NEET MDS Lessons
General Surgery
Tracheostomy
Tracheostomy is a surgical procedure that involves creating an opening in the trachea (windpipe) to facilitate breathing. This procedure is typically performed when there is a need for prolonged airway access, especially in cases where the upper airway is obstructed or compromised. The incision is usually made between the 2nd and 4th tracheal rings, as entry through the 1st ring can lead to complications such as tracheal stenosis.
Indications
Tracheostomy may be indicated in various clinical scenarios, including:
- Acute Upper Airway Obstruction: Conditions such as severe allergic reactions, infections (e.g., epiglottitis), or trauma that obstruct the airway.
- Major Surgery: Procedures involving the mouth, pharynx, or larynx that may compromise the airway.
- Prolonged Mechanical Ventilation: Patients requiring artificial ventilation for an extended period, such as those with respiratory failure.
- Unconscious Patients: Situations involving head injuries, tetanus, or bulbar poliomyelitis where airway protection is necessary.
Procedure
Technique
- Incision: A horizontal incision is made in the skin over the trachea, typically between the 2nd and 4th tracheal rings.
- Dissection: The subcutaneous tissue and muscles are dissected to expose the trachea.
- Tracheal Entry: An incision is made in the trachea, and a tracheostomy tube is inserted to maintain the airway.
Complications of Tracheostomy
Tracheostomy can be associated with several complications, which can be categorized into intraoperative, early postoperative, and late postoperative complications.
1. Intraoperative Complications
- Hemorrhage: Bleeding can occur during the procedure, particularly if major blood vessels are inadvertently injured.
- Injury to Paratracheal Structures:
- Carotid Artery: Injury can lead to significant hemorrhage and potential airway compromise.
- Recurrent Laryngeal Nerve: Damage can result in vocal cord paralysis and hoarseness.
- Esophagus: Injury can lead to tracheoesophageal fistula formation.
- Trachea: Improper technique can cause tracheal injury.
2. Early Postoperative Complications
- Apnea: Temporary cessation of breathing may occur, especially in patients with pre-existing respiratory issues.
- Hemorrhage: Postoperative bleeding can occur, requiring surgical intervention.
- Subcutaneous Emphysema: Air can escape into the subcutaneous tissue, leading to swelling and discomfort.
- Pneumomediastinum and Pneumothorax: Air can enter the mediastinum or pleural space, leading to respiratory distress.
- Infection: Risk of infection at the incision site or within the tracheostomy tube.
3. Late Postoperative Complications
- Difficult Decannulation: Challenges in removing the tracheostomy tube due to airway swelling or other factors.
- Tracheocutaneous Fistula: An abnormal connection between the trachea and the skin, which may require surgical repair.
- Tracheoesophageal Fistula: An abnormal connection between the trachea and esophagus, leading to aspiration and feeding difficulties.
- Tracheoinnominate Arterial Fistula: A rare but life-threatening complication where the trachea erodes into the innominate artery, resulting in severe hemorrhage.
- Tracheal Stenosis: Narrowing of the trachea due to scar tissue formation, which can lead to breathing difficulties.
Advanced Trauma Life Support (ATLS)
Introduction
Trauma is a leading cause of death, particularly in the first four decades of life, and ranks as the third most common cause of death overall. The Advanced Trauma Life Support (ATLS) program was developed to provide a systematic approach to the management of trauma patients, ensuring that life-threatening conditions are identified and treated promptly.
Mechanisms of Injury
In trauma, injuries can be classified based on their mechanisms:
Overt Mechanisms
- Penetrating Trauma: Injuries caused by objects that penetrate the skin and underlying tissues.
- Blunt Trauma: Injuries resulting from impact without penetration, such as collisions or falls.
- Thermal Trauma: Injuries caused by heat, including burns.
- Blast Injury: Injuries resulting from explosions, which can cause a combination of blunt and penetrating injuries.
