Spirochete Basics and Related Conditions for the Physician Assistant Exam
The spirochete-related diseases can be debilitating and disabling to the max if they aren’t detected early, as the Physician Assistant Exam (PANCE) will expect you to know. The spirochetes are Gram-negative bacteria. Rocky Mountain spotted fever is also covered, which is caused by a Gram-negative coccobacillus, not a spirochete. Its clinical presentation and mode of transmission are similar to Lyme disease.
Rocky Mountain spotted fever
Rocky Mountain spotted fever is a tick-borne illness that can be fatal if it isn’t recognized and promptly treated. It’s caused by the bacterium Rickettsia rickettsii. Historically, it was found in and around the Rocky Mountains, but today you can find it all across the United States. It’s particularly prevalent in the Southeast.
The initial symptoms can include high fever, nausea, anorexia, and vomiting. This combination can be confusing to the clinician because you can attribute these generalized symptoms to a number of illnesses. The classic triad for Rocky Mountain spotted fever is fever, rash, and headache. These symptoms can occur anywhere from 3 to 14 days after the initial tick bite.
Here are three key points concerning Rocky Mountain spotted fever:
The fever associated with this condition isn’t a sissy fever. People with Rocky Mountain spotted fever are toxic and sick, with fevers on the order of 38.9–39.4°C.
This illness can affect multiple organ systems and can cause acute respiratory distress syndrome, acute renal failure, elevated liver enzymes, and low platelets, to name but a few.
The treatment is doxycycline. It’s usually given for 10 to 14 days. Be aware that a side effect of this medication is photosensitivity.
Lyme disease is similar to Rocky Mountain spotted fever in three ways: Lyme disease is a tick-borne illness, it has a characteristic skin rash, and it’s treated with doxycycline; however, treatment for Lyme disease lasts 21 days, not 10 to 14.
Lyme disease is transmitted by the deer tick, and the bacterium mainly responsible is Borrelia burgdorferi. Lyme disease can affect multiple body areas, and the presentations can be confusing because Lyme disease is a great mimicker of other medical conditions, including rheumatologic conditions. Here are three key points about Lyme disease:
The characteristic skin rash is called erythema migrans. It looks like a bull’s-eye, and it usually appears on an extremity, although it can appear anywhere. The time course to presentation of the rash can vary. It can occur a few days after the tick bite, or it may not present itself for a few weeks. Again, this characteristic skin rash isn’t always present.
Lyme disease can do a lot more than just cause a skin rash. It can affect the heart, the joints, and the central nervous system. One big clinical manifestation you need to be aware of is Lyme-induced meningitis.
Lyme disease can cause a Lyme carditis. The most common clinical presentation of Lyme carditis is second- or third-degree heart block in a person with no cardiac risk factors. The person usually needs emergent cardiac pacing as well as intravenous ceftriaxone for treatment, not just oral doxycycline. This is a very high-yield testing point.
The laboratory evaluation of Lyme disease is based on two tests: the enzyme-linked immunosorbent assay and the western blot. Both must be positive to confirm a diagnosis of Lyme disease. They may be negative early in the course of the disease, so they need to be clinically repeated, especially if you have a high clinical suspicion that Lyme disease is present.
Lyme disease has been implicated in chronic fatigue and fibromyalgia syndrome as an inciting factor of a persistent systemic inflammatory response. Fibromyalgia syndrome can be debilitating.
Syphilis, an STD, is caused by the bacterium Treponema pallidum. Syphilis occurs in several stages: primary, secondary, and tertiary. If you treat it early, you can usually prevent progression to the next stage. Think about the clinical aspects of syphilis as they pertain to each stage of the disease:
Primary syphilis: The initial manifestation of syphilis is the painless lesion known as the chancre. It can present within 1 week or as late as 3 months after exposure. The lesion is maculopapular, usually located in the penile region in males and the cervical region in females. The treatment is one dose of benzathine penicillin administered intramuscularly.
Secondary syphilis: If untreated, primary syphilis can progress to a secondary syphilis. The main clinical manifestation is a rash that can affect the hands and feet as well as the upper and lower extremities. Symptoms include condyloma latum, which are grapelike clusters of warts that can present in various places. Reddish papules all over the body are a possibility, too.
Tertiary syphilis: Tertiary syphilis, also called neurosyphilis, can cause dementia, which may be an initial presentation. There are another 18 symptoms, too, including blindness, depression, and seizures. The treatment for tertiary syphilis is intravenous penicillin, given over several weeks.
The initial lab test used to screen for syphilis is the rapid plasma reagent. If it’s positive, then a Venereal Disease Research Laboratory test is often ordered next. The best confirmatory test for syphilis is the fluorescent treponemal antibody absorption test. This test can stay positive for a lifetime — it doesn’t wane with treatment.
You’re evaluating a 65-year-old man who is being treated for a bacterial infection. He complains of shortness of breath and shaking chills. On physical examination, his temperature is 37.8°C, pulse is 100 beats per minute, and his blood pressure is 90/60 mmHg. He says that these symptoms occurred a few hours after taking the prescribed antibiotic. What’s the most likely cause of this man’s symptoms?
(A) Resistant syphilitic infection
(B) Untreated Gonococcus
(C) Immunosuppression with HIV
(D) Jarisch-Herxheimer reaction
(E) Complicated urinary tract infection (UTI)
The correct answer is Choice (D). Sometimes after you initiate treatment for bacterial infection, the person begins to feel worse before he or she feels better.