Tetanus

From Anvita Health Wiki

Contents 1 Etiology 2 Epidemiology 3 Pathology 4 Clinical-manifestations 5 Laboratory 6 Complications 7 Differential-diagnosis 8 Management 9 More General Terms 10 Additional Terms 11 References

Etiology

• most cases follow acute injury

• puncture wound
• laceration
• abrasion

• complications of chronic conditions

• skin ulcers
• abscesses
• gangrene

• other conditions

• burns
• frost bite
• middle ear infection
• surgery
• abortion
• childbirth
• drug abuse 'skin popping'

Epidemiology

• occurs largely in inadequately immunized individuals
• most common in warm climates & during summer months
• occurs more commonly in males
• in countries without immunization program, tetanus occurs largely in infants & young children
• in USA, 60 cases of tetanus reported to CDC 1991-94; 37 cases in 2001 [3]

Pathology

• contamination of wounds with spores of C. tetani is probably common
• germination & toxin production takes place in wound with low redox potential
• C tetani does not evoke inflammation
• tetanus toxin released by autolysis of vegetative organisms binds to peripheral motor neuron terminals, is internalized, retrogradely transported to nerve cell bodies in spinal cord & brain stem, then migrates across synapse to presynaptic terminals of inhibitory neurons
• tetanus toxin inhibits release of glycine & GABA from inhibitory neurons thus increasing the resting firing rate of alpha motor neurons
• loss of inhibition may also affect preganglionic sympathetic neurons in the lateral gray matter of the spinal cord, resulting in increased adrenergic tone
• tetanus toxin may also inhibit neurotransmitter release at neuromuscular junction
• recovery requires sprouting of new nerve terminals
• in localized disease, only the nerves supplying the affected muscle are involved
• in generalized disease, the toxin enters the lymphatics & blood stream & is spread to distant nerve terminals
• tetanus toxin does not cross the blood brain barrier

Clinical-manifestations

• onset 3-14 days after injury ( median 7 days)
• increased tone in masseter muscle ( trismus, lockjaw)
• dysphagia
• neck, shoulder, & back pain
• rigid abdomen
• stiff proximal muscles
• hands & feet relatively spared
• sustained contraction of the face
• sustained contraction of the back muscles ( opisthotonos)
• painful generalized muscle contractions
• respiratory failure

• laryngospasm
• apnea

• fever
• autonomic dysfunction

• hypertension
• tachycardia
• cardiac arrhythmias
• hyperpyrexia
• diaphoresis
• peripheral vasoconstriction

Laboratory

• wound cultures

• Clostridium tetani may be isolated from wounds of patients without tetanus
• Clostridium tetani may not be recovered from wounds of patients with tetanus

• leukocytosis
• cerebrospinal fluid is normal
• electromyogram

Complications

• pneumonia
• muscle rupture
• rhabdomyolysis
• thrombophlebitis
• pulmonary embolus
• decubitus ulcer

Differential-diagnosis

• alveolar abscess ( trismus)
• strychnine poisoning
• dystonic drug reactions

• phenothiazines
• metoclopramide

• hypercalcemic tetany
• meningitis
• encephalitis
• rabies
• intra-abdominal disorder (rigid abdomen)

Management

• general measures

• quiet room in intensive care unit ( ICU)
• cardiopulmonary monitoring
• wound exploration, cleaning, debriding

• prophylaxis

• tetanus toxoid ( dT) if patient is > 6 years of age

• immunization status unknown
• < 3 immunizations with tetanus toxoid
• no tetanus immunization in last 10 years
• contaminated wound & no tetanus immunization in last 5 years

• human tetanus immune globulin ( TIG)

• 250 units IM

• antibiotics

• penicillin G 10-12 million units QD for 10 days
• clindamycin or erythromycin if allergic to penicillin

• control of muscle spasms

• benzodiazepines (1st line)

• diazepam
• lorazepam

• barbiturates (2nd line)
• chlorpromazine (2nd line)
• propofol ( Diprivan)
• dantrolene
• baclofen

• airway protection

• intubation
• tracheostomy

• autonomic dysfunction

• optimal therapy not defined
• suggested agents

• labetalol (has been associated with sudden death)
• esmolol (may be associated with unopposed alpha activity)
• clonidine
• morphine
• magnesium sulfate

More General Terms

• bacterial infection

Additional Terms

• Clostridium tetani
• diphtheria & tetanus toxoid (dT, Td)
• tetanus immune globulin (Hyper-Tet, TIG, tetanus antitoxin)
• tetanus toxin (TeTx); tetanospasmin
• tetanus toxoid
• tetany

References

1. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 633-34
2. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 901-904
3. Journal Watch 24(12):99, 2004 Kruszon-Moran DM, McQuillan GM, Chu SY. Tetanus and diphtheria immunity among females in the United States: are recommendations being followed? Am J Obstet Gynecol. 2004 Apr;190(4):1070-6. PMID: [1]
4. Tetanus: NIH Institute and Center Resources [2]

tetanus