📚 NEET MDS Lecture Notes
Histopathological techniques
General PathologyHistopathological techniques
Histopathological examination studies tissues under the microscope. During this study, the pathologist looks for abnormal structures in the tissue. Tissues for histopathological examination are obtained by biopsy. Biopsy is a tissue sample from a living person to identify the disease. Biopsy can be either incisional or excisional.
Once the tissue is removed from the patient, it has to be immediately fixed by putting it into adequate amount of 10% Formaldehyde (10% formalin) before sending it to the pathologist.
The purpose of fixation is:
1. to prevent autolysis and bacterial decomposition and putrefaction
2. to coagulate the tissue to prevent loss of easily diffusible substances
3. to fortify the tissue against the deleterious effects of the various stages in the preparation of sections and tissue processing.
4. to leave the tissues in a condition which facilitates differential staining with dyes and other reagents.
Herpetic Gingivostomatitis
PedodonticsHerpetic Gingivostomatitis
Herpetic gingivostomatitis is an infection of the oral cavity caused by the herpes simplex virus (HSV), primarily HSV type 1. It is characterized by inflammation of the gingiva and oral mucosa, and it is most commonly seen in children.
Etiology and Transmission
- Causative Agent: Herpes simplex virus (HSV).
- Transmission: The virus is communicated through
personal contact, particularly via saliva. Common routes include:
- Direct contact with an infected individual.
- Transmission from mother to child, especially during the neonatal period.
Epidemiology
- Prevalence: Studies indicate that antibodies to HSV are present in 40-90% of individuals across different populations, suggesting widespread exposure to the virus.
- Age of Onset:
- The incidence of primary herpes simplex infection increases after 6 months of age, peaking between 2 to 5 years.
- Infants under 6 months are typically protected by maternal antibodies.
Clinical Presentation
- Incubation Period: 3 to 5 days following exposure to the virus.
- Symptoms:
- General Symptoms: Fever, headache, malaise, and oral pain.
- Oral Symptoms:
- Initial presentation includes acute herpetic gingivostomatitis, with the gingiva appearing red, edematous, and inflamed.
- After 1-2 days, small vesicles develop on the oral mucosa, which subsequently rupture, leading to painful ulcers with diameters of 1-3 mm.
Course of the Disease
- Self-Limiting Nature: The primary herpes simplex infection is usually self-limiting, with recovery typically occurring within 10 days.
- Complications: In severe cases, complications may arise, necessitating hospitalization or antiviral treatment.
Treatment
- Supportive Care:
- Pain management with analgesics for fever and discomfort.
- Ensuring adequate hydration through fluid intake.
- Topical anesthetic ointments may be used to facilitate eating and reduce pain.
- Severe Cases:
- Hospitalization may be required for severe symptoms or complications.
- Antiviral agents (e.g., acyclovir) may be administered in severe cases or for immunocompromised patients.
Recurrence of Herpetic Infections
- Reactivation: Recurrent herpes simplex infections are due to the reactivation of HSV, which remains dormant in nerve tissue after the primary infection.
- Triggers for Reactivation:
- Mucosal injuries (e.g., from dental treatment).
- Environmental factors (e.g., sunlight exposure, citrus fruits).
- Location of Recurrence: Recurrent infections typically occur at the same site as the initial infection, commonly manifesting as herpes labialis (cold sores).
Antimania Drugs
PharmacologyAntimania Drugs
MANIC SYMPTOMSMANIC SYMPTOMS
Elevated or irritable mood
Increased activity or psychomotor agitation
Reduced need for sleep
Inflated self esteem or grandiosity
Increased or pressure of speech
Flight of ideas
These drugs are used to treat manic-depressive illness.
