Respiratory Medicine

Contents

• Respiratory Case Taking

1. History Taking
2. Symptoms of Chest Disease- (Cough, Expectoration, Wheezes, Dyspnea, Hemoptysis, Chest Pain)
3. Investigation- (Chest X-ray, Pulmonary Function Test)

• Basic Respiratory

1. Clinical Anatomy
2. Developmental Disorder

• Respiratory Disease

1. Acute Bronchitis
2. Pneumonia
3. Pulmonary Tuberculosis- (Complication)
4. Extra Pulmonary Tuberculosis
5. Suppurative Lung Syndrome
6. Pleural Diseases
7. Bronchial Asthma
8. Hypersensitivity Pneumonitis
9. Smoking
10. Chronic Obstructive Pulmonary Disease
11. Lung Cancer
12. Disease of Mediastinum
13. Respiratory Failure
14. ARDS
15. Oxygen Therapy
16. Pulmonary Thromboembolic Disease
17. Pulmonary Hypertension
18. Pulmonary Fibrosis
19. Lung Collapse and Atelectesia
20. Disease of the Chest Wall
21. Disease of the Diaphragm
22. Uncommon Chest Diseases
23. Chest Radiology
24. Investigations in Chest Medicine

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Respiratory Alkalosis

Causes

• Stimulated respiratory drive
  • CNS
    • CVA, ICH, psychogenic
  • Hypermetabolic
    • Thyrotoxicosis
    • Pregnancy (Progesterone)(Secondary to reduced FRC)
    • Sepsis (fever) (often before metabolic acidosis)
    • DT, anxiety, pain
    • DKA and aspirin OD
  • Environmental
    • HYPERthermia (Heat tetany)
  • Drugs
    • Aspirin OD
    • Progesterone
  • Liver failure (encephalopathy) with hyperammonaemia (ammonia)
• Iatrogenic mechanical ventilation

Hypoxemia induced

• Pneumonia, PE, asthma
• Congenital heart disease
• Chronic altitude compensation
• Early in altitude acclimatisation

Compensation for metabolic acidosis

NOTE:

• Self-perpetuating process: Hyperventilation removes CO2 which causes cerebral acidosis and stimulates further increase in ventilation
• Chronic respiratory alkalosis is unique in that it CAN have full metabolic compensation (Only acid-base disorder that allows this)

Clinical

• Associated changes
  • HYPOcalcaemia, HYPOkalaemia, HYPOphosphatemia
  • Decreased Co2 reduces H+ binding, increases negative charge of proteins and increases binding of calcium to proteins
    • Thus reducing ionised calcium
  • Hypocalcaemia with tetany and carpopedal spasm
• Shift 02 dissociation curve to the left (Alkalosis) (Increased affinity of Hb for O2)

Correction

• Treat underlying cause
• Re-breather mask

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Respiratory Acidosis

Causes

• Decreased respiratory drive
  • CNS:
    • CVA, tumour, infection (encephalitis), haemorrhage
  • Drugs
    • Narcotics and sedatives
• Decreased chest wall movement
  • Neurological
    • NM disorders, Guillain-Barre
    • Myasthenia gravis, demyelinating disorders
    • Tetanus
  • Toxicity
    • Muscle relaxants, Organophosphates, fentanyl
  • Respiratory (Acute)
    • Trauma, surgery, chest wall deformity
    • Tension pneumothorax, pleural effusion
    • Upper airway obstruction
  • Equipment
    • Increased dead space, improper connection
• Obstructive pulmonary disease (chronic)
  • COPD, asthma, pneumonia

Clinical

• Vasodilation, sweaty, tachycardic, mydriasis, asterixis
• Confusion
• Drowsy and ALOC

Correction

• Renal compensation is slow and requires ventilatory changes for treatment
• Increase alveolar minute ventilation

NOTE:

• Usually the rise in pCO2 will stimulate the respiratory centre to increase minute volume.
• If this fails then rapid rise in pCO2 with sedation and failure of respiratory drive and death

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Acid Base Disorders

Arterial blood gas analysis is used to determine the adequacy of oxygenation and ventilation, assess respiratory function and determine the acid–base balance. These data provide information regarding potential primary and compensatory processes that affect the body’s acid–base buffering system.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis

Interpret the ABGs in a stepwise manner:

