INTERNAL MEDICINE ∼ Prepared by: Kiam Seong Group 437, Syih Ying, Pek Kum, Soon Kee and etc Group 405 (2008/09)
PREPARATION FOR INTERNAL MEDICINE MODULE CONTROL 2008/09
1. Community‐acquired pneumonia.Aetiology.Pathogenesis.Clinical features.Diagnostics. Treatment.
Definition: Acute inflammation located in lung tissue &provoke by infectious agents due to disorder in protective mechanism, characterized by
intraalveolar exudation &infiltration by inflammatory cells.
Etiology:
COMMUNITY –ACQUIRED PNEUMONIA
‐Is caused most commonly by bacteria that traditionally have been divided into 2 groups, typical and atypical
A. Typical organisms in community –acquired pneumonia(around 85%)
• Streptococcus pneumonia (pneumococcus)
• Haemophilus influenza (is associated with asthma and COPD) and
• Moraxella catarrhalis (in patients with chronic bronchitis)
RARE BACTERIAL PATHOGENS in community acquired pneumonia are:
• Klebsiella pneumonia (in persons with chronic alcoholism)
• Staphylococcus aureus (in sitting of postviral influenza)
• Pseudomonas aeruginosa (in patients with bronchiectasis)
B. ATYPICAL PATHOGENS IN community –acquired pneumonia (around 15%)
• Legionella pneumophilia
• Mycoplasma pneumoniae
• Chlamydia psittaci
• Coxiella burnetii
*Do not mix community –acquired due to atypical flora with “ atypical virus (SARS‐ severe acute respiratory syndrome)
Pathogenesis
• Decrease resistance of human body (hypogammaglobulinemia,defect in phagocytosis, neutropenia,decrease T4 lymphocytes)
• Decrease body immune system (cold weather‐mucus ciliary work slowly so easy for microbes to enter,smoking, accompanying
diseases such as diabetes mellitus,chronic renal failure,intoxication, not enough vitamins,minerals such as iodine,
calcium,zink,magnesium,silium ,disorder of digestive tract mainly in ileum)
*local protective mechanism:mucus ciliary function,Ig sec A in mucus,alveolar macrophage,sneeze,cough,enzyme lysozyme,Ig G
Clinical features:
Typical (predominantly pneumococcal pneumonia produces the following:
• sudden onset of fever and shaking chills, pleuritic chest pain, and production of rust colored sputum
• x‐ray‐ consolidation of lungs
• Examination of sputum in case of pneumococcal pneumonia shows gram positive diplococci in chains
*This clinical picture was recognized as “typical” (classical) pneumonia
“Atypical” community –acquired pneumonia
• gradual onset of fever with subfebrile temperature without shaking chills
• A prodrome of it consists of headache, photophobia, sore throat, and eventually a dry, nonproductive cough
• The sputum does not contain gram positive diplococci (pneumococci)
• Although these patients were not feeling well, they were not critically ill,no intoxication,no pleurisy
• Laboratory evaluations showed white blood cell counts to be normal
Diagnosis
• Physical examination detects signs of consolidation
• Crackles in auscultation
• Pulmonary infiltrate on the chest x‐ray
sputum examination
• pneumococcal pneumonia‐ rust color sputum
• Pseudomonas and Haemophilus ‐green sputum
• Anaerobic infections produce foul smelling sputum
• Klebsiella ‐ Currant‐jelly sputum
• Malaise, myalgias and exertional dyspnea may be observed
• Patients may complain of other nonspecific symptoms. Which include
‐headaches, vomiting, nausea
*these symptoms are accompanied by intoxication
‐ environmental and occupational exposures or patient has recently traveled or had contact with animals that might serve as a source
of an infectious agent
‐Patient may report
Together in delivering excellence (T.I.D.E.) INMDM1-ORAL Page 1 GKS437/09-
,INTERNAL MEDICINE ∼ Prepared by: Kiam Seong Group 437, Syih Ying, Pek Kum, Soon Kee and etc Group 405 (2008/09)
- Exposure to turkeys, chicken, ducks in case of Chlamydia psittaci infection
- Exposure to contaminated air conditioning cooling towers in case of Legionella pneumophila infection
