rash of Lyme you’re pretty much done.

The caveat here is that many patients with Lyme, don’t have the target rash. In many cases of rash of Lyme don’t have the central clearing. If you see a macularopapular or petechial rash that starts from the wrist and ankles and move centrally towards the trunk sometimes affecting the palms and soles, it points you to the rickettsial disease of Rocky Mountain spotted fever.

If it starts on the trunk, and then spread outwards, you more likely have a case of rickettsia from a flea bite-causing Typhus. Depending on which rickettsia or flea was responsible, you may or may not see a black eschar.

Leptospirosis [Weil’s Disease] has the characteristic conjunctive suffusion. And in more severe cases, patients will also be jaundiced. Now, let’s talk about the characteristic exposures.

If your patient remembers a tick bite think of borrelia which can cause Lyme and Relapsing Fever. Rickettsia which can cause Rocky Mountain spotted fever and Typhus and Erlichia, which causes or Erlichiosis or Anaplasmosis,depending on the region of the United States. Tularemia is transmitted by ticks as well as when people come into contact with infected rabbits and wild rodents.

Contact with animals should make you consider Q fever or Brucellosis, Leptospirosis and Tularemia. Here’s a cool Pearl Q fever spores have been found 10 miles downwind of animals. These spores can fly.

The last helpful clues are your basic labs. If you see the triad leukopenia, thrombocytopenia, and elevated liver enzymes, suspect an Anaplasmosis, Erhlichiosis, Ricketsial disease and Relapsing Fever. Brucella and Leptospirosis might also sometimes fall under this category. if you’re also seeing a concurrent hemolytic anemia, don’t forget about the babesiosis, which is not doxycycline responsive.

There are many other zoonotic infections, of course, some of which are treated with supportive care, or even other antibiotics. But the key here is that this list of zoonotic infections are incredibly responsive to doxycycline and doxycycline should be given even before a definitive diagnosis (which is often serological) is made.

So in summary, remember this entity of doxycycline deficiency, the core clinical syndrome is fever, headache, and myalgia. Things to clue you in on, history. Examine lab findings are the right exposure, a characteristic rash or leukopenia, thrombocytopenia, and elevated liver enzymes. Rapid improvement with doxycycline is a powerful clue while you wait for your diagnostic confirmation.

Return to page 1 of this post.

 

This entry was posted in Clinical Problem Solvers, Diagnostic Schema, Infectious Diseases. Bookmark the permalink.