NEET MDS Synopsis
Thalassemia
Pathology
Thalassemias are a heterogeneous group of hereditary blood disorders characterized by faulty globin chain synthesis resulting in defective hemoglobin, which can lead to anemia
Thalassemia provides partial resistance against malaria.
Beta thalassemia
- most commonly seen in people of Mediterranean descent
Etiology
usually due to point mutations in promoter sequences or splicing sites
β-globin locus - short arm of chromosome 11
In a normal cell, the β-globin chains are coded by a total of two alleles . Thus, there are two forms of the disease.
Beta thalassemia minor (trait): one defective allele
Beta thalassemia major (Cooley's anemia): two defective alleles
Pathophysiology
Inefficient erythropoiesis → anemia
Beta thalassemia minor and major: faulty β-globin chain synthesis → ↓ β-chains→ ↑ γ-,δ-chains → ↑ HbF and ↑ HbA2
Alpha thalassemia
most commonly seen in people of Asian and African descent
Etiology
usually due to deletion of at least one out of the four existing alleles
Inheritance pattern: autosomal recessive
In a normal cell, the α-globin chains are coded by a total of four alleles.
Thus, there are four forms of the disease. The severity of alpha thalassemia depends on the number of defective α-globin alleles.
- Silent carrier (minima form): one defective allele (-α/αα)
- Alpha thalassemia trait (minor form) -Two defective alleles ,Cis-deletion is common amongst Asian populations, whereas trans-deletions are more common in African populations
- Hemoglobin H disease: three defective alleles
- Hemoglobin Bart disease (major form): four defective alleles
Pathophysiology
Alpha thalassemia major (HbH disease) and Bart disease: faulty α-globin chain synthesis → ↓ α-chains → ↑ β-, γ-chains → ↑ HbH, ↑ Hb-Bart's
Itraconazole
Pharmacology
Itraconazole:
The drug may be given orally or intravenously.
Chronic myelocytic leukaemia
General Pathology
Chronic myelocytic leukaemia
Commoner in adults (except the Juvenile type)
Features:
- Anaemia.
- Massive splenomegaly
- Bleeding tendencies.
- Sternal tenderness.
- Gout and skin manifestations
Blood picture:
- Marked leucocytosis of 50,-1000,000 cu.mm, often more
- Immature cells of the series with 20-50 % myelocytes
- Blasts form upto 5-10% of cells
- Basophils may be increased
- Leuocyte alkaline phosphate is reduced
- Anaemia with reticutosis and nucleated RBC
- Platelets initially high levels may fall later if patient goes into blast crisis.
Bone marrow:
- Hyper cellular marrow.
- Myeloid hyperplasia with more of immature forms, persominatly myelocytes.
Chromosomal finding. Philadelphia (Phi) chromosome is positive adult cases .It is a short chromosome due to deletion of long arm of chromosome 22 (translocated to no.9),
Juvenile type :- This is Ph1 negative has more nodal enlargement and has a worse prognosis, with a greater proneness to infections and haemorrhage
Transpalatal Arch
OrthodonticsTranspalatal Arch (TPA) is an orthodontic appliance used
primarily in the upper arch to provide stability, maintain space, and facilitate
tooth movement. It is a fixed appliance that connects the maxillary molars
across the palate, and it is commonly used in various orthodontic treatments,
particularly in conjunction with other appliances.
Components of the Transpalatal Arch
Main Wire:
The TPA consists of a curved wire that spans the palate, typically
made of stainless steel or a similar material. The wire is shaped to fit
the contour of the palate and is usually 0.036 inches in diameter.
Attachments:
The ends of the wire are attached to the bands or brackets on the
maxillary molars. These attachments can be soldered or welded to the
bands, ensuring a secure connection.
Adjustment Mechanism:
Some TPAs may include loops or bends that can be adjusted to apply
specific forces to the teeth, allowing for controlled movement.
Functions of the Transpalatal Arch
Stabilization:
The TPA provides anchorage and stability to the posterior teeth,
preventing unwanted movement during orthodontic treatment. It helps
maintain the position of the molars and can prevent them from drifting.