Physical
A. The common symptoms and signs (due to intoxication and respiratory failure) are as follows:
‐‐fever (temperature >38.5’c),tachypnea, tachycardia,central cyanosis
‐these symptoms are non‐specific and indicate severity of the disease, not etiology.They can’t help to diagnosis pneumonia, but they
determine therapy and prognosis
B. The most important information on physical examination is connected with sign of lung tissue consolidation due to local
inflammation
‐‐dullness to percussion, increase tactile vocal fremitus, decreased intensity of breath sounds, crackle (crepitation) at the beginning and
resolving of inflammation, local rales, pleural friction rub
The main doctors task on physical examination is revealing of asymmetric pathology
Imaging studies:
chest x‐ray is indicates focal acoustic pathology & any clinical situation accompanied by chronic or prolonged cough:
chest x‐ray in typical case of pneumonia indicate a segmental or lobar opacity or infiltration corresponding to the impaired area
Lab studies‐ complete blood count
‐leukocytosis with a left shift
Leucopenia is an ominous sign of impending sepsis and poor outcome
Procedures
• Bronchoscopy
‐Brochial washing specimens can be obtained. Protected brush and brochoalveolar lavage can be performed for quantitative cultures
• Thoracentesis
‐this is an essential procedure in patients with a parapneumonic pleural effusion
‐obtaining fluid from the pleural space for laboratory analysis allows for the differentiation between simple and complicated effusions.
This determination helps guide further therapeutic intervention
Complication
‐pleural effusion,empyema,pulmonary abscess, respiratory failure, acute heart failure, death
Treatment
‐ Categorized into 4 group because of different micrological spectrum is suggested for each group
st
A)1 major category includes outpatients aged 60years or younger without comorbidity
‐antibiotic treatment with one of the newer macrolides (clarithromycin,azithromycin)
nd
B)2 group combines Community‐acquired pneumonia occurring in out patients with comorbidity or aged 60 years or older
‐recommended therapy id:
nd
‐2 generation cephalosporin (cefuroxime) or
‐beta lactam + a beta lactamase inhibitor (amoxicillin‐clavulanate) or
‐a newer fluroquinolone (levofloxacin /moxifloxacin)
C)Community‐acquired pneumonia requiring hospitalization.The recommended therapy is
nd
‐2 generation cephalosporin (cefuroxime) or
rd
‐3 generation cephalosporin (ceftriaxone) or
‐amoxicillin‐clavulanate
nd rd
‐combination therapy is advised with 2 /3 generation cephalosporin+macrolides
D)severe Community‐acquired pneumonia requiring ICU care:
‐combination therapy is advised with
rd
‐a macrolide plus 3 generation cephalosporin (eg ceftazidime) or
‐triple therapy with ceftazidine or carbapenem + amikacin +macrolides or fluoroquinolone (ciprofloxacin)
2. Hospital‐acquired pneumonia.Aetiology.Pathogenesis.Clinical features.Diagnostics. Treatment
Definition:Defines as pneumonia occurring more than 48 hours after admission to the hospital
It is a major cause of morbidity and mortality in hospitalized patients
Etiology:
The most common organisms:Staphylococcus aureus, Klebsiella pneumonia,Gram‐ negative pathogens(enterobacter,pseudomonas
aeroginosa , e.coli )
*S.aureus pneumonic generally occurs in those who abuse intravenous drugs : in hospitalized patients and patients with prosthetic devices: it
spreads hematogenously to the lungs from contaminated local sites
Together in delivering excellence (T.I.D.E.) INMDM1-ORAL Page 2 GKS437/09-
,INTERNAL MEDICINE ∼ Prepared by: Kiam Seong Group 437, Syih Ying, Pek Kum, Soon Kee and etc Group 405 (2008/09)
Infection by Pseudomonas aeroginosa tend to cause pneumonia in the patients, requiring mechanical ventilation.
