FUNGAL INFECTION

Aspergillosis

Opportunistic infections caused by Aspergillus sp and inhaled as mold conidia, leading to hyphal growth and invasion of blood vessels, hemorrhagic necrosis, infarction, and potential dissemination to other sites in susceptible patients.

Symptoms and Signs: Noninvasive or, rarely, minimally locally invasive colonization of preexisting cavitary pulmonary lesions also may occur in the form of fungus ball (aspergilloma) formation or chronic progressive aspergillosis.

Primary superficial invasive aspergillosis is uncommon but may occur in burns, beneath occlusive dressings, after corneal trauma (keratitis), or in the sinuses, nose, or ear canal.

Invasive pulmonary aspergillosis usually extends rapidly, causing progressive, ultimately fatal respiratory failure unless treated promptly and aggressively. A. fumigatus is the most common causative species.

 Extrapulmonary disseminated aspergillosis may involve the liver, kidneys, brain, or other tissues and is usually fatal. Primary invasive aspergillosis may also begin as an invasive sinusitis, usually caused by A. flavus, presenting as fever with rhinitis and headache

Thalassaemia. Genetic based defect in synthesis of one of the normal chains.

Beta thalassaemia --->  reduced Hb A and increased HbF (α2, Y2) HBA2(α2)

Alpha thalassaemia  --->   reduced  Hb-A, Hb-A2 and Hb-F-with formation of Hb-H(β4) and Hb Barts (Y4).
Thalassaemia may manifest as trait or disease or with intermediate manifestation.

Features:
•    Microcytic hypochromic RBC is in iron deficjency.
•    Marked anisopoikilocytsis  with prominent target cells.
•    Reticulocytosis and nucleated RBC seen.
•    Mongoloid facies and X-ray findings characteristic of marrow hyperplasia
•    Decreased osmotic. fragility.
•    Increased marrow iron (important difference from iron deficiency anaemia).
•    Haemosiderosis, especially with repeated transfusions.

Diagnosis is by Hb electrophoresis and by Alkali denaturation test (for HbF).

Cholangitis

Cholangitis is inflammation of the bile ducts. 
1. It is usually associated with biliary duct obstruction by gallstones or carcinoma, which leads to infection with enteric organisms. This results in purulent exudation within the bile ducts and bile stasis. 
2. Clinically, cholangitis presents with jaundice, fever, chills. leukocytosis, and right upper quadrant pain
 

ADRENAL INSUFFICIENCY

Adrenocortical hypofunction is either primary (adrenocrtical) or secondary (ACTH deficiency). Primary insufficiency is divided into acute & chronic. 
Acute Adrenocortical Insufficiency occurs most commonly in the following clinical settings
- massive adrenal hemorrhage including  Waterhouse-Friderichsen syndrome 
- Sudden withdrawal of long-term corticosteroid therapy
- Stress in those with chronic adrenal insufficiency 

Massive adrenal hemorrhage may destroy the adrenal cortex sufficiently to cause acute adrenocortical 
insufficiency. This condition may occur 
1. in patients maintained on anticoagulant therapy 
2. in postoperative patients who develop DIC
3. during pregnancy 
4. in patients suffering from overwhelming sepsis (Waterhouse-Friderichsen syndrome) 

Waterhouse-Friderichsen syndrome is a catastrophic syndrome classically associated with Neisseria meningitidis septicemia but can also be caused by other organisms, including Pseudomonas species, pneumococci & Haemophilus influenzae. The pathogenesis of the syndrome remains unclear, but probably involves endotoxin-induced vascular injury with associated DIC.

Chronic adrenocortical insufficiency (Addison disease) results from progressive destruction of the adrenal cortex. More than 90% of all cases are attributable to one of four disorders: 
1. autoimmune adrenalitis (the most common cause; 70% of cases) 
2. tuberculosis &fungal infections 
3. AIDS
4. Metastatic cancers   
In such primary diseases, there is hyperpigmentation of the skin oral mucosa due to high levels of MSH (associated with high levels of ACTH).

Autoimmune adrenalitis is due to autoimmune destruction of steroid-producing cells. It is either isolated associated other autoimmune diseases, such as Hashimoto disease, pernicious anemia, etc. 

Infections, particularly tuberculous and fungal

Tuberculous adrenalitis, which once was responsible for as many as 90% of cases of Addison disease, has become less common with the advent of antituberculous therapy. When present, tuberculous adrenalitis is usually associated with active infection elsewhere, particularly the lungs and genitourinary tract. Among fungi, disseminated infections caused by Histoplasma capsulatum is the main cause. 

