NEET MDS Lessons
General Pathology
Parvoviruses
- smallest DNA virus
- erythema infectiosum (fifth disease) is characterized by a confluent rash usually beginning on the cheeks ("slapped face") which extends centripetally to involve the trunk; fever, malaise and respiratory problems; and arthralgias and joint swelling (50%).
other associations:
- aplastic anemia in patients with chronic hemolytic anemias (e.g., sickle cell disease, spherocytosis).
- repeated abortions associated with hydrops fetalis.
- pure RBC aplasia by involving the RBC precursors (no reticulocytes peripherally).
-chronic arthritis
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).
Seborrheic keratosis
1. A round, brown-colored, flat wart.
2. Most often seen in middle-aged to older adults.
3. A benign lesion.
Eosinopenia:
Causes
-Corticoid effect (Cushing's syndrome or therapy).
-Stress.
Other lung diseases
1.Sarcoidosis
1. Sarcoidosis
a. More common in African-Americans.
b. Associated with the presence of noncaseating granulomas.
Sarcoidosis is an immune system disorder characterised by non-necrotising granulomas (small inflammatory nodules). Virtually any organ can be affected, however, granulomas most often appear in the lungs or the lymph nodes.
Signs and symptoms
- Sarcoidosis is a systemic disease that can affect any organ. Common symptoms are vague, such as fatigue unchanged by sleep, lack of energy, aches and pains, dry eyes, blurry vision, shortness of breath, a dry hacking cough or skin lesions. The cutaneous symptoms are protean, and range from rashes and noduli (small bumps) to erythema nodosum or lupus pernio
- Renal, liver, heart or brain involvement may cause further symptoms and altered functioning. Manifestations in the eye include uveitis and retinal inflammation
- Sarcoidosis affecting the brain or nerves is known as neurosarcoidosis.
- Hypercalcemia (high calcium levels) and its symptoms may be the result of excessive vitamin D production
- Sarcoidosis most often manifests as a restrictive disease of the lungs, causing a decrease in lung volume and decreased compliance (the ability to stretch). The vital capacity (full breath in, to full breath out) is decreased, and most of this air can be blown out in the first second. This means the FEV1/FVC ratio is increased from the normal of about 80%, to 90%.
Treatment
Corticosteroids, most commonly prednisone
2. Cystic fibrosis
a. Transmission: caused by a genetic mutation (nucleotide deletion) on chromosome 7, resulting in abnormal chloride channels.
b. The most common hereditary disease in Caucasians.
c. Genetic transmission: autosomal recessive.
d. Affects all exocrine glands. Organs affected include lungs, pancreas, salivary glands, and intestines. Thick secretions or mucous plugs are
seen to obstruct the pulmonary airways and intestinal tracts.
e. Is ultimately fatal.
f. Diagnostic test: sweat test—sweat contains increased amounts of chloride.
3. Atelectasis
a. Characterized by collapse of the alveoli.
b. May be caused by a deficiency of surfactant and/or hypoventilation of alveoli.
Cytopathologic techniques
Cytopathology is the study of cells from various body sites to determine the cause or nature of disease.
Applications of cytopathology:
- Screening for the early detection of asymptomatic cancer
2. Diagnosis of symptomatic cancer
3. Surveillance of patients treated for cancer
Cytopathologic methods
There are different cytopathologic methods including:
1. Fine-needle aspiration cytology (FNAC) -In FNAC, cells are obtained by aspirating the diseased organ using a very thin needle under negative pressure.
Superficial organs (e.g. thyroid, breast, lymph nodes, skin and soft tissues) can be easily aspirated.
Deep organs, such as the lung, mediastinum, liver, pancreas, kidney, adrenal gland, and retroperitoneum are aspirated with guidance by fluoroscopy, ultrasound or CT scan.
- Exfoliative cytology
Refers to the examination of cells that are shed spontaneously into body fluids or secretions. Examples include sputum, cerebrospinal fluid, urine, effusions in body cavities (pleura, pericardium, peritoneum), nipple discharge and vaginal discharge.
- Abrasive cytology
Refers to methods by which cells are dislodged by various tools from body surfaces (skin, mucous membranes, and serous membranes). E.g. preparation of cervical smears with a spatula or a small brush to detect cancer of the uterine cervix at early stages.
TOXOPLASMOSIS
Infection with Toxoplasma gondii, causing a spectrum of manifestations ranging from asymptomatic benign lymphadenopathy to life-threatening CNS disease, chorioretinitis, and mental retardation.
Symptomatic infections may present in several ways
Acute toxoplasmosis may mimic infectious mononucleosis with lymphadenopathy, fever, malaise, myalgia, hepatosplenomegaly, and pharyngitis. Atypical lymphocytosis, mild anemia, leukopenia, and slightly abnormal liver function tests are common. The syndrome may persist for weeks or months but is almost always self-limited.
A severe disseminated form characterized by pneumonitis, myocarditis, meningoencephalitis, polymyositis, diffuse maculopapular rash, high fevers, chills, and prostration. Acute fulminating disease is uncommon.
Congenital toxoplasmosis usually results from a primary (and often asymptomatic) acute infection acquired by the mother during pregnancy. The risk of transplacental infection increases from 15% to 30 to 60% for maternal infections acquired in the 1st, 2nd, or 3rd trimester of gestation, respectively