Viruses Flashcards
Name all the members of the picornavirus family and their shared characteristics
Shared features:
- Positive sense, Replicate in cytoplasm, Form large polyportein product activated by cleavage into smaller segments
- Naked; Acid-stable; Fecal-oral transmission
Members: Hep A, Rhinovirus, Polio, Coxacki A & B
This virus is most known for causing acute viral hepatitis (vomiting, pain, fever, nausea, & RUQ pain). It can cause aversion to smoking tobacco and has no chronic state.
Hepatitis A
This is the cause of the common cold. It’s transmission is respiratory inhalation and is acid labile (both unlike the other picornaviruses)
Rhinovirus
Young patient presents with generalized flu symptoms and has started to develop asymmetric paralysis in the lower legs that seems to be ascending. The problem apepars to be in the anterior horn and LMN cell bodies. What agent causes this?
Polio
Patient comes in with a red vesicular rash on his hands, feet, and mouth. Labs show no bacteria or fungal infection, and it is the middle of July. What is the most likely culprit?
Coxsackie A virus
A patient presents with extremely sharp pain in one side of his chest that makes it difficult to breathe. X ray shows a dilated heart. Labs show no bacteria or fungal infection. What is most likely diagnosis?
Coxsackie B virus –> causes “The Devil’s Grip” (aka: Bornholm’s disease / Pleurodynia)
A 30 year old male presents with explosive watery diarrhea. HPI shows he just got home from a cruise. Labs show no bacteria or fungal infection. What is most likely diagnosis?
Norovirus –> most common cause of viral gastroenteritis & is 90% of all cruise outbreaks
What are the members of the Flavivirus family and what are their shared characteristics?
Shared features: Enveloped; Non-segmented ssRNA viruses
-Transmission: Aedes Egyptei Mosquito (except Hep C)
Members: Dengue virus, Yellow Fever virus, West Nile virus, & Hep C
Pt in Africa presents with fever, headache, and intense muscle & joint pains. Serology shoes thrombocytopenia & Pt is at bleeding risk. Labs show no bacteria or fungal infection. What is most likely diagnosis?
Dengue virus
Pt in Africa presents with jaundice, backache, bloody stool, and bloody vomit. Labs show no bacteria or fungal infection. What is most likely diagnosis?
Yellow Fever virus
Pt in Africa presents with neurologic symptoms due to encephalitis. He also has myelitis with resulting flaccid paralysis & meningitis. Labs show no bacteria or fungal infection. What is most likely diagnosis?
West Nile virus
An IV drug user presents with with jaundice and RUQ pain. Serology shows increased ALT and liver enzymes and biopsy shows high level of lymphocytes in portal tract. What is the most likely diagnosis and what is this patient at risk for in the future?
Pt has Hep C (80% of cases go chronic) –> has chance of hepatocellular carcinoma
A 5 year old presents with a maculopapular rash that starts on the face and spreads down the body; the spots do not darken or coalesce (combine). Physical exam also shows fever w/ postauricular and occipital lymphadenopathy. Labs show no bacteria or fungal infection. What is most likely diagnosis?
Rubella
What is the triad of congenital Rubella?
Cataracts + Sensory-neural deafness + Patent ductus arteriosis
Patient presents with acute bronchitis, fever, myalgia, lethargy, cough, and sore throat. Labs show no bacteria or fungal infection. Serum shows a virus with a helical shaped capsule. What is most likely diagnosis?
Coronavirus –> SARS (Severe acute respiratory syndrome)
This virus causes influenza (the “flu”). CSF shows high protein with low WBC count (albumino-cytologic dissociation). Name the virus and its unique feature of replication, the 3 important virulence factors, and the 2 most important clinical associations.
- Orthomyxovirus –> only RNA virus that replicates in nucleus
- Hemagluttinin (HA): binds sialic acid & causes RBC clumping
- Neurominidase (NA): cleaves sialic acids
- M2 protein: creates pH for viral uncoating - Pneumonia (staph. aureus especially)
- Guillain-Barre Syndrome (ascending paralysis)
If a child is suspected to have a viral infection with Orthomyxovirus, what is a primary medication contraindication and resulting risk factor?
Aspirin –> can cause Reye’s syndrome (life-threatening encephalitis + liver failure)