AIDS patients are at risk for developing adrenal insufficiency from several infectious (cytomegalovirus, Mycobacterium avium-intracellulare) and noninfectious (Kaposi sarcoma) complications.
 
Metastatic neoplasms: the adrenals are a fairly common site for metastases in persons with disseminated carcinomas. Although adrenal function is preserved in most such patients, the metastatic growths sometimes destroy sufficient adrenal cortex to produce a degree of adrenal insufficiency. Carcinomas of the lung and breast are the major primary sources. 

Secondary Adrenocortical Insufficiency

Any disorder of the hypothalamus and pituitary, such as metastatic cancer, infection, infarction, or irradiation, that reduces the output of ACTH leads to a syndrome of hypoadrenalism having many similarities to Addison disease. In such secondary disease, the hyperpigmentation of primary Addison disease is lacking because melanotropic hormone levels are low. 

Secondary adrenocortical insufficiency is characterized by low serum ACTH and a prompt rise in plasma cortisol levels in response to ACTH administration. 

Pathological features of adrenocortical deficiency 

- The appearance of the adrenal glands varies with the cause of the insufficiency. 
- In secondary hypoadrenalism the adrenals are reduced to small, uniform, thin rim of atrophic yellow cortex that surrounds a central, intact medulla. Histologically, there is atrophy of cortical cells with loss of cytoplasmic lipid, particularly in the zonae fasciculata and reticularis. 
- In primary autoimmune adrenalitis there is also atrophy of the cortex associated with a variable lymphoid infiltrate that may extend into the subjacent medulla. The medulla is otherwise normal.  
- In tuberculosis or fungal diseases there is granulomatous inflammatory reaction. Demonstration of the responsible organism may require the use of special stains.  
- With metastatic carcinoma, the adrenals are enlarged and their normal architecture is obscured by the infiltrating neoplasm.  
 

Leukaemias
Uncontrolled proliferation of leukocyte precursors (may be with associated red cell and platelet series proliferation).

Factors which may playa causal role are.
- Viral
- Radiation.
- Genetic.

Classification

1. Acule leukaemia:

a. Lymphocytic (lymphoblastic).
b. Myelocytic and promyelocytic (myeloblastic).
c. Monocytic.
d. Myelomonocytic.
e. Undifferentiated (Stem cell).

2. Chronic leukaemia:

a. Lymphocytic
b. Myelocytic

3. Miscellaneous:
a. Erythroleukaemia (De Guglielmo's disease).
b. Eosinophilic leukaemia.
c. Megakaryocytic leukaemia.

Bronchitis

Bronchitis is an obstructive pulmonary disease characterized by inflammation of the bronchi of the lungs

Signs and symptoms

persistent cough that produces sputum

shortness of breath (dyspnea) on exertion

hypercapnia

insufficient oxygenation of the blood hypoxemia leading to cynosis

Severe chronic bronchitis will commonly lead to cor pulmonale and heart failure.

Pathology

an increase in the number of goblet cells with mucus blocking the airway clusters of pigmented alveolar macrophages

the presence of inflammatory cells (e.g. neutrophils) scarring (fibrosis) of the walls of the bronchioles

Diagnosis

• decreased intensity of breath sounds (rhonchi) and extended expiration.
• a sputum culture has pathogenic microorganisms
• a chest x-ray that reveals hyperinflation and increased bronchovascular markings
• a pulmonary function test that shows an increase in the lung's residual volume and a decreased vital capacity

Pathophysiology

• The initiating event in developing bronchitis appears to be chronic irritation due to inhalation of certain chemicals
• earliest clinical feature of bronchitis is increased secretion of mucus by submucousal glands of the trachea and bronchi
• Damage caused by irritation of the airways leads to inflammation and infiltration of the lung tissue by neutrophils
• The neutrophils release substances that promote mucousal hypersecretion
• As bronchitis persists to become chronic bronchitis, a substantial increase in the number of goblet cells in the small airways is seen
• The role of infection in the pathogenesis of chronic bronchitis appears to be secondary.

Treatment

Quit smoking, Oxygen therapy, bronchodilator drugs

Prognosis

Pulmonary hypertension, cor pulmonale, and chronic respiratory failure are possible complications of chronic bronchitis

In severe chronic bronchitis is poor