The Differential Diagnosis and Underlying Pathologies – Respiratory System Example

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"The Differential Diagnosis and Underlying Pathologies" is a perfect example of a paper on the respiratory system.   Discuss the differential diagnosis and underlying pathologies for a 60-year-old male complaining of loss of weight, shortness of breath, and a persistent cough with traces of blood in his sputum. Discuss referral options.   The subject under discussion for differential diagnosis is a 60-year-old male who is complaining of weight loss, shortness of breath, and a persistent cough with traces of blood in his sputum or  hemoptysis. Cough, shortness of breath, and sputum production is mainly the symptom of the respiratory system.

The pulmonary disorders can be divided into four main categories; obstructive lung diseases, restrictive lung diseases, pulmonary infections, and lung  tumors. Obstructive lung diseases majorly consist of emphysema, chronic bronchitis, bronchiectasis, and asthma. The restrictive lung diseases include pneumoconiosis, infiltrative interstitial diseases, and chest wall disorders. Pneumonia and tuberculosis comprise the major and common pulmonary infections. Lung carcinomas are common in late stages of life mostly after the 50s and the incidence is more common in males (Kumar et al 2007).     The symptom of chronic shortness of breath or  dyspnoea  is associated with emphysema, chronic bronchitis, chronic asthma, and pneumoconiosis.

Cardiac  dyspnoea  is another form which is caused mainly because of left-sided heart failure. It occurs at exertion, during the night or in supine position termed as  orthopnoea  (Siegenthaler, 2007). Associated symptoms with  dyspnoea  help in finding the underlying pathology, for instance, fever and cough point towards pulmonary infections like pneumonia and TB (McPhee et al 2012). The subject of the case presents with persistent cough pointing towards the chronic nature of the cough. Conditions causing chronic  dyspnoea  also cause a chronic cough. However, it is also found in bronchogenic carcinoma, bronchiectasis, and chronic granulomatous diseases including tuberculosis (Friedman, 2001).

Production of trachea-bronchial secretions along with saliva while coughing is called  expectoration and indicates towards pathologies which include bronchiectasis, bronchitis, or pneumonia (Siegenthaler, 2007).     The patient manifests with traces of blood in his cough indicating both a productive cough and  hemoptysis.   Tuberculosis is a major cause of  hemoptysis, after this bronchiectasis and carcinoma of lung are important. Lesser important causes include lobar pneumonia and lung abscess (Lloyd, 1938). Chronic bronchitis is another common cause of  hemoptysis. Weight loss is most of the time the earliest presentation of many chronic illnesses.

Associations with any gastrointestinal symptoms, dietary habits, increase or decrease in appetite and social/psychiatric history are important for an accurate diagnostic approach. Weight loss associated with respiratory symptoms points towards an underlying cause of tuberculosis or carcinoma of the lung (Freidman, 2001).     The history of the patient is important as it can indicate significant diagnostic clues. A family history of tuberculosis in any close family relative indicates the chances of tuberculosis infection (Lloyd, 1938). Positive travel history, weight loss manifestation, and recurrent fever or tiredness by the patient also indicate towards the cause of tuberculosis (Bidwell &   Pachner  2005).

The patient gives a history of exertion, tickling sensation in the throat, and very rarely complains of cough. Other than history other important investigations include physical examination, laboratory tests, and imaging techniques (Lloyd, 1938). On physical examination, the positive diagnostic indicators include cachexia finding in inspection and tympani percussion over the lung apices (Bidwell &   Pachner  2005). The chest X-ray shows a characteristic localized area of infiltration in the lung. The sputum should be sent for acid-fast bacillus test for  Mycobacterium Tuberculosis  (Lloyd, 1938).     Cavitary  lesions in the X-ray film, increased white blood cell count in CBC, positive acid-fast culture tests are important diagnostic clues for tuberculosis.

Positive human  immunodeficiency virus tests also indicate an increased risk for tuberculosis (Bidwell &   Pachner  2005). Tuberculosis is caused by the inhalation of an acid-fast bacillus Mycobacterium Tuberculosis and the organism affects mainly the lower part of the upper lobes or the lower lobes. Primary TB can reactivate and can result in secondary TB (Goljan, 2010).     Bronchiectasis is another cause of  hemoptysis  along with persistent cough and expectoration. It is the dilatation of the bronchi caused by the collapse of the elastic tissue and cartilage of the bronchi.

It can be caused by TB, any bronchial obstruction, cystic fibrosis, or other bronchial infections (Goljan, 2010).   The clinical features of the disease include chronic persistent cough associated with sputum of  mucopurulent  and foul-smelling characteristics. Traces of blood are also resentful in the sputum. Another important physical finding in patients of bronchiectasis is clubbing of fingers (Kumar et al 2007). Important clues on history might include history or recurrent respiratory tract infections, weight loss history, and chronic lung disease (Bidwell &   Pachner  2005).

