NEET MDS Synopsis
Rheumatic Fever - Major and Minor Criteria
Medicine
Rheumatic fever occurs after a streptococcal infection (usually caused by Group A Beta-Hemolytic Strep (GABHS)).
It is an inflammatory condition that affects the joints, skin, heart and brain.
Major criteria are referred to as Jones criteria
J – Joint involvement which is usually migratory and inflammatory joint involvement that starts in the lower joints and ascends to upper joints
O – (“O” Looks like heart shape) – indicating that patients can develop myocarditis or inflammation of the heart
N – Nodules that are subcutaneous
E – Erythema marginatum which is a rash of ring-like lesions that can start in the trunk or arms. When joined with other rings, it can create a snake-like appearance
S – Sydenham chorea is a late feature which is characterized by jerky, uncontrollable, and purposeless movements resembling twitches
Minor criteria include
C – CRP Increased
A – Arthralgia
F – Fever
E – Elevated ESR
P – Prolonged PR Interval
A – Anamesis
L – Leukocytosis
Diagnosis of rheumatic fever is made after a strep infection (indicated by either throat cultures growing GABHS OR elevated anti-streptolysin O titers in the blood) and:
Two major criteria OR
One major criterion and two minor criteria
NEOPLASIA
General Pathology
NEOPLASIA
An abnormal. growth, in excess of and uncoordinated with normal tissues Which persists in the same excessive manner after cessation of the stimuli which evoked the change.
Tumours are broadly divided by their behaviors into 2 main groups, benign and malignant.
Features
Benign
Malignant
General
Rate of growth
Mode of growth
Slow
Expansile
Rapid
Infiltrative
Gross
Margins
Haemoeehage
Circumscribed often Encapsulated
Rare
III defined
Common
Microscopic
Arrangement
Cells
Nucleus
Mitosis
Resemble Parent Tissues
Regular and uniform in shape and size
Resembles parent Cells
Absent or scanty
Varying degrees of structural differentiation
Cellular pleomorphism
Hyper chromatic large and varying in shape and size
Numerous and abnormal
Through most tumours can be classified in the benign or malignant category . Some exhibits an intermediate behaviours.
CLASSIFICATION
Origin
Benign
Malignant
Epithelial
Surface epithelium
Glandular epithelium
Melanocytes
Papilloma
Adenoma
Naevus
Carcinoma
Adenoca cinoma
Melanocarcinoma(Melanoma)
Mesenchymal
Adipose tissue
Fibrous tissue
Smooth tissue
Striated muscle
Cartilage
Bone
Blood vessels
Lymphoid tissue
Lipoma
Fibroma
Leiomyoma
Rhabdomyoma
Chondroma
Osteoma
Angioma
Liposarcoma
Fibrosarcoma
Leimyosarcoma
Chondrosarcoma
Osteosarcoma
Angiosarcoma
Lymphoma
Some tumours can not be clearly categorized in the above table e.g.
Mixed tumours like fibroadenoma of the breast which is a neoplastic proliferation of both epithelial and mesenchmal tissues.
Teratomas which are tumours from germ cells (in the glands) and totipotent cells
(in extra gonodal sites like mediastinun, retroperitoneum and presacral region). These are composed of multiple tissues indicative of differentiation into the derivatives of the three germinal layers.
Hamartomas which are malformations consisting of a haphazard mass of tissue normally present at that site.
The Layers of the Pharyngeal Wall
AnatomyThe Layers of the Pharyngeal Wall
The pharyngeal wall is composed of 5 layers. From internal to external, they are as follows.
Mucous membrane: this lines the pharynx and is continuous with all chambers with which it communicates.
Submucosa
Pharyngobasilar fascia: this is a fibrous layer that is attached to the skull.
Muscular layer: this is composed of inner longitudinal and outer circular parts.
Buccopharyngeal fascia: this is a loose connective tissue layer.
