gas gangrene & tetanus

Tetanus &Gas Gangrene

BYPROF GOUDA ELLABBAN

SUEZ CANAL UNIV. HOSPITAL/ EGYPT

Tetanus 

•Tetanus [TET-nus] is a condition that affects the nervous system and causes painful, uncontrolled muscle spasms. •People get tetanus when spores of the tetanus bacteria enter the body through an open wound and produce a powerful nerve poison. •Tetanus spores are found throughout the environment, usually in soil, dust, and animal waste. •Tetanus is preventable through immunization.•Because of widespread use of tetanus vaccine, the condition is now rare.

• Causes, incidence, and risk factors   • Spores of the bacterium Clostridium tetani live

in the soil and are found around the world. In the spore form, C. tetani may remain dormant in the soil, and it can remain infectious for more than 40 years.

• Tetanus causes approximately five deaths per year in the U.S. Internationally, reports show up to 1 million cases annually, mostly in developing countries.

• Tetanus infections in newborns accounts for about half of tetanus-related deaths in developing countries.

• Infection begins when the spores are introduced into an injury or wound.

• The spores germinate, releasing active bacteria that multiply and produce a neurotoxin called tetanospasmin.

• Tetanospasmin selectively blocks inhibitory nerve transmission from the spinal cord to the muscles, allowing the muscles to go into severe spasm.

• Spasmodic contractions can be so powerful that they tear the muscles or cause compression fractures of the vertebrae.

• Tetanus often begins with mild spasms in the jaw muscles (trismus), neck muscles, and facial muscles.

• Stiffness rapidly develops in the chest, back, abdominal muscles, and sometimes the laryngeal muscles (which then interferes with breathing).

• Muscular seizures (tetany) cause sudden, powerful, and painful contraction of muscle groups. These episodes can cause fractures and muscle tears.

• Without treatment, one out of three affected people die. The mortality rate for newborns with untreated tetanus is even higher: two out of three. With proper treatment, less than 10% of infected patients die.

• The incubation period is 5 days to 15 weeks, with 7 days as the average.

• About 100 cases of tetanus occur every year in the U.S., the vast majority in un-immunized individuals or those whose last immunization was no longer current.

• In developing countries, tetanus frequently causes death in newborn infants when the umbilical stump becomes infected.

• Symptoms   • Spasms and tightening of the jaw muscle ("lockjaw") • Stiffness and spasms of various muscle groups

– Neck muscles – Chest muscles – Abdominal muscles – Back muscles, often causing arching (opisthotonos)

• Tetanic seizures (painful, powerful bursts of muscle contraction) • Irritability • Fever • Additional symptoms that may be associated with this disease: • Excessive sweating • Swallowing difficulty • Hand or foot spasms • Drooling • Uncontrolled urination and/or defecation

Differential diagnosis

• Tetany• Strychnine poisoning • Meningitis• Epilepsy• Hysteria

• investigations:

• Diagnosis of tetanus is based on the history and physical findings that are characteristic of the disease.

• Diagnostic studies generally are of little value, as cultures of the wound site are negative for C. tetani two-thirds of the time. When the culture is positive, it confirms the diagnosis of tetanus

Tests

• Culture of the wound site (may be negative even if tetanus is present)

• Tetanus antibody test • Other tests may be used to rule out

meningitis, rabies, strychnine poisoning, or other diseases with similar symptoms.

• Prevention    • Tetanus is completely preventable by active

tetanus immunization.• Immunization is thought to provide protection for

10 years.• In the U.S., immunizations begin in infancy with

the DTaP series of shots. • Td vaccine is used as a booster to maintain

immunization in teenagers and adults.• Older teenagers and adults who have sustained

injuries, should receive booster immunization for tetanus if more than 10 years have passed since the last booster.

• Thorough cleaning of all injuries and wounds and the removal of dead or severely injured tissue (debridement), when appropriate, may reduce the risk of developing tetanus.

• It is the dirt, not the rust, that carries the risk for tetanus.

• Treatment   • Control and reverse the tetany with antitoxin (tetanus

immune globulin). • Give penicillin to kill C. tetani (other antibiotics such as

clindamycin, erythromycin, or metronidazole can be used in patients who are allergic to penicillin).

• Remove and destroy the source of the toxin through surgical exploration and cleaning of the wound (debridement).

• Treat symptoms. Muscle spasms can be treated with muscle relaxants such as diazepam.

• Bedrest with a nonstimulating environment (dim light, reduced noise, and stable temperature) may be recommended.

• Sedation may be necessary to keep the affected person calm.

• Respiratory support with oxygen, endotracheal tube, and mechanical ventilation may be necessary.

• Complications   • Airway obstruction • Respiratory arrest • Heart failure • Pneumonia • Fractures • Brain damage due to lack of oxygen during

spasms

Gas Gangrene

Definition • Gas gangrene (clostridial myonecrosis) is a

life-threatening infection of muscle tissue caused mainly by Clostridium perfringens.