Important findings on physical examination include displacement of the apex beat due to the severity of the condition and  auscultatory  signs. Bronchial type of breath sounds should be recognized and unilateral basal moist  rales  are  auscultated. X-ray chest shows bronchial dilation and sputum tests for acid-fast bacillus must also be carried out to rule out tuberculosis (Lloyd, 1938). Bronchoscopy should be carried out to rule out carcinoma and also help in finding the accurate site of bleeding (Siegenthaler, 2007).   Examination of the upper respiratory tract is also important which may show  rhinorrhoea, sore throat, pale nasal mucosa, sinusitis and inflammation of the mucosal membranes indicating recurrent respiratory  infections  (George, 2005)    Chronic Bronchitis is defined as a productive cough for a minimum period of 3 months for two consecutive years.

It is strongly associated with cystic fibrosis and smoking history.   The underlying pathology shows hyperactivity of the mucous glands and obstruction of the terminal bronchioles. Mucus plugs in bronchi, loss of ciliated epithelium, fibrosis of bronchial epithelium, and goblet cell metaplasia are the significant changes observed in chronic bronchitis (Goljan, 2010). Chronic cough defined as a cough for more than three weeks is an important clinical feature of chronic bronchitis.

Chronic cough can lead to hoarseness of voice, exhaustion, pain, hernias, and insomnia. Other than chronic bronchitis it can also be caused by a foreign body, post-viral infection, and asthma (Hui  et al 2011). It is most common in the age group of 45-60 years showing an increased ratio among the men. Apart from smoking, it is also caused by excessive smoke inhalation by those who live in urban areas. Clinically it presents with expectoration, cyanosis and the patients are called “ blue bloaters” (Kumar et al 2007).

The patient gives a physical history of productive cough and tobacco usage. In cases of acute exacerbation of chronic cases of bronchitis the patient manifest with fever, breathlessness, wheezing, tympani to percussion, and hypoxic signs. The chest X-rays show hyperinflation of lungs or it might show no changes at all (Bidwell &   Pachner  2005). Important pulmonary tests in this condition include total lung capacity which is decreased and chronic respiratory acidosis is observed in arterial blood gases. PaCO2 is greater than 45 mm HG and bicarbonate levels are greater than 30 mm Hg (Goljan, 2010).     Bronchogenic carcinoma accounts for another important cause of  hemoptysis, weight loss, and persistent cough in men older than 50 years.

Bronchial epithelium accounts for 95% of the site of origin of lung carcinomas. Individuals with a history of habitual smoking (two packs each day for 20 years) are at an increased risk of developing carcinoma as compared to non-smokers. Prolonged inhalation of asbestos, arsenic, chromium, mustard gas, and nickel also increases the risk for carcinoma. The lung carcinoma presents with a history of chronic  cough and sputum production.   Haemoptysis  and weight loss are also significant clinical features (Kumar et al 2007).

On physical examination dull percussion notes, weak bronchial sounds on auscultation and cachexia are significant. Bronchoscopy is also important for the histological examination of the lung tissues to confirm malignancy (Lloyd, 1938). Patients who present with symptoms of  hemoptysis  for more than one week, have a history of smoking, and are older than 40 years are always indicated bronchoscopy (McPhee et al 2012).     Lobar pneumonia is most commonly caused by  S. pneumonia  however the common cause of pneumonia in the elderly is  Moraxella  catarrhalis.   It manifests with fever,   dyspnoea  associated with chest pain, persistent cough with the  mucopurulent  type of expectoration, and sometimes  hemoptysis.   Haemoptysis  is not a major manifestation of this condition (Kumar et al 2007).

On physical examination, dull percussion notes and unilateral  rales  are the positive findings. Moreover, fever and productive cough are observed in the individual’ s history. Sputum shows positive results for Gram staining and culture sensitivity tests (Bidwell &   Pachner  2005).   Bronchophony,   egophony, increased vocal  fremitus,   and bronchial breath sounds are recognized in pneumonia patients. Chest X-rays show areas of consolidation (Goljan, 2010).     The differential diagnosis of the patient can be established on the provided symptoms.

Based on the symptoms presented, the patient may be considered to suffer from diseases which include tuberculosis, bronchogenic carcinoma, pneumonia, bronchiectasis as well as chronic bronchitis. A thorough history and physical examination should be conducted on the patient to assess the final condition. This should be aided with the respiratory system assessments and investigations to reach a final diagnosis.  


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Bottom of FormTop of FormSIEGENTHALER, W. (2007). Differential diagnosis in internal medicine: from symptom to diagnosis. Stuttgart, Thieme.

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