NEET MDS Synopsis
Intubation
General SurgeryIntubation
Intubation is a critical procedure in airway management, and the choice of
technique—oral intubation, nasal intubation, or tracheostomy—depends on the
clinical situation, patient anatomy, and specific indications or
contraindications.
Indications for Each Intubation Technique
1. Oral Intubation
Oral intubation is often the preferred method in emergency situations and
when nasal intubation is contraindicated. Indications include:
Emergent Intubation: Situations such as cardiopulmonary
resuscitation (CPR), unconsciousness, or apnea.
Oral or Mandibular Trauma: When there is significant
trauma to the oral cavity or mandible that may complicate nasal access.
Cervical Spine Conditions: Conditions such as
ankylosis, arthritis, or trauma that may limit neck movement.
Gagging and Vomiting: In patients who are unable to
protect their airway due to these conditions.
Agitation: In cases where the patient is agitated and
requires sedation and airway protection.
2. Nasal Intubation
Nasal intubation is indicated in specific situations where oral intubation
may be difficult or impossible. Indications include:
Nasal Obstruction: When there is a blockage in the oral
route.
Paranasal Disease: Conditions affecting the nasal
passages that may necessitate nasal access.
Awake Intubation: In cases where the patient is
cooperative and can tolerate the procedure.
Short (Bull) Neck: In patients with anatomical
challenges that make oral intubation difficult.
3. Tracheostomy
Tracheostomy is indicated for long-term airway management or when other
methods are not feasible. Indications include:
Inability to Insert Translational Tube: When oral or
nasal intubation fails or is not possible.
Need for Long-Term Definitive Airway: In patients
requiring prolonged mechanical ventilation or airway support.
Obstruction Above Cricoid Cartilage: Conditions that
obstruct the airway at or above the cricoid level.
Complications of Translational Intubation: Such as
glottic incompetence or inability to clear tracheobronchial secretions.
Sleep Apnea Unresponsive to CPAP: In patients with
severe obstructive sleep apnea who do not respond to continuous positive
airway pressure (CPAP) therapy.
Facial or Laryngeal Trauma: Structural
contraindications to translaryngeal intubation.
Contraindications for Nasal Intubation
Severe Fractures of the Midface: Nasal intubation is
contraindicated due to the risk of further injury and complications.
Nasal Fractures: Similar to midface fractures, nasal
fractures can complicate nasal intubation and increase the risk of injury.
Basilar Skull Fractures: The risk of entering the
cranial cavity or causing cerebrospinal fluid (CSF) leaks makes nasal
intubation unsafe in these cases.
Contraindications for Oral Intubation
Severe Facial or Oral Trauma:
Significant injuries to the face, jaw, or oral cavity may make
oral intubation difficult or impossible and increase the risk of
further injury.
Obstruction of the Oral Cavity:
Conditions such as large tumors, severe swelling, or foreign
bodies that obstruct the oral cavity can prevent successful
intubation.
Cervical Spine Instability:
Patients with unstable cervical spine injuries may be at risk of
further injury if neck extension is required for intubation.
Severe Maxillofacial Deformities:
Anatomical abnormalities that prevent proper visualization of
the airway or access to the trachea.
Inability to Open the Mouth:
Conditions such as trismus (lockjaw) or severe oral infections
that limit mouth opening can hinder intubation.
Severe Coagulopathy:
Patients with bleeding disorders may be at increased risk of
bleeding during the procedure.
Anticipated Difficult Airway:
In cases where the airway is expected to be difficult to manage,
alternative methods may be preferred.
Contraindications for Tracheostomy
Severe Coagulopathy:
Patients with significant bleeding disorders may be at risk for
excessive bleeding during the procedure.
Infection at the Site of Incision:
Active infections in the neck or tracheostomy site can increase the
risk of complications and should be addressed before proceeding.
Anatomical Abnormalities:
Significant anatomical variations or deformities in the neck that
may complicate the procedure or increase the risk of injury to
surrounding structures.
Severe Respiratory Distress:
In some cases, if a patient is in severe respiratory distress,
immediate intubation may be prioritized over tracheostomy.
Patient Refusal:
If the patient is conscious and refuses the procedure, it should not
be performed unless there is an immediate life-threatening situation.
Inability to Maintain Ventilation:
If the patient cannot be adequately ventilated through other means,
tracheostomy may be necessary, but it should be performed with caution.
Unstable Hemodynamics:
Patients with severe hemodynamic instability may not tolerate the
procedure well, and alternative airway management strategies may be
required.