Covert Mechanisms
- Blunt Trauma: Often results in internal injuries that may not be immediately apparent.
- Penetrating Trauma: Can include knife wounds and other sharp objects.
- Penetrating Knife: Specific injuries from stabbing.
- Gunshot Injury: Injuries caused by firearms, which can have extensive internal damage.
The track of penetrating injuries can often be identified by the anatomy involved, helping to determine which organs may be injured.
Steps in ATLS
The ATLS protocol consists of a systematic approach to trauma management, divided into two main surveys:
1. Primary Survey
- Objective: Identify and treat life-threatening conditions.
- Components:
- A - Airway: Ensure the airway is patent. In patients with a Glasgow Coma Scale (GCS) of 8 or less, immediate intubation is necessary. Maintain cervical spine stability.
- B - Breathing: Assess ventilation and oxygenation. Administer high-flow oxygen via a reservoir mask. Identify and treat conditions such as tension pneumothorax, flail chest, massive hemothorax, and open pneumothorax.
- C - Circulation: Evaluate circulation based on:
- Conscious level (indicates cerebral perfusion)
- Skin color
- Rapid, thready pulse (more reliable than blood pressure)
- D - Disability: Assess neurological status using the Glasgow Coma Scale (GCS).
- E - Exposure: Fully expose the patient to assess for injuries on the front and back.
2. Secondary Survey
- Objective: Conduct a thorough head-to-toe examination to identify all injuries.
- Components:
- AMPLE: A mnemonic to gather important patient
history:
- A - Allergy: Any known allergies.
- M - Medications: Current medications the patient is taking.
- P - Past Medical History: Relevant medical history.
- L - Last Meal: When the patient last ate.
- E - Events of Incident: Details about the mechanism of injury.
- AMPLE: A mnemonic to gather important patient
history:
Triage
Triage is the process of sorting patients based on the severity of their condition. The term "triage" comes from the French word meaning "to sort." In trauma settings, patients are categorized using a color-coded system:
- Red: First priority (critical patients, e.g., tension pneumothorax).
- Yellow: Second priority (urgent cases, e.g., pelvic fracture).
- Green: Third priority (minor injuries, e.g., simple fracture).
- Black: Zero priority (patients who are dead or unsalvageable).
Blunt Trauma
- Common Causes: The most frequent cause of blunt trauma is road traffic accidents.
- Seat Belt Use: Wearing seat belts significantly reduces
mortality rates:
- Front row occupants: 45% reduction in death rate.
- Rear seat belt use: 80% reduction in death rate for front seat occupants.
- Seat Belt Injuries: Marks on the thorax indicate a fourfold increase in thoracic injuries, while abdominal marks indicate a threefold increase in abdominal injuries.
Radiographs in Trauma
Key radiographic views to obtain in trauma cases include:
- Lateral cervical spine
- Anteroposterior chest
- Anteroposterior pelvis
1 Cellulitis: a non-suppurative inflammation of subcutaneous tissue, extending along connective tissue planes and across intercellular spaces.
Spreading inflammation in the tissue planes is called cellulitis. There is wide spread swelling, redness and pain without definite localization.
Caused by Streptococcus pyogenes.. If general condition of the patient is undermined, as in diabetes, cellulitis spreads rapidly and leads to Septicemia (infection in the blood).Redness, itching and stiffness is present in the site of inoculation (where the bacteria enter the skin), local Gangrene (death of the tissue) may occur. The appearance of skin creases or wrinkles, indicates resolution (healing).
Treatment
1. Rest , Appropriate antibiotics.
Cellulitis of the neck: Is a complication of wounds tonsillitis or mastoiditis Ludwig’s angina is the term applied to sub-maxillary cellulitis. The two dangers of cervical cellulitis are:
1. Oedema of glottis - with possible asphyxia (respiratory obstructon )
2. Mediastinitis - In ludwig’s angina the floor of the mouth become oedematous. The tongue can be seen displaced, turned upwards by swelling and oedema. The patient is unable to close the mouth owing to oedema of the tongue and the floor of the mouth. This can also CCC when the tongue is bitten by a wasp.
