Empiric Treatment: Pneumonia

Overview of Pneumonia diseases.asp?did=38http:// diseases.asp?did=38

What is pneumonia? Pneumonia is an inflammatory illness of the lung. Frequently, it is described as lung parenchyma/alveolar (microscopic air-filled sacs of the lung responsible for absorbing oxygen from the atmosphere) inflammation and (abnormal) alveolar filling with fluid.

What Causes Pneumonia? Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites, and chemical or physical injury to the lungs.

Pneumonia The alveoli are tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place.

Bronchiole Bronchiole: A tiny tube in the air conduit system within the lungs that is a continuation of the bronchi and connects to the alveoli (the air sacs) where oxygen exchange occurs. Bronchiole is the diminutive of bronchus, from the word bronchos by which the Greeks referred to the conduits to the lungs.

Symptoms of Pneumonia Fever Chills Cough Pleurisy: inflamed membranes around the lungs Dyspnea: Difficult or labored breathing; shortness of breath

Diagnosis of Pneumonia Pneumonia usually produces distinctive sounds; these abnormal sounds are caused by narrowing of airways or filling of the normally air-filled parts of the lung with inflammatory cells and fluid, a process called consolidation.

Diagnosis of Pneumonia In most cases, the diagnosis of pneumonia is confirmed with a chest x-ray. For most bacterial pneumonias, the involved tissue of the lung appears on the x-ray as a dense white patch (because the x-ray beam does not get through), compared with nearby healthy lung tissue that appears black (because the x-rays get through easily, exposing the film). Viral pneumonias typically produce faint, widely scattered white streaks or patches.

Two Types of Pneumonia Community-Acquired Pneumonia (CAP): individual residing in their homes Hospital-Acquired Pneumonia (HAP): individuals residing in hospitals

Community-Acquired Pneumonia Typical: Sudden onset of fever, chills, pleuritic chest pain, productive cough –Streptococcus pneumoniae –Haemophilus influenzae Atypical: often preceeded by mild respiratory illness –Legionella spp. –Mycoplasma pneumoniae –Chlamydophila pneumoniae

Bacterial Causes of CAP Streptococcus pneumoniae16-60% Haemophilus influenzae3-38% Legionella spp2-30% Mycoplasma pneumoniae1-20% Other aerobic Gram-neg7-18% Chlamydophila pneumoniae6-12% Staphylococcus aureus2-5%

Treatment of CAP

Mild –Macrolide (azithromycin, clarithromycin) –Macrolide +  -lactam –Doxycycline –Quinolone (moxifloxacin, levofloxacin, gemifloxacin) Severe –  -lactam + macrolide –  -lactam + quinolone

Treatment of CAP Severe –  -lactam + macrolide –  -lactam + quinolone

HAP is also divided into two classes: Early onset HAP: occurs within first five days of hospitalization Late onset HAP: occurs after 5 days of hospitalization

Bacterial Causes of Early Onset HAP Methicillin-sensitive Staphylococcus aureus29-35% Haemophilus influenzae23-33% Enterobacteriaceae5-25% Streptococcus pneumoniae7-23%

Bacterial Causes of Late Onset HAP Pseudomonas aeruginosa39-64% Acinetobacter spp.6-26% Enterobacteriaceae16-31% Methicillin-resistant S. aureus0-2%

Treatment of Early Onset HAP

Ceftriaxone Quinolone (Levofloxacin, Moxiflocacin, Ciprofloxacin) Ampicillin/sulbactam Ertapenem

Treatment of Late Onset HAP

Antipseudomonal cephalosporin: ceftazidime, cefepime Or Carbapenem: Imipenem, Meropenem Or Extended spectrum penicillin/  -lactamase inhibitor: piperacillin/tazobactam ++++ Quinolone (ciprofloxacin, levofloxacin) Or Aminoglycoside (gentamicin, tobramycin, amikacin) If MRSA is suspected, add: Vancomycin or Linezolid Use a combination regimen from the first and second categories below:

Urinary Tract Infections ses.asp?did=281http:// ses.asp?did=281

Urinary System

Mild and Severe UTI’s Mild –Involve only the urethra and bladder –Referred to as “acute cystitis” –Symptoms include dysuria (painful urination) urinary frequency hematuria (blood in urine)

Mild and Severe UTI’s Severe –Infection of the upper urinary tract involves the spread of bacteria to the kidney –Symptoms include fever, chills, nausea, vomiting and flank pain –Called “pyelonephritis”

‘Complicated’ and ‘Uncomplicated’ UTI’s Uncomplicated: occur in young, healthy, nonpregnant women Complicated: All other UTI’s

Bacterial Causes of Uncomplicated UTI’s Escherichia coli53-79% Proteus mirabilis4-5% Staphylococcus saprophyticus3% Klebsiella spp.2-3% Other Enterobacteriaceae3%

Treatment of Uncomplicated Acute Cystitis

Oral trimethoprim-sulfamethoxazole Oral quinolones (ciprofloxacin, levofloxacin)

Treatment of Uncomplicated Acute Pyelonephritis

Quinolones: Ciprofloxacin, levofloxacin Third generation cephalosporins: Ceftriaxone, cefotaxime, ceftizoxime If Gram positive organisms seen in urine: –Aminopenicillin (amoxicillin) –Aminopenicillin +  -lactamase inhibitor: (amoxicillin + clavulanate) –Aminopenicillin + aminoglycoside (ampicillin + gentamicin)

Treatment of Complicated Urinary Tract Infections

Fourth generation cephalosporins (cefepime) Quinolones: Ciprofloxacin, Levofloxacin If Gram-positive bacteria seen in urine: –Aminopenicillin + aminoglycoside: Ampicillin + gentamicin

Pelvic Inflammatory Disease iseases.asp?did=791http:// iseases.asp?did=791

Female Reproductive Organs

PID is the general term for an infection that has traveled through the vagina, to the uterus, and then to other parts of the pelvis

Symptoms of PID Abnormal bleeding Dyspareunia (pain during sexual intercourse) Vaginal discharge Lower abdominal pain Fever chills

Bacterial Causes of PID Neisseria gonorrhoeae27-56% Chlamydia trachomatis22-31% Anaerobic and facultative bacteria (Bacteria that can live under aerobic or anaerobic conditions)20-78%

Treatment of PID

Mild to Moderate Disease –Oral quinolone: Levofloxacin, ofloxacin + oral metronidazole –Single IM dose of cephalosporin + oral doxycycline + oral metronidazole

Treatment of PID Severe Disease (regimen 1) –Cephalosporin with anaerobic activity (cefotetan, cefoxitin) + doxycycline (active against atypical C. trachomatis) Severe Disease (regimen 2) –Clindamycin (active against C. trachomatis and against many anaerobes) + Gentamicin (effective against Gram-negative N. gonorrhoeae) Those that are severely ill should be admitted to the hospital and treated initially with intravenous agents.

Meningitis ses.asp?did=162http:// ses.asp?did=162 index.htmhttp:// index.htm

Meningitis Meningitis is the inflammation of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis may develop in response to a number of causes, most prominently bacteria, viruses and other infectious agents, but also physical injury, cancer, or certain drugs.

Meninges: the membranes that envelope the brain and the spinal cord.

Symptoms of Meningitis Headache Fever Neck stiffness Altered mental status Photophobia Nausea Vomiting Seizures

Diagnosis of Meningitis The most important test used to diagnose meningitis is the lumbar puncture (commonly called a spinal tap). Lumbar puncture (LP) involves the insertion of a thin needle into a space between the vertebrae in the lower back and the withdrawal of a small amount of CSF.