Posterior Pituitary Syndromes
General Pathology
Posterior Pituitary Syndromes
The posterior pituitary, or neurohypophysis, is composed of modified glial cells (termed pituicytes) and axonal processes extending from nerve cell bodies in the hypothalamus. The hypothalamic neurons produce two peptides: antidiuretic hormone (ADH) and oxytocin that are stored in axon terminals in the neurohypophysis.
The clinically important posterior pituitary syndromes involve ADH production and include
1. Diabetes insipidus and
2. Inappropriate secretion of high levels of ADH.
- ADH is released into the general circulation in response to increased plasma oncotic pressure & left atrial distention.
- It acts on the renal collecting tubules to increase the resorption of free water.
- ADH deficiency causes diabetes insipidus, a condition characterized by polyuria. If the cause is related to ADH Diabetes insipidus from - - ADH deficiency is designated as central, to differentiate it from nephrogenic diabetes insipidus due to renal tubular unresponsiveness to circulating ADH.
- The clinical manifestations of both diseases are similar and include the excretion of large volumes of dilute urine with low specific gravity. Serum sodium and osmolality are increased as a result of excessive renal loss of free water, resulting in thirst and polydipsia.
- ADH excess causes resorption of excessive amounts of free water, with resultant hyponatremia.
- The most common causes of the syndrome include the secretion of ectopic ADH by malignant neoplasms (particularly small-cell carcinomas of the lung), and local injury to the hypothalamus and/or neurohypophysis.
- The clinical manifestations are dominated by hyponatremia, cerebral edema, and resultant neurologic dysfunction.
Oxycodone
Pharmacology
Oxycodone
About equal potency to morphine. Very effective orally.
It is combined with aspirin or acetaminophen for the treatment of moderate pain and is available orally
Oxycodone is a semisynthetic compound derived from thebaine, with agonist activity primarily at mu receptors.
Classification of Local anesthetics
Pharmacology
Classification
I) Esters
1. Formed from an aromatic acid and an amino alcohol.
2. Examples of ester type local anesthetics:
Procaine
Chloroprocaine
Tetracaine
Cocaine
Benzocaine- topical applications only
2) Amides
1. Formed from an aromatic amine and an amino acid.
2. Examples of amide type local anesthetics:
Articaine
Mepivacaine
Bupivacaine
Prilocaine
Etidocaine
Ropivacaine
Lidocaine
Alveolar Osteitis
Oral and Maxillofacial SurgeryDry Socket (Alveolar Osteitis)
Dry socket, also known as alveolar osteitis,
is a common complication that can occur after tooth extraction, particularly
after the removal of mandibular molars. It is characterized by delayed
postoperative pain due to the loss of the blood clot that normally forms in the
extraction socket.
Key Features
Pathophysiology:
After a tooth extraction, a blood clot forms in the socket, which is
essential for healing. In dry socket, this clot is either dislodged or
dissolves prematurely, exposing the underlying bone and nerve endings.
The initial appearance of the clot may be dirty gray, and as it
disintegrates, the socket may appear gray or grayish-yellow, indicating
the presence of bare bone without granulation tissue.
Symptoms:
Symptoms of dry socket typically begin 3 to 5 days after
the extraction. Patients may experience:
Severe pain in the extraction site that can radiate to the ear,
eye, or neck.
A foul taste or odor in the mouth due to necrotic tissue.
Visible empty socket with exposed bone.
Local Therapy:
Management of dry socket involves local treatment to alleviate pain
and promote healing:
Irrigation: The socket is irrigated with a warm
sterile isotonic saline solution or a dilute solution of hydrogen
peroxide to remove necrotic material and debris.
Application of Medications: After irrigation,
an obtundent (pain-relieving) agent or a topical anesthetic may be
applied to the socket to provide symptomatic relief.
Prevention:
To reduce the risk of developing dry socket, patients are often
advised to:
Avoid smoking and using straws for a few days post-extraction,
as these can dislodge the clot.
Follow postoperative care instructions provided by the dentist
or oral surgeon.
