Pulmonary Infections Pathology Study Guide

Pulmonary Infections Pathology Video

Pulmonary Infections

Pulmonary infections are disease of the lungs due to microorganisms.

Pulmonary infections include:

Pneumonia (various types)
Tuberculosis

Pneumonia

Pneumonia is a parenchymal lung infection.

Pneumonia may occur when the body’s natural defenses are weakened (e.g. impaired cough reflex, damage to mucociliary escalator, or mucus plugging).

Symptoms of pneumonia include:

Fever
Chills
Productive cough that with yellow-green (pus) or rusty colored (bloody) sputum
Tachypnea
Pleuritic chest discomfort

Medical and lab findings of pneumonia include:

Diminished breath sounds
Dullness to percussion
Elevated WBC count
Chest X-ray
Sputum gram stain and culture

Blood cultures are used to make the diagnosis of pneumonia.

Three common patterns of pneumonia may be detected on chest X-ray which include:

Lobar pneumonia
Bronchopneumonia
Interstitial pneumonia

Pneumonia. A chest x-ray of a patient with severe viral pneumonia due to SARS Not altered. Public Domain
Pneumonia. Chest radiograph of an 88 year old man, about one week after onset of fever, fatigue and mild coughing. Lab tests detected both Influenza A virus and Haemophilus influenzae. It shows multifocal, patchy consolidation, mainly in the right upper lobe. Mikael Häggström, M.D. Not altered. CC0
Pneumonia. A pleural effusion: as seen on chest X-ray. The A arrow indicates fluid layering in the right chest. The B arrow indicates the width of the right lung. The volume of the lung is reduced because of the collection of fluid around the lung. Not altered, Public Domain
Pneumonia. Right middle lobe pneumonia in a child as seen on plain X-ray James Heilman, MD - Not altered. CC BY-SA 4.0
Pneumonia. CT of the chest demonstrating right-sided pneumonia (left side of the image) James Heilman, MD - Not altered. CC BY-SA 3.0
Pneumonia. Cavitating pneumonia due to MRSA as seen on a CT scan James Heilman, MD - Not altered, CC BY-SA 4.0

Lobar Pneumonia

Lobar pneumonia is characterized by the consolidation of a whole lung lobe.

Lobar pneumonia is typically caused by bacteria which include:

Streptococcus pneumonia (95 percent)
Klebsiella pneumonia

Typical gross lobar pneumonia presents in phases:

Congestion resulting from edema and clogged vessels
Exudate, neutrophils, and hemorrhage cause red hepatization, which gives the typically spongy lung a solid consistency by filling the alveolar air spaces
Gray hepatization as a result of red blood cell (RBC) breakdown in the exudate

Lobar Pneumonia. Chest radiograph of a lobar pneumonia, affecting the right middle lobe. Mikael Häggström, M.D. - Not altered. CC0
Lobar Pneumonia. Micrograph of lobar pneumonia, H&E stain. Department of Pathology, Calicut Medical College - Not altered. CC BY-SA 4.0

Bronchopneumonia

Bronchopneumonia is characterized by patchy, sporadic consolidation, concentrated on the bronchioles.

Bronchopneumonia is frequently bilateral and multifocal.

Bronchopneumonia is caused by different bacterial species.

Bronchopneumonia. Histopathology of bronchopneumonia, showing neutrophils filling a bronchiole. Mikael Häggström, M.D. - CC0

Interstitial Pneumonia

Interstitial pneumonia is also known as atypical pneumonia.

Diffuse interstitial infiltrates are the defining features of interstitial pneumonia.

Interstitial pneumonia presents with only a few minor upper respiratory symptoms (low fever, little sputum) which is an ‘atypical’ presentation.

Interstitial pneumonia is typically caused by bacteria or viruses.

