Bacterial Infections

Opportunistic Infections

Opportunistic infections are those caused by organisms that do not ordinarily harm healthy people but occur in people with impaired defenses (immuno-compromised hosts). Broadly, immuno-compromised hosts are categorized into three categories:

1. Primary immunodeficiency syndromes, mostly congenital.
2. Secondary immunodeficiency syndromes e.g. AIDS, haematological malignancies, splenectomy etc.
3. Therapeutic immunosuppression.

1. Infection in the Immuno-compromised Host. In: Oxford Textbook of Medicine, Weatherall DJ, Ledingham JGG, Warrell DA (eds), 1996, Oxford University Press, pp 1027-35.
2. Diagnosis and Treatment of Fungal infections. In: Harrison’s Principles of Internal Medicine, Braunwald E., Fauci AS, Kasper DL et al (eds), 15th Edition, 2001, McGraw Hill Company Inc., pp 1168-70.
3. Pneumocystis carini Infection. In: Harrison’s Principles of Internal Medicine, Braunwald E., Fauci AS, Kasper DL et al (eds), 15th Edition, 2001, McGraw Hill Company Inc., pp 1168-70.

Tetanus

An acute neurological disorder resulting from contamination of a wound (may be a trivial one) by an obligate anaerobic organism, C lostridium tetani.

Grade I or Mild – muscle rigidity with few or no spasms.
Grade II or Moderate – trismus, dysphagia, rigidity, and shortlasting spasms.
Grade III or Severe – frequent explosive spasms, autonomic dysfunction particularly sympathetic over-activity may be present.
Grade IV or very severe – features of grade III plus violent autonomic disturbances involving the CVS – severe hypo or hypertension.

• Other presentations include local, cephalic (cranial nerves) or neonatal tetanus (within 2 weeks of life).
• Complications include respiratory failure, respiratory infections, barometric trauma due to prolonged ventilator support, persistent hypotension, labile hypertension, cardiac arrhythmia, sepsis and sudden death.

Treatment

Nonpharmacological

Admit in a quiet room/ICU with minimum stimulation, cardiopulmonary monitoring, protection of airways/respiratory support (intubation / tracheostomy) with or without ventilation, cleaning/exploration/ debridement of wound. Maintain hydration and enteral/parenteral nutrition with high calorie and high protein diet.

Pharmacological

Grade I tetanus

1. As above.
2. Tab. Diazepam 5-20 mg 3 times a day in mild tetanus; slow IV infusion in moderate to severe tetanus. Not to exceed a dose of 80-100 mg in 24 hours.
   If spasms not controlled.
   Inj. Phenobarbitone 200 mg IM every 8-12 hours.
   Or
   Inj. Chlorpromazine 50 mg IM in adults 4 times a day.
   The ideal sedative and muscle relaxant schedule for each patient should be individualized. An objective guide to decrease in rigidity is relaxation of abdominal muscles.

Grade II

1. As above.
2. Tracheostomy.

Grade III and IV

1. As above.
2. Ventilator support.
3. Inj. Pancuronium 2-4 mg IV.
   Or
   Inj. Gallamine 20-40 mg IV.
4. In case of hypotension
   Inj. Dopamine/Dobutamine 10-40 mcg/kg/min infusion titrated to maintain systolic BP of 100 mm Hg.
   If bradyarrhythmias Inj. Atropine 0.6-1.2 mg IV.
   If hypertension (for details see section on hypertension)

In addition give following to all the patients
Inj. Crystalline penicillin 2 mega units 6 hourly IV for 10 days.
Or
Inj. Metronidazole 500 mg 8 hourly or 1 g 12 hourly.
(Other antibiotics may be required according to need of infected wound).
Inj. Human tetanus immunoglobulin (TIG) 3000-5000 units IV or IM.
Or
Inj. Equine antiserum, 10,000 units by slow IV Injection after sensitivity test (If human TIG is not available).
Antiserum should be given before local manipulation of the wound.
(CAUTION: Tetanus immunoglobulin does not produce natural immunity and a full course of immunization with tetanus toxoid should be administered once the patient has recovered).

References

1. Tetanus. In: Harrison’s Principles of Internal Medicine. Braunwald E., Fauci AS, Kasper DL et al (eds), 15th Edition, 2001, McGraw Hill Company Inc., pp. 918-20.
2. Tetanus. In:Oxford Textbook of Medicine, Weatherall DJ, Ledingham JGG, Warrell DA (eds), 1996, Oxford University Press, pp 624-30.

Typhoid (Enteric Fever)

1. Tab. Paracetamol 500-1000 mg 6 to 8 hourly to reduce headache and fever (for details see section on fever).
2. Tab. Ciprofloxacin 10 mg/kg in 2 divided doses, upto a maximum of 750 mg twice a day for 10-14 days (for 1 week after the fever subsides).
   Or
   Inj. Ciprofloxacin 200 mg IV twice a day (initial treatment in severely ill hospitalized patient).

   If no response after 5 days,
   Inj. Ceftriaxone 50-60 mg/kg per day IV or IM in 2 divided doses or as a single dose for 7-10 days (preferred in pregnant women patients, children or patients resistant to quinolones).
   Or
   Inj. Cefixime 20 mg/kg per day in 2 divided doses for 14 days.
   If there is no response after 5 days, alternative diagnosis should be considered.
   Report to the physician immediately if abdominal symptoms worsen or occurrence of bleeding per rectum or alteration in sensorium and shock (severe typhoid with high risk of fatality).

3. Severe typhoid with shock or patients with enteric encephalopathy should be hospitalized and treated as above plus Inj. Dexamethasone 3 mg/kg IV first dose followed by 1 mg/kg IV every 6 hourly for 8 doses.
   Chronic Carrier State (patients who continue to excrete bacilli in stool for more than 1 year).
   Tab. Ciprofloxacin 750 mg twice a day for 28 days.

Patient education

• Small frequent feeds should continue. Give plenty of oral fluids and compensate for increased fluid loss from the body due to high grade fever.
• Fever usually lasts 5-7 days even after starting effective treatment in most cases. Frequent change of therapy should therefore be avoided.
• The treatment should be completed till the patient has been afebrile for at least 7 days as incomplete treatment increases the risk of relapse and emergence of resistance.
• Three types of vaccines are available to prevent this disease. (see section on immunization for details).

References

Salmonellosis. In: Harrison’s Principles of Internal Medicine. Braunwald E, Fauci AS, Kasper DL et al (eds), 15th Edition, 2001, McGraw Hill Company Inc., pp 970-975.