Tetanus - Causes, Symptoms and Treatments

Lockjaw or tetanus is an acute exotoxinmediated infection caused by the anaerobic, spore-forming, gram-positive bacillus Clostridium tetani. Usually, such infection is systemic; less often, localized.

Tetanus is fatal in up to 60% of unimmunized persons, usually within 10 days of onset. When symptoms devclop within 3 days after exposure, the prognosis is poor.

Causes of Tetanus:

Normally, transmission is through a puncture wound that is contaminated by soil, dust, or animal excreta containing C. tetani, or by way of burns and minor wounds. After C. tetani enters the body, it causes local infection and tissue necrosis. It also produces toxins that then enter the blood­stream and lymphatics and eventually spread to central nervous system tissue.

Tetanus occurs worldwide, but it's more prevalent in agricultural regions and developing countries that lack mass immunization programs. It's one of the most common causes of neonatal deaths in developing countries, where infants of unimmunized mothers are delivered under unsterile conditions. In such infants, the unhealed umbilical cord is the portal of entry.

In America, about 75% of all cases occur between April and September.

Signs and symptoms of Tetanus:

The incubation period varies from 3 to 4 weeks in mild tetanus to less than 2 days in severe tetanus. When symptoms occur within 3 days after injury, death is more likely. If tetanus remains localized, signs of onset are spasm and increased muscle tone near the wound.

If tetanus is generalized (systemic), indications include marked muscle hypertonicity, hyperactive deep tendon reflexes, tachycardia, profuse sweating, low­grade fever, and painful, involuntary muscle contractions:

. neck and facial muscles, especially cheek muscles - locked jaw (trismus) and a grotesque, grinning expression called risus sardonicus

. somatic muscles-arched-back rigidity (opisthotonos), boardlike abdominal rigidity

. intermittent tonic convulsions lasting several minutes, which may result in cyanosis and sudden death by asphyxiation.

Despite such pronounced neuromuscular symptoms, cerebral and sensory functions remain normal. Complications include atelectasis, pneumonia, pulmonary emboli, acute gastric ulcers, flexion contractures, and cardiac arrhythmias.

Neonatal tetanus is always generalized. The first clinical sign is difficulty in sucking, which usually appears 3 to 10 days after birth. It progresses to total inability to suck, with excessive crying, irritability, and nuchal rigidity.

Diagnosis of Tetanus:

Frequently, diagnosis must rest on clinical features and a history of trauma and no previous tetanus immunization. Blood cultures and tetanus antibody tests are often negative; only a third of patients have a positive wound culture. Cerebrospinal fluid pressure may rise above normal. Diagnosis also must rule out meningitis, rabies, phenothiazine or strychnine toxicity, and other conditions that mimic tetanus.

Treatment of Tetanus:

Within 72 hours after a puncture wound, a patient with no previous history of tetanus immunization first requires tetanus immune globulin (TIG) or tetanus antitoxin to confer temporary protection. Next, he needs active immunization with tetanus toxoid. A patient who has not received tetanus immunization within 5 years needs a booster injection of tetanus toxoid.

If tetanus develops despite immediate postinjury treatment, the patient will require airway maintenance and a muscle relaxant, such as diazepam, to decrease muscle rigidity and spasm. If muscle contractions aren't relieved by muscle relaxants, a neuromuscular blocker may be needed. The patient with tetanus needs high-dose antibiotics (penicillin administered I.V., if he's not allergic to it).

Special considerations of Tetanus:

When caring for the patient with a puncture wound:

• Thoroughly debride and cleanse the injury site with 3% hydrogen peroxide, and check the patient's immunization history. Record the cause of injury. If it's a dog bite, report the case to local public health authorities.
• Before giving penicillin and TIG, antitoxin, or toxoid, obtain an accurate history of allergies to immunizations or penicillin. If the patient has a history of any allergies, keep epinephrine 1:1,000 and resuscitative equipment available.
• Stress the importance of maintaining active immunization with a booster dose of tetanus toxoid every 10 years.

After tetanus develops:

• Maintain an adequate airway and ventilation to prevent pneumonia and atelectasis. Suction often and watch for signs of respiratory distress. Keep emergency airway equipment on hand because the patient may require artificial ventilation or oxygen administration.
• Maintain an I.V. line for medications and emergency care if necessary.
• Monitor electrocardiography frequently for arrhythmias. Accurately record intake and output, and check vital signs often.
• Turn the patient frequently to prevent pressure sores and pulmonary stasis.
• Because even minimal external stimulation provokes muscle spasms, keep the patient's room dark and quiet. Warn visitors not to upset or overly stimulate the patient.
• If urinary retention develops, insert an indwelling urinary catheter.
• Give muscle relaxants and sedatives as ordered, and schedule patient care to coincide with heaviest sedation.
• Insert an artificial airway, if necessary, to prevent tongue injury and maintain airway during spasms.
• Provide adequate nutrition to meet the patient's increased metabolic needs. The patient may need nasogastric feedings or hyperalimentation.