Pulmonary Infections Flashcards
How does the TB skin test work? False Positives?
The TST – or Mantoux test – assesses inflammation in the dermis following intradermal injection of tuberculin protein. The test needs to be read 48–72 hours after administration. The diameter of induration gives a semiquantitative assessment of the likelihood of LTBI. False positives can result from previous bacilli Calmette-Guérin (BCG) vaccination and exposure to environmental Mycobacterium spp.
How does the Tb quant test work?
Interferon gamma release assays utilize the ability of human lymphocytes to survive for a short period in a test tube. If primed by previous TB infection, lymphocytes will produce detectable amounts of gamma interferon.
List the bacteria that may cause a cavitary lung lesion?
Gram +:
Staph A and Strep
Gram -: klebsiella Pseudomonas E. Coli Burkholderia
Anaerobes in oral flora like: Arachnia, Bacteroides, Bifidobacterium, Eubacterium, Fusobacterium, Lactobacillus, Leptotrichia, Peptococcus
Misc: Nocardia and Actinomyces (filamentous bacteria)
what are the fungal etiologies of cavitary lesions?
Aspergillus, histoplasmosis, Coccidioidomycosis (valley fever), Cryptococcus, Blastomycosis (rare)
When initiating Abx for a patient with a cavitary lung lesion, and TB has not been ruled out, what do you want to avoid?
Avoid Fluoroquinolone use, given the fact that it is second line for TB infections and we want to not induced resistance (this is a John McKinnon pro tip)
In PCP suspected patients who are hypoxic you should get what:
In patients presenting with hypoxia, an arterial blood gas sample should be obtained to determine the alveolar-arterial oxygen gradient, which can help determine the severity of the PCP infection.
Treatment of adolescents with CAP?
Adolescents with non-severe CAP and signs of an atypical pneumonia are typically treated initially with a macrolide such as azithromycin.
what does a Hantavirus infection look like?
Given this patient’s presentation with fever, cough, thrombocytopenia, elevated lactate-dehydrogenase (LDH) level, and leukocytosis with immunoblasts on smear, after travel to the southwestern United States, this patient likely is infected with hantavirus, which, as his significant respiratory failure indicates, has progressed into hantavirus cardiopulmonary syndrome (HCPS). A chest radiograph reveals severe diffuse interstitial edema, involving all lung fields, with extracorporeal-membrane-oxygenation (ECMO) catheters inserted. This is classic for noncardiogenic edema developing from capillary leak syndrome in the setting of viral infection. Common features of hantavirus infection include pronounced thrombocytopenia, leukocytosis with immunoblasts, and elevated LDH and liver-enzyme levels. Many of these features are notable at presentation. The immunoblasts may be seen only when the patient develops pulmonary edema.
Hantavirus has rodent reservoirs; this virus is transmissible through direct contact with infected animals. After an initial incubation phase of approximately 2 to 3 weeks, hantavirus manifests first with nonspecific prodromal symptoms, such as fevers, chills, malaise, and weakness. The course progresses to involve nausea, vomiting, diarrhea, headaches, abdominal pain, and shortness of breath. These symptoms are rapidly followed by a massive capillary leak, leading to non-cardiogenic pulmonary edema, shock, coagulopathy, arrhythmias, and death. Diagnosis is made by antibody recognition to hantavirus. Treatment involves supportive care, including the use of ECMO, if indicated. Despite supportive care, the mortality rate is 38%.
Due to its high mortality rate and capacity of dissemination through respiratory droplets, hantavirus is listed as a potential category-C bioterrorism agent by the Centers for Disease Control (CDC). Category-C agents carry a high morbidity or mortality rate (or both) but must be heavily engineered for mass dissemination. Category-A and -B agents are more readily available for mass dissemination, as discussed in the answer explanations below.
When are pneumonia vaccines indicated? what types and when?
For healthy individuals, pneumonia vaccines are indicated starting at age 65. According to the CDC, the prior recommended dosing was to give the patient PCV13 at age 65 and the PPSV23 one year later. This has been changed. The new guidelines recommend only the PPSV23 unless the patient specifically wants both vaccines. Then the prior dosing schedule should be followed. If the patient wants both vaccines and the PPSV23 is given by mistake first, the PCV13 can be given one year later. Both of these vaccines may be given earlier than 65 for certain medical conditions, but a final dose of PPSV23 should still be repeated at age 65.
Diphtheria has what symptoms? Treatment and complications?
This patient’s symptoms are secondary to diphtheria, as evidenced by his new onset of fever, pharyngitis, gray-white exudate that covers the tonsils and pharynx (pseudomembrane), and cervical adenopathy. Symptoms of diphtheria usually begin 2 to 5 days after infection. The pseudomembrane usually covers the tonsils and pharynx but can extend up or down the airway. Occasionally, the pseudomembrane can become so large that it causes stridor or can be aspirated, which leads to death. The pseudomembrane should be a site of culture for suspected cases of diphtheria. The pseudomembrane generally adheres tightly to the underlying mucous membranes and bleeds when scraped. A culture obtained would most likely reveal nonencapsulated, nonmotile, Gram-positive bacilli that are characteristic of Corynebacterium diphtheriae.
While this diagnosis is rare in the postvaccination era, these infections are still prevalent in parts of the world that are unvaccinated. Mortality rates up to 30% to 40% have been reported in the United States. Initial signs and symptoms are frequently nonspecific and are consistent with most forms of pharyngitis. Cardiac manifestations typically occur 1 to 2 weeks after the diagnosis and are secondary to toxin production. These can manifest as myocarditis (up to 60% of cases), congestive heart failure, complete heart block, ST-T wave abnormalities, or dysrhythmias.
Erythromycin and penicillin are both recommended for the treatment of diphtheria. Some studies suggest that erythromycin may be better at eradication of the carrier state. Penicillin is recommended for household contacts who may not be able to tolerate the duration of erythromycin treatment.
Pertussis is a diagnosis made how? Treatment?
Bordetella pertussis infection (“whooping cough”), for which first-line treatment is a macrolide, such as azithromycin, clarithromycin, or erythromycin. Per the Centers for Disease Control and Prevention (CDC) case definition, pertussis is a clinical diagnosis that does not require diagnostic testing in patients who do not have a more likely diagnosis and who present with one of the following:
An acute cough lasting longer than 2 weeks with one pertussis-associated symptom (paroxysmal cough, post-tussive emesis, inspiratory whoop, apnea) or
An acute cough that is of any length of duration with one pertussis-associated symptom and direct contact with a laboratory-confirmed case of pertussis.
20% of adults with chicken pox will develop what? What are other things that mimic this?
Varicella pneumonia develops in approximately 20% of adults with chickenpox and typically occurs 3-7 days after the onset of rash. The distinctive feature of this condition is the presence of a rash containing papules, vesicles, and scabs in various stages of development. Fever, malaise, and itching are usually also part of the clinical picture. Coxsackievirus and echovirus can also lead to the manifestation of pneumonia and vesicular rash. Rickettsial pox should be considered in patients with history of tick bite. In these patients, a small papule develops following a tick bite, eventually resulting in a black, crusty scab. Symptoms are non-specific and flu-like including fever, chills, weakness, and myalgias, but the most distinctive symptom is a rash that breaks out, spanning the entire body.
When treating for PCP Pneumonia what do we do?
Start Bactrim if story is convincing and LDH is high. Need to calculate A-a gradient. If not oxygenating well also start steroids on these patients.