1. Determine the adequacy of oxygenation (PaO2)
   • Normal range: 80–100 mmHg (10.6–13.3 kPa)
2. Determine pH status
   • Normal pH range: 7.35–7.45 (H+ 35–45 nmol/L)
   • pH <7.35: Acidosis is an abnormal process that increases the serum hydrogen ion concentration, lowers the pH and results in acidaemia.
   • pH >7.45: Alkalosis is an abnormal process that decreases the hydrogen ion concentration and results in alkalaemia.
3. Determine the respiratory component (PaCO2)
4. Primary respiratory acidosis (hypoventilation) if pH <7.35 and HCO3– normal.
   • Normal range: PaCO2 35–45 mmHg (4.7–6.0 kPa)
   • PaCO2 >45 mmHg (> 6.0 kPa): Respiratory compensation for metabolic alkalosis if pH >7.45 and HCO3– (increased).
   • PaCO2 <35 mmHg (4.7 kPa): Primary respiratory alkalosis (hyperventilation) if pH >7.45 and HCO3– normal. Respiratory compensation for metabolic acidosis if pH <7.35 and HCO3– (decreased).
5. Determine the metabolic component (HCO3–)
   • Normal HCO3– range 22–26 mmol/L
   • HCO3 <22 mmol/L: Primary metabolic acidosis if pH <7.35. Renal compensation for respiratory alkalosis if pH >7.45.
   • HCO3 >26 mmol/L: Primary metabolic alkalosis if pH >7.45. Renal compensation for respiratory acidosis if pH <7.35.

Additional Definitions

• Osmolar Gap
  • Use: Screening test for detecting abnormal low MW solutes (e.g. ethanol, methanol & ethylene glycol [Reference])
  • An elevated osmolar gap (>10) provides indirect evidence for the presence of an abnormal solute which is present in significant amounts [Reference]
  • Osmolar gap = Osmolality – Osmolarity
  • Osmolality (measured)
    • Units: mOsm/kg
    • Measured in laboratory and returned as the plasma osmolality
  • Osmolarity (calculated)
    • Units: mOsm/l
    • Osmolarity = (1.86 x [Na⁺]) + [glucose] + [urea] + 9  (using values measured in mmol/l)
    • Osmolarity = (1.86 x [Na⁺]) + glucose/18 + BUN/2.8 + 9 (using US units of mg/dl)
  • NOTE: even though the units of measured (mOsm/kg) and calculated (mOsm/l) are different [Reference], strictly they cannot be subtracted from one another… However, the value of the difference is clinically useful so the problem is usually overlooked!

Arterial Blood Gas (ABG) Interpretation Chart

Simple table to calculate Respiratory compensation in Acidosis and Alkalosis

Simple calculation to predict changes in HCO3– from PaCO2
	HCO3 (Baseline 24 mmol/L)
Every 10 mmHg D PaCO2 from baseline 40 mmHg	ACUTE	CHRONIC
↑PaCO2	1	4
↓PaCO2	2	5

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Complication & Sequelae of Pulmonary TB

To understand the complication of Tb, first of all we need to know the pathological fate of the disease complex. As we know that, the primary TB consist of some characteristic components which are the Ghon's Focus (granuloma), Lymphadenitis and Lymphangitis. So, the fate of these complex may be either heal in 90% of cases or Spread in 10% of cases.

Healing of TB by fibrosis will lead to [1]Pulmonary Fibrosis. This fibrosis will eventually cause the bronchi to dilate, known as [2]Brochiectasis. The healing of TB of the upper zones of the lung will cause Bronchiectasis Sicca Hemorrhagica whish is characterized by recurrent [3]Massive Hemoptysis.

While in case of spreading, the Ghon's focus may be enlarge then rupture into the bronchi causing [4]TB Pneumonia or into the blood vessels will cause [5]Hematogenous TB which then progress to Miliary TB. Because of the Ghon's focus presence as the subpleural lesion, when it rupture into the pleura will cause TB [6]Pleural Effusion. The rupture of this granuloma will live a hole [7]Cavitation inside the lung.

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Wheezes

Wheezes are continuous musical adventitious lung sounds. It occurs due to airway narrowing either to spasm or endoluminal or extraluminal obstruction. It occurs when air flows rapidly through a narrow airway (bronchospasm, thick secretions, edema), causing fluttering of the airway wall at one or more sites. Always signifies bronchi & upper airway obstruction, it may be heard by an unaided ear or with stethoscope.

