Module 5 Path Continued: Herpes: Rocky, Qfever Flashcards
How does a patient contract cytomegalovirus (HHV-5)?
Via body fluids (transplacental, saliva, urine, breast milk, blood transfusions) and organ transplant or vertically transmitted
What types of patients are at risk of contracting HHV-5?
Immunocompromised patients
1) Patients taking steroids
2) HIV/AIDS (CD4 less than 50)
In a immunocompetent person with HHV-5 what kind of infection will patients get?
Mononucleosis (but usually with EBV)
What is the most common organ transplant that leads to CMV?
Kidney so you will get nephritis
What is the most commonly affected in AIDS patients with CMV?
Retinitis -> cotton wool appearance
–can also affect lungs (interstitial pneumonina), GI( esophagitis), gastritis and duodenitis and colitis
CMV has a tropism for what?
Endothelial cells
Polyclonal B cell activator
What is the best investigation for CMV?
PCR (its a virus)
What are the cytopathic effects of CMV?
Cytomegalo (enlarged cell and nucleus)
Formation of intranuclear basophilic inclusions (owls eyes)
Intracytoplasmic inclusions which are mostly basophilic but can be eosinophilic
marginated chromatin
Patients can get what symptom of CMV if it affects the lungs?
Dry cough (nothing to cough up)
What does HHV5 become latent in?
B cell lymphoma
What are the three M’s of Herpes viruses?
- Chromatin Margination (splitting apart of the chromatin to nucleus)
- Multinucleated Giant Cells
- Nuclear molding ( coming together of nuclei)
What is the pathogenesis for herpes Zoster?
Inhalation of respiratory droplets —- chicken pox —- varicella zoster dormant in DRG —- activates when immunocompromised state (stress because cortisol suppresses the immune system)
If patient has shingles and you have never had chickenpox nor had the vaccine, are you at risk of contracting shingles?
The patient can actually give you the chickpox virus but not actual shingles.
(patient has to be in the vesicle stage though)
What is the presentation of a patient with Shingles?
Painful vesicles and these rupture and to become ulcers and never cross midline and stay in the dermatome of the DRG
What is a complication of shingles?
Even after healing you can get something called post herpetic neuralgia —-neuropathic pain syndrome after shingles lesions are gone
What is the best investigation of shingles? what is the first investigation?
Best: PCR (its a virus so always PCR)
First: Tzanck smear – scrape the vesicle and stain with Giemsa to visualize Tzanck cells (mutlinucleated giant cells ) in syncytia formation
What are the intranuclear eosinophilic inclusions?
Cowdry Type A (only seen in Herpes Zoster)
At what dermatomes does Shingles appear?
T4 (nipple) to the T10 (Umbilicus)
Rabies is normally transmitted to humans from dogs and bat,however, in the US what is the most common way to become infected with rabies?
Bite of a Raccoon or a droppling from a bat into an open cut
What is the prognosis for a patient infected with rabies?
This is based on the site of the bite (distance from bite site to brain determines prognosis)
- –so getting bite on the leg or toe is a much better prognosis then arm or face
- -travels PNS to CNS retrograde axonal transport