Antibiotic protocol for prevention of endocarditis from dental procedures
Oral Medicine
Antibiotic protocol for prevention of endocarditis from dental procedures
Local or no anaesthesia
- Oral amoxicillin 3 g 1 hour before procedure
- if allergic to penicillin or have had more than a single dose in previous month: oral clindamycin 600 mg 1 hour beforeprocedure
- patients who have had endocarditis: amoxicillin and gentamycin, as under general anaesthesia
General anaesthesia: no special risk
- Amoxicillin 1 g intravenous at induction, then oral amoxicillin 500 mg 6 hours later
- oral amoxicillin 3 g 4 hours before induction then oral amoxicillin 3 g as soon as possible after procedure
- oral amoxicillin 3 g and oral probenecid 1 g 4 hours before procedure
General anaesthesia: special risk
- Patients with a prosthetic valve or who have had endocarditis are at special risk
- Amoxicillin 1 g and gentomycin 120 mg both intravenous at induction, then oral amoxicillin 500 mg 6 hours later
General anaesthesia: penicillin not suitable
- Patients who are allergic to penicillin or who have received more than a single dose of a penicillin in the previous month need different antibiotic cover
- Vancomycin 1 g intravenous over at least 100 minutes then intravenous gentamycin 120 mg at induction or 15 minutes before procedure
- teicoplanin 400 mg and gentamycin 120 mg both intravenous at induction or 15 minutes before procedure
- clindamycin 300 mg intravenous over at least 10 minutes at induction or 15 minutes before procedure then oral or
intravenous clindamycin 150 mg 6 hours later
Growth Spurts
PedodonticsGrowth Spurts in Children
Growth in children does not occur at a constant rate; instead, it is
characterized by periods of rapid increase known as growth spurts.
These spurts are significant phases in physical development and can vary in
timing and duration between individuals, particularly between boys and girls.
Growth Spurts: Sudden increases in growth that occur at
specific times during development. These spurts are crucial for overall
physical development and can impact various aspects of health and
well-being.
Timing of Growth Spurts
The timing of growth spurts can be categorized into several key periods:
Just Before Birth
Description: A significant growth phase occurs in
the fetus just prior to birth, where rapid growth prepares the infant
for life outside the womb.
One Year After Birth
Description: Infants experience a notable growth
spurt during their first year of life, characterized by rapid increases
in height and weight as they adapt to their new environment and begin to
develop motor skills.
Mixed Dentition Growth Spurt
Timing:
Boys: 8 to 11 years
Girls: 7 to 9 years
Description: This growth spurt coincides with the
transition from primary (baby) teeth to permanent teeth. It is a
critical period for dental development and can influence facial growth
and the alignment of teeth.
Adolescent Growth Spurt
Timing:
Boys: 14 to 16 years
Girls: 11 to 13 years
Description: This is one of the most significant
growth spurts, marking the onset of puberty. During this period, both
boys and girls experience rapid increases in height, weight, and muscle
mass, along with changes in body composition and secondary sexual
characteristics.
Quad helix appliance
OrthodonticsQuad helix appliance is an orthodontic device used to expand
the upper arch of teeth. It is typically cemented to the molars and features a
U-shaped stainless steel wire with active helix springs, helping to correct
issues like crossbites, narrow jaws, and crowded teeth. ### Components of the
Quad Helix Appliance
Helix Springs:
The appliance contains two or four active helix springs that exert
gentle pressure to widen the dental arch.
Bands:
It is attached to the molars using bands, which provide a stable
anchor for the appliance.
Wire Framework:
Made from 38 mil stainless steel wire, the framework allows for
customization and adjustment by the orthodontist.
Functions of the Quad Helix Appliance
Arch Expansion:
The primary function is to gradually widen the upper arch, creating
more space for crowded teeth.
Correction of Crossbites:
It helps in correcting posterior crossbites, where the lower teeth
are positioned outside the upper teeth.
Molar Stabilization:
The appliance stabilizes the molars in their correct position during
treatment.
Indications for Use
Narrow Upper Jaw:
Ideal for patients with a constricted upper arch.
Crowded Teeth:
Used when there is insufficient space for teeth to align properly.
Class II and Class III Cases:
Effective in treating specific malocclusions that require arch
expansion.
Advantages of the Quad Helix Appliance
Non-Invasive:
It is a non-surgical option for expanding the dental arch.
Fixed Design:
As a fixed appliance, it does not rely on patient compliance for
activation.
Customizable:
The design allows for adjustments to meet individual patient needs.
Limitations of the Quad Helix Appliance
Initial Discomfort:
Patients may experience mild discomfort or pressure during the first
few weeks of use.
Oral Hygiene Challenges:
Maintaining oral hygiene can be more difficult, requiring diligent
cleaning around the appliance.
Adjustment Period:
It may take time for patients to adapt to speaking and swallowing
with the appliance in place.