NEET MDS Synopsis
Glomerulonephritis
General Pathology
Glomerulonephritis
Characterized by inflammation of the glomerulus.
Clinical manifestations:
Nephrotic syndrome (nephrosis) → Most often caused by glomerulonephritis.
Laboratory findings:
(i) Proteinuria (albuminuria) and lipiduria—proteins and lipids are present in urine.
(ii) Hypoalbuminemia—decreased serum albumin due to albuminuria.
(iii) Hyperlipidemia—especially an increase in plasma levels of low-density lipoproteins and cholesterol.
Symptoms
severe edema, resulting from a decrease in colloid osmotic pressure due to a decrease in serum albumin.
Instrument formula
Conservative DentistryInstrument formula
First number : It indicates width of blade (or of primary
cutting edge) in 1/10 th of a millimeter (i.e. no. 10 means 1 mm blade width).
Second number :
1) It indicates primary cutting edge angle.
2) It is measured form a line parallel to the long axis of the instrument
handle in clockwise centigrade. Expressed as per cent of 360° (e.g. 85 means 85% of 360 = 306°).
3)The instrument is positioned so that this number always exceeds 50. If the
edge is locally perpendicular to the blade, then this number is normally omitted
resulting in a three number code.
Third number : It indicates blade length in millimeter.
Fourth number :
1)Indicates blade angle relative to long axis of handle in clockwise
centigrade.
2) The instrument is positioned so that this number. is always 50 or less. It
becomes third number in a three number code when
2nd number is omitted.
TEMPOROMANDIBULAR JOINT -ARTICULAR SURFACES COVERED BY FIBROUS TISSUE
Dental Anatomy
ARTICULAR SURFACES COVERED BY FIBROUS TISSUE
TMJ is an exception form other synovial joints. Two other joints, the acromio- and sternoclavicular joints are similar to the TMJ. Mandible & clavicle derive from intramembranous ossificiation.
Histologic
Fibrous layer: collagen type I, avascular (self-contained and replicating)
Proliferating zone that formes condylar cartilage
Condylar cartilage is fibrocartilage that does not play role in articulation nor has formal function
Capsule: dense collagenous tissue (includes the articular eminence)
Synovial membrane: lines capsule (does not cover disk except posterior region); contains folds (increase in pathologic conditions) and villi
Two layers: a cellular intima (synovial cells in fiber-free matrix) and a vascular subintima
Synovial cells: A (macrophage-like) syntesize hyaluronate
B (fibroblast-like) add protein in the fluid
Synovial fluid: plasma with mucin and proteins, cells
Liquid environment: lubrication, ?nutrition
Disk: separates the cavity into two comprartments, type I collagen
anterior and posterior portions
anetiorly it divides into two lamellae one towards the capsule, the other towards the condyle
vascular in the preiphery, avascular in the center
Ligaments: nonelastic collagenous structures. One ligament worth mentioning is the lateral or temporomandibular ligament. Also there are the spheno- and stylomandibular with debatable functional role.
Innervations
Ruffini
Posture
Dynamic and static balance
Pacini
Dynamic mechanoreception
Movement accelerator
Golgi
Static mechanoreception
Protection (ligament)
Free
Pain
Protection joint
Megaloblastic anaemia
General Pathology
Megaloblastic anaemia
Metabolism: B12(cyanocobalamin) is a coenzyme in DNA synthesis and for maintenance of nervous system. Daily requirement 2 micro grams. Absorption in terminal ileum in the presence gastric intrinsic factor. It is stored in liver mainly-
Folic acid (Pteroylglutamic acid) is needed for DNA synthesis.. Daily requirement 100 micro grams. Absorption in duodenum and jejunum
Causes of deficiency .-
- Nutritional deficiency-
- Malabsorption syndrome.
- Pernicious anaemia (B12).
- Gastrectomy (B12).
- Fish tapeworm infestation (B12).
- Pregnancy and puerperium (Folic acid mainly).
- Myeloproliferative disorders (Folic acid).
- Malignancies (Folic acid).
- Drug induced (Folic-acid)
Features:
(i) Megaloblastic anaemia.
(ii) Glossitis.
(iii) Subacute combined degeneration (in B12deficiency).
Blood picture :
- Macrocytic normochromic anaemia.
- Anisocytosis and poikilocytosis with Howell-Jolly bodies and basophilic stippling.
- Occasional megalo blasts may be-seen.
- Neutropenia with hypersegmented neutrophills and macropolycytes.
- Thrombocytopenia.
- Increased MVC and MCH with normal or decreased MCHC.
Bone marrow:
- Megaloblasts are seen. They are larger with a more open stippled chromatin. The nuclear maturation lags behind. the cytoplasmic maturation. Maturation arrest is seen (more of early forms).