Clinical:
• At least 2 of the following symptoms: fever ,cough,leucocytosis (>10000wbc/l),purulent sputum
• Dyspnea, hypoxemia,pleuritic chest pain
Pathogenesis
• Colonization of bacteria in pharynx & stomach is the most important
• Pharynx colonization is promoted by:
‐exogenous factor:instrumentation of upper airways with nasogastric &tracheal tubes, contamination by dirty hands & equipment &
treatment with broad spectrum antibiotic therapy that promotes emergence of drug resistant organism
‐patient factors: malnutrition,advance age,altered consciousness,swallowing disorders &underlying pulmonary & systemic disease
• Aspiration of infected pharyngeal or gastric secretion delivers bacteria directly to lower airway, followed by development of pneumonia
in affected segment or lobe.
• Impaired cellular & mechanical defense mechanisms in lung increased risk of lower respiration infection of mucociliary clearance, trauma
to mucociliary escalator system & interference of coughing
• Tracheal intubation increased risk of lower respiration infection of mucociliary clearance, trauma to mucociliary escalator system &
interference of coughing
• Tight binding of bacteria (pseudomonas) to tracheal epithelium make clearance of these organism from lower airways difficult
Diagnosis
Essential of diagnosis of hospital‐ acquired (nosocomial ) pneumonia
• Occurs more than 48 hours after admission to the hospital
• One or more clinical findings (fever, cough,leukocytosis, purulent sputum) in most patients
• Especially frequent in patients requiring intensive care and mechanical ventilation
• Pulmonary infiltration on chest x‐ray,additional finding can include pleural effusions &cavitations, clearing of pulmonary infiltrates can
take 6 weeks or longer.
Lab finding:blood culture: leucocytosis (>10000 wbc/l), sputum culture & gram stain indicates the course
Treatment
‐coamoxiclav 500mg 3t/d daily
rd
‐Gram –ve bacteria‐3 generation cephasporin(eg cefiroxime), aminoglycosides (eg.gentamicin)
‐Pseudomonas :iv ciprofloxacin or ceftazidime
‐possible combination:aminoglycoside or ciprofloxac +amoxicillin‐clavulanate or ceftazidime or imipenem + vancomycin
*pneumonia is not treated with gentamycin or penicillin
3.Aspiration pneumonia. Aetiology. Pathogenesis. Clinical features. Diagnostics. Treatment
Definition’s a bronchopneumonia that develops due to entrance of foreign material that enter the bronchial tree, usually oral or gastric
content.
Etiology: predominantly anaerobic pathogens:streptococcus pneumonia,staphylococcus aureus,Haemophilus influenzae,Enterobacteriaceae
Pathogenesis
• Poor dentation –periondontal diseases increase number of anaerobic bacteria .Inhale of oropharyngeal material that colonized by upper
airway flora.
• Condition associated with altered or reduced consciousness specifically predispose the patient : alcohol abuse,seizures, drug
overdose,stroke,coma,general anesthetics, intubation of airways,CNS problem,head trauma. In the absence of a tracheo‐esophageal
fistula, aspiration occurs only during periods of impaired consciousness(eg during sleeping), in reflux esophagitis with an esophageal
stricture, or in bulbar palsy. Host factors (as in alcoholism )that suppress cough &mucociliary clearance
• Disorder of vomiting reflux. Aspiration of a massive amount of gastric contents, also known as Mendelson syndrome, can produce acute
respiratory distress within 1 hour.The acidity of gastric content results in chemical burns to the tracheobronchial tree.Depend on acidity
of the aspirate, a chemical pneumonitis can develop,& bacterial pathogens (anaerobic may add the inflammation)
• Secondary lung disorder due to septic emboli in the lung (because of sepsis,endocarditis)
Clinical
• Location depend on patients position: right middle &lower lung lobes common sites of infiltrate formation due to large caliber& more
vertical orientation of right main stem bronchus, aspirate while standing can have bilateral lower lung lobe infiltrates,right upper lobe
common for alcoholic who aspirate in prone position.