Lumbar puncture ncture.swf?random= http://antbits.net/first_consult/lumbar_pu ncture.swf?random= stigations.asp?sid=13http:// stigations.asp?sid=13

Diagnosis of Meningitis The CSF is then examined under a microscope to look for bacteria or fungi. Normal CSF contains set percentages of glucose and protein. These percentages will vary with bacterial, viral, or other causes of meningitis. For example, bacterial meningitis causes a greatly lower than normal percentage of glucose to be present in CSF, as the bacteria are essentially "eating" the host's glucose, and using it for their own nutrition and energy production.

Diagnosis of Meningitis Normal CSF should contain no infection-fighting cells (white blood cells), so the presence of white blood cells in CSF is another indication of meningitis. Some of the withdrawn CSF is also put into special lab dishes to allow growth of the infecting organism, which can then be identified more easily. Special immunologic and serologic tests may also be used to help identify the infectious agent.

Bacterial Causes of Acute Bacterial Meningitis months: –Streptococcus agalactiae –Escherichia coli –Listeria monocytogenes 3 month - 6 yrs: –Neisseria meningitidis –Streptococcus pneumoniae –Haemophilus influenzae

Bacterial Causes of Acute Bacterial Meningitis 16 yrs - 50 yrs –Streptococcus pneumoniae –Neisseria meningitidis > 50 yrs –Streptococcus pneumoniae –Listeria monocytogenes –Aerobic Gram-negative bacilli

Treatment of Bacterial Meningitis

Third-generation cephalosporins: cefotaxime, ceftriaxone + Vancomycin (coverage against resistant Streptococcus pneumoniae) If patient 50 years Same as above, but also Add ampicillin to provide coverage of L. monocytogenes and S. agalactiae.

Cellulitis Cellulitis is an inflammation of the connective tissue underlying the skin, that can be caused by a bacterial infection.

Cellulitis

Bacterial Causes of Cellulitis Staphylococcus aureus 13-37% Streptococcus pyogenes4-17% Other streptococci1-18%

Treatment of Cellulitis

Mild Disease (oral formulations) –Antistaphylococcal penicillins (Dicloxacillin) –First Generation Cephalosporins (Cephalexin, Cefadroxil) –Clindamycin –Macrolides (Erythromycin, azithromycin, clarithromycin) Severe Disease (intravenous formulations) –Antistaphylococcal penicillins (Nafcillin, oxacillin) –First-generation cephalosporins (cefazolin) –Clindamycin

Treatment of Cellulitis If MRSA is suspected –Vancomycin –Linezolid –Daptomycin –Tetracyclines (Tigecycline, doxycycline) –Sulfa drugs (Trimethoprim- sulfamethoxazole) –Clindamycin

Otitis Media diseases.asp?did=879http:// diseases.asp?did=879

Symptoms of Otitis Media Otalgia (ear pain) Hearing Loss Irritability Anorexia Apathy Fever Swelling around the ear Otorrhea (discharge from the affected ear)

Bacterial Causes of Acute Otitis Media Streptococcus pneumoniae 25-50% Haemophilus influenzae15-30% Moraxella catarrhalis3-20%

Treatment of Acute Otitis Media

First Line Therapy –High Dose Amoxicillin If Mild Allergy to Penicillin –Cefdinir, Cefpodoxime, Cefuroxime axetil If Type 1 Hypersensitivity Allergic Reaction –Macrolide (Azithromycin, Clarithromycin, Erythromycin with sulfisoxazole)

Sulfisoxazole Used in combination with Erythromycin Sulfmethoxazole Used in combination with Trimethoprim (co-trimoxazole)

Infective Endocarditis

Causes of Endocarditis There are many ways that bacteria can enter the bloodstream and cause endocarditis. Even a small cut can enable bacteria that normally live on the skin to enter the bloodstream. In some cases, this occurs during a dental or surgical procedure. In many cases, however, it is not clear how the bacteria first got into the bloodstream.

