-IBIS-1.5.0-
tx
respiratory system
pneumonia
diagnoses
definition and etiology
definition:
An acute infection of the parenchyma (alveolar spaces and/or interstitial tissue) of one or both lungs.
etiology:
Pneumonia is classified by the extent of lung involvement:
Lobar: One entire lobe is involved
Segmental or lobular: Parts of one lobe are involved.
Bronchopneumonia: When it affects the alveoli next to the bronchi.
Pneumonia is also classified by the associated microorganism involved in creating the infection: under the main listings of bacterial or nonbacterial:
Bacterial: Pneumococcal pneumonia (the most common), Strep pneumoniae, Staph aureus, Group A hemolytic strep, Klebsiella pneumoniae, Hemophilus influenzae, Francisella tularensis
Non-bacterial: Viruses, fungi, rickettsias.
Risk factors for developing pneumonia include URI; malnutrition; hospitalization; debility or immobilization; alcoholism; exposure; coma; hypostasis; foreign object aspiration into the lungs; decreased cough reflex (e.g. from smoking); COPD; major bony abnormality or deformity (e.g. severe kyphoscoliosis); bronchial tumor; and treatment with immunosuppressive drugs.
signs and symptoms
signs and symptoms:
Often, pneumonia is preceded by a URI.
The onset is typically sudden. The following are typical for pneumonia (viral pneumonia may not be as severe).
Shaking chills.
Cough with sputum (mucoid, bloody or purulent) production.
Fever.
Chest pain.
Dyspnea with tachypnea.
Headache.
Decreased respiratory excursion on affected side.
Dullness on percussion.
Auscultation uncovers high or low-pitched crackles.
(+) bronchial breath sounds with (+) egophony and bronchophony.
(+) x-ray.
Patient flexed over to affected side, and the shoulder of affected side may droop. There may be recurrent flushing of one or both cheeks.
lab findings:
(+) sputum analysis for bacteria.
Increased WBCs with left shift; in non-bacterial pneumonia, the WBC count may be normal or even low.
(+) x-ray.
course and prognosis
In pneumococcal pneumonia patients, 90-95% of patients aged 2-50 years old recover uneventfully after treatment. Factors that decrease the chance of survival include: patient <1 or > 60 year old; (+) blood culture; involvement of >2 lobes; WBC count of <5000; BUN >70 mg/100 ml; underlying systemic disease; or development of meningitis, endocarditis or other extrapulmonary illness. Early treatment leads to the best prognosis. Viral and Mycoplasma pneumonia are much more benign, often self-limiting and rarely need treatment other than rest and support (although pneumonia from Influenza A can be severe and fatal; and in either case, the illness may last for weeks).
differential diagnosis
pleurisy
bronchitis
pulmonary embolism
bronchiectasis
pulmonary edema
footnotes