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TETANUS

TETANUS. The word tetanus comes from the Greek tetanos, which is derived from the term teinein, meaning to stretch. Tetanus appears in military medical documents throughout the ages. Slapping infected dung on the umbilical cords. Background. CLINCAL TYPES.

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TETANUS

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  1. TETANUS

  2. The word tetanus comes from the Greek tetanos, which is derived from the term teinein, meaning to stretch. Tetanus appears in military medical documents throughout the ages. Slapping infected dung on the umbilical cords Background

  3. CLINCAL TYPES

  4. The 4 clinical types of tetanus are • generalized, • local, • cephalic, • neonatal

  5. NEONATAL TETANUS

  6. Neonatal tetanus is a major cause of infant mortality in underdeveloped countries, but this form is rare in the United States. Infection results from cord contamination during unsanitary delivery conditions, coupled with a lack of maternal immunization.

  7. At the end of the first week of life, infected infants become irritable, feed poorly, and develop rigidity with spasms. This form of tetanus has a very poor prognosis for survival.

  8. Cephalic Tetanus

  9. Cephalic tetanus is uncommon and usually occurs following head trauma or otitis media. Patients with this form present with cranial nerve palsies. The infection may be localized or may become generalized.

  10. Pathophysiology

  11. Tetanus results from infection with C tetani, a mobile, spore-forming, anaerobic, gram-positive bacillus. This bacillus is found in or on soil, manure, dust, clothing, skin, and 10-25% of human GI tracts. The spores need tissue with the proper anaerobic conditions to germinate; the ideal media are wounds with tissue necrosis.

  12. Under anaerobic conditions, the spores of C tetani germinate and produce 2 toxins: tetanolysin (a hemolysin with no recognized pathologic activity) and tetanospasmin, which is responsible for tetanus. The action of the latter helps explain the clinical manifestations of the disease.

  13. Tetanospasmin is synthesized as a single 151-kd chain and is cleaved to generate toxins with 2 chains joined by a single disulfide bond. The heavy chain (100 kd) is responsible for specific binding to neuronal cells and for protein transport. The light chain (50 kd) blocks the release of neurotransmitters.

  14. INTERNATIONALLY Reports show up to 1 million cases annually, mostly in underdeveloped countries. Neonatal tetanus accounts for 50% of the tetanus-related deaths in developing countries.

  15. Tetanus results in approximately 5 deaths per year in the United States. • Mortality in the United States resulting from generalized tetanus is 30% overall, 52% in patients older than 60 years, and 13% in patients younger than 60 years. • Residual neurologic sequelae are uncommon. Mortality usually results from autonomic dysfunction (ie, extremes in blood pressure, dysrhythmia, cardiac arrest).

  16. Mortality/Morbidity

  17. Age: In the United States, 59% of cases and 75% of deaths occur in persons aged 60 years or older.

  18. History

  19. Most cases in the United States occur in patients with a history of only partial immunization. Persons who inject drugs also constitute a high-risk group. • Symptoms usually begin 8 days after the infection, but onset may range from 3 days to 3 weeks. • Patients may report a sore throat with dysphagia (early sign).

  20. Localized tetanus causes muscle rigidity at the site of spore inoculation. • The initial manifestation may be local tetanus, in which the rigidity affects only 1 limb or area of the body where the clostridium-containing wound is located.

  21. Physical signs

  22. : Common first signs of tetanus are headache and muscular stiffness in the jaw (ie, lockjaw), followed by neck stiffness, difficulty swallowing, rigidity of abdominal muscles, spasms, and sweating.

  23. Patients often are afebrile. • Severe tetanus results in opisthotonos, flexion of the arms, extension of the legs, periods of apnea resulting from spasm of the intercostal muscles and diaphragm, and rigidity of the abdominal wall. • Late in the disease, autonomic dysfunction develops, with hypertension and tachycardia alternating with hypotension and bradycardia.

  24. Causes • The source of infection usually is a wound (~65%), which often is minor (eg, wood or metal splinters, thorns). Chronic skin ulcers are the source in approximately 5% of cases, and in the remainder of cases, no obvious source is identified

  25. The US Centers for Disease Control and Prevention (CDC) statistics from 1982-84 are as follows: • Infected lacerations or puncture wounds (69%) • Infected chronic wounds and abscesses (20%) • Exposure via intravenous drug abuse (3%) • Neonates (1%) • Other or no identifiable cause (7%)

  26. Possible causes not usually associated with tetanus • Otitis media • Burns • Intranasal foreign bodies • Corneal abrasions • Foreign bodies • Dental or surgical procedures

  27. Other Problems to be Considered: • Strychnine poisoningDental infectionsLocal infectionsHysteriaNeoplasmsEncephalitis

  28. LAB STUDIES

  29. Laboratory findings are not diagnostically valuable, but they may help exclude strychnine poisoning. • Blood counts and blood chemical findings are unremarkable. • A lumbar puncture is not necessary. Cerebrospinal fluid (CSF) is normal, except for an increased opening pressure, especially during spasms.

  30. Blood counts and blood chemical findings are unremarkable. • Serum antitoxin levels more than 0.01 U/mL usually are protective, making the diagnosis less likely.

  31. Imaging Studies: • Imaging studies of the head and spine reveal no abnormalities

  32. MEDICAL CARE

  33. Passive immunization with human tetanus immune globulin (TIG) shortens the course of tetanus and may lessen its severity. A dose of 500 U appears as effective as larger doses. • Supportive therapy may include ventilatory support and pharmacologic agents that treat reflex muscle spasms, rigidity, and tetanic seizures.