- Immature cells of granulocyte series are also larger.
-Giant stab forms (giant metamyelocytes).
Chemical Composition of Urine
Physiology
Normal Chemical Composition of Urine
Urine is an aqueous solution of greater than 95% water, with a minimum of these remaining constituents, in order of decreasing concentration:
Urea 9.3 g/L.
Chloride 1.87 g/L.
Sodium 1.17 g/L.
Potassium 0.750 g/L.
Creatinine 0.670 g/L .
Other dissolved ions, inorganic and organic compounds (proteins, hormones, metabolites).
Urine is sterile until it reaches the urethra, where epithelial cells lining the urethra are colonized by facultatively anaerobic gram-negative rods and cocci. Urea is essentially a processed form of ammonia that is non-toxic to mammals, unlike ammonia, which can be highly toxic. It is processed from ammonia and carbon dioxide in the liver.
SPIROCHETAL DISEASE -Syphilis
General Pathology
SPIROCHETAL DISEASE
Syphilis
A contagious systemic disease caused by the spirochete Treponema pallidum, characterized by sequential clinical stages and by years of latency.
ACQUIRED SYPHILIS
T. pallidum is a delicate spiral organism about 0.25 µm wide and from 5 to 20 µm long, identified by characteristic morphology and motility with a darkfield microscope or fluorescent techniques
In acquired syphilis, T. pallidum enters through the mucous membranes or skin, reaches the regional lymph nodes within hours, and rapidly disseminates throughout the body. In all stages of disease, perivascular infiltration of lymphocytes, plasma cells, and, later, fibroblasts causes swelling and proliferation of the endothelium of the smaller blood vessels, leading to endarteritis obliterans.
In late syphilis, T. pallidum elicits a granulomatous-like (gummatous) reaction causing masses, ulcerations, and necrosis. Inflammation may subside despite progressive damage, especially in the cardiovascular and central nervous systems.
The CNS is invaded early in the infection. During the secondary stage of the disease, > 30% of patients have abnormal CSF and may have symptoms of meningitis
Symptoms, Signs, and Course
The incubation period of primary syphilis can vary from 1 to 13 wk but is usually from 3 to 4 wk. The disease may present at any stage and long after the initial infection
Primary stage: The primary lesion, or chancre generally evolves and heals within 4 to 8 wk in untreated patients. After inoculation, a red papule quickly erodes to form a painless ulcer with an indurated base that, when abraded, exudes a clear serum containing numerous spirochetes
The regional lymph nodes usually enlarge painlessly and are firm, discrete, and nontender. Chancres occur on the penis, anus, and rectum in men and on the vulva, cervix, and perineum in women. Chancres may also occur on the lips or the oropharyngeal or anogenital mucous membranes.
Secondary stage: Cutaneous rashes usually appear within 6 to 12 wk after infection and are most florid after 3 to 4 mo.
Frequently, generalized, nontender, firm, discrete lymphadenopathy and hepatosplenomegaly are palpable. Over 80% of patients have mucocutaneous lesions, 50% have generalized lymphadenopathy, and about 10% have lesions of the eyes (uveitis), bones (periostitis), joints, meninges, kidneys (glomerulitis), liver, and spleen.
Acute syphilitic meningitis may develop, with headache, neck stiffness, cranial nerve lesions, deafness, and, occasionally, papilledema.
Condyloma lata--hypertrophic, flattened, dull pink or gray papules at the mucocutaneous junctions and in moist areas of the skin--are extremely infectious. Hair often falls out in patches, leaving a moth-eaten appearance (alopecia areata).
Latent stage
In the early latent period (< 2 yr after infection), infectious mucocutaneous relapses may occur, but after 2 yr contagious lesions rarely develop, and the patient appears normal. About 1/3 of untreated persons develop late syphilis
Late or tertiary stage: Lesions may be clinically described as (1) benign tertiary syphilis of the skin, bone, and viscera, (2) cardiovascular syphilis, or (3) neurosyphilis.
The typical lesion is a gumma, an inflammatory mass that evolves to necrosis and fibrosis and that is frequently localized but may diffusely infiltrate an organ or tissue
Benign tertiary syphilis of the bones results in either periostitis with bone formation or osteitis with destructive lesions causing a deep, boring pain, characteristically worse at night. A lump or swelling may be palpable.
