Pertussis

2015-02-14T00:59:42Z

Kavita: Created Pertussis page

== Pertussis ==
Kavita Joshi, MD and Alex Koyfman, MD
Department of Emergency Medicine, UT Southwestern Medical Center / Parkland Memorial Hospital, Dallas, Texas, USA

=== Background ===

*“Whooping cough”. The “whoop” is caused on inspiration between coughs.
*Most common in kids < 1yo, because they haven’t completed the whole vaccine series, AND adults, who have waning immunity.
*One of the only vaccine preventable diseases that has increased in prevalence recently
*Up to 20% of adults with cough >2 weeks have serologic evidence of pertussis
*Bordetella genus (gram negative bacterium)

=== Pathophysiology ===

*Transmitted by aerosolized droplets, extremely contagious
*Infects ciliated respiratory cells (rarely