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General Surgery

SHOCK

Shock  is  defined  as  a  pathological  state  causing  inadequate  oxygen  delivery  to  the peripheral tissues and resulting in lactic acidosis, cellular hypoxia and disruption of normal metabolic condition.

CLASSIFICATION

Shock is generally classified into three major categories:

1.    Hypovolemic shock

2.    Cardiogenic shock

3.    Distributive shock

Distributive shock is further subdivided into three subgroups:

a.    Septic shock

b.    Neurogenic shock

c.    Anaphylactic shock

Hypovolemic  shock  is  present  when  marked  reduction  in  oxygen  delivery results from diminished cardiac output secondary to inadequate vascular volume. In general, it results from loss of fluid from circulation, either directly or indirectly.
e.g.    ?    Hemorrhage
    •    Loss of plasma due to burns
    •    Loss of water and electrolytes in diarrhea
    •    Third space loss (Internal fluid shift into inflammatory exudates in
        the peritoneum, such as in pancreatitis.)

Cardiogenic shock is present when there is severe reduction in oxygen delivery secondary to impaired cardiac function. Usually it is due to myocardial infarction or pericardial tamponade.

Septic Shock (vasogenic shock) develops as a result of the systemic effect of infection. It is the result of a septicemia with endotoxin and exotoxin release by gram-negative and gram-positive bacteria. Despite normal or increased cardiac output and oxygen delivery, cellular oxygen consumption is less than normal due to impaired extraction as a result of impaired metabolism.

Neurogenic shock results primarily from the disruption of the sympathetic nervous system which may be due to pain or loss of sympathetic tone, as in spinal cord injuries.

PATHO PHYSIOLOGY OF SHOCK

Shock stimulates a physiologic response. This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic and renal vessels leads to renal cortical necrosis and acute renal failure. If not corrected in time, shock leads to organ failure and sets up a vicious circle with hypoxia and acidosis.

CLINICAL FEATURES

The clinical presentation varies according to the cause. But in general patients with hypotension and reduced tissue perfusion presents with:
•    Tachycardia
•    Feeble pulse
•    Narrow pulse pressure
•    Cold extremities (except septic shock)
•    Sweating, anxiety
•    Breathlessness / Hyperventilation
•    Confusion leading to unconscious state

PATHO PHYSIOLOGY OF SHOCK

Shock stimulates a physiologic response. This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic and renal vessels leads to renal cortical necrosis and acute renal failure. If not corrected in time, shock leads to organ failure and sets up a vicious circle with hypoxia and acidosis.

CLINICAL FEATURES

The clinical presentation varies according to the cause. But in general patients with hypotension and reduced tissue perfusion presents with:
•    Tachycardia
•    Feeble pulse
•    Narrow pulse pressure
•    Cold extremities (except septic shock)
•    Sweating, anxiety
•    Breathlessness / Hyperventilation
•    Confusion leading to unconscious state

Dautrey Procedure

The Dautrey procedure is a surgical intervention aimed at preventing dislocation of the temporomandibular joint (TMJ) by creating a mechanical obstacle that restricts abnormal forward translation of the condylar head. This technique is particularly beneficial for patients who experience recurrent TMJ dislocations or subluxations, especially when conservative management strategies have proven ineffective.

  1. Indications:

    • The Dautrey procedure is indicated for patients with a history of recurrent TMJ dislocations. It is particularly useful when conservative treatments, such as physical therapy or splint therapy, have failed to provide adequate stabilization of the joint.
  2. Surgical Technique:

    • Osteotomy of the Zygomatic Arch: The procedure begins with an osteotomy, which involves surgically cutting the zygomatic arch, the bony structure that forms the prominence of the cheek.
    • Depressing the Zygomatic Arch: After the osteotomy, the zygomatic arch is depressed in front of the condylar head. This depression creates a physical barrier that acts as an obstacle to the forward movement of the condylar head during jaw opening or excessive movement.
    • Stabilization: The newly positioned zygomatic arch limits the range of motion of the condylar head, thereby reducing the risk of dislocation during functional activities such as chewing or speaking.
  3. Mechanism of Action:

