Clinical management of diphtheria in nelson.pptx

Diphtheria introduction diagnosis treatment complications and prevention

1. Diphtheria

2. Pathology Corynebacterium diphtheriae aerobic, nonencapsulated, non–spore-forming, mostly nonmotile, pleomorphic, gram-positive bacilli Spreads through airborne respiratory droplets, direct contact with respiratory secretions of symptomatic individuals, or exudate from infected skin lesions (Asymptomatic respiratory tract carriage is 3-5%) Causes Respiratory Tract Diphtheria Cutaneous diphtheria Paralysis of the palate and hypopharynx is an early local effect of diphtheria toxin. Toxin absorption can lead to systemic manifestations like kidney tubule necrosis , Thrombocytopenia , Cardiomyopathy , Demyelination of nerves

3. Pathology Usually remains in the superficial layers  inducing local inflammatory reaction  produce a potent polypeptide exotoxin  inhibits protein synthesis and causes local tissue necrosis and resultant local inflammatory response  Dense necrotic coagulum of organisms  Gray-brown, leather-like adherent pseudomembrane

4. Clinical presentation Incubation period of 2-4 days (range 1-10 days) Tonsils or pharynx (94%), nose and larynx the next 2 most common sites Sore throat Fever Dysphagia, hoarseness, malaise, or headache are uncommon Membrane formation, which can extend to involve the uvula (which may cause toxin-mediated paralysis), soft palate, posterior oropharynx, hypopharynx, or glottic areas Soft tissue edema and enlarged lymph nodes can cause a bull-neck appearance Significant risk for suffocation

5. Clinical presentation Classic cutaneous diphtheria is an indolent, nonprogressive infection characterized by a superficial, ecthyma -like, nonhealing ulcer with a gray -brown membrane. Pain
Tenderness
Erythema
Exudate Diagnosis : A portion of membrane should be removed and submitted for culture along with underlying exudate for culture and sensitivity
Selective medium (e.g., cystine -tellurite blood agar or Tinsdale agar)
Gram stain or specific fluorescent antibody is unreliable

6. Complications Toxic Cardiomyopathy 10–25% of patients with respiratory diphtheria and responsible for 50–60% of deaths Correlates directly with the extent and severity of exudative local oropharyngeal disease, as well as delay in administration of antitoxin Subtle signs of myocarditis , usually 2nd to 3rd week ( from 1st to 6th week) Tachycardia disproportionate to fever Prolonged P-R interval and changes in the ST-T wave on an electrocardiograph Dilated and hypertrophic cardiomyopathy detected by echocardiogram Single or progressive cardiac dysrhythmias Atrioventricular dissociation and ventricular tachycardia Heart failure and Elevation of the serum aspartate transaminase

7. Toxic Neuropathy Parallel the severity of primary infection and are multiphasic in onset.
Acutely or 2-3 wk , hypesthesia and local paralysis of the soft palate, weakness of the posterior pharyngeal, laryngeal, and facial nerves  nasal quality in the voice, difficulty in swallowing, and risk for aspiration
Rarely at 2-3 wk , Vasomotor center dysfunction 5 th wk , Cranial neuropathies, oculomotor and ciliary paralysis  strabismus, blurred vision, or difficulty with accommodation 10 days to 3 mo , Symmetric demyelinating polyneuropathy  motor deficits with diminished deep tendon reflexes Recovery from myocarditis and neuritis is often slow but usually complete

8. Treatment Specific antitoxin is the mainstay of therapy Administered on the basis of clinical diagnosis and efficacy diminishes with elapsed time Neutralizes only free toxin Single empirical dose of 20,000-100,000 units based on the degree of toxicity, site and size of the membrane, and duration of illness Skin testing must be performed and desensitize if positive Available intravenous immunoglobulin preparations contain low titers of antibodies  not recommended Antimicrobial therapy Halt toxin production, treat localized infection, and prevent transmission of the organism to contacts Susceptible to Penicillins, erythromycin, clindamycin, rifampin, and tetracyclines Only erythromycin or penicillin is recommended

