Chickenpox (varicella)
 - primarily a childhood disease (70%)
 - incubation period 14-16 days; highly contagious; infectious 2 days before the vesicles until the last one dries.
 - present with generalized, intensely pruritic skin lesions starting as macules vesicles pustules (MVP-most valuable player) usually traveling centrifugally to the face and out to the extremities; unlike smallpox vesicles, chickenpox vesicles appear in varying stages of development as successive crops of lesions appear; intranuclear inclusions similar to HSV.
 - pneumonia develops in 1/3 of adults; MCC death in chickenpox.
 - association with Reye's syndrome if child takes aspirin. 

THE ADRENAL GLANDS 
ADRENAL CORTEX 
The adrenal cortex synthesizes three different types of steroids: 
1. Glucocorticoids (principally cortisol), which are synthesized primarily in the zona fasciculata 
2. Mineralocorticoids, the most important being aldosterone, which is generated in the zona glomerulosa; and 
3. Sex steroids (estrogens and androgens), which are produced largely in the zona reticularis.  

ADRENAL MEDULLA

The adrenal medulla is populated by cells derived from the neural crest (chromaffin cells) and their supporting (sustentacular) cells. 
They secrete catecholamines in response to signals from preganglionic nerve fibers inthe sympathetic nervous system.

G-6 PD Deficiency

Occurs in Negroes, Mediterranean races, India and far East. It confers a protection Against falciparum malaria.

It is transmitted as X-linked trait of intermediate dominance (variable effect in homozygous females). 

Haemolysis may be induced by :
•    Primaquin and other anti malarials.
•    Other drugs like chloramphenicol , analgesics, antitubercular drugs etc.
•    Infections.
•    Ingestion of Vicia faba bean (favism).
•    Diabetic acidosis
 

 LUNG ABSCESS  Lung abscess is a localised area of necrosis of lung tissue with suppuration.

 It is of 2 types:

 - Primary lung abscess that develops in an otherwise normal lung. The commonest cause is aspiration of infected material.

 - Secondary lung abscess that develops as a complication of some other disease of the lung or from another site

ETIOPATHOGENESIS.

 The microorganisms commonly isolated from the lungs in lung abscess are streptococci, staphylococci and various gram-negative organisms. These are introduced into the lungs from one of the following mechanisms:

 1.   Aspiration of infected foreign material.

 2. Preceding bacterial infection.

 3.  Bronchial obstruction.

 4. Septic embolism.

 5. Miscellaneous (i) Infection in pulmonary infarcts, (ii) Amoebic abscesses, (iii) Trauma to the lungs. (iv) Direct extension from a suppurative focus.

Abscesses may be of variable size from a few millimeters to large cavities, 5 to 6 cm in diameter. The cavity often contains exudate. An acute lung abscess is initially surrounded by acute pneumonia and has poorly-defined ragged wall. With passage of time, the abscess becomes chronic and develops fibrous wall.

Microscopic Examination

The characteristic feature is the destruction of lung parenchyma with suppurative exudate in the lung cavity. The cavity is initially surrounded by acute inflammation in the wall but later there is replacement by exudate of lymphocytes, plasma cells and macrophages. In more chronic cases, there is considerable fibroblastic proliferation forming a fibrocollagenic wall.

Polycystic kidney disease

Characterized by the formation of cysts and partial replacement of renal parenchyma.
Genetic transmission: autosomal dominant.
Clinical manifestations:

 hypertension, hematuria, palpable renal masses, and progression to renal failure. Commonly associated with berry
aneurysms. 

Respiratory Viral Diseases

Respiratory viral infections cause acute local and systemic illnesses. The common cold, influenza, pharyngitis, laryngitis (including croup), and tracheobronchitis are common.

An acute, usually afebrile, viral infection of the respiratory tract, with inflammation in any or all airways, including the nose, paranasal sinuses, throat, larynx, and sometimes the trachea and bronchi.

Etiology and Epidemiology

Picornaviruses, especially rhinoviruses and certain echoviruses and coxsackieviruses, cause the common cold. About 30 to 50% of all colds are caused by one of the > 100 serotypes of rhinoviruses.

Symptoms and Signs

Clinical symptoms and signs are nonspecific.

After an incubation period of 24 to 72 h, onset is abrupt, with a burning sensation in the nose or throat, followed by sneezing, rhinorrhea, and malaise.

Characteristically, fever is not present, particularly with a rhinovirus or coronavirus. Pharyngitis usually develops early; laryngitis and tracheobronchitis vary by person and causative agent. Nasal secretions are watery and profuse during the first days, but become more mucoid and purulent.

Cough is usually mild but often lasts into the 2nd wk.