  34. Benzodiazepines have emerged as the mainstay of symptomatic therapy for tetanus. To prevent spasms that last longer than 5-10 seconds, administer diazepam intravenously, typically 10-40 mg every 1-8 hours. Vecuronium (by continuous infusion) or pancuronium (by intermittent injection) are adequate alternatives.

  35. Penicillin G, which has been used widely for years, is not the drug of choice. Metronidazole (eg, 0.5 g q6h) has comparable or better antimicrobial activity, and penicillin is a known antagonist of GABA, as is tetanus toxin. • Physicians also use sedative hypnotics, narcotics, inhalational anesthetics, neuromuscular blocking agents, and centrally acting muscle relaxants (eg, intrathecal baclofen).

  36. To date, reports indicate that more than 26 adults with severe tetanus have been treated with intrathecal baclofen. A representative dose of the continuous infusion is 1750 mcg per day. Case reports and small case series outline the efficacy of intrathecal baclofen in controlling muscle rigidity. The effects of baclofen begin within 1-2 hours and persist 12-48 hours. The half-life elimination of baclofen in CSF ranges from 0.9-5 hours.

  37. After lumbar intrathecal administration, the cervical-to-lumbar concentration ratio is 1:4. The major adverse effect of baclofen is a depressed level of consciousness (LOC) and respiratory compromise.

  38. Drug Category: Antimicrobials -- Therapy must cover all likely pathogens in the context of the clinical setting. Drug Name • Metronidazole (Flagyl) -- A study comparing oral metronidazole to intramuscular penicillin showed better survival, shorter hospitalization, and less progression of disease in the metronidazole group (dosed at 0.5 g q6h or 1 g q12h IV for 7-10 d). • Adult Dose • 0.5 g PO q6h for 7-10 d; alternatively, 1 g IV q12h for 7-10 d • q12h

  39. Pediatric Dose • 15-30 mg/kg/d PO divided bid/tid for 7 d, or 40 mg/kg once; not to exceed 2 g/dWeight-based dosing:Body weight <2000 g0-7 days: 7.5 mg PO/IV q24h8-28 days: 7.5 mg PO/IV q12hBody weight >2000 g0-7 days: 7.5 mg PO/IV q12h8-28 days: 15 mg PO/IV

  40. Doxycycline (Vibramycin) -- Inhibits protein synthesis and thus bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria. • Adult Dose • 100 mg IV q12h • Pediatric Dose • <8 years: Not recommended>8 years: 2-4 mg/kg/d IV q12h

  41. Further Inpatient Care: • Administer a second dose (usually the first is upon discharge from the hospital) of tetanus-diphtheria vaccine or diphtheria-pertussis-tetanus vaccine, and administer a third dose 4 weeks after the second dose.

  42. Deterrence/Prevention: • An effective vaccine termed tetanus toxoid has been available for many years. Administer tetanus toxoid in combination with diphtheria toxoid and pertussis vaccine (DTP) to children at ages 2 months, 4 months, 6 months, 12-15 months, and between 4-6 years. Administer tetanus and diphtheria (TD) toxoid to children aged 7 years or older.

  43. Recommend a tetanus booster shot every 10 years. • Administer tetanus and diphtheria (TD) toxoid to children aged 7 years or older. Recommend a tetanus booster shot every 10 years.

  44. The tetanus vaccine and the combination TD vaccine are very safe and effective; however, infrequent adverse effects include a slight fever and soreness, redness, or swelling at the injection site. • Patients cannot contract tetanus from the vaccine. • Candidates for TD vaccine include all adults who have not had a booster shot in the last 10 years, adults who have recovered from tetanus (ie, lockjaw) disease, and adults who have never received immunization against tetanus.

  45. Physicians must thoroughly clean wounds and remove dead or devitalized tissue. If the patient has not had a tetanus toxoid booster in the previous 10 years, administer a single booster injection on the day of injury. For severe wounds, consider administering a booster if more than 5 years have elapsed since the last dose. • Consider administering TIG, antitoxin, or antibiotics if the patient has not been previously immunized with a series of at least 3 doses of toxoid.

  46. Given the risk of tetanus after bites of all kinds, administer TIG and tetanus toxoid to patients who have had 2 or fewer primary immunizations. Physicians may administer tetanus toxoid alone to patients who have completed a primary immunization series but who have not received a booster in more than 5 years. • Almost 70% of a random sample of US residents aged 6 years or older have protective levels of tetanus antibodies. By age 60-69 years, the prevalence of protective antibodies is less than 50%, and by age 70 years, the prevalence is approximately 30%.

  47. Complications: • Complications include spasm of the vocal cords and/or spasms of the respiratory muscles that cause interference with breathing. Other complications include fractures of the spine or long bones, hypertension, abnormal heartbeats, coma, generalized infection, clotting in the blood vessels of the lung, pneumonia, and death.

  48. Patients experience severe pain during each spasm. During the spasm, the upper airway can be obstructed, or the diaphragm may participate in the general muscular contraction. • Sympathetic overactivity is the major cause of tetanus-related death in the intensive care unit. Sympathetic hyperactivity usually is treated with labetalol at 0.25-1 mg per minute as needed for blood pressure control or with morphine at 0.5-1 mg/kg per hour by continuous infus

  49. Neonatal tetanus follows infection of the umbilical stump, most commonly resulting from a failed aseptic technique in a mother who is inadequately immunized. The mortality rate of neonatal tetanus exceeds 90%, and developmental delays are common among survivors

  50. Prognosis: • Current statistics indicate that the mortality rate in mild and moderate tetanus is approximately 6%; for severe tetanus, the mortality rate may be as high as 60%. • CDC reports from 1982-90 show that the overall case-fatality rate in the United States is 21-31%

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