Causes of wheezy chest:

• Generalized (Bronchial Asthma, COPD, Bronchitis, Trachiobronchitis, Bronchiolitis, Bronchiectasis, Cystic Fibrosis, Allergic Bronchopulmonary Aspergillsis, Carcinoid Tumor, Left Sided Heart failure [Cardiac Asthma], Uremia [Renal Asthma] & Anaphylaxis)
• Localized [Localized bronchial Obstruction]

1. Intraluminal (Foreign body Inhalation, Bronchial Obstruction by mucus plugs, Bronchial Carcinoma, Carcinoid Tumor & Endobronchial TB)
2. Lumenal (Bronchial Stenosis & Stricture)
3. Extralumenal (Compression by enlarged lymph node or mediastinal mass) 

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6 Cardinal Symptoms of Respiratory System:

1. Cough
2. Expectoration
3. Wheezes
4. Haemoptysis
5. Dyspnea
6. Chest pain

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Dyspnea

Dyspnea is a subjective complaint by the patient feeling or consciousness of difficulty in breathing concerning the rate, depth or rhythm. It is a symptoms that can be expressed as:

• Difficult of breathing
• Difficult or laboured breathing
• Undue awareness of breathing 
• Need to breath more
• Uncomfortable or unpleasant breathing

Grading of dyspnea:

Two scoring systems can be adopted to evaluate the dyspnea changing it from subjective complaint to objective event.

• American Thoracic Society Score (ATS)

Grade	Description
0	No breathlessness except with strenuous exercise
1	Breathlessness when hurrying on the level or walking up a slight hill
2	Walk slower than people of the same age on the level because of breathlessness or has to stop for breath when walking at town pace on the level
3	Stop for breath after walking about 100 yards (96 meter) or a few on the level
4	Too breathless to leave the house or breathless when dressing or undressing

• New York Heart Association Score (NYHA)

Grade	Description
1	Dyspnea on more than ordinary activity
2	Dyspnea on ordinary activity
3	Dyspnea on less than ordinary activity
4	Dyspnea on rest

The interpretation of dyspnea includes the following points:

• Onset:-

1. Within minutes or hours [Acute, i.e. Dyspnea as in emergency] (Acute attack of Asthma, Pulmonary Edema, Tension Pneumothorax, Acute Massive Pulmonary Embolism, Pneumonia & Sizable foreign body Aspiration)
2. Within days or weeks (Cardiac Failure, Thrombo-embolic Disease, Pleural Effusion, Anemia & Hyperthyroidism) 
3. Within months or years (COPD & Pulmonary Hypertension)

• Course:-

1. Progressive (Interstitial Pulmonary Fibrosis, Pulmonary Hypertension, COPD, Cardiomyopathy)
2. Intermittent (Bronchial Asthma) 

• Relation to time:-

1. Nocturnal [At night] (Bronchial Asthma, Cardiac Asthma & Obstructive Sleep Apnea)

• Relation to posture:-

1. Orthopnea [On lying down] (Left Sided Heart failure, Acute Asthma, Mediastinal Syndrome, Tense Ascites, COPD, Bilateral phrenic nerve paralysis)
2. Platypnea [On upright position] (Multiple recurrent Pulmonary Emboli, Bibasilar Pneumonia, Bilateral Pleural Effusion, Bibasilar arteriovenous shunt & Pulmonary arteriovenous malformation)
3. Talepnea [On lying lateral side] (Unilateral Lung & Pleural Disease:- Unilateral Pleural Effusion, Tension Pneumothorax, Destroyed lung & Atelectatic-Consolidated Lung)

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6 Cardinal Symptoms of Respiratory System:

1. Cough
2. Expectoration
3. Wheezes
4. Haemoptysis
5. Dyspnea
6. Chest pain

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Expectoration

Expectoration entails the passage of sputum out of the respiratory tract, excluding saliva. The interpretation of expectoration includes the following points:

• Onset:- 

1. Acute (Acute Bronchitis, Pneumonia, Acute Abscess & Empyema with bronchopleural fistula)
2. Gradual (TB, Chronic Bronchitis & Bronchiectasis) 

• Course:-

1. Progressive (Infection uncontrolled by antibiotics)
2. Regressive (Spontaneous improvement or good response to the antibiotics used)
3. Intermittent (Chronic Bronchitis & Bronchiectasis) 

• Duration:-

1. Long duration (Chronic Bronchitis & Chronic Lung Abscess)
2. Short duration (Acute Bronchitis, Pneumonia & Acute Lung Abscess) 