Space Maintenance:
The TPA can be used to maintain space in the upper arch, especially
after the premature loss of primary molars or in cases of crowding.
Tooth Movement:
The appliance can facilitate the movement of teeth, particularly the
molars, by applying gentle forces. It can be used to correct crossbites
or to expand the arch.
Support for Other Appliances:
The TPA can serve as a support structure for other orthodontic
appliances, such as expanders or functional appliances, enhancing their
effectiveness.
Indications for Use
Space Maintenance: To hold space for permanent teeth
when primary teeth are lost prematurely.
Crossbite Correction: To help correct posterior
crossbites by repositioning the molars.
Arch Expansion: In conjunction with other appliances,
the TPA can assist in expanding the dental arch.
Stabilization During Treatment: To provide anchorage
and prevent unwanted movement of the molars during orthodontic treatment.
Advantages of the Transpalatal Arch
Fixed Appliance: Being a fixed appliance, the TPA does
not require patient compliance, ensuring consistent force application.
Versatility: The TPA can be used in various treatment
scenarios, making it a versatile tool in orthodontics.
Minimal Discomfort: Generally, the TPA is
well-tolerated by patients and does not cause significant discomfort.
Limitations of the Transpalatal Arch
Limited Movement: The TPA primarily affects the molars
and may not be effective for moving anterior teeth.
Adjustment Needs: While the TPA can be adjusted, it may
require periodic visits to the orthodontist for modifications.
Oral Hygiene: As with any fixed appliance, maintaining
oral hygiene can be more challenging, and patients must be diligent in their
oral care.
Factors Considered for Prescribing Fluoride Tablets
Public Health Dentistry
Factors Considered for Prescribing Fluoride Tablets
Child's Age:
Different age groups require different dosages.
Children older than 4 years may receive lozenges or chewable tablets,
while those younger than 4 are typically prescribed liquid fluoride drops.
Fluoride Concentration in Drinking Water:
The fluoride level in the child's drinking water is crucial.
If the fluoride concentration is less than 1 part per million (ppm),
systemic fluoride supplementation is recommended.
Risk of Dental Caries:
Children at higher risk for dental decay may need additional fluoride
supplementation.
Regular dental assessments help determine the need for fluoride.
Overall Health and Dietary Needs:
Consideration of the child's overall health and any dietary restrictions
that may affect fluoride intake.
Recommended Doses of Fluoride Tablets
For Children Aged 6 Months to 4 Years:
Liquid drops are typically prescribed in doses of 0.125, 0.25, and 0.5
mg of fluoride ion.
For Children Aged 4 Years and Older:
Chewable tablets or lozenges are recommended, usually at doses of 0.5 mg
to 1 mg of fluoride ion.
Adjustments Based on Water Fluoride Levels:
Doses may be adjusted based on the fluoride content in the child's
drinking water to ensure adequate protection against dental caries.
Duration of Supplementation:
Fluoride supplementation is generally continued until the child reaches
16 years of age, depending on their fluoride exposure and dental health
status.
Functions of the blood
PhysiologyFunction of Blood
transport through the body of
oxygen and carbon dioxide
food molecules (glucose, lipids, amino acids)
ions (e.g., Na+, Ca2+, HCO3−)
wastes (e.g., urea)
hormones
heat
defense of the body against infections and other foreign materials. All the WBCs participate in these defenses
Hemorrhage
Oral and Maxillofacial SurgeryTypes of Hemorrhage
Hemorrhage, or excessive bleeding, can occur during and after surgical
procedures. Understanding the different types of hemorrhage is crucial for
effective management and prevention of complications. The three main types of
hemorrhage are primary, reactionary, and secondary hemorrhage.
1. Primary Hemorrhage
Definition: Primary hemorrhage refers to bleeding that
occurs at the time of surgery.
Causes:
Injury to blood vessels during the surgical procedure.
Inadequate hemostasis (control of bleeding) during the operation.
Management:
Immediate control of bleeding through direct pressure,
cauterization, or ligation of blood vessels.
Use of hemostatic agents or sutures to secure bleeding vessels.
Clinical Significance: Prompt recognition and
management of primary hemorrhage are essential to prevent significant blood
loss and ensure patient safety during surgery.
