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IM - Infectious Diseases - Respiratory Tract, GI Tract , and CNS

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tonystep1's version from 2017-08-04 05:04

CLINICAL FEATURES INFECTIONS OF THE UPPER AND LOWER RESPIRATORY TRACTS

Question Answer
Typical CAPAcute onset of fever and shaking chills // Cough productive of thick, purulent sputum // Pleuritic chest pain (suggests pleural effusion) // Dyspnea // Tachycardia, tachypnea // Late inspiratory crackles, bronchial breath sounds, increased tactile and vocal fremitus, dullness on percussion // Pleural friction rub (associated with pleural effusion)
Atypical CAPInsidious onset-headache, sore throat, fatigue, myalgias // Dry cough (no sputum production) // Fevers (chills are uncommon) // Pulse-temperature dissociation-normal pulse in the setting of high fever // Wheezing, rhonchi, crackles
Lung AbscessThe majority of cases have an indolent onset; some present more acutely. // Cough-Foul-smelling sputum is consistent with anaerobic infection. It sometimes is blood tinged // Shortness of breath // Fever, chills // Constitutional symptoms: fatigue, malaise, weight loss
Primary TBUsually asymptomatic // Pleural effusion may develop // If the immune response is incomplete, the pulmonary and constitutional symptoms of TB may develop. This is known as progressive primary TB. //
Secondary (active) TBConstitutional symptoms-fever, night sweats, weight loss, and malaise are common. // Cough progresses from dry cough to purulent sputum // Hemoptysis suggests advanced TB. // Apical rales may be present on examination
Extrapulmonary TBMay involve any organ. // The lymph nodes, pleura, genitourinary tract, spine, intestine, and meninges are some of the common sites of infection. // Miliary TB refers to hematogenous dissemination of the tubercle bacilli. May present with organomegaly, reticulonodular infiltrates on CXR, and choroidal tubercles in the eye
Influenzarapid onset of fever, chills, malaise, headache, nonproductive cough, and sore throat. Nausea may also be present.
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CXR FINDINGS INFECTIONS OF THE UPPER AND LOWER RESPIRATORY TRACTS

Question Answer
Typical CAPLobar consolidation // Multilobar consolidation indicates very serious illness.
Atypical CAPDiffuse reticulonodular infiltrates // Absent or minimal consolidation
Lung AbscessThis reveals thick-walled cavitation with air-fluid levels. //located in dependent, poorly ventilated lobes
Tuberculosis (TB)Classic findings are upper lobe infiltrates with cavitations
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ORGANISMS AND TREATMENT FOR INFECTIONS OF THE UPPER AND LOWER RESPIRATORY TRACTS

Question Answer
Atypical CAPIn people younger than 60 years of age, the most common organisms are S. pneumoniae, Mycoplasma, Chlamydia, and Legionella. // doxycycline cover all of these organisms and are the first-line treatment
Typical CAPa second- or third-generation cephalosporin is the first-line treatment.
CAP For hospitalized patientsa fluoroquinolone alone or a third-generation cephalosporin plus a macrolide is appropriate
Lung AbscessPrevotella, Peptostreptococcus, Fusobacterium, Bacteroides spp. // Hospitalization is often required if lung abscess is found. Postural drainage should be performed. // Gram-positive cocci-ampicillin or amoxicillin/clavulanic acid, ampicillin/sulbactam, or vancomycin for 5. aureus // Anaerobes-clindamycin or metronidazole // If gram-negative organisms are suspected, add a fluoroquinolone or ceftazidime. regimen. After this initial 2-month phase, a phase of 4 months is recommended using INH and rifampin
Tuberculosis (TB)Patients with active TB must be isolated until sputum is negative for AFB. // First-line therapy is a four-drug regimen: isoniazid (INH), rifampin, pyrazinamide,and ethambutol or streptomycin. // The initial treatment regimen consists of 2 months of treatment with the four-drug
InfluenzaTreatment is largely supportive. Amantadine or rimantadine decrease the duration of symptoms. Only give antibiotics for secondary bacterial infections
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INFECTIONS OF THE CENTRAL NERVOUS SYSTEM CLINICAL FEATURES

Question Answer
Meningitisa. Headache (may be more severe when lying down) // b. Fevers // c. Nausea and vomiting // d. Stiff, painful neck // e. Malaise // f. Photophobia // g. Alteration in mental status (confusion, lethargy, even coma) // Nuchal rigidity: stiff neck, with resistance to flexion of spine (may be absent) // Kerning's sign-inability to fully extend knees when patient is supine with hips flexed (90°) // Brudzinski's sign-flexion of legs and thighs that is brought on by passive flexIon of the neck
EncephalitisPatients often have a prodrome of headache, malaise, and myalgias // Within hours to days, patients become more acutely ill. // Patients frequently have signs and symptoms of meningitis (e.g. , headache, fever,photophobia, nuchal rigidity) . // In addition, patients have altered sensorium, possibly including confusion, delirium, disorientation, and behavior abnormalities // Focal neurologic findings (e.g. , hemiparesis, aphasia, cranial nerve lesions) and seizures may also be present.
Brain AbscessThese are mainly due to mass effect rather than systemic infection: headache (most common symptom) , change in mental status, seizures, nausea, vomiting, and nuchal rigidity may be seen. Note that fever and chills may be absent.// With progression, intracranial abscess may cause an increasing mass effect.
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DIAGNOSIS OF INFECTIONS OF THE CENTRAL NERVOUS SYSTEM

