ACUTE LOBAR PNEUMONIA

ACUTE LOBAR PNEUMONIA

It is the commonest of all specific pneumonias.

AETIOLOGY

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Predisposing causes

  • Age: All ages but 50% of cases are below 50 years of age.
  • Sex: Both
  • Seasons: Common in winter and rainy seasons.
  • Devitalising conditions, e.g. overwork, exposure to chill and cold, diabetes, chronic malnutrition, chronic avitaminosis etc.
  • Addiction to alcohol and smoking.
  • Overcrowding and poor sanitary condition.
  • Acute and chronic respiratory diseases such as influenza, chronic bronchitis, bronchiectasis, cystic fibrosis of lungs.
  • Immunological disorders such as in leukaemia, multiple myeloma, agammaglobulinaemia, lymphoma, etc.
  • Inhalation of foreign materials as in coma, anaesthesia, achalasia and oesophageal carcinoma.
  • Drugs -Steroids, cytotoxic and immunosuppressive drugs, radiation.
    Exciting causes
    ACUTE LOBAR PNEUMONIA…..|…Organisms are mentioned in specific pneumonias above Streptococcus pneumoniae is responsible 60%-80 % of community acquired pneumonias. Of more than 30 different types of pneumococci, 1-10 are commonly found to be involved but type 3 is most virulent of all. Other organisms in community acquired pneumonia are. H. influenzae, S. aureus, Legionella pneumophilia, Gram negative enteric rods and anaerobes. In nosocomial pneumonias, however, the organisms are
    quite different. Gram negative enteric rods particularly
    P. aeruginosa and S. aureus are mostly responsible, S. pneumoniae is very rare.
    It is to be remembered that it is extremely difficult to isolate the offending organism from sputum, pleural fluid or from blood.
    PATHOLOGY
    It is traditionally described in four stages but due to antibiotics and chemotherapeutic agents all these stages are not seen now a-days. The process usually affects only one lobe but may spread to other lobe of same lung or to opposite lung. The lower lobes particularly of right side is commonly affected Sometimes one or few segments of a lobe may also be involved. There is also inflammation of overlying pleura.
    Stage of Hyperaemia or Congestion
    In this stage the alveoli look more reddish than normal and vascular congestion is marked, alveoli are crepitant to touch and float in water.
    Microscopically slight swelling and congestion of alveolar wall may be present.
    Stage of Red Hepatisation
    Alveoli look still more reddish than before, friable to touch and sink in water. Because the alveoli are solidified like liver and red in colour this stage is called red hepatisation.
    Microscopically extreme swelling and congestion of alveolar wall, packing up of alveolar spaces completely with exudates containing chiefly RBC with few pus cells, fibrin and mucus are present.
    Stage of Grey Hepatisation
    The alveoli look grayish, friable to touch and sink in water. As the alveoli are solidified like liver and grey in colour this stage is called grey hepatisation.
    Microscopically alveolar walls are still swollen and congested. Alveolar spaces contain exudates which do not fill up the spaces completely and a clear zone all around remains. Exudates contain chiefly pus cells but few RBC and fibrin are also seen.
    Stage of Resolution
    Alveoli are normal in appearance both on naked eye and microscopic examination.
    These stages are usually seen in pneumococcal pneumonia.
    CLINICAL FEATURES
    Onset is sudden.
    SYMPTOMS
    Temperature is continued in type 103°-105°F (38.9-40.5 °C) may be associated with single shaking chill in about 80% of cases. Sometimes there may be hypothermia.
    Pain in the right side of the chest in about 70% of cases is seen due to associated pleurisy. If diaphragmatic pleura is affected there may be shoulder pain, referred upper abdominal pain and rigidity. For this, sometimes acute abdomen is misdiagnosed.
    Dyspnoea
    Cough with tenacious sputum, gradually rusty (or pinkish) sputum may develop.