    • By altering the position of the zygomatic arch, the Dautrey procedure effectively changes the biomechanics of the TMJ. The new position of the zygomatic arch prevents the condylar head from translating too far forward, which is a common cause of dislocation.
  4. Postoperative Care:

    • Following the procedure, patients may require a period of recovery and rehabilitation. This may include:
      • Dietary Modifications: Soft diet to minimize stress on the TMJ during the healing process.
      • Pain Management: Use of analgesics to manage postoperative discomfort.
      • Physical Therapy: Exercises to restore normal function and range of motion in the jaw.
  5. Outcomes:

    • The Dautrey procedure has been shown to be effective in preventing recurrent TMJ dislocations. Patients often experience improved joint stability and a better quality of life following the surgery. Successful outcomes can lead to reduced pain, improved jaw function, and enhanced overall satisfaction with treatment.

TMJ Ankylosis

Temporomandibular Joint (TMJ) ankylosis is a condition characterized by the abnormal fusion of the mandibular condyle to the temporal bone, leading to restricted jaw movement. This condition can significantly impact a patient's ability to open their mouth and perform normal functions such as eating and speaking.

Causes and Mechanisms of TMJ Ankylosis

  1. Condylar Injuries:

    • Most cases of TMJ ankylosis result from condylar injuries sustained before the age of 10. The unique anatomy and physiology of the condyle in children contribute to the development of ankylosis.
  2. Unique Pattern of Condylar Fractures in Children:

    • In children, the condylar cortical bone is thinner, and the condylar neck is broader. This anatomical configuration, combined with a rich subarticular vascular plexus, predisposes children to specific types of fractures.
    • Intracapsular Fractures: These fractures can lead to comminution (fragmentation) and hemarthrosis (bleeding into the joint) of the condylar head. A specific type of intracapsular fracture known as a "mushroom fracture" occurs, characterized by the comminution of the condylar head.
  3. Formation of Fibrous Mass:

    • The presence of a highly osteogenic environment (one that promotes bone formation) following a fracture can lead to the organization of a fibrous mass. This mass can undergo ossification (the process of bone formation) and consolidation, ultimately resulting in ankylosis.
  4. Trauma from Forceps Delivery:

    • TMJ ankylosis can also occur due to trauma sustained during forceps delivery, which may cause injury to the condylar region.

Etiology and Risk Factors

Laskin (1978) outlined several factors that may contribute to the etiology of TMJ ankylosis following trauma:

  1. Age of Patient:

    • Younger patients have a significantly higher osteogenic potential and a more rapid healing response. The articular capsule in younger individuals is not as well developed, allowing for easier displacement of the condyle out of the fossa, which can damage the articular disk. Additionally, children may exhibit a greater tendency for prolonged self-imposed immobilization of the mandible after trauma.
  2. Type of Fracture:

    • The condyle in children has a thinner cortex and a thicker neck, which predisposes them to a higher proportion of intracapsular comminuted fractures. In contrast, adults typically have a thinner condylar neck, which usually fractures at the neck, sparing the head of the condyle within the capsule.
  3. Damage to the Articular Disk:

    • Direct contact between a comminuted condyle and the glenoid fossa, either due to a displaced or torn meniscus (articular disk), is a key factor in the development of ankylosis. This contact can lead to inflammation and subsequent bony fusion.
  4. Period of Immobilization:

    • Prolonged mechanical immobilization or muscle splinting can promote orthogenesis (the formation of bone) and consolidation in an injured condyle. Total immobility between articular surfaces after a condylar injury can lead to a bony type of fusion, while some movement may result in a fibrous type of union.

Walsham’s Forceps

Walsham’s forceps are specialized surgical instruments used primarily in the manipulation and reduction of fractured nasal fragments. They are particularly useful in the management of nasal fractures, allowing for precise adjustment and stabilization of the bone fragments during the reduction process.

