NEET MDS Lessons
General Pathology
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.
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
1. Human papillomavirus types 6 and 11 → condyloma acuminta (venereal warts).
2. Molluscum contagiosum is characterized by a bowl shaped lesion filled with keratin, the latter containing the viral inclusions (molluscum bodies) in the squamous cells.
Pyelonephritis
- A bacterial infection that affects the renal tubules, interstitium, and renal pelvis.
- One of the most common renal diseases.
- Usually caused by gram-negative, rod-shaped bacteria that are part of the normal flora of the enteric tract. Most commonly caused by Escherichia coli, followed by Proteus, Klebsiella, and Enterobacter.
- The infecting bacteria are usually from the patient’s own enteric flora an example of an endogenous infection.
- Usually associated with a urinary tract infection (acute pyelonephritis) or involved with another precipitating condition, such as obstruction (chronic pyelonephritis).
Osteopetrosis (Albers-Schönberg disease or marble bone disease)
is a group of rare genetic disorders characterized by reduced osteoclast-mediated bone resorption and therefore defective bone remodelling. The bones are solid and heavy with no medullary canal, long ends are bulbous, small neural foramina compress nerves. The affected bone is grossly dense but fractures occur readily like a piece of chalk.
Patients frequently have cranial nerve compressions by the surrouding bone, and recurrent infections. The latter is attributable to diminished hematopoiesis resulting from reduced marrow space with impressive hepatosplenomegaly due to extramedullary hematopoiesis
a. Caused by abnormal osteoclasts. This results in defective bone remodeling (i.e., abnormally low bone resorption) and increased bone density, which may invade into bone marrow space.
b. Causes severe defects in infants, including:
(1) Anemia and infections—caused by decreased bone marrow.
(2) Blindness, deafness, paralysis of facial muscles—caused by the narrowing of cranial nerve foramina.
(3) Is life-threatening.
(4) Oral findings include delayed eruption of teeth.
c. Disease is less severe in adults
Psoriasis
1. Characterized by skin lesions that appear as scaly, white plaques.
2. Caused by rapid proliferation of the epidermis.
3. Autoimmune pathogenesis; exact mechanism is unclear.
INFLUENZA
An acute viral respiratory infection with influenza, a virus causing fever, coryza, cough, headache, malaise, and inflamed respiratory mucous membranes.
Influenza B viruses typically cause mild respiratory disease
Symptoms and Signs
mild cases:
Chills and fever up to 39 to 39.5° C
Prostration and generalized aches and pains, Headache, photophobia and retrobulbar aching
Respiratory tract symptoms may be mild at first, with scratchy sore throat, substernal burning, nonproductive cough, and sometimes coryza. Later, the lower respiratory illness becomes dominant; cough can be persistent and productive.
severe cases
sputum may be bloody. Skin is warm and flushed. Soft palate, posterior hard palate, tonsillar pillars, and posterior pharyngeal wall may be reddened, but no exudate appears. Eyes water easily, and the conjunctiva may be mildly inflamed
Encephalitis, myocarditis, and myoglobinuria are infrequent complications of influenza and, if present, usually occur during convalescence