    Malaise, weakness, headache, aches all over the body, loss of appetite and in severe cases delirium and cofusion may develop due to toxaemia.
    In elderly patients deterioration of mental functions and confusion are very important findings.
    SINGS
    General survey
    Patient is toxic. Face is flushed, alae nasi are moving. Central cyanosis may be present. Pulse is rapid, respiration is hurried. Pulse-respiration ratio is markedly altered (2:1). This is said to be characteristic. Herpes labialis may be present. Temperature is high. The skin is hot and moist but pallor may sometimes be present due to peripheral vasoconstriction, There may be hypotension, rarely jaundice and neck stiffness may be present.
    Examination of the chest
    Stage of congestion
    Expansion over affected part of the chest is restricted. Percussion shows impaired resonance. Breath sound is vesicular but diminished, crepitations called indux crepitations are heard.
    Stage of consolidation (usually after 48 hours)
    Inspection: Restricted movement of the affected part of the chest.
    Palpation: Vocal fremitus on the affected side is increased. Trachea and apex beat are in normal positions.
    Percussion: Woody dullness over the affected part is present.
    Auscultation: Breath sound is tubular in type (high pitched bronchial), vocal resonance is increased; there may be bronchophony or whispering pectoriloquy, aegophony may be present. Adventitious sounds are usually absent.
    The signs of consolidation are typically present in pneumococcal pneumonia on the 4th to 5th day of the onset of the disease and are absent when:
    (a) the consolidation is deep seated
    (b) there is associated pleural effusion or empyema
    (c) the communicating bronchus is blocked (Massive pneumonia)
    (d) in elderly individual.
    Massive pneumonia: It is pneumonia en masse. Exudates not only fill up the alveoli but also the bronchial tubes. Therefore, vocal fremitus is absent, Percussion note is dull and breath sound is absent with absence of vocal resonance and adventitious sounds and thus this condition exactly mimics pleural effusion but there will be no evidence of mediastinal shiff.
    Stage of resolution
    Breath sound becomes vesicular or broncho-vesicular. Plenty of medium and coarse moist sounds appear which are called redux crepitations.
    It is to be remembered that these signs are usually absent in the aged and only few rhonchi may be present.
    SPECIAL INVESTIGATIONS
    M. Blood shows high leucocytosis, e.g., 15,000-20,000/mm3 with preponderance of polymorphs which may be 85 %- 90%. Polymorph may show toxic granulations. Absence of leucocytosis has a poor prognosis. This may sometimes be seen in overwhelming infection. Sometimes there may be leukaemoid reaction.
  • Sputum may show the causative organisms but false positive result is seen in about 35% of cases.
  • X-ray of the chest will show opacity over the affected region. It may persist for 6-8 weeks. Associated pleural effusion is usually indicative of S. aureus or Strep. pyogenes pneumonia, cavitation is also present when pneumonia is due to these organisms. Cavitation is seen in Staph. aureus, Pseudomonas, Klebsiella, Legionella and Mycobacterial infection.
  • Blood culture may become positive (20%-25 %).
  • Bronchoscopic aspiration of secretion or Bronchoalveolar lavage are required for exact identification of offending organisms in nosocomial infection…..|…. ACUTE LOBAR PNEUMONIA
    COMPLICATIONS
  • General
    a) Нуperрyrexia.
    b) Septicaemia.
    c) Delayed resolution, which may indicate:
    i) low vitality
    ii) different causative organism other than pneumococci not responding to the antibiotics used
    iii) associated complications, e.g. empyema, lung abscess or pyopericardium.
  • Pulmonary
    a) Lung abscess or Suppurative pneumonitis.
    b) Pleural effusion (4%-8%).
    c) Empyema (0.5%-2% ) .
    d) Respiratory failure.
    e) Creeping or double pneumonia.
    f) Gangrene of the lung.