Symptoms of Endocarditis Symptoms are non-specific, making endocarditis difficult to diagnose: Fatigue Malaise Weakness Weight loss Fever Chills Dyspnea on exertion (shortness of breath)

Bacterial Causes of Endocarditis Viridans group streptococci18-48% Staphylococcus aureus22-32% Enterococci7-11% Coagulase-negative staphylococci 7-11% HACEK organisms2-7%

Viridans Group streptococci Viridans streptococcus are alpha- hemolytic, normal flora of the oral, respiratory tract, and GI mucosa. They are the major cause of bacterial endocarditis in people with damaged heart valves. They may enter the blood stream after dental procedures.

HACEK Organisms A HACEK organism is one of a set of slow-growing Gram negative bacteria that form a normal part of the human flora. They are a frequent cause of endocarditis in children. The name is formed from their initials: Haemophilus aphrophilus, Haemophilus parainfluenzae and Haemophilus paraphrophilus Actinobacillus actinomycetemcomitans Cardiobacterium hominis Eikenella corrodens Kingella kingae

Empiric Therapy for Infective Endocarditis Vancomycin + Gentamicin –Vancomycin is effective against S. aureus and viridans group streptococci –When used in combination with Gentamicin, activity is extended to the majority of enterococcal strains Even intensive therapy may not be sufficient, and surgical intervention is often required Despite intensive antibiotic therapy, mortality remains high: 20-25%.

Prosthetic Valve Endocarditis Many cases of endocarditis are associated with prosthetic valves in the heart Sometimes these infections occur within two months after the valve is installed and are thus thought to be hospital acquired Sometimes they occur 6-20 month after surgery and are thus thought to be community acquired

Treatment of Prosthetic Valve Endocarditis Vancomycin + Gentamicin + Rifampin –With or without cefepime or ceftriaxone

Intravascular-Related Catheter Infections

200,000 catheter-related infections occur each year in the U.S. Should be suspected in anyone with an intravascular catheter and a fever of unclear etiology. Diagnosis may involve: –Removal and culture of the catheter –Growth of bacteria from blood cultures

What type of bacteria cause catheter-related infections? Skin flora, including: –Staphylococcus epidermidis 32-41% –Staphylococcus aureus 5-14% –Enteric Gram-negative bacilli 5-11% –Psuedomonas aeruginosa 4-7%

Treatment of Intravascular Catheter-related Infections

Treatment of Catheter Related Infections Hospital setting where MRSA is uncommon –Antistaphylocccal penicillin: Nafcillin, Oxacillin Hospital setting where MRSA is common –Vancomycin Immunocompromised or severely ill patient –Add cephalosporin to initial antibiotic regimen –Ceftazidime, cefepime

Intra-Abdominal Infections

Causes of Intra-abdominal infections Usually caused by contamination of the usually sterile abdomen with microbial flora of the bowel Can be quite severe, leading to sepsis and death

Bacterial Causes of Intra- abdominal Infections Gram-negative bacilli –Escherichia coli 32-61% –Enterobacter spp. 8-26% –Klebsiella spp.6-26% –Proteus spp.4-23%

Bacterial Causes of Intra- abdominal Infections Gram-positive cocci –Enterococci 18-24% –Streptococci 6-55% –Staphylococci 6-16%

Bacterial Causes of Intra- abdominal Infections Anaerobic bacteria –Bacteroides spp. –Clostridium spp.

Treatment of Intra-abdominal Infections Due to their polymicrobial nature, the antibiotic regimen must be very broad spectrum, including Gram-negative bacilli, Gram-positive cocci, and anaerobic bacteria

Treatment of Intra-Abdominal Infections  -Lactam/  -lactamase inhibitor combinations (piperacillin/tazobactam) Carbapenems (imipenem, meropenem) Aminoglycoside (gentamicin, tobramycin, amikacin) + metronidazole Ciprofloxacin + metronidazole

Treatment of Intra-abdominal Infections