  1. Design:

    • Curved Blades: Walsham’s forceps feature two curved blades—one padded and one unpadded. The curvature of the blades allows for better access and manipulation of the nasal structures.
    • Padded Blade: The padded blade is designed to provide a gentle grip on the external surface of the nasal bone and surrounding tissues, minimizing trauma during manipulation.
    • Unpadded Blade: The unpadded blade is inserted into the nostril and is used to secure the internal aspect of the nasal bone and associated fragments.
  2. Usage:

    • Insertion: The unpadded blade is carefully passed up the nostril to reach the fractured nasal bone and the associated fragment of the frontal process of the maxilla.
    • Securing Fragments: Once in position, the nasal bone and the associated fragment are secured between the padded blade externally and the unpadded blade internally.
    • Manipulation: The surgeon can then manipulate the fragments into their correct anatomical position, ensuring proper alignment and stabilization.
  3. Indications:

    • Walsham’s forceps are indicated for use in cases of nasal fractures, particularly when there is displacement of the nasal bones or associated structures. They are commonly used in both emergency and elective settings for nasal fracture management.
  4. Advantages:

    • Precision: The design of the forceps allows for precise manipulation of the nasal fragments, which is crucial for achieving optimal alignment and aesthetic outcomes.
    • Minimized Trauma: The padded blade helps to reduce trauma to the surrounding soft tissues, which can be a concern during the reduction of nasal fractures.
  5. Postoperative Considerations:

    • After manipulation and reduction of the nasal fragments, appropriate postoperative care is essential to monitor for complications such as swelling, infection, or malunion. Follow-up appointments may be necessary to assess healing and ensure that the nasal structure remains stable.

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.

An ulcer is a break in the continuity of the skin or the mucous membrane.

Mode of onset:  Traumatic ulcers heal when the traumatic agent is removed., If it persists it becomes chronic as in the case of dental ulcer of the tongue. Ulcers may develop spontaneously as in the case of gumma (syphilitic ulcer). It may develop with varicose veins called varicose ulcer, which develops in the lower third of the leg.

Sometimes a malignant ulcer develops in a scar called Marjolin’s ulcer. Special features are:

 No pain - as there are no nerves. It does not spread - as there is scar tissue. No metastases - as there are no lymphatics Treatment:- Wide excision.

Classification of Ulcer

A) Pathologically

I. Non-specific ulcers:

a. Due to infected wound after trauma, that is physical or chemical agents.

b. Due to local infection example dental ulcer, pressure sore

 Specific ulcers: Caused by specific infection

a. Syphilitic ulcers (Hunterian chancre)

b. Tubercular  ulcers, actinomycosis

Trophic ulcer:- Caused by two factors:

Diminished nutrition due to inadequate blood supply to the tissues

Eg. Ulcers in Buerger’s Disease, Artherosclerosis

b. Diminished or absence of sensation of the skin leading to perforating ulcer of the foot

iv. Malignant ulcer: Due to squamous cell carcinoma, rodent ulcers and melanoma.

B) Clinical classification of ulcers

1. Acute Ulcer:  The edge is inflamed oedematous and painful with slough in the floor and n o granulation tissue. Profuse purulent Discgarge seen

2. Healing ulcers: edge sloping with bluish margin The floor is covered with a red, healthy granulation tissue.

3. Chronic or callous ulcer (non- healing) There is no tendency to heal by itself, the base is jndurated  unhealthy granulation tissue is present in the floor The edge is rounded and thickened.

Chronic ulcer occur due to:

Chronic infection , Defective circulation , Foreign body, Persistent local oedema , Malignancy , Diabetes , Malnutrition (loss of proteins), Gout

Specific Ulcers

Tubeculous Ulcer

Edge Undermined, floor contains granulation tissue a watery discharge is present. Caseous material is found in the floor of the ulcer. It usually occurs in tubercular lymphadenitis in the neck, axilla or groin.

Syphilitic Ulcer

a) Huntarian Chancre or  primary sore or hard chancre: usuaIly occurs over the genitalia especially on penis. Occurs in the primary stage of syphilis Ulcer is round or oval, it is hard,indurated, elevated and painless It feels like a button, discharges serum containing spirochetes (cork screw) which is highly infective.

b) In the Secondary stage mucous patches and condylomata occurs The ulcers are shallow white patches, of sodden thickness which occur in the mouth and tongue. Condyloma are hypertrophied epithelium with serous discharge occurring in mucocutaneous junction around the anus. The regional lymphnod (inguinal transverse chain) are enlarged.

c) In tertiary stage of syphilis gummatous ulcers occur They have a punched  out edge and wash Ieather floor. They occur on the subcutaneous bones like sternum and tibia. They are painless and refuse to heal.