Interstitial Pneumonia. Micrograph of usual interstitial pneumonia (UIP). UIP is the most common pattern of idiopathic interstitial pneumonia (a type of interstitial lung disease) and usually represents idiopathic pulmonary fibrosis. H&E stain. Autopsy specimen. No machine-readable author provided. KGH assumed (based on copyright claims). Not altered. CC BY-SA 3.0
Interstitial Pneumonia. Pneumocystis pneumonia can present with interstitial lung disease, as seen in the reticular markings on this AP chest x-ray. KGH Not altered. Public Domain
Chest tomography (CT) images and pathology results of several cases.1A: The CT shows a paving stone sign and air bronchograms in patients with pulmonary alveolar proteinosis (case 2 in Table 2). 1B: Under light microscopy, the case of pulmonary alveolar proteinosis (case 2) shows evidence of periodic acid-Schiff-positive material filling the alveoli. Interstitial cell infiltrates, including lymphocytes and plasma cells with type II cell hyperplasia, are found. 2A: Multiple thin-walled cysts are seen in the subpleural region in the CT image of lipoid pneumonia (case 6). 2B: Light microscopy of lipoid pneumonia (case 6) shows a large amount of cholesterol crystallization in the alveolar spaces with lymphoid follicles in the alveolar septa. 3A: The CT image of non-specific interstitial pneumonia (case 15) shows reticulation on the background of ground glass opacity and interlobular septal thickening. 3B: A typical pathology picture of cellular non-specific interstitial pneumonia (case 15). The lungs are uniformly involved. Interstitial chronic inflammation consists of lymphocytes and plasma cells. 4A: On the background of ground glass opacity, thin-walled cysts are scattered in the lung fields (case 20, lymphocytic interstitial pneumonia). 4B: In case 20, dense interstitial lymphoid infiltrates, including lymphocytes and plasma cells with type II cell hyperplasia, are observed. The alveolar septal interstitium is expanded by fibrosis. Lymphoid follicles are present. 5A: In case 24, a case of acute interstitial pneumonia, a patchy high-density shadow and bronchograms are seen in the CT image. 5B: Case 24 exhibits diffuse alveolar damage by light microscopy. The alveolar septal interstitium is expanded. Fibroblast proliferation and hyaline membrane disease are shown. Application of clinico-radiologic-pathologic diagnosis of diffuse parenchymal lung diseases in children in China. Xu D, Chen Z, Chen H, Huang R, Zhao S, Liu X, Zhou C, Peng Y, Yuan X, Zou J, Zhang H, Zhao D, Liu E, Zheng Y, Zhong L, Lu M, Lu J, Nong G - PloS one (2015). Not Altered. CC.
Interstitial Pneumonia. End-stage interstitial lung disease This photo of an autopsy lung with end-stage pulmonary fibrosis was taken in the early 1980s and digitized in 1999. It has been projected in many lectures in the intervening years. While this Ektachrome transparency is a bit worse for wear after so long, still, the archival value of Ektachrome is not to be dismissed. Photograph by Ed Uthman, MD. Public domain. Posted 7 Jan 99. Not altered. Public Domain
Histologic features of explanted lungs showing non-specific interstitial pneumonia (NSIP) with diffuse alveolar damage (DAD) pattern in a patient who clinically suggested with acute interstitial pneumonia. Diffuse interstitial thickening and chronic inflammatory cell infiltration are observed in both lobes, suggesting NSIP (A). In addition, focal DAD pattern is also observed in the right lobe (B) (Hematoxylin and eosin stain; original magnification: ×200). Clinico-pathological Analysis of the Lungs from Patients with Lung Transplantation in a Single Institute in Korea. Kim H, Jeon YK, Lee HJ, Kim YT, Chung DH - Journal of Korean medical science (2015). Not Altered. CC.
A 45-year-old smoking man diagnosed with desquamative interstitial pneumonia (DIP) by a) cryo-transbronchial lung biopsy (haematoxylin–eosin stain) showing b) thick alveolar septa filled by numerous macrophages with c) CD68 staining. A 67-year-old man diagnosed with silicosis by d) cryo-transbronchial lung biopsy showing e) a silicotic nodule (black arrow) and f) silica crystals with polarised light (white arrow). Transbronchial cryobiopsy in interstitial lung disease: experience in 106 cases – how to do it. ERJ Open Research. Not Altered. CC.

Aspiration Pneumonia

Aspiration pneumonia is seen in individuals who are at risk for aspiration, such as alcoholics and people who are unconscious.

The oropharynx’s anaerobic bacteria, such as Bacteroides, Fusobacterium, and Peptococcus, are typical causes of aspiration pneumonia.

Aspiration pneumonia classically leads to a right lower lobe abscess (due to the angle of the bronchus), but may present in different lobes.

Compared to the left, the right main stem bronchus branches anatomically at a less sharp angle.