2. Reactionary Hemorrhage
Definition: Reactionary hemorrhage occurs within a few
hours after surgery, typically when the initial vasoconstriction of damaged
blood vessels subsides.
Causes:
The natural response of blood vessels to constrict after injury may
initially control bleeding. However, as the vasoconstriction diminishes,
previously damaged vessels may begin to bleed again.
Movement or changes in position of the patient can also contribute
to the reopening of previously clamped vessels.
Management:
Monitoring the patient closely in the immediate postoperative period
for signs of bleeding.
If reactionary hemorrhage occurs, surgical intervention may be
necessary to identify and control the source of bleeding.
Clinical Significance: Awareness of the potential for
reactionary hemorrhage is important for postoperative care, as it can lead
to complications if not addressed promptly.
3. Secondary Hemorrhage
Definition: Secondary hemorrhage refers to bleeding
that occurs up to 14 days postoperatively, often as a result of infection or
necrosis of tissue.
Causes:
Infection at the surgical site can lead to tissue breakdown and
erosion of blood vessels, resulting in bleeding.
Sloughing of necrotic tissue may also expose blood vessels that were
previously protected.
Management:
Careful monitoring for signs of infection, such as increased pain,
swelling, or discharge from the surgical site.
Surgical intervention may be required to control bleeding and
address the underlying infection.
Antibiotic therapy may be necessary to treat the infection and
prevent further complications.
Clinical Significance: Secondary hemorrhage can be a
serious complication, as it may indicate underlying issues such as infection
or inadequate healing. Early recognition and management are crucial to
prevent significant blood loss and promote recovery.
Dental Terms
Dental Anatomy
CONTACT POINT.:-The point on the proximal surface where two adjacent teeth actually touch each other is called a contact point.
INTERPROXIMAL SPACE.:-The interproximal space is the area between the teeth. Part of the interproximal space is occupied by the interdental papilla. The interdental papilla is a triangular fold of gingival tissue. The part of the interproximal space not occupied is called the embrasure.
EMBRASURE. :-The embrasure occupies an area bordered by interdental papilla, the proximal surfaces of the two adjacent teeth, and the contact point (fig 4-18). If there is no contact point between the teeth, then the area between them is called a diastema instead of an embrasure.
OCCLUSAL
The occlusal surface is the broad chewing surface found on posterior teeth (bicuspids and molars).
OCCLUSION.:-Occlusion is the relationship between the occlusal surfaces of maxillary and mandibular teeth when they are in contact. Many patterns of tooth contact are possible. Part of the reason for the variety is the mandibular condyle's substantial range of movement within the temporal mandibular joint.
Malocclusion occurs when any abnormality in occlusal relationships exist in the dentition. Centric occlusion, is the centered contact position of the chewing surfaces of mandibular teeth on the chewing surface (occlusal) of the maxillary teeth.
OCCLUSAL PLANE.:-Maxillary and mandibular teeth come into centric occlusion and meet along anteroposterior and lateral curves. The anteroposterior curve is called the Curve of Spee in which the mandibular arch forms a concave (a bowl-like upward curve). The lateral curve is called the Curve of Wilson . The composite (combination) of these curves form a line called the occlusal plane, and is created by the contact of the upper and lower teeth
VERTICAL AND HORIZONTAL OVERLAP. :-Vertical overlap is the extension of the maxillary teeth over the mandibular counterparts in a vertical direction when the dentition is in centric occlusion Horizontal overlap is the projection of maxillary teeth over antagonists (something that opposes another) in a horizontal direction.
KEY TO OCCLUSION.:-The occlusal surfaces of opposing teeth bear a definite relationship to each other. In normal jaw relations and when teeth are of normal size and in the correct position, the mesiofacial cusp of the maxillary first molar occludes in the facial groove of the mandibular first molar. This normal relationship of these two teeth is called the key to occlusion.
PERMANENT DENTITION
The permanent dentition consists of 32 teeth. Each tooth in the permanent dentition is described in this section. It should be remembered that teeth show considerable variation in size, shape, and other characteristics from one person to another. Certain teeth show a greater tendency than others to deviate from the normal. The descriptions that follow are of normal teeth.