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The Gorgas Courses in Tropical Medicine Heersink School of Medicine

The Gorgas Courses in Tropical Medicine

University of Alabama at Birmingham

2002 Case #3

 Universidad Peruana Cayetano Heredia
(Links to Other 2002 Cases are at bottom of this page)
The following case was seen in the Emergency Room at Cayetano Heredia National Hospital by Gorgas Course participants.
Image for 02/15/02History: 52 yo with minor puncture wound of the foot eight days earlier.  4 days prior to admission he noted the onset of muscular back pain.  1 day later onset of painful spasm in the muscles of mastication.  2 days prior to admission, onset of periodic episodes of very painful generalized contractions affecting the lower back, the chest wall, and the masseter muscles.  No suspicious dietary ingestions, no animal bites, and no exposure to anyone that was ill.

Epidemiology: Lifelong farmer from a rural area 2 hours from Lima.

Physical Examination: Afebrile.  BP 120/70, HR 80.  No adenopathy or organomegaly.  Patient conscious and alert.  Facial expression, as shown in digital image on web page, exaggerated during periods of spasm.  All muscle groups spastic, sensory examination grossly normal.  Lower back arched, with examiner able to easily slide hand along bed under patient without touching the back.

Labs/X-ray: Hematocrit 44.  WBC 8.8, N differential.  Normal arterial blood gases and CXR.  Urinalysis, renal function normal.
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University of Alabama at Birmingham

2002 Case #3
Diagnosis and Discussion

 Universidad Peruana Cayetano Heredia
(Links to Other 2002 Cases are at bottom of this page)
Diagnosis: Tetanus, generalized form.
Discussion: Generalized tetanus is a purely clinical diagnosis with highly characteristic features and the diagnosis is usually made within a few minutes of arrival at a medical facility.  In general, disease begins with trismus or lockjaw, which are spasms of the masseter muscles, although, as in our patient, initial symptoms may occur in other muscle groups.  After a variable period the symptoms progress to generalized muscular rigidity, on which is superimposed increasingly severe generalized reflex muscular spasms manifested by the characteristic sardonic smile (risus sardonicus), opisthotonos (arched back), and spasm of respiratory muscles and larynx.  In severe cases there are prolonged spasms occurring less than 1 hour apart, and in very severe cases there is autonomic hyperactivity with sweating, salivation, arrythmias, hyper- or hypo-tension, hyperthermia, etc.  Some aspects of generalized disease can be mimicked by hypocalcemic tetany, phenothiazine induced dystonia, epilepsy, rabies, strychnine poisoning, or narcotic withdrawal, but the history of wound (not always elicited), epidemiology, and clinical course of tetanus usually lead to little confusion.  Mild localized tetanus in which trismus does not progress to generalized disease with reflex spasms is rare.  In the initial phase, the trismus itself has a broader differential diagnosis including dipththeria, partotitis, retropharyngeal abscess, and traumatic injury.

Disease is caused by a toxin, tetanospasmin, released by the Clostridium tetani, which infect the wound.  Spread of toxin is both retrograde through the affected axons as well as via blood to nerve endings in other parts of the body.  Masseters are usually affected first due to their short axons.  The action is pre-synaptic, irreversible, and blocks inhibitory neurotransmitter action leading to muscle spasm.  Poor prognostic indicators include short incubation period (<7 days="" from="" time="" of="" the="" wound="" to="" onset="" symptoms="" short="" period="" 48="" hours="" first="" reflex="" spasm="" and="" high="" risk="" portal="" entry="" compound="" fracture="" gynecologic="" postoperative="" burns="" p=""> Management is complex and must be done in a well-equipped Intensive Care Unit (ICU).  Non-ICU care is associated with almost universal mortality.  General principles are listed here, but detailed written dosing protocols must be available and used for most interventions.

 

  1. Airway - in generalized tetanus, immediate endotracheal intubation to protect against laryngeal spasm is indicated.  For those with poor prognostic signs, where even survivors will require weeks of intensive care while synapses regenerate, immediate or early tracheostomy is advised.
  2. Relaxation-Sedation - must be titrated to eliminate reflex spasm.  Large amounts of diazepam, up to 20 mg/kg/day by IV bolus need to be used.  Our patient received 100 mg of diazepam by IV push in the first hour in the ER.  Patients are relatively refractory to the sedating and respiratory depressive effects of diazepam.  Chlorpromazine can be used to augment the effect of diazepam.  If this regimen does not control spasm, artificial ventilation and complete neuromuscular blockade with vecuronium as the drug of choice is indicated.
  3. Neutralize toxin - either human hyperimmune globulin (ideal) or equine anti-tetanus globulin (preceded by an intradermal test dose) should be given intramuscularly.  Some centers give a portion of the globulin intrathecally.  A primary series of tetanus toxoid should be initiated, as disease does not protect against future infection.
  4. Treat portal of entry - surgical debridement and antibiotics.  Penicillin is classically used but many now use metronidazole due to a single study implicating penicillin as an antagonist of the effects of the muscle relaxants.
  5. General care - includes usual ICU considerations but also intense avoidance of light and stimuli as these readily precipitate reflex spasm.
  6. Treat any sympathetic hyperactivity - labetalol or esmolol seems best for this; alternatively, the combination of morphine and clonidine can be used.

This patient had poor prognostic indicators on arrival (short incubation, short time of onset) and received equine anti-tetanus serum due to an inability to afford the very expensive human preparation.  He subsequently succumbed to ICU related complications.

 

 
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