Infectious Flashcards
What is first-line treatment for malignant otitis externa (characterized by necrotizing inflammation of the external auditory canal)?
IV ciprofloxacin
What are the two most common infectious causes of brain abscess in an immunocompetent patient?
Strep viridans and Staph aureus (from infected adjacent tissues such as sinuses or otitis media)
What viruses should patients be tested for with idiopathic thrombocytopenia purpura (ITP)?
Both HIV and hepatitis C can decrease platelet counts
What is Ramsay Hunt syndrome?
Bell’s palsy caused by herpes zoster. Vesicles are typically seen on the outer ear
What is the classic triad of invasive pulmonary aspergillosis and how does it appear on CT chest?
Fever, pleuritic chest pain, and hemoptysis. Appears as nodules with surrounding ground-glass opacities (halo sign).
What are features of HSV retinitis?
Affects immunocompromised patients (e.g. HIV). Characterized by rapidly progressing bilateral necrotizing retintis (initially will present with keratitis and conjunctivitis with eye pain, followed by rapidly progressive visual loss). Fundoscopic exam reveals widespread, pale, peripheral lesions and central necrosis of the retina.
How does CMV retinitis present?
Painless visual loss. Funduscopy shows fluffy or granular retinal lesions located near the retinal vessels and associated hemorrhages.
What is a bright red, firm, friable, exophytic nodule in an HIV infected patient most likely?
Bacillary angiomatosis - from a Bartonella infection
What medication is indicated for mild-moderate C. diff and what medication is indicated for severe C. diff infections?
Mild-moderate: oral metronidazole
Severe: Oral vancomycin
In a patient who has previously received a rabies vaccine, what interventions are needed if they are bitten by a reservoir animal?
Just a repeat vaccine, no need for immunoglobulin
What is the treatment for Pneumoncystis pneumonia (PCP)?
Preferred: TMP-SMX plus adjunctive corticosteroids.
Alternatives include dapsone, atovaquone, and primaquine
What are common symptoms in disseminated Mycobacterium avium complex (MAC) infection?
Nonspecific symptoms (e.g. fever, cough, abdominal pain, diarrhea, night sweats, weight loss, etc) in the presence of splenomegaly and elevated alk phos
What area of the lungs to TB most often infect?
The apices (high oxygen tensions and slower lymphatic elimination.
What is the treatment of choice for pregnant/lactating women and children <8 yrs with early Lyme disease?
Amoxicillin
What is the workup for Pneumocystis pneumonia?
Increased LDH levels, diffuse reticular infiltrates on imaging, and induced sputum or BAL (stain)
What is tick-borne paralysis?
Pts present with progressive ascending paralysis over hours to days. There is not a prodromal illness or fever. CSF examination is usually normal. Due to release of neurotoxin from the tick (takes 4-7 days of feeding). Removing the tick results in complete recovery
What is the treatment for scabies?
Topical 5% permethrin or oral ivermectin
What GI infection is associated with bloody diarrhea in the absence of fever?
E. coli
What empiric antibiotic coverage should patients have if they have febrile neutropenia if the neutropenia is severe?
Anti-pseudomonal coverage
What patients are most at risk for serious Vibrio vulnificus infections?
Patients with liver disease, especially hemochromatosis (increased iron levels act as a growth catalyst) - at risk for necrotizing fasciitis
What PNA are pts with COPD at risk for?
H. influenzae
What does an alcoholic patient with current jelly sputum likely have?
Klebsiella PNA
How is neutropenic fever treated?
3rd or 4th gen cephalosporin (ceftazidime or cefipime)
– Add vanc if line infxn suspected or if septic shock develops.
– Add amphoB if no improvement and no source found in 5 days.
What is neutropenic fever?
- Defined by a single temp > 101.3 or sustained temp >100.4 for 1hr. ANC < 500.
- Mucositis 2/2 chemo causes bacteremia (usually from gut)
- MC bugs are pseudomonas or MRSA (if port present).
What exam should you never do in a patient with neutropenic fever?
Digital rectal exam - can cause translocation of gut flora across the wall because they have mucositis
What are symptoms of a cavernous sinus thrombus?
Headache that can become intolerable is most common. Patients often have a low-grade fever and periorbital edema that develops several days after the headache. Pts may also get increased ICP with papilledema and vomiting. Can have unilateral or bilateral cranial nerve (III, IV, V, and VI) palsies
What organism is responsible for most deep infections following puncture wounds?
Pseudomonas aeruginosa
What is the presentation of ehrlichiosis?
After a tick bite (southeastern and south central US - lone star tick). Flu-like illness (fever, HA, myalgias, chills), confusion, rash uncommon, leukopenia, and thrombocytopenia. Can also have elevated LFTs.
Treat with doxycycline
What is the treatment of choice for bacterial conjunctivitis?
Topical erythromycin
What are symptoms of dengue fever?
Retro-orbital pain, fever, malaise, and myalgia are typically described by patients who have contracted dengue, and are accompanied by exanthem (maculopapular rash) and lymphadenopathy. There are typically hematologic findings such as leukopenia and thrombocytopenia
What medication should HIV positive patients be taking prophylactically if they live in the Ohio and Mississippi river valleys with a CD4 count <150?
Itraconazole for Histoplasma capsulatum