Ludwig’s angina: Ludwig - characterized by a brawny (non pitting) swelling of the sub-mandibular region, corn with inflammatory oedema of the mouth. It is the combined cervical and intrabuccal signs that constitute the characteristic feature of the lesion. The cause of the condition is virulent, usually streptococcal infection of the cellular tissue surrounding the sub-mandibular salivary gland.
Clinical features
The swollen tongue is pushed towards the palate and forwards through the open mouth, while the cellulitis extends down the neck.
The most dangerous plane, is deep to the deep fascia.
Ludwig’s angina is an infection of closed fascial space and if .untreated, the inflammatory exudate often passes via, the tunnel occupied by stylohyhoid to the submucosa of glottis, in which event the patient is in immediate danger of death from oedema of the glottis.
Treatment
1. antibiotics on Early Diagnosis
2. In cases where the swelling, both cervical and intrabuccal, does not subside rapidly with such treatment, a curved incision, beneath the jaw is made and this decompresses the closed fascial space. The incision is deepened and after displacing the superficial lobe of the sub-mandibular salivary gland, the mylohyoid muscle are divided. This decompresses the closed fascjal space referred to. The wound is lightly sutured and drained. The operation can be conducted with greatest safety under local anaesthesia.
Bacteraemia and Septicemia
Bacteraemia and septicaemia means the organisms are present in the blood. Clinical features are those of severe infection and shock: , Pyrexia is intermittent , Rigors , Jaundice is due to liver damage, Acute renal failure may occur , Peripheral circulatory failure, lntravascular coagulation indicates a fatal outcome
causative focus found and treated surgically .g., Appendicetomy in perforated appendix
2. Blood culture taken
3. Broad spectrum antibiotic is given
4. Blood transfusion is given.
5. Injection hydrocortisone is given.
Pyaemia
Pyaemia is due to infected emboli circulating in blood stream. Pyaemia is characterized by: -
1. Rigors
2. Intermittent fever
3. Formation of abscess in vital organs like heart or brain.
Treatment
1. Is to prevent emboli reaching the blood stream
2. Broad spectrum antibiotic is given.
3. Abscess are incised and drained
If not treated portal pyaemia with multiple abscesses in liver occur, which is a dangerous condition.
Acute Abscess : An abscess a collection of pus.
Bacteria which cause pus formation is called pyogenic organisms. Bacteria reach the infected area by:
1. Direct route: eg. Penetrating wound
Local extension: From adjacent focus of infection
2 Lymphatics
4. Blood stream
Pyogenic membrane surrounds the abscess and is infiltration with (leukocytes and bacteria.
Pus: Pus contains dead leukocytes and bacteria. It reaches the surface of the body or is discharged into a hollow viscous.
Symptoms: patient feels ill., Throbbing pain is characteristic of suppuration. Pain becomes more severe in the dependent position. E.g. infected finger,
Classical signs
Temperature is elevated , Rigors, inflammation
Fluctuation: Present in the later stages, and reveals the presence of pus. Prevention
1. An abscess can sometimes be aborted by antibiotics in the early stage.,. Rest, Elevation of the affected part.
Treatment
Is incision and drainage of abscess
Hilton’s method of opening an abscess:
It is used where important anatomical structures like the blood vessels and nerves are preesnt, as in the neck, axilla and groin. The skin and superficial fascia is incised. A sinus forceps is thrust into the abscess cavity. The blades are opened and the pus is drained. A gloved finger is introduced and loculi are broken. A ribbon gauze is lightly packed and antibiotics are given. This is done under surface anaesthesia i.e., ethyl chloride spray.
