It's not something that I commonly ask patients with #CAP but I think I will insert the question about them owning a parrot or bird into my questioning
In the 1960s and 1970s it was the model organism that laid the foundation for modern chlamydia research.
Psittacosis is also known as avian chlamydiosis, ornithosis, and parrot fever.
It causes an atypical pneumonia when it infects the lungs.
All birds are susceptible, pet birds and poultry are most frequently involved in transmission to humans but not human to human
It can also be found in non-avian domestic animals, such as cattle & sheep, but cases of clinical disease & transmission to humans have not been proven
It is thought to comprise approximately 1% of all CAP cases but only <50 are reported in the US each year
Due to lack of routine testing, incidence & prevalence are hard to establish.
It is transmitted by air droplets from feces, urine, respiratory secretions, & feather dust.
Dried organisms remain viable for months. YIKES
Infection in the mucosal surfaces of the lung promotes a host immune response, leading to an autoimmune reaction and manifesting as atypical pneumonia
It commonly presents in a young to middle-aged man w/ fever (most common symptom), chills, headache, myalgia, and dry cough.
When systemic, it may present w/ hepatosplenomegaly, hepatitis, endocarditis, myocarditis, and encephalitis
And wait for it......A pulse-temp dissociation (#FagetsSign) has been described for psittacosis pneumonia.
Confirmation is w/ serologic testing, namely micro-immunofluorescent antibody test (MIF).
Cultures are discouraged due to being difficult, infectious to lab personnel
Tx is with doxycycline 100 mg PO or intravenously (IV) 2 times per day for 7 to 10 days.
Macrolides are second-line agents. Azithromycin 250 to 500 mg PO once daily is favored over erythromycin.
Full recovery may take from 6 to 8 weeks, including residual changes on chest films.
Mortality rate in the United States is < 1% with early diagnosis and appropriate treatment
Hematogenous dissemination then can occur typically 4 to 10 weeks later, giving rise to secondary syphilis. <40% of pts w/ syphilis have primary syphilis diagnosed. These “Secondary” lesions last for several weeks before spontaneously resolving. Coined “early, latent infection”
What does late infection mean? When syphilitic lesions recur after 1 year from the initial eruption, or seropositivity is detected more than 1 year after the initial eruption, it is termed late latent syphilis.
Some optics neuritis pearls in a short #Medtweetorial 🧵…. We all know that optic neuritis is frequently associated with multiple sclerosis (MS). But optic nerve inflammation can exist from autoimmunity, infection, granulomatous disease, paraneoplastic disorders, & demyelination
Classical ON from MS is unilateral, moderate, painful color vision loss with an afferent pupillary defect & normal fundus examination.
In those with ON, 95% of patients showed unilateral vision loss & 92% had associated retroorbital pain that frequently worsened w/ eye movement.
If you have not listened to the @CuriousClinPod most recent podcast (Episode 10: Why does metronidazole treat both bacterial and parasitic infections?) then I suggest you tune in.
I'll summarize their show notes here in short #medtweetorial
First a question:
Was metronidazole first used as an antibiotic or as an antiparasitic?
If you guessed antiparasitic, then you would be correct!
It was developed in the 1950s to treat the parasite trichomonas & then was used in the 1960s to treat other parasitic infections, like giardia and amoebiasis.
A 31-year-old M born and raised in Brazil w/ no PMH presented with a 3 mon history of worsening DOE, orthopnea, 7kg weight loss, abdominal distention, dry cough, and syncope
An interesting fact from @3owllearning : Depending on the clinical problems, the studies of disease probability for differential diagnosis often show 10 - 25% of cases are unexplained, even after careful examination and testing.