5 cellular
5. Immunologic agents – it protects the host against various injurious agents but it may
also turn lethal and cause cell injury e.g.
hypersensitivity reactions;
anaphylactic reactions; and
autoimmune diseases
6. Nutritional derangements – A deficiency or an excess of nutrients may result in
nutritional imbalances.
Nutritional deficiency diseases may be due to overall deficiency of nutrients
(e.g. starvation), of protein calorie (e.g. marasmus, kwashiorkor), of minerals
(e.g. anaemia), or of trace elements.
Nutritional excess is a problem of affluent societies
resulting in obesity, atherosclerosis, heart disease and hypertension.
7. Aging – Cellular aging or senescence leads to impaired ability of the cells to
undergo replication and repair, and ultimately lead to cell death culminating in death
of the individual.
8. Psychogenic diseases
9. Iatrogenic factors – diseases as well as deaths attributed to iatrogenic causes
(owing to physician). Examples include occurrence of disease or death due to error in
judgment by the physician and untoward effects of administered therapy (drugs,
radiation).
10. Idiopathic diseases. – Idiopathic means of unknown cause.
2. PSEUDOTUMOURS
Definition: An enlargement that resembles a tumor that may result from
inflammation, accumulation of fluid, or other causes, and may or may not
regress spontaneously.
Pseudotumour is a pathological lesion that grossly or clinically bears the
resemblance to a genuine tumour BUT its nature is nonneoplastic. In biological
aspect all pseudotumours are benign.
Pathological changes included in the category Pseudotumours:
Cysts –Inflammation –Developmental anomalities-Hyperplasia
Pseudotumour: Epidermoid cyst
The cyst is a cavity that arises from dilatation of pre-existing structure and is
generally lined by epithelium.
These are a common type of keratineous cysts (cysts filled with keratin). They
are situated in the dermis or subcutaneous tissue and appear spontaneously. The
cyst is filled with horny keratinous material. A foreign body reaction may occur
when the wall of cyst ruptures, thus forming a keratin induced granuloma.
7
Induced by epidermis being transplanted into deeper skin layers from
trauma.
Inflammatory Pseudotumours: These are a group of inflammatory
enlargements, especially in the orbit of the eye, which clinically look like
tumours but surgical exploration and pathologic examination fail to reveal any
evidence of neoplasm.
They are
composed of granulation tissue with leukocyte
infiltration.
Pseudotumor cerebri: Idiopathic cerebral oedema and raised intracranial
pressure without neurological signs except occasional sixth cranial nerve palsy.
17. BACTERIAL PNEUMONIAS.
Bacterial infection of the lung parenchyma is the most common cause of pneumonia or
consolidation of one or both the lungs. Two types of acute bacterial pneumonias are
distinguished
lobar pneumonia and
broncho-(lobular-) pneumonia, each with distinct etiologic agent and morphologic
changes.
Another type is confluent pneumonia which combines the features of both lobar
and bronchopneumonia.
Lobar Pneumonia
Lobar pneumonia is an acute bacterial infection of a part of a lobe, the entire lobe, or
even two lobes of one or both the lungs.
Etiology:
1. Pneumococcal pneumonia caused by streptococcus pnemonia.
2. Staphylococcal pneumonia. Staphylococcus aureus causes pneumonia by
haematogenous spread of infection.
4. Pneumonia by gram-negative aerobic bacteria. Less common causes of lobar
pneumonia are gram-negative bacteria like Haemophilus influenzae, Klebsiella
pneumoniae (Friedlanders bacillus), Pseudomonas, Proteus and Escherichia
coli, H. influenza
COMPLICATIONS.
1. Organisation. In about 3% of cases, resolution of the exudate does not occur
but instead it undergoes organisation. There is ingrowth of fibroblasts from the
alveolar septa resulting in fibrosed, tough, airless leathery lung tissue. This type
of post-pneumonic fibrosis is called carnification.
2. Pleural effusion inflammation of the pleura with effusion.
3. Empyema. lobar pneumonia develop encysted pus in the pleural cavity termed
empyema.
4. Lung abscess – especially when there is secondary infection by other
organisms.
5. Metastatic infection. Occasionally, infection in the lungs and pleural cavity in
lobar pneumonia may extend into the pericardium and the heart causing purulent
pericarditis, bacterial endocarditis and myocarditis, brain abscess.
CLINICAL FEATURES
Shaking and chills
Fever, malaise with pleuritic chest pain, dyspnoea and
cough with expectoration which may be mucoid, purulent or even bloody
tachycardia, and tachypnoea, and sometimes cyanosis if the patient is
severely hypoxaemic.
Bronchopneumonia (Lobular Pneumonia)
Bronchopneumonia or lobular pneumonia is infection of the terminal bronchioles that
extends into the surrounding alveoli resulting in patchy consolidation of the lung.
Etiology
? Staphylococci, streptococci,
? Pneumococci, Klebsiella pneumonia, Haemophilus influenzae,
? And gram-negative bacilli like Pseudomonas and coliform bacteria.
Complication bronchiectasis.
Clinical features
The patients of bronchopneumonia are generally infants or elderly individuals. There
may be history of preceding bed-ridden illness, chronic debility, and aspiration of
gastric contents or upper respiratory infection.
32. INFLAMMATIONS OF THE LARYNX.
INFLAMMATORY CONDITIONS
1. ACUTE LARYNGITIS. This may occur as a part of the upper or lower respiratory
tract infection. Atmospheric
pollutants like cigarette smoke, exhaust fumes, industrial and domestic smoke etc
predispose the larynx to acute bacterial and viral infections. Streptococci and H.
Influenzae cause acute epiglottitis which may be life-threatening. Acute laryngitis may
occur in some other illnesses like typhoid, measles and influenza. Acute
pseudomembranous (diphtheric) laryngitis occurs due to infection with C. diphtheriae.
2. CHRONIC LARYNGITIS. Chronic laryngitis may occur from repeated attacks of
acute inflammation, excessive smoking, chronic alcoholism or vocal abuse. The
surface is granular due to swollen mucous glands. There may be extensive squamous
metaplasia due to heavy smoking, chronic bronchitis and atmospheric pollution.
3. TUBERCULOUS LARYNGITIS. Tuberculous laryngitis occurs secondary to
pulmonary tuberculosis. Typical
caseating tubercles are present on the surface of the larynx.
4. ACUTE OEDEMA OF THE LARYNX. This hazardous condition is an acute
inflammatory condition, causing
swelling of the larynx that may lead to airway obstruction and death by suffocation.
Acute laryngeal oedema may occur due to trauma, inhalation of irritants, drinking hot
fluids or may be infective in origin.