• Amount:- Big amount = >100 cc (bronchorrhea), due to Chronic Suppurative Lung Diseases which are:

1. Bronchiectasis
2. Chronic Lung Abscess 
3. Infected Cystic Lung
4. Empyema with Bronchopleural Fistula 

It also may be due to: Chronic Bronchitis, Asthma, Alveolar Cell Carcinoma & Acute Organophosphorous Poisoning 

• Colour:- It may be diagnostic:

1. Greenish (Infection with gram negative organism e.g. Pseudomonas due to formation of pyocyen pigment)
2. Rusty (Golden brown sputum due to altered haemoglobin in Stretococcal Pneumonia)
3. Red Current Jelly (Klebsiella Pneumonia & Bronchial Adenoma)
4. Haemoptysis (Bloody sputum)
5. Anchovy Sauce (Chocolate coloured sputum in Amoebic Lung Abscess)
6. Black (Melanoptysis in smokers, coal workers pneumoconiosis & Mucormycosis)
7. Reddish Tinge (Aerosolized brochodilators, Serratia Marcens Pneumonia & Secondary inhalation of iron oxide in glass sanders)
8. Blue (Copper miners)
9. Watery (Alveolar Cell Carcinoma)
10. Tricoptysis (Cough of hair due to rupture of dermoid cyst into a bronchus)
11. Chalky material/small stones (Broncholithiasis which is due to prior infections with TB, Histoplasmosis or Coccidiodomycosis)

• Aspect:-

1. Frothy sputum in Pulmonary Edema
2. Purulent sputum in Suppurative Lung Disease
3. Thick mucoid pellets in Bronchial Asthma 

• Odour (smell):-  It may be diagnostic:

1. Offensive putrid (Anaerobic organism infection in Suppurative Lung Disease)
2. Distinctive (Gram negative infection, similar to E-coli on a culture medium)

• Relation to time:-

1. Day (Morning cough of smokers or Suppurative Lung Disease)
2. Night (Bronchial Asthma, Cardiac Asthma or Acute Pulmonary Edema) 
3. Variable Morning or Nocturnal (Bronchial Asthma)
4. All over the day

• Relation to posture:- Only in Suppurative Lung Disease

1. Leaning forward or praying in Bronchiectasis
2. Lying on healthy side in Chronic Lung Abscess 

• Associated haemoptysis

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6 Cardinal Symptoms of Respiratory System:

1. Cough
2. Expectoration
3. Wheezes
4. Haemoptysis
5. Dyspnea
6. Chest pain

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Cough

Batuk adalah gejala yang paling biasa dialami oleh pesakit paru-paru. Pesakit dianggap mengalami batuk kronik apabila dia mengalami gejala ini lebih dari 3 minggu. Selain itu, batuk juga dikelaskan kepada: batuk kering & batuk produktif.

• Dry Cough: mungkin berlaku disebabkan oleh masalah pernafasan atau bukan masalah pernafasan
• Productive Cough (with sputum): hanya berlaku disebabkan oleh masalah saluran udara (pernafasan)

Di samping itu, terdapat beberapa ciri-ciri batuk yang penting untuk dikenal pasti bagi mencapai diagnostik penyakit, seperti:

Sebab-sebab Batuk Kering

A) Masalah Pernafasan:

1. Acute Upper & Lower Respiratory Tract Infection: (Selsema, Acute Rhinitis & Sinusitis, Acute Pharyngitis, Acute Bronchitis, Tracheitis & Tracheobronchitis dan Pneumonia)
2. Reactive Airway Dysfunction Syndrome: (Peningkatan kereaktifan saluran pernafasan mengakibatkan batuk kering berterusan, disebabkan oleh jangkitan virus)
3. Bronchial Asthma
4. TB
5. Foreign Body Inhalation 
6. Pleural Disease
7. Interstitial Lung Diseases & extrinsic Allergic Alveolitis
8. Lung Congestion 
9. Pulmonary Embolism
10. Mediastinal Mass
11. Bronchial Adenoma & Bronchial Carcinoma

B) Bukan Masalah Pernafasan:

1. Gastroesophageal Reflux Disease (GERD)
2. Central causes
3. Reflex
4. Drug Induced
5. Psychogenic Cough  

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6 Cardinal Symptoms of Respiratory System:

1. Cough
2. Expectoration
3. Wheezes
4. Haemoptysis
5. Dyspneoa
6. Chest pain

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