Antibioma
If antibiotic is given the pus in the abscess frequently becomes sterile and a large brawny edematous swelling remains which takes many weeks to resolve.
Treatment: explore the mass with a wide-bore aspirating needle
Most antibiornas are due to late, inadequate, and ineffective antibiotics.
CANCRUM ORIS
Is an infective gangrene of cheek and lip.
may occur as a complication of kala azar, enteric fever and children with poor oral hygiene.
The lesion starts as an acute inflammatory patch on oral mucosa which is seen ulcerated.
The affected part of the cheek or the lip gradually becomes gangrenous.
Focal vascular thrombosis and sepesis occur.
When slough separates, a part of the cheek or lip sloughs out to form a buccal fistula with ugly deformity. The adjacent jaw may be infected too.
Various organisms are found - specially Fusiform bacillus and_Borrellia vincenti.
The foetid odour, gangrenous patch of cheek or lip, purulent discharge from the mouth, fever and toxaemia are the characteristic features. The patient is unable to open the mouth properly.
Treatment
1. Antibiotics, multivitamins and repeated mouth washes
2 Neostibamine in kala-azar. Sequestrectomy in chronic osteomyelitis of the mandible.
4. Plastic reconstruction of the lip or cheek for unsightly deformity undertaken.
CARBUNCLE
Is an infective gangrene of the subcutaneous tissue. It is due to staphylococcal aureus infection. It is uncommon before the age of 40. Males are the usual sufferers. Diabetes may be present. It often occurs on the nape of the neck.
Clinical features
Subcutaneous tissue becomes painful and indurated. Ove skin is red. Unless treated promptly, extension will occur and late softening. The skin gives way and thick pus and slough are discharged.
Usually, there is one central large slough, surrounded by smaller areas of necrosis. Infection extends widely and fresh openings appear
Treatment
1. Many carbuncles are aborted, if penicillin is used adequately in the early stage.
2. Local treatment consists of hygroscopic dressings being given ie. magsulph-glycerin dressing Later the carbuncle is excised with a cruciate incision.
3. If the gap is large and when the granulation tissue comes to the surface, skin grafting is done.
Suture Materials
Sutures are essential in surgical procedures for wound closure and tissue approximation. Various types of sutures are available, each with unique properties, advantages, and applications. Below is a summary of some commonly used suture materials, including chromic catgut, polypropylene, polyglycolic acid, and polyamide (nylon).
1. Chromic Catgut
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Description:
- Chromic catgut is a natural absorbable suture made from collagen derived from the submucosa of sheep intestines or the serosa of beef cattle intestines. It is over 99% pure collagen.
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Absorption Process:
- The absorption of chromic catgut occurs through enzymatic digestion by proteolytic enzymes, which are derived from lysozymes contained within polymorphonuclear leukocytes (polymorphs) and macrophages.
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Absorption Rate:
- The absorption rate depends on the size of the suture and whether it is plain or chromicized. Typically, absorption is completed within 60-120 days.
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Applications:
- Commonly used in soft tissue approximation and ligation, particularly in areas where a temporary support is needed.
2. Polypropylene (Proline)
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Description:
- Polypropylene is a synthetic monofilament suture made from a purified and dyed polymer.
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Properties:
- It has an extremely high tensile strength, which it retains indefinitely after implantation. Polypropylene is non-biodegradable, meaning it does not break down in the body.
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Applications:
- Ideal for use in situations where long-term support is required, such as in vascular surgery, hernia repairs, and other procedures where permanent sutures are beneficial.
3. Polyglycolic Acid
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Description:
- Polyglycolic acid is a synthetic absorbable suture formed by linking glycolic acid monomers to create a polymer.
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Properties:
- It is known for its predictable absorption rate and is commonly used in various surgical applications.
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Applications:
- Frequently used in soft tissue approximation, including in gastrointestinal and gynecological surgeries, where absorbable sutures are preferred.