Question Answer
Bacterial meningitisElevated WBC count-PMNs predominate // Low glucose // High protein // Gram stain-positive in 75% to 80% of patients with bacterial meningitis
Aseptic meningitisThere is an increase in mononuclear cells. Typically a lymphocytic pleocytosis is present. // Protein is normal or slightly elevated. // Glucose is usually normal. // CSF may be completely normal
EncephalitisPerform an LP to examine CSF, // Lymphocytosis (>5 WBC/fLL) with normal glucose is consistent with viral encephalitis (similar CSF as in viral meningitis) . CSF cultures are usually negative. // CSF PCR is the most specific and sensitive test for diagnosing many various viral encephalitides, including HSV- 1 , CMV, EBV, and VZV // MRI of the brain Can rule out focal neurologic causes, such as an abscess //
HSV-1 encephalitisIncreased areas of T2 signal in the frontotemporal localization // EEG it would show unilateral or bilateral temporal lobe discharges.
Brain AbscessCT scan-typically shows focal, low-density mass with peripheral enhancement and variable degree of surrounding edema // Aspiration or surgical excision-is diagnostic
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TREATMENT AND MANAGEMENT INFECTIONS OF THE CENTRAL NERVOUS SYSTEM

Question Answer
Bacterial meningitisEmpiric antibiotic therapy-Start immediately after LP is performed. If a CT scan must be performed or if there are anticipated delays in LP, give antibiotics first. // Intravenous (IV) antibiotics Initiate immediately if the CSF is cloudy or if bacterial infection is suspected. // Steroids-if cerebral edema is present
For all close contacts of patients with meningococcusgive l dose of IM ceftriaxone.
Vaccinations for meningitis criteriaVaccinate all adults >65 years for S. pneumoniae // Vaccinate asplenic patients for S. pneumoniae, N. meningitidis, and H. influenzae (organisms with capsules) // Vaccinate immunocompromised patients for meningococcus
Aseptic meningitisNo specific therapy other than supportive care is required. The disease is self-limited. // Analgesics and fever reduction may be appropriate
EncephalitisSupportive care, mechanical ventilation if necessary // Antiviral therapy // HSV encephalitis-acyclovir for 2 to 3 weeks // CMV encephalitis-ganciclovir or foscarnet // Management of possible complications
Brain AbscessMay involve IV antibiotics, surgical drainage, and/or glucocorticoids, depending on size of abscess and presence of mass effect // Broad-spectrum antibiotics if bacterial cause is unknown // Parenteral antibiotics for at least 4 to 6 weeks
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INFECTIONS OF THE GASTROINTESTINAL TRACT CLINICAL FEATURES

Question Answer
Acute Viral HepatitisClassified as acute ( <6 months of liver inflammation) // Acute hepatitis has a wide spectrum of clinical presentations, ranging from virtually asymptomatic to fulminant liver failure. // jaundice // Dark-colored urine // RUQ pain // Nausea and vomiting // Fever and malaise // Hepatomegaly may also be present // Hepatic encephalopathy // Hepatorenal syndrome // Bleeding diathesis
Chronic Viral hepatitiswide variety of presentations // asymptomatic ("chronic carriers") and may only present with late complications of hepatitis, such as cirrhosis or hepatic cell carcinoma (HCC).
BotulismThe severity of illness ranges widely, from mild, self-limiting symptoms, to rapidly fatal disease. // Abdominal cramps, nausea, vomiting, and diarrhea are common // The hallmark clinical manifestation is symmetric, descending flaccid paralysis // It starts with dry mouth, diplopia, and/or dysarthria. Paralysis of limb musculature occurs later.
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Viral Hepatitis Transmission

Question Answer
Hepatitis A and Eare transmitted via the fecal-oral route and are more prevalent in developing countries
Hepatitis Btransmitted parenterally or sexually.
Hepatitis CThe main route of transmission is parenteral // more prevalent in IV drug users. Sexual or perinatal transmission is not common.
Hepatitis Drequires the outer envelope of the Hb5Ag for replication and therefore can only be transmitted as a coinfection with HBV, or as a superinfection in a chronic HBV carrier.
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Hepatitis B Serology Disease Course

Question Answer
Hepatitis B surface antigen (HBs,Ag)Present in acute or chronic infection // Detectable as early as 1 to 2 weeks after infection // It persists in chronic hepatitis regardless of whether symptoms are present // If virus is cleared, then HB,Ag is undetectable.
Hepatitis B e antigen (HBe.Ag)Reflects active viral replication. and presence indicates infectivity // Appears shortly after HBs,Ag
Anti-HB,Ag antibody lanti-HBs)Present after vaccination or after clearance of HB,Ag-usually detectable 1 to 3 months after infection // In most cases, presence of anti-HBs indicates immunity to HBV
Hepatitis B core antibody lanti-HBc)Assay of lgM and lgG combined // Useful because it may be the only serological marker of HBV infection during the "window period" in which HB,Ag is disappearing, but anti-HB,Ag is not yet detectable // Does not distinguish between acute and chronic infection, and presence does not indicate immunity
HBV DNA measured by PCRif it persists for more than 6 weeks, patient is likely to develop chronic disease
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TREATMENT AND MANAGEMENT OF GI INFECTIONS

Chronic HBV :Treat with interferon (IFN)-a. Alternatively, treat with lamivudine
Question Answer
Chronic HCVTreat with IFN-a and ribavirin.
hepatitis A and ETreatment for hepatitis A and E is supportive
advanced disease hepatitisConsider liver transplantation in advanced disease, although recurrence can occur after transplantation.
BotulismAdmit the patient and observe respiratory status closely. Gastric lavage is helpfulonly within several hours after ingestion of suspected food. // If suspicion of botulism is high, administer antitoxin (toxoid) as soon as laboratory specimens are obtained (do not wait for the results). // Contaminated wounds -- wound cleansing and penicillin
Intra-abdominal AbscessTreatment typically involves drainage of the abscess.
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