Human case study based on the respiratory system

Answer

Diagnosis of Community-Acquired Pneumonia

            Community-acquired pneumonia (CAP) is a significant threat to public health. The community-acquired bacterial pneumonia (CABP) is considered as the dominant presenting disease in various urgent care settings. CABP is one of the major causes of infectious deaths and causes more deaths than either prostate or breast cancer (Harnett, 2017). At risk population, include children and the elderly (McCance et al., 2014). This paper proceeds to discuss the differential diagnoses of CAP, final diagnosis and a highlight of normal versus abnormal lung auscultation, palpation and percussion findings.

            Differential diagnosis of CAP includes differentiation of influenza and pneumonia. First of all, both influenza and pneumonia may manifest with similar symptoms. Secondly, influenza acts as a predisposing factor for developing pneumonia.  Pneumonia may complicate influenza, thus, resulting in significant mortality and morbidity (Harnett, 2017).

Tuberculosis (TB) tests should not be excluded since pulmonary TB cases may be misdiagnosed as CAP. TB symptoms may be strikingly similar to those experienced in CAP. Clinical courses may help in clinical differentiation of TB and CAP. On appropriate treatment, fever resolves among the hospitalized TB patients in about 16 days and 3 days among the CAP patients (Grossman et al., 2014). Caution should be taken during differential diagnosis since influenza or TB may co-occur with CAP.

            Characteristics symptoms may help to provide the presumptive diagnosis of CAP, thus raising the need for further tests and examinations. Assessment findings that serve to confirm pneumonia include the presentation of symptoms such as a dry cough, sudden onset of chills or fever, and rusty colored sputum (Harnett, 2017; Jain et al., 2015). Other important symptoms include chest pain, tachypnea, dyspnea, abnormal lung examination, and/or respiratory failure (Jain et al., 2015). Abnormal lung examination is performed through analysis of lung auscultation, palpation, and percussion (McCance et al., 2014).

Normally bronchial breath sounds are relatively louder, high pitched and that breathing in and out is equal. Besides, there is a pause between breathing in and out. Similarly, normal vesicular breathing is audible over the thoracic region but softer and lower pitched than bronchial breathing.  In pathological state, breath sounds may be diminished or absent. Bubbling or crackling sounds may be heard due presence and movement of fluids in alveoli (McCance et al., 2014). 

Normal lung palpitation is observed when the thumb and hand move equally on left and right when the examiner places fingers and thumb about 2inches below a patent’s axilla. Asymmetrical chest expansion may indicate swelling, chest skeletal abnormalities, and perhaps pneumonia. Percussion generates sounds on a spectrum ranging from flat to dull sounds depending on the density of a given underlying tissue. Normal lung percussion is tympanic or resonant to percussion; while, a pathological lung is dull to percussion due to increased tissue density, consolidation or effusion (McCance et al., 2014).

Streptococcus pneumoniae stands out as the leading causative agent of bacterial pneumonia both in the US and globally (Harnett, 2017). Thus it should be the primary pathogen of interest when performing microbiological tests. If confirmed, then drug susceptibility test is necessary since S. pneumonia has recently developed resistance to various antibiotics including macrolides (Harnett, 2017). The microbiological basis of CAP should be determined so as to administer the right medications for the right conditions (Jain et al., 2015). Apart from symptoms, other diagnostic tests such as serological, biochemical, culturing and radiographic techniques helps to further the diagnosis of CAP.

Specimens for laboratory diagnosis of CAP include sputum, blood, pleural fluids, brochoalveolar-lavage specimens, and endotracheal aspirates (Jain et al., 2015; McCance et al., 2014). Serological tests help to build on CAP diagnosis. For instance lowered white blood cell count and reduced percentage of lymphocytes may indicate a bacterial pneumonia. Other test such as urine antigen tests and blood cultures may help in detection and confirmation of pathogens including Legionella and S. pneumonia. Sputum cultures are also helpful (Harnett, 2017). It has been established that the ratio of the neutrophil-lymphocyte count (NLR) is relatively lower among the pulmonary TB patient compared with bacterial CAP. NLR is a better diagnostic discrimination of TB from CAP compared with procalcitonin and C-reactive protein low levels (Grossman et al., 2014).

 The chest X-ray is regarded as the gold standard for diagnosis of CAP. Based on a case history of the current illness, physical exam and subjective symptoms a standard chest radiograph should be produced; with posterior-anterior and lateral views. Other possible causes of reported symptoms can be ruled out through chest X-ray. Chest X-ray may help confirm early cases of CAP in the absence of visible infiltrates (Harnett, 2017).

Diagnosis of CAP depends on the presence of new infiltrate demonstrated through a chest radiograph. Other imaging techniques may be utilized. Besides, recently acquired characteristic symptoms are also fundamental for confirming diagnosis (Grossman et al., 2014). However, identification of the causative agent is limited through radiography, thus, other approaches such as serological, biochemical and culturing techniques should also be relied on (Grossman et al., 2014). It is important to link symptoms, abnormal lung examinations, laboratory and radiographic results when diagnosing CAP. Other diseases which have similar symptoms as CAP should be ruled out first before an intervention plan is developed.