Aspiration Pneumonia. Not altered. KGH CC BY-SA 3.0
Aspiration Pneumonia. Aspiration pneumonia in a ventilated person with a central line and nasogastric tube James Heilman, MD. Not altered. CC BY-SA 4.0

Tuberculosis (TB)

As a result of first-time exposure to aerosolized Mycobacterium tuberculosis, primary tuberculosis (TB) develops.

Tuberculosis (TB) results in the hilar lymph nodes undergoing fibrosis and calcification to produce a Ghon complex as well as localized, caseating necrosis of the lung.

Although primary tuberculosis (TB) usually has no symptoms, it results in a positive purified protein derivative (PPD) test result.

When Mycobacterium tuberculosis reactivates, secondary tuberculosis (TB) develops.

Reactivation of Mycobacterium tuberculosis is frequently caused by AIDS, although it can also be caused other immune compromising issues such as disease or advanced age.

Tuberculosis (TB) usually occurs at the lung’s apex due to the high oxygen tension in that region of the lungs.

Tuberculosis (TB) creates a cavitary foci of caseous necrosis and has the potential to cause tuberculous bronchopneumonia or miliary pulmonary tuberculosis.

Symptoms of tuberculosis (TB) include:

Fever
Weight loss
Night sweats
Cough with hemoptysis

Histology of tuberculosis (TB) shows caseating granulomas, and positive acid-fast bacilli (AFB) stain.

Common sites for systemic dissemination of tuberculosis (TB) include:

Meninges (meningitis)
Cervical lymph nodes
Kidneys (sterile pyuria)
Lumbar vertebrae (Pott disease)

Tuberculosis. Microscopy of tuberculous epididymitis. H&E stain Department of Pathology, Calicut Medical college. Not altered. CC BY-SA 4.0
Tuberculosis. Mantoux tuberculin skin test Greg Knobloch -Not altered. Public Domain
Tuberculosis. An anteroposterior X-ray of a patient diagnosed with advanced bilateral pulmonary tuberculosis. This AP X-ray of the chest reveals the presence of bilateral pulmonary infiltrate (white triangles), and „caving formation“ (black arrows) present in the right apical region.The diagnosis is far-advanced tuberculosis. Unknown author - This media comes from the Centers for Disease Control and Prevention's Public Health Image Library (PHIL), with identification number #2543. Not altered. Public Domain
Tuberculosis. The main symptoms of variants and stages of tuberculosis are given, with many symptoms overlapping with other variants, while others are more (but not entirely) specific for certain variants. Multiple variants may be present simultaneously. Mikael Häggström.. Not altered. Public Domain
(a) Normal fimbrial end, (b) unilateral proximal tubal block, (c) bilateral proximal block, (d) mild proximal tubal dilatation, (e) irregular tubal lumen and fimbriae (tuberculous salpingitis). Imaging techniques for assessment of tubal status. Panchal S, Nagori C - Journal of human reproductive sciences (2014). Not Altered. CC.
(a CT image, b PETimage, c fused PET/CTimage). The 18F-FDGPET/CTimage shows enlarged adrenal tumours with bilateral intense uptake of 18F-FDG. The SUVmax of the left adrenal tumour was 12.1 and the attenuation value 33 HU, and the SUVmax value of the right adrenal tumour was 14.4 and the attenuation value 29 HU; the liver SUVmax was 2.4. The final histopathological diagnosis was bilateral adrenal tuberculosis. What parameters from 18F-FDG PET/CT are useful in the evaluation of adrenal lesions?: Kunikowska J, Matyskiel R, Toutounchi S, Grabowska-Derlatka L, Koperski L, Królicki L - European journal of nuclear medicine and molecular imaging (2014). Not altered. CC.
Fluorescence images (100× oil). (A) negative control, phosphate-buffered saline in place of the specific monoclonal antibody, (B) negative control, Escherichia coli in place of the Mycobacterium tuberculosis. (C, D, and F) Specific interaction of bioconjugated nanoparticles with M. tuberculosis; (E) the nonspecific interaction (autofluorescence) despite displaying M. tuberculosis with bright fluorescence. Validity of bioconjugated silica nanoparticles in comparison with direct smear, culture, and polymerase chain reaction for detection of Mycobacterium tuberculosis in sputum specimens: Ekrami A, Samarbaf-Zadeh AR, Khosravi A, Zargar B, Alavi M, Amin M, Kiasat A - International journal of nanomedicine (2011). Not altered. CC.