Soft Sore (chanchroid)

They are painful muitiple ulcers, with copious discharge. They are caused by Bacillus Ducrey  lncubation time is 3 to 4 days. located on glans penis and prepuce is due to venereal infection. They are associated with enlarged called bilateral inguinal lymphnodes

Tropical ulcer:

a) Oriental Sore - due to L. Tropica (lieshmaniasis)

b) Ulcers and sinuses are due to guinea worm abscess

c) Histoplasmosis with multiple ulcers on the tibia.

d) Chronic ulcers due to yaws

e) Amoebic ulcers occur in colon_and rectum , flask shaped ulcers , undermined edge , caused by  Entamoeba Histolytica

Varicose Ulcer:

Associated with varicose veins. Occurs on the inner aspect of the lower third of leg , chronic ulcer The surrounding area is pigmented and eczema is present. The sore is longitudinally oval It does not penetrate the deep fascia and is painless The base is adherent to the periosteum of the tibia

Rodent ulcer

Usually Occurs on the face above a line joining the lobule of the ear to the angle of the mouth. Usually occurs at the inner canthous of the eye . Edge is raised and rolled, Erodes the deeper structures and the bone, the lyrnph nodes are not involved.

Treatment: If small wide excision is done with skin grafting, If large, radiotherapy is given.

Malignant Ulcer

Occurs due to chronic irritation as in the case of malignant ulcer of the tongue. The edge is everted. The floor is covered with slough and tumor tissue The regional lymph nodes are hard.

Initially mobile later becomes hard

Treatment: Wide excision is done.

Marjolin ulcer: Malignant Ulcer occurring on scar of Burns

Neuromuscular Blockers in Cardiac Anesthesia

In  patient on β-blockers, the choice of neuromuscular blockers (NMBs) is critical due to their potential cardiovascular effects. Here’s a detailed analysis of the implications of using fentanyl and various NMBs, particularly focusing on vecuronium and its effects.

Key Points on Fentanyl and β-Blockers

  • Fentanyl:

    • Fentanyl is an opioid analgesic that can cause bradycardia due to its vagolytic activity. While it has minimal hemodynamic effects, the bradycardia it induces can be problematic, especially in patients already on β-blockers, which reduce heart rate and blood pressure.
  • β-Blockers:

    • These medications reduce heart rate and blood pressure, which can compound the bradycardic effects of fentanyl. Therefore, careful consideration must be given to the choice of additional medications that may further depress cardiac function.

Vecuronium

  • Effects:

    • Vecuronium is a non-depolarizing neuromuscular blocker that has minimal cardiovascular side effects when used alone. However, it can potentiate decreases in heart rate and cardiac index when administered after fentanyl.
    • The absence of positive chronotropic effects (unlike pancuronium) means that vecuronium does not counteract the bradycardia induced by fentanyl, leading to a higher risk of significant bradycardia and hypotension.
  • Vagal Tone:

    • Vecuronium may enhance vagal tone, further predisposing patients to bradycardia. This is particularly concerning in patients on β-blockers, as the combination can lead to compounded cardiac depression.

Comparison with Other Neuromuscular Blockers

  1. Pancuronium:

    • Vagolytic Action: Pancuronium has vagolytic properties that can help attenuate bradycardia and support blood pressure. It is often preferred in cardiac anesthesia for its more favorable hemodynamic profile compared to vecuronium.
    • Tachycardia: While it can induce tachycardia, this effect may be mitigated in patients on β-blockers, which can blunt the tachycardic response.
  2. Atracurium:

    • Histamine Release: Atracurium can release histamine, leading to hemodynamic changes such as increased heart rate and decreased blood pressure. These effects can be minimized by slow administration of small doses.
  3. Rocuronium:

    • Minimal Hemodynamic Effects: Rocuronium is generally associated with a lack of significant cardiovascular side effects, although occasional increases in heart rate have been noted.
  4. Cis-Atracurium:

    • Cardiovascular Stability: Cis-atracurium does not have cardiovascular effects and does not release histamine, making it a safer option in terms of hemodynamic stability.

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