Cardiovascular syphilis: A dilated, usually fusiform aneurysm of the ascending or transverse aorta, narrowing of the coronary ostia, or aortic valvular insufficiency usually appears 10 to 25 yr after the initial infection
Neurosyphilis
In meningovascular neurosyphilis, brain involvement is signaled by headache, dizziness, poor concentration, lassitude, insomnia, neck stiffness, and blurred vision. Mental confusion, epileptiform attacks, papilledema, aphasia, and mono- or hemiplegia may also occur
Diagnosis:
Two classes of serologic tests for syphilis (STS) aid in diagnosing syphilis and other related treponemal diseases: screening, nontreponemal tests using lipoid antigens detect syphilitic reagin and include the Venereal Disease Research Laboratory (VDRL) and the rapid plasma reagin (RPR) tests. Specific treponemal tests detect antitreponemal antibodies and include fluorescent treponemal antibody absorption (FTA-ABS) test, microhemagglutination assay for antibodies to T. pallidum (MHA-TP), and Treponema pallidum hemagglutination assay (TPHA).
In darkfield microscopy, light is directed obliquely through the slide so that rays striking the spirochetes cause them to appear as bright, motile, narrow coils against a dark background
Endodontic Filling Techniques
Pedodontics
Endodontic Filling Techniques
Endodontic filling techniques are essential for the successful treatment of
root canal systems. Various methods have been developed to ensure that the canal
is adequately filled with the appropriate material, providing a seal to prevent
reinfection.
1. Endodontic Pressure Syringe
Developed By: Greenberg; technique described by
Speeding and Karakow in 1965.
Features:
Consists of a syringe barrel, threaded plunger, wrench, and threaded
needle.
The needle is placed 1 mm short of the apex.
The technique involves a slow withdrawing motion, where the needle
is withdrawn 3 mm with each quarter turn of the screw until the canal is
visibly filled at the orifice.
2. Mechanical Syringe
Proposed By: Greenberg in 1971.
Features:
Cement is loaded into the syringe using a 30-gauge needle, following
the manufacturer's recommendations.
The cement is expressed into the canal while applying continuous
pressure and withdrawing the needle simultaneously.
3. Tuberculin Syringe
Utilized By: Aylord and Johnson in 1987.
Features:
A standard 26-gauge, 3/8 inch needle is used for this technique.
This method allows for precise delivery of filling material into the
canal.
4. Jiffy Tubes
Popularized By: Riffcin in 1980.
Features:
Material is expressed into the canal using slow finger pressure on
the plunger until the canal is visibly filled at the orifice.
This technique provides a simple and effective way to fill the
canal.
5. Incremental Filling
First Used By: Gould in 1972.
Features:
An endodontic plugger, corresponding to the size of the canal with a
rubber stop, is used to place a thick mix of cement into the canal.
The thick mix is prepared into a flame shape that corresponds to the
size and shape of the canal and is gently tapped into the apical area
with the plugger.
6. Lentulospiral Technique
Advocated By: Kopel in 1970.
Features:
A lentulospiral is dipped into the filling material and introduced
into the canal to its predetermined length.
The lentulospiral is rotated within the canal, and additional paste
is added until the canal is filled.
7. Other Techniques
Amalgam Plugger:
Introduced by Nosonwitz (1960) and King (1984) for filling canals.
Paper Points:
Utilized by Spedding (1973) for drying and filling canals.
Plugging Action with Wet Cotton Pellet:
Proposed by Donnenberg (1974) as a method to aid in the filling
process.
Hockey Stick or London Hospital Elevator
Oral and Maxillofacial SurgeryHockey Stick or London Hospital Elevator
The Hockey Stick Elevator, also known as the London
Hospital Elevator, is a dental instrument used primarily in oral
surgery and tooth extraction procedures. It is designed to facilitate the
removal of tooth roots and other dental structures.
Design and Features
Blade Shape: The Hockey Stick Elevator features a
straight blade that is angled relative to the shank, similar to the Cryer’s
elevator. However, unlike the Cryer’s elevator, which has a
triangular blade, the Hockey Stick Elevator has a straight blade with a
convex surface on one side and a flat surface on the other.
Working Surface:
The flat surface of the blade is the working
surface and is equipped with transverse serrations.
These serrations enhance the instrument's grip and contact with the root
stump, allowing for more effective leverage during extraction.
Appearance: The instrument resembles a hockey stick,
which is how it derives its name. The distinctive shape aids in its
identification and use in clinical settings.
Principles of Operation
Lever and Wedge Principle:
The Hockey Stick Elevator operates on the same principles as the
Cryer’s elevator, utilizing the lever and wedge principle.
This means that the instrument can be used to apply force to the tooth
or root, effectively loosening it from the surrounding bone and
periodontal ligament.
Functionality:
The primary function of the Hockey Stick Elevator is to elevate and
luxate teeth or root fragments during extraction procedures. It can be
particularly useful in cases where the tooth is impacted or has a curved
root.