1. Lithium
2. Carbamazepine
3. Valproic acid
Mechanisms of action
1. Lithium works inside the cell to block conversion of inositol phosphate to inositol.
2. Carbamazepine blocks sodium channels
3. Valproic acid blocks sodium and calcium channels
PHARMACOKINETICS
Absorbed readily and almost completely from the GI tract; peak concentrations in 1-2 hrs
Lithium toxicity
1. Nausea, diarrhea, convulsions, coma, hyperreflexia, cardiac arrhythmias, hypotension.
2. Thyroid enlargement; increases thyroid stimulating hormone (TSH) secretion; may cause hypothyroidism.
3. Polydipsia, polyuria (lithium inhibits the effect of antidiuretic hormone on the kidney).
Clinical applications concerning lithium
- Patients must be warned against sodium-restricted diets because sodium restriction leads to greater retention of lithium by the kidney.
- Patients must have regular (e.g., monthly) blood checks because the margin of safety is narrow.
Endocrine Effects – Goitre and hypothyroidism commonly
Cardiac Effects:– ECG changes(common) - T-wave flattening/inversion and appearance of U wavesflattening/inversion and appearance of U waves
Li and Pregnancy -1st Trimester:Cardiovascular anomalies of the newborn, especially Ebstein's malformation
- 3rd Trimester: Neonatal goiter, CNS depression, hypotonia ("floppy baby" syndrome)
Drug–drug interactions of lithium
Diuretics and newer nonsteroidal anti-inflammatory drugs (NSAIDs) reduce lithium excretion and may cause lithium toxicity.
Osteomyelitis
Oral Maxillofacial SurgeryOsteomyelitis
Staphylococcus aureus causes osteomyelitis.
TYPES OF OSTEOMYELITIS
1.Suppurative Osteomyelitis - onset 4 weeks - Deep bacterial invasion into medullary & cortical bone - polymicrobial infection anaerobes such as Bacteriods, Porphyromonas or Provetella.
Staphylococci may be a cause when an open fracture is involved. Mandible is more prone than maxilla as vascular supply is readily compromised.
2.Focal Sclerosing Osteomylitis(Condensing osteitis) - Localized areas of bone sclerosis. Bony reaction to low-grade peri-apical infection or unusually strong host defensive response. Association with an area of inflammation is critical.
3. Diffuse Sclerosing Osteomylitis - Chronic intraosseous bacterial infection creates a smoldering mass of chronically inflammed granulation tissue.
4. Proliferative Periostitis(Periostitis ossificans & Garee’s osteomyelitis) - periosteal reaction to the presence of inflammation. Affected periosteum forms several rows of reactive vital bone that parallel each other & expand surface of altered bone.
- Radiopaque laminations of bone roughly parallel each other & underlying cortical surface. Laminations may vary from 1-12 in number. Radiolucent separations often are present between new bone & original cortex.
Conditions that weaken the immune system increase a person's risk for osteomyelitis, including:
Diabetes (most cases of osteomyelitis stem from diabetes)
Sickle cell disease
HIV or AIDS
Rheumatoid arthritis
Intravenous drug use
Alcoholism
Long-term use of steroids
Hemodialysis
Poor blood supply
Recent injury
Bone surgery, including hip and knee replacements, also increase the chance of bone infection.
Osteomyelitis in Children and Adults
In children, osteomyelitis is usually acute. Acute osteomyelitis comes on quickly, is easier to treat, and overall turns out better than chronic osteomyelitis. In children, osteomyelitis usually shows up in arm or leg bones.
In adults, osteomyelitis can be either acute or chronic.
Acute osteomyelitis develops rapidly over a period of seven to 10 days. The symptoms for acute and chronic osteomyelitis are very similar
Clinical features of chronic osteomyelitis are usually limited to :
- Pain and tenderness: the pain is minimal,
- Non healing bony and overlying soft tissue wounds with induration of soft tissues,
- Intraoral or extraoral draining fistulae,
- Thickened or “wooden” character of bone,
- Enlargement of mandible, because of deposition of subperiosteal new bone.
- Pathological fractures may occur,
- Sterile abscess (Brodie’s abscess), common to long bones is rare in jaws.
- Teeth in the area tend to become loose and sensitive to palpation and percussion.