This fascia is continuous with the fascia covering the buccinator and pharyngeal muscle.
It contains the pharyngeal plexus of nerves and veins.
Classification
Pharmacology
Classification
1. Natural Alkaloids of Opium
Phenanthrenes -> morphine, codeine, thebaine
Benzylisoquinolines -> papaverine, noscapine
2. Semi-synthetic Derivatives
diacetylmorphine (heroin) hydromorphone, oxymorphone hydrocodone, oxycodone
3. Synthetic Derivatives
phenylpiperidines pethidine, fentanyl, alfentanyl, sufentnyl
benzmorphans pentazocine, phenazocine, cyclazocine
propionanilides methadone
morphinans levorphanol
SINUS & FISTULA
General Surgery
Sinus
It is a tubular track lined by granulation tissue and open at one end which is at the surface,
eg. Tuberculous Sinus
Fistula
A tubular track lined by granulation tissue and open at both ends.at least one of which communicates with a hollow viscus. it can be internal or external.
Causes
1. Inadequate drainage
Abscess bursting at the non dependent part
Incision at the non-dependent part.
Narrow outer opening leading to collection of exudates in the cavity.
2. Presence of foreign body like sequestrum or slough.
3. Persistence of infection.
4. When the track is lined by epithelium
5. Specific causes, TB., Syphilis, etc.
6. Marked fibrosis of the wall with obliteration of blood vessels.
7. Poor general condition causing delayed healing.
Treatment
1. control of specific infection,
2. Thorough excision of track to open up the cavity. Removal of foreign body and scraping of the epithelium
3. Through Scrapping of the wall to expose healthy tissue
4. Wound laid open and allowed to heal from the bottom leaving no pocket,
The External Ear
AnatomyThe External Ear
The auricle (L. auris, ear) is the visible, shell-like part of the external ear.
It consists of a single elastic cartilage that is covered on both surfaces with thin, hairy skin.
The external ear contains hairs, sweat glands, and sebaceous glands.
The cartilage is irregularly ridged and hollowed, which gives the auricle its shell-like form.
It also shapes the orifice of the external acoustic meatus.
The Ear Lobule
The ear lobule (earlobe) consists of fibrous tissue, fat and blood vessels that are covered with skin.
The arteries are derived mainly from the posterior auricular artery and the superficial temporal artery.
The skin of the auricle is supplied by the great auricular and auriculotemporal nerves.
The great auricular nerve supplies the superior surface and the lateral surface inferior to the external acoustic meatus with nerve fibres from C2.
The auriculotemporal nerve supplies the skin of the auricle superior to the external acoustic meatus.
The External Acoustic Meatus
This passage extends from the concha (L. shell) of the auricle to the tympanic membrane (L. tympanum, tambourine). It is about 2.5 cm long in adults.
The lateral 1/3 of the S-shaped canal is cartilaginous, whereas its medial 2/3 is bony.
The lateral third of the meatus is lined with the skin of the auricle and contains hair follicles, sebaceous glands, and ceruminous glands.
The latter glands produce cerumen (L. cera, wax).
The medial two-thirds of the meatus is lined with very thin skin that is continuous with the external layer of the tympanic membrane.
The lateral end of the meatus is the widest part. It has the diameter about that of a pencil.
The meatus becomes narrow at its medial end, about 4 mm from the tympanic membrane.
The constricted bony part is called the isthmus.
Innervation of the external acoustic meatus is derived from three cranial nerves:
The auricular branch of the auriculotemporal nerve (derived from the mandibular, CN V3).
The facial nerve (CN VII) by the branches from the tympanic plexus.
The auricular branch of the vagus nerve (CN X).
The Tympanic Membrane
This is a thin, semi-transparent, oval membrane at the medial end of the external acoustic meatus.
It forms a partition between the external and middle ears.
The tympanic membrane is a thin fibrous membrane, that is covered with very thin skin externally and mucous membrane internally.