• Characterized by:– rapid onset of myonecrosis– gas production– sepsis

Statistics

• Rare disease.• Only 1,000 to 3,000 cases occur in U.S.A

annually.• mortality rate of 25%, but it can be 100% in

patients with spontaneous gas gangrene or those with delayed treatment.

Risk Factors

• Trauma or recent surgical wound • Vascular disease • Immunocomprission• Diabetes• Malignant disease• Hypoalbuminemia• Burns• Chronic alcoholism

Gas Gangrene

Posttraumatic

Postoperative

Spontaneous

1

2

3

Modes of Infection

1.Posttraumatic gas gangrene (60%):– Most of these cases involve automobile

accidents.– Crush injuries, compound fractures, gunshot

wounds, thermal or electrical burns, and frostbite.

– Farm or industrial injuries contaminated with soil.

– Intramuscular or subcutaneous injections with medications or drugs (rare).

Modes of Infection

Modes of Infection

2. Postoperative clostridial infections follow cases of:

– Colon resection– Ruptured appendix– Bowel perforation– Biliary or other GI surgery– Septic back-street abortions are the main

cause of uterine gas gangrene

Modes of Infection

3. Spontaneous gas gangrene without external wound or injury occurs frequently in patients who have serious underlying conditions.– Colorectal adenocarcinoma is the most prevalent risk factor

in this group.– Hematologic malignancy is also a major premorbid

condition.– In children, neutropenia represents the single most

important risk factor for spontaneous C.septicum infections.– The remaining cases are associated with diabetes or

neutropenic colitis.– In many cases, no predisposing condition can be found.

Clinical Presentation

1. Symptoms:– moderate to severe pain around a skin injury – progressive swelling around a skin injury – moderate to high fever – skin color initially pale, later dusky progressing to dark

red or purple – vesicle formation, coalescent– blisters filled with brown-red fluid – foul-smelling brown-red or bloody fluid discharge– sweating

Clinical Presentation

2. Signs:• Pallor• Cold extremities• Low blood pressure• Tachycardia• Crepitus may be felt• Sepsis may develop• Jaundice is possible

shock

Complications

• Disfiguring or disabling permanent tissue damage

• Jaundice with liver damage • Kidney failure• Sepsis • Shock • Delirium• Coma

Differential Diagnosis

• Necrotizing fasciitis • Abdominal abcess• Penetrating abdominal trauma• Abortion• Clostridial cholecystitis• Bacterial sepsis• Septic shock

Investigations1.Lab Studies:

– CBC or peripheral blood smear analysis may suggest hemolysisbut not show leukocytosis.

– A Gram stain of the exudate or infected tissues.– The chemistry profile may show significant metabolic

abnormalities (metabolic acidosis and renal failure) frequentlyassociated with tissue injuries and hypotension.

2.Imaging Studies: – Plain X-ray.– CT scans are also helpful, especially in abdominal cases.

3.Other Tests: – ELISA is not widely available but represents a potential diagnostic tool.

4.Histopathology:– Widespread myonecrosis, destruction of other connective tissues, and few neutrophils in the

infected area. Leukocyte aggregates are found in the border regions.

Treatment

IN GENERAL:

The combination of aggressive surgical debridement and effective antibiotic therapy is the determining factor for

successful treatment

1. Prehospital Care: – Oxygenation– Intravenous (IV) fluids

2. Emergency Department Care: – Continue managing the airway and breathing of the patient.– Frequent assessment of the circulatory status is necessary.– Use vasoconstrictors only if absolutely necessary.– Administer tetanus toxoid if indicated.– Administer antibiotics.– Correct electrolyte abnormalities.– Check compartment pressures.

Treatment cont.

Treatment cont.

3. Medical Care:i. Antibiotics significantly improves survival:

• Historically, large doses of penicillin G was the drug of choice.• Currently, a combination of penicillin and clindamycin is widely used. • Recent studies show that protein synthesis inhibitors (eg,

clindamycin, chloramphenicol, tetracycline) may be more effective. • A combination of clindamycin and metronidazole is a good choice for

patients allergic to penicillin.

ii. Intensive supportive care in patients with end-organ failure.iii. Analgesics.iv. Hyperbaric oxygen therapy.

4. Surgical Care:-

i. General:• Fasciotomy for compartment syndrome.• Daily debridement as needed to remove all necrotic tissue.

ii. Specific:• Extremities: amputation may be necessary and life-saving.• Abdominal: requires excision of the body wall musculature.• Uterine: following septic abortion usually necessitates

hysterectomy.

Treatment cont.

Prevention

• Cleaning wounds and removing foreign objects and dead tissue.

• Watch for signs of infection (such as redness, pain, drainage, or swelling around a wound),

• Intravenous antibiotics are used before, during, and after abdominal surgery to prevent postoperative infection.

Thank you