Pneumonia:
dr. moshtak wtwt FIBMS
**definition: defined as an acute respirotery illness associated with recently developed radiological pulmonary shadowing , may be segmantal, lobar, multilobar & bronchopneumonia.
**Types: lobar pn: homogenous consolidation of one or more lung lobes often associated with pleural inflamation. Bronchopn: its more patchy alveolar consolidation associated with bronchial & bronchiolar inflamation often affecting both lower lobes.
**classification: 1- community-acquired pn (viral, bacterial) 2- hospital-acquired pn (nosocomial) 3- suppurative & aspirational pn (lung abscess) 4- pn in the immunocompromised patients.
Viral pneumonia:
causes: influenza, parainfleunza, measles, RSV, varicella, CMV.
() risk factors: *old age & children *chronic disease of the heart, lung or kidney *women in the last trimester of pregnancy.
() clinical features: *dry cough, dyspnea & malaise. *unremarkable physical examination *CXR= interstitial pattern
()complication: influenza-induced necrosis of resp epithelium predisposes to bacterial colonization, like strep. Pneumonia or staph. Aureus.
() community-acquired pn (CAP):
*Introduction: 1- incidence varies with the age. 2- accounts for one-fifth of childhood deaths 3- affect 2 million of children per year under the 5 years. 4- most patients managed at home, hospital admission 20-40% 5- MR at home is very low < 1%, hospital death rate 5-10% & may be as high as 50% in sever cases.
*Transmission: spread by droplet inhalation
*Pathogenesis: when organism settles in the alveoli, an inflammatory response ensues. Two phases : congestion, red & grey hepatisation. Finally resolution with little or no scarring.
() factors predisposes to CAP: *smoking *CS therapy *HIV *alcohol *old age *recent influ infection *pre-existing lung diseases *multiple myloma *sickle cell disease *contact with sick birds & farm environment
() Organisms: *strep. Pn *mycoplasma pn *chlamydia psittaci *ch pn. *legionella * H . Infleunza *staph. Aureus *coxiella burnetti *klebsialla *actinomyces israelli
() Clinical features: typically presents as acute illness with fever, rigors, sweating, vomiting, anorxia & headache. Pulmonary == cough, sputum, pleuritic chest pain & confusion. O/E pyrexi, tachycardia, tachypnea, hypotension, after 2 days, the consolidation will appear with dull on percussion & bronchial breathing, whispering pectorilquy & aegophony. When resolution occur, fine crackles & then coarse which indicate liquefaction of alveolar exudates.
()Specific features of pn: **pneumococcal pneumonia: (30%) caused by strept. Pneumonia, rusty sputum, herpetic features, lobar or multilobar on CXR. **Chlamydia pn: (5-15%) pharyngitis, sinusitis, increase LFT, diagnose serologically, CXR show small segmental infilterates. **Mycoplasma pn: (9%) insidious onset, few signs on chest with systemic features complicated by myocarditis, pericarditis, meningoencephalitis, hemolytic anemia, stevens johnson syndrom, erythema nodusum & GB. CXR lobar consolidation with hilar LAP. **Legionella pneumophilia: (5%) traveler history with systemic symptoms like headache, confusion, malaise, myalgia& diarrhea. Hyponatremia, hypoalbuminemia, high LFT & CK. CXR consoli slow to resolve. **Haemophilus infleunzae: (3%) COPD, Bronchiactasis, CXR bronchopn. **Staph aureus: (2-5%) may cause osteomyelitis, endocarditis & brain abscess CXR cavitation. **Chlamydia psittaci:(<1%)contact with bird, hepatosplenomegally , CXR lower lobe consolidation.
()Investigations:
1- CXR: appear within 12-18 h.
2- microbiological : *sputum for gram stain & culture *blood culture *serology for mycoplasma, chlam, legionella.
3- Oximetry:
4- general blood tests: WBC, LFT, RFT, CRP. () Diff Dx: *pulmonary infarction *pul TB *pul odema *pul eosinophilia *bronchoalveolar cell ca. *cholecystitis, acute pancreatitis, subphrenic absecess, hepatic amebiasis.
() Assessement of disease severity: hospital CURB-65: *Confusion *Urea > 7 mmol/l * RR > 30/M * B Pr <90 or < 60 mmHg *65 years of age if 0-1 treated at home if 2 consider hospital treatment if 3 or > for ICU admission. () features of high mortality: A- clinical: B- Lab *age>60 years, male *Pa O2<8kPa *RR > 30 min * WBC < 4000/mm3 *Bpr < 90 mmHg, <90 mmHg *WBC > 20 000/mm3 *confusion *BU > 7 mmol/l *multilobar on CXR * positive blood culture *underlying diseases * hypoalbuminemia
() management: 1-general: 2- O2: 3- Ventilation: indications for RCU: *CURB score > 3 not respond to treatment *persistent hypoxia < 8 kPa despite high conc O2 *progressive hypercapnea *severe acidosis *shock *depressed conciousness 4- fluid balance: 5- antibiotic treatment: *uncomplicated pn 7-10 days, but 14 days for Legionella, or Klebseilla *oral Ab are adequate unless has severe illness, impaired conc, loss swallowing reflex or malabsorption.
() in uncomplicated pn: *amoxicillin 500mg 8-h orally. *if allergic to pencillin: clarithromycin 500mg 12h orally. *if staph : flucloxacillin 1-2 g 6h IV plus clarithromycin 500mg 12h IV *if mycoplasma or legionella: clarithromycin 500mg 12h IV *if chlamydia: tetracycline or erythromycine. *if H. infleunzae: ampicillin plus 3rd generation cephalosporin. *if Klebsialla: cephalosporin plus fluoroquinolone or aminoglycoside. () in severe CAP: *Clarithromycin 500mg 12h IV Or erythromycin 500mg 6h plus either Co-amoxiclav 1.2 g 8h IV or ceftriaxone 1-2 g daily. ()Complications: failure to respond to therapy may indicate: 1- wrong AB 2- mixed infection 3- bronchial obstruction 4- wrong diagnosis 5- complications as follow: * para-pneumonic effusion *empyma *lobar collapse *thromboembolic disease *pneumothorax *lung abcess *ARDS, renal failure, multi-organ failure *ectopic abcess *hepatitis, pericarditis, myocarditis, meningoencephalitis
() Discharge & Follow-up: @ discharge depend on no more than one of the followings: 1- RR > 24/m 2- systolic Bpr < 90 mmHg 3- Sa O2< 90%. 4- inability to intake oral 5- abnormal mental state () Prevention: 1- influenza vaccine: (yearly) for: elderly, chronic lung or heart diseases, DM, AIDS, health care worker, sickle cell diseases. 2- polyvalent Pneumococcal poly saccharide vaccine: (5 years) for: elderly, chronic heart or lung diseases, sickle cell diseases, asplenic patients, Hodgkin disease, multiple myloma, cirrhosis, DM, AIDS.