The tympanic membrane shows a concavity toward the meatus with a central depression, the umbo, which is formed by the end of the handle of the malleus.
From the umbo, a bright area referred to as the cone of light, radiates anteroinferiorly.
The external surface of the tympanic membrane is supplied by the auriculotemporal nerve.
Some innervation is supplied by a small auricular branch of the vagus nerve (CN X); this nerve may also contain some glossopharyngeal and facial nerve fibres.
Coagulation Tests: PT and PTT
Oral and Maxillofacial SurgeryCoagulation Tests: PT and PTT
Prothrombin Time (PT) and Partial Thromboplastin
Time (PTT) are laboratory tests used to evaluate the coagulation
pathways involved in blood clotting. Understanding these tests is crucial for
diagnosing bleeding disorders and managing patients with specific factor
deficiencies.
Prothrombin Time (PT)
Purpose: PT is primarily used to assess the extrinsic
pathway of coagulation.
Factors Tested: It evaluates the function of factors I
(fibrinogen), II (prothrombin), V, VII, and X.
Clinical Use: PT is commonly used to monitor patients
on anticoagulant therapy (e.g., warfarin) and to assess bleeding risk before
surgical procedures.
Partial Thromboplastin Time (PTT)
Purpose: PTT is used to assess the intrinsic
pathway of coagulation.
Factors Tested: It evaluates the function of factors I
(fibrinogen), II (prothrombin), V, VIII, IX, X, XI, and XII.
Clinical Use: PTT is often used to monitor patients on
heparin therapy and to evaluate bleeding disorders.
Specific Factor Deficiencies
In certain bleeding disorders, specific factor deficiencies can lead to
increased bleeding risk. Preoperative management may involve the administration
of the respective clotting factors or antifibrinolytic agents to minimize
bleeding during surgical procedures.
Hemophilia A:
Deficiency: Factor VIII deficiency.
Management: Administration of factor VIII
concentrate before surgery.
Hemophilia B:
Deficiency: Factor IX deficiency.
Management: Administration of factor IX concentrate
before surgery.
Hemophilia C:
Deficiency: Factor XI deficiency.
Management: Administration of factor XI concentrate
or fresh frozen plasma (FFP) may be considered.
Von Willebrand’s Disease:
Deficiency: Deficiency or dysfunction of von
Willebrand factor (vWF), which is important for platelet adhesion.
Management: Desmopressin (DDAVP) may be
administered to increase vWF levels, or factor replacement therapy may
be used.
Antifibrinolytic Agent:
Aminocaproic Acid: This antifibrinolytic agent can
be used to help stabilize clots and reduce bleeding during surgical
procedures, particularly in patients with bleeding disorders.
Lost Wax Process
Dental Materials
Lost Wax Process
The lost wax casting process is widely used as it offers asymmetrical casting withnvery fine details to be manufactured relatively inexpensively. The process involves producing a metal casting using a refractory mould made from a wax replica pattern.
The steps involved in the process or the lost wax casting are:
1 . Create a wax pattern of the missing tooth / rim
2 . Sprue the wax pattern
3 . Invest the wax pattern
4 . Eliminate the wax pattern by burning it (inside the furnace or in hot water). This will create a mould.
5 . Force molten metal into the mould - casting.
6 . Clean the cast.
7 . Remove sprue from the cast
8 . Finish and polish the casting on the die .
The lost-wax technique is so named because a wax pattern of a restoration is invested in a ceramic material, then the pattern is burned out ("lost") to create a space into which molten metal is placed or cast. The entire lost-wax casting process .
Wax pattern removal:
Sprue former can be used to remove the pattern. If not the pattern is removed with a sharp probe. Then the sprue former is attached to it. The pattern should be removed directly in line with the principle axis of the tooth or the prepared cavity. Any rotation of the pattern will distort it. Hollow sprue pin is advisable because of its greater retention to the pattern.