• Cough,fever,chills,malaise,myalgias,shortness of breath,dyspnea on exertion, purulent sputum, haemoptysis,pleuritic chest pain
• Nonspecific symptom:headache,nausea,vomiting,anorexia,weight loss
Diagnosis
Together in delivering excellence (T.I.D.E.) INMDM1-ORAL Page 3 GKS437/09-
, INTERNAL MEDICINE ∼ Prepared by: Kiam Seong Group 437, Syih Ying, Pek Kum, Soon Kee and etc Group 405 (2008/09)
Physical exam depend on organism involved,severity & extent of the diseases,patient’s health status &comorbidities(present of periondantal
disease such as gingivitis with bad breath)
A.The common symptoms and signs (due to intoxication and respiratory failure) are as follows:
‐‐fever (temperature >38.5’c),tachypnea, tachycardia,central cyanosis (non specific so cant use to diagnosis)
B.Important information on physical examination : sign of lung tissue consolidation due to local inflammation
‐‐dullness tp percussion, increase tactile vocal fremitus, decreased intensity of breath sounds, crackle (crepitation) at the beginning and
resolving of inflammation, local rales, pleural friction rub
The main doctors task on physical examination is revealing of asymmetric pathology.Presence of focal area of lung tissue consolidation
has most diagnostic value
Imaging studies:
x‐ray of chest findings in typical case of pneumonia indicate a segmental or lobar opacity or infiltration corresponding to the impaired
area(normally posterior segments of upper lobe,superior segments of lower lobes)
Lab studies‐ complete blood count
‐leukocytosis with a left shift These finding may be absent in elderly or debilitated patients
Leucopenia is an ominous sign of impending sepsis and poor outcome
sputum examination
‐. A single pathogen present on the gram stain is typical for pneumonia.Sputum normaly gain by bronchoscopy more accurate compared
sputum excreated by mouth
‐the main value is to exclude the presence of anaerobic microorganisms such as streptococcus pneumonia through special smear and cultures
Other tests
‐ABG determination: Evaluation of the patient’s gas exchange is essential in order to decide if hospital admission,oxygen supplementation,or
other efforts are indicated
Pulse oximetry of less than 90% indicates significant hypoxia :an ABG determination be performed in these patients
Procedures
• Flexible fiberoptic Bronchoscopy is performed
‐Brochial washing specimens can be obtained. Protected brush and brochoalveolar lavage can be performed for quantitative cultures
Treatment
• Cuferoxime 1g iv 6hourly & metronidazole 500mg iv 8 hourly for 5 days
• Oral cefaclor& metronidazole for a prolonged period depending on bacterial sensitivities
• Clindamycin, metronidazole+amoxicillin+clavulanate
• Antibiotic for empiric use:aminoglycoside/ciprofloxacin
• 3rd generation cephalosporin/amoxicillin with clavulanate
• To increase immune:long term principle treatment, immunomodulator,detoxication by NACL, vitamins,antioxidants,glucose
solution,mucolytics, albumins
4.Pneumonia in immunocompromised patients. Aetiology.Pathogenesis.Clinical features. Diagnostics. Treatment
Definition:immunocompromised patients develop pneumonia with all usual organisms & with a number of organisms which do not normally
cause illness in healthy hosts.Howewer with HAART (highly active antiviral therapy) the incidence of these infections has fallen dramatically in
AIDS patients
Etiology:Streptococcus pneumonia,H.influenza,Staph.aureus,M.catarrhalis,M.pneumonia,Gram –ve bacilli, fungi such as
Cryptococcus,candida,aspergillus, Pneumocystis carinii, viruses such as CMV,HSV, mycobacteria
Pathogenesis
Most common is pneumocystis carinii, particularly when CD4 lymphocyte count <200/mm3 and also in patients receiving immunosuppressive
therapy.This fungus found in air & pneumonia arises from reinfection.This organism damages alveolar epithelium, which impedes gas
exchange &reduce lung compliance.
Clinical
The onset is often insidious over a period of weeks,with a prolonged period of weeks,with a prolonged period of increasing shortness of breath
(usually on exertion),non productive cough,fever,malaise.
Clinical examination:tachypnoea,tachycardia,cyanosis
Physical examination:fine crackles are heard on auscultation
Diagnosis
Together in delivering excellence (T.I.D.E.) INMDM1-ORAL Page 4 GKS437/09-