Micro USMLE 8-26(7) Flashcards
This patient presents with symptoms of rhinorrhea, headache, sneezing, sore throat, and postnasal drip, all of which are consistent with an?
upper respiratory infection (URI). Rhinovirus is the most frequent cause of the common cold in otherwise healthy individuals, responsible for about 50% of all viral URIs annually. Rhinovirus is a non-enveloped, positive-sense, single-stranded linear RNA virus classified in the Picornaviridae family.
Adenovirus manifests with exudative tonsillitis, cervical adenopathy, and conjunctivitis. Coronavirus is the second most common cause of the common cold. It can also cause otitis media. Individuals with coronavirus present similarly to this patient. Orthomyxovirus causes ?
the flu, not a URI. Parainfluenza virus causes pneumonia, bronchitis or croup (in children) and manifests with more severe symptoms including fever.
Rhinovirus, a single-stranded linear RNA virus of the family Picornaviridae, is the most common cause of upper respiratory infections in adults. Coronaviruses are ?
the second most common cause of URI in adults and should also be considered, particularly if the patient reports a second URI of the season.
This pediatric patient, who was treated for a sore throat 10 days before presentation, has red-tinged urine and edema. In combination with findings of decreased complement, hematuria, and proteinuria on urinalysis, his symptoms point to a diagnosis of?
poststreptococcal glomerulonephritis
Post infectious glomerulonephritis presents between 1 and 3 weeks after a streptococcal infection (skin or throat) with a nephritic syndrome. A type III hypersensitivity reaction is characterized by ?
antigen-antibody complexes that lead to complement activation. Glomerulonephritis streptococcal infection Throat Nephritic syndrome Reaction Type III hypersensitivity
A delayed allergic reaction to penicillin usually manifests with a maculopapular or morbilliform rash 72 hours after exposure to the drug and can therefore be ruled out as the cause of this child’s symptoms. Other hypersensitivity reactions may also be eliminated as the etiology.
A type 1 hypersensitivity reaction is IgE mediated and manifests with different signs and symptoms including ?
rhinoconjunctivitis and anaphylaxis.
A type II hypersensitivity reaction is antibody mediated as IgG binds to an antigen on the surface of target cells. A type IV hypersensitivity reaction is mediated by helper T cells and macrophages and does not involve antibodies.
A 5-month-old girl with respiratory distress (cough, wheezing, subcostal retraction) and a viral prodrome (fever, cough, runny nose), most likely has bronchiolitis. This lung infection is most commonly caused by respiratory syncytial virus (RSV), a single-stranded negative-sense RNA virus that is a member of the family Paramyxoviridae. Transmission is through close contact with an infected individual and typically occurs during the fall and winter. Bronchiolitis is usually self-limiting. In RSV infection, the viral surface contains two characteristic proteins. G protein enables viral attachment to the respiratory epithelium. F protein enables fusion to the respiratory epithelium and causes?
membranes of nearby cells to merge, forming the characteristic syncytia observed on histopathology. Although RSV infection can be diagnosed by direct immunofluorescence of the viral antigen, this test is rarely performed.
The pathogenesis of Bordetella pertussis involves an exotoxin that inactivates Gi to increase cAMP. The mechanism of allergic rhinitis involves IgE-mediated mast cell and basophil degranulation. The pathogenicity of Haemophilus influenzae is partly due to its ?
polyribosylribitol capsule that inhibits phagocytosis and can result in epiglottitis. Mycoplasma pneumoniae infections can induce the generation of oxygen free radicals, which contributes to epithelial necrosis within the lungs and the pathogenesis of bronchiolitis in children.
The most common cause of bronchiolitis in infants and young children ≤5 years of age is RSV, a member of the family Paramyxoviridae, that causes inflammation of the small airways. Its pathogenesis involves the surface protein F, which causes?
nearby cells to merge and induces the characteristic syncytial appearance in pathology. Clinically, the patient may present with rhinorrhea, cough, fever, and decreased appetite.
This patient presents with recurrent oral ulcers localized on the lips, and a biopsy of the lesion shows multinucleated giant cells (see circles on image). These findings suggest an infection with?
herpes simplex virus type 1 (HSV-1) that is causing herpes labialis, or ?cold sores? on the lips. A key finding here is the presence of multinucleated giant cells and intranuclear inclusions, which are characteristic (but not specific) for HSV.
HSV-1 infection can cause a number of other syndromes when an individual is infected for the first time, or upon reactivation of the latent virus. Of the answer options, only keratoconjunctivitis is correct
Impetigo is a localized bacterial infection of the superficial skin that manifests with honey-colored, crusted skin lesions, not painful vesicles as the patient presented is experiencing.
Macular rash may be caused by herpesvirus HHV-6 and HHV-7, associated with roseola infantum. These specific herpesvirus are not known to lead to lip ulcers.
Infectious mononucleosis is associated with Epstein-Barr virus (EBV) infection, while a mononucleosis-like infection can occur with cytomegalovirus (CMV) infection in adults. Although EBV and CMV are herpesviruses, they do not cause recurrent ulcers on the lips.
Oral thrush is a sign of infection with?
fungal Candida species. Symptoms can include painful fissures on the corners of the mouth, but not recurrent ulcers on the lips.
Shingles is caused by a reactivation of varicella zoster virus (VZV) which is also a herpesvirus. VZV can show intranuclear inclusions on pathology but does not cause ulcers on the li
Infection with herpes simplex virus type 1 (HSV-1) may cause herpes labialis (cold sores), which are recurrent ulcers localized on the lips. HSV-1 infection can also manifest as?
keratoconjunctivitis, temporal lobe encephalitis, or gingivostomatitis. Biopsy of an HSV lesion shows characteristic multinucleated giant cells and intranuclear inclusions.
Type 1ColdUlcerLips
This patient presents with myalgia, fever, chills, and headache, followed by development of a dry cough and pulmonary edema. He had recently visited rural Colorado to clean out a cabin. This patient most likely has a ?
hantavirus infection.
Hantavirus is a genus in the Bunyaviridae family that causes the hantavirus pulmonary syndrome, which starts with fevers, headaches, severe myalgias, gastrointestinal upset, dizziness, and chills. Patients initially have no respiratory symptoms. As the disease progresses, however, the virus causes capillary leak syndrome in the lungs, resulting in pulmonary edema.
Plasmodium falciparum is the protozoan responsible for malaria. Patients present with paroxysms of fever, shaking chills, and sweating. Pulmonary edema may be present, but malaria is unlikely in the United States, since malaria eradication programs succeeded by 1951. The other viruses do not present with bilateral pulmonary edema. Alphavirus is responsible for?
viral encephalitis, which presents with a sudden onset of headache, high fever, chills, and vomiting, which may progress to disorientation, seizures, or coma. Patients infected with a flavivirus will typically present with acute fever, gastrointestinal symptoms, and headache. Infection with West Nile virus presents with signs of encephalitis, gastrointestinal distress, and fever.
Hantavirus is contracted through exposure to deer mouse droppings or urine. Hantavirus causes hantavirus pulmonary syndrome, which starts with fevers, headaches, severe myalgias, gastrointestinal upset, and dizziness. As the disease progresses, the virus causes capillary leak syndrome in the lungs resulting in?
pulmonary edema.