  • Cardiovascular
    a) Hypertension.
    b) Deep vein thrombosis.
    c) Peripheral circulatory failure.
    d) Pyopercarditis (0.1%).
    e) Congestive cardiac failure.
    f) Acute endocarditis.
  • Alimentary
    a) Jaundice (obstructive).
    b) Peritonitis.
    c) Acute dilatation of stomach.
    d) Abdominal distension.
    e) Paralytic ileus.
  • Neurological
    a) Meningism.
    b) Meningitis.
  • Renal
    a) Oliguria, at times anuria
  • Ocular
    a) Pneumococcal conjunctivitis.
  • Ear
    a) Acute suppurative otitis media.
  • Bones and joints
    a) Osteomyelitis
    b) Suppurative arthritis.
  • Hypersensitivity to drugs
    COURSE AND PROGNOSIS
    The temperature in untreated cases falls by crisis within 7-10 days. However, this is not found now-a-days due to early institution of chemotherapeutic agents. The mortality rate in Pneumococcal pneumonia is 5% but in Staphylococcal and Klebsiella pneumonia it is 25% and 40% respectively.
    Prognosis is poor in extremes of age or in cases with jaundice, circulatory failure, anuria, multilobar involvement, leukopenia, infection by type 3 pneumococci or where the resistance of the host is poor due to diabetes, malnutrition etc.
    DIFFERENTIAL DIAGNOSIS
    Pleural Effusion
    Onset is gradual, evidence of mediastinal shift, absence of breath sound, vocal fremitus and resonance are usually seen clinically. X-ray and blood examination are also helpful.
    Collapse of the lung
    Toxaemia is absent. Mediastinal shift if present is on the same side of dullness, flattening of chest and aggregation of ribs are also present on the same side of dullness. Skiagram of the chest and routine blood examination will be helpful….|…ACUTE LOBAR PNEUMONIA
    Pulmonary Embolism
    Sudden onset of retrosternal pain and breathlessness, evidence of leg vein thrombosis, ECG changes are present. Toxaemia, high temperature, typical signs of consolidation are lacking.
    Bronchogenic Carcinoma
    Aged male patient with a smoking habit, clubbing, radiological and bronchoscopic findings are distinguishing features.
    Pulmonary Tuberculosis
    Low grade pyrexia, insidious onset, weight loss, night sweat, anorexia and presence of pulmonary signs in the apical region are helpful differentiating points. X-ray chest is helpful.
    MANAGEMENT
  • Rest in bed in propped up position.
  • Oxygen inhalation by nasal catheter or mask so as to correct cyanosis. Humidified O2 prevents drying of alveolo- bronchial secretion.
  • Penicillin is the drug of choice for average cases, 1 mega unit IM 6 hourly or about 7 to 10 days. For Staphylococcal pneumonia-See below. Tetracycline and Erythromycin may be given when the patient is allergic to Penicillin. In Penicillin resistant cases Cephalosporin should be used. Antibiotics however differ in different cases. In mild cases oral therapy in OPD may be done but in risk cases parenteral therapy in indoor set-up should be done.
  • To relieve cough, Codeine phosphate 15-30 mg, linctus pholcodin 2-4 cc orally.
  • If the patient is delirious, diazepam may be given.
  • If there is hypotension or peripheral circulatory failure, glucose saline infusion with circulatory stimulants and steroids particularly Hydrocortisone should be started.
  • For pleural pain Codeine phosphate 15-30 mg orally or in severe cases Pethidine hydrochloride 100 mg IM can be given if there is no contraindication.
  • Diet: Liquid diet to start with and gradually as temperature subsides high protein and high calorie diet with plenty of fluid and electrolytes can be given.
    CAUSES OF FAILURE RESPONSE TO THERAPY
  • Incorrect or wrong diagnosis such as pulmonary tuberculosis, bronchogenic carcinoma, pulmonary embolism.
  • Resistance of the organisms as in infections by Staphylo aureus, Klebsiella pneumoniae, Psittacosis, Q-fever, Mycoplasma pneumoniae.
  • Superadded complications-Pleural effusion, empyema, lung abscess.
  • Hypersensitivity to Penicillin (5% of cases)

ACUTE LOBAR PNEUMONIA