9. Erythromycin (40-50 mg/kg/day divided every 6 hr by mouth [PO] or intravenously [IV]; maximum 2 g/day)
Aqueous crystalline Penicillin G (100,000-150,000 units/kg/day divided every 6 hr IV or intramuscularly [IM]), or Procaine Penicillin (300,000 units every 12 hr IM for those ≤10 kg in weight; 600,000 units every 12 hr IM for those >10 kg in weight) for 14 days Antibiotic therapy is not a substitute for antitoxin therapy Disease is eliminated if at least 2 successive cultures of specimens from the nose and throat (or skin) obtained 24 hr apart after completion of therapyh  negative Supportive treatment Droplet precautions
Contact precautions Bed rest usually for ≥2 wk Case fatality rate of almost 10% for respiratory tract diphtheria

10. Prevention All suspected diphtheria cases should be reported Asymptomatic Case Contacts: Closely monitored for illness for 7 days Cultures performed Antimicrobial prophylaxis is presumed effective and is administered regardless of immunization status Single injection of benzathine penicillin G or erythromycin Diphtheria toxoid vaccine, in age-appropriate form, is given to immunized individuals who have not received a booster dose within 5 yr Children who have not received their 4th dose or uncertain should be vaccinated Asymptomatic Carriers: Antimicrobial prophylaxis is given for 10-14 days An age-appropriate preparation of diphtheria toxoid is administered immediately if a booster has not been given within 1 yr Droplet precautions and contact precautions

11. Vaccines : It decreases local tissue spread, prevents toxic complications, diminishes transmission of the organism, and provides herd immunity when 70 to 80 % vaccinated The pediatric (6 mo to 6 yr) preparations (i.e., DTaP [diphtheria and tetanus toxoids with acellular pertussis vaccine], DT [diphtheria and tetanus toxoids vaccine]) contain 6.7-25.0 Lf( limit of flocculation ) units of diphtheria toxoid per 0.5 mL dose The adult preparation ( Td ; 10% of pediatric diphtheria toxoid dose, Tdap [diphtheria and tetanus toxoids with acellular pertussis vaccine]) contain no more than 2-2.5 Lf units of toxoid per 0.5 mL dose For children 6 wk to 6 yr of age Five 0.5 mL doses of diphtheria-containing (D) vaccine ( DTaP preferred) are given in the primary series, including doses at 2, 4, and 6 mo of age, and a 4th dose, an integral part of the primary series, at 15-18 mo. A booster dose is given at 4-6 yr of age (unless the 4th primary dose was administered at ≥4 yr) For persons ≥7 yr old not previously immunized Three 0.5 mL doses of lower-level diphtheria-containing (d) vaccine are given in a primary series of 2 doses at least 4 wk apart and a 3rd dose 6 mo after the 2nd dose. The 1st dose should be Tdap, and subsequent doses should be Td.

12. Only contraindication to tetanus and diphtheria toxoid is a history of neurologic or severe hypersensitivity reaction after a prior dose
For children <7 yr old in whom pertussis immunization is contraindicated, DT is used
Those whose immunization is begun with DTaP or DT before 1 yr of age should have a total of five 0.5 mL doses of diphtheria-containing (D) vaccines by 6 yr of age
Whose immunization is begun at around 1 yr old, the primary series is three 0.5 mL doses of diphtheria-containing (D) vaccine, with a booster given at 4-6 yr , unless the 3 rd dose was given after the 4 th birthday
A booster dose, consisting of the adult preparation of Tdap , is recommended at 11-12 yr of age
Adolescents 13-18 yr old who missed the Td or Tdap booster dose at 11-12 yr or in whom it has been ≥5 yr since the Td booster dose also should receive a single dose of Tdap if they have completed the DTP/ DTaP series.
There is no association of DT or Td with convulsions
Haemophilus influenzae type b ( Hib ), meningococcal, and pneumococcal conjugate vaccines containing diphtheria toxoid (PRP-D) or the variant of diphtheria toxin, CRM197 protein, are not substitutes for diphtheria toxoid immunization and do not affect reactogenicity