4. Polyamide (Nylon)
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Description:
- Polyamide, commonly known as nylon, is a synthetic non-absorbable suture that is chemically extruded and generally available in monofilament form.
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Properties:
- Nylon sutures have a low coefficient of friction, making passage through tissue easy. They also elicit minimal tissue reaction.
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Applications:
- Used in a variety of surgical procedures, including skin closure, where a strong, durable suture is required.
Types of Brain Injury
Brain injuries can be classified into two main categories: primary and secondary injuries. Understanding these types is crucial for effective diagnosis and management.
1. Primary Brain Injury
- Definition: Primary brain injury occurs at the moment of impact. It results from the initial mechanical forces applied to the brain and can lead to immediate damage.
- Examples:
- Contusions: Bruising of brain tissue.
- Lacerations: Tears in brain tissue.
- Concussions: A temporary loss of function due to trauma.
- Diffuse axonal injury: Widespread damage to the brain's white matter.
2. Secondary Brain Injury
- Definition: Secondary brain injury occurs after the initial impact and is often preventable. It results from a cascade of physiological processes that can exacerbate the initial injury.
- Principal Causes:
- Hypoxia: Reduced oxygen supply to the brain, which can worsen brain injury.
- Hypotension: Low blood pressure can lead to inadequate cerebral perfusion.
- Raised Intracranial Pressure (ICP): Increased pressure within the skull can compress brain tissue and reduce blood flow.
- Reduced Cerebral Perfusion Pressure (CPP): Insufficient blood flow to the brain can lead to ischemia.
- Pyrexia: Elevated body temperature can increase metabolic demands and worsen brain injury.
Glasgow Coma Scale (GCS)
The Glasgow Coma Scale is a clinical tool used to assess a patient's level of consciousness and neurological function. It consists of three components: eye opening, verbal response, and motor response.
Eye Opening (E)
- Spontaneous: 4
- To verbal command: 3
- To pain stimuli: 2
- No eye opening: 1
Verbal Response (V)
- Normal, oriented: 5
- Confused: 4
- Inappropriate words: 3
- Sounds only: 2
- No sounds: 1
Motor Response (M)
- Obeys commands: 6
- Localizes to pain: 5
- Withdrawal flexion: 4
- Abnormal flexion (decorticate): 3
- Extension (decerebrate): 2
- No motor response: 1
Scoring
- Best Possible Score: 15/15 (fully alert and oriented)
- Worst Possible Score: 3/15 (deep coma or death)
- Intubated Cases: For patients who are intubated, the verbal score is recorded as "T."
- Intubation Indication: Intubation should be performed if the GCS score is less than or equal to 8.
Additional Assessments
Pupil Examination
- Pupil Reflex: Assess size and light response.
- Uncal Herniation: In cases of mass effect on the ipsilateral side, partial third nerve dysfunction may be noted, characterized by a larger pupil with sluggish reflex.
- Hutchinson Pupil: As third nerve compromise increases, the ipsilateral pupil may become fixed and dilated.
Signs of Base of Skull Fracture
- Raccoon Eyes: Bilateral periorbital hematoma, indicating possible skull base fracture.
- Battle’s Sign: Bruising over the mastoid process, suggesting a fracture of the temporal bone.
- CSF Rhinorrhea or Otorrhea: Leakage of cerebrospinal fluid from the nose or ear, indicating a breach in the skull base.
- Hemotympanum: Blood in the tympanic cavity, often seen with ear bleeding.
Types of Head Injury
1. Extradural Hematoma (EDH)
Overview
- Demographics: Most common in young male patients.
- Association: Always associated with skull fractures.
- Injured Vessel: Middle meningeal artery.
- Common Site of Injury: Temporal bone at the pterion (the thinnest part of the skull), which overlies the middle meningeal artery.
- Location of Hematoma: Between the bone and the dura mater.
Other Common Sites
- Frontal fossa
- Posterior fossa
- May occur following disruption of major dural venous sinus.
Classical Presentation
- Initial Injury: Followed by a lucid interval where the patient may only complain of a headache.
- Deterioration: After minutes to hours, rapid
deterioration occurs, leading to:
- Contralateral hemiparesis
- Reduced consciousness level
- Ipsilateral pupillary dilatation (due to herniation)
Imaging
- CT Scan: Shows a lentiform (lens-shaped or biconvex) hyperdense lesion between the brain and skull.
Treatment
- Surgical Intervention: Immediate surgical evacuation via craniotomy.
- Mortality Rate: Overall mortality is 18% for all cases of EDH, but only 2% for isolated EDH.
2. Acute Subdural Hematoma (ASDH)
Overview
- Location: Accumulates in the space between the dura and arachnoid.
- Injury Mechanism: Associated with cortical vessel disruption and brain laceration.
- Primary Brain Injury: Often associated with primary brain injury.
Presentation
- Consciousness: Impaired consciousness from the time of impact.
Imaging
- CT Scan: Appears hyperdense, with hematoma spreading diffusely and having a concavo-convex appearance.
Treatment
- Surgical Intervention: Evacuation via craniotomy.
- Mortality Rate: Approximately 40%.
3. Chronic Subdural Hematoma (CSDH)
Overview
- Demographics: Most common in patients on anticoagulants and antiplatelet agents.
- History: Often follows a minor head injury weeks to months prior.
- Pathology: Due to the tear of bridging veins leading to ASDH, which is clinically silent. As the hematoma breaks down, it increases in volume, causing mass effect on the underlying brain.
Clinical Features
- Symptoms may include:
- Headache
- Cognitive decline
- Focal neurological deficits (FND)
- Seizures
- Important to exclude endocrine, hypoxic, and metabolic causes in this group.
Imaging
- CT Scan Appearance:
- Acute blood (0–10 days): Hyperdense
- Subacute blood (10 days to 2 weeks): Isodense
- Chronic (> 2 weeks): Hypodense
Treatment
- Surgical Intervention: Bur hole evacuation rather than craniotomy.
- Anesthesia: Elderly patients can often undergo surgery under local anesthesia, despite comorbidities.
4. Subarachnoid Hemorrhage (SAH)
Overview
- Causes: Most commonly due to aneurysms for spontaneous SAH, but trauma is the most common cause overall.
- Management: Conservative treatment is often employed for trauma cases.
5. Cerebral Contusions
Overview
- Definition: Bruising of the brain tissue due to trauma.
- Mechanism: Often occurs at the site of impact (coup) and the opposite side (contrecoup).
- Symptoms: Can range from mild confusion to severe neurological deficits depending on the extent of the injury.
Imaging
- CT Scan: May show areas of low attenuation (hypodense) or high attenuation (hyperdense) depending on the age of the contusion.
Treatment
- Management: Depends on the severity and associated injuries; may require surgical intervention if there is significant mass effect.
Inflammation is the respone of the body to an irritant.
Stages of Inflammation
1. General: Temperature Raised. In severe cases bacteremia or septicemia ,rigors may occur.
2. Local: classical signs of inflammation are due to hyperemia and inflammation exudate
i) Heat: inflammed area feels warmer than the surrounding tissues.
ii) Redness
iii) Tenderness: Due to pressure of exudate on the surrounding nerves If the exudate is under tension, e.g. a furuncle (boil) of the ear, pain is severe.
iv) swelling
v) Loss of function.
The termination of Inflammation
This may be by:1. Resolution 2. Suppuration 3. Ulceration 4. Ganangren s. Fibrosis
Management
i. Increase the patients resistance., Rest, Relief of pain by analgesics, Diet: High protein and high calorie diet with vitamins, Antibiotics, Prevent further contamination of wound.
Surgical measures
1. Excision: If possible as in appendicectomy.
2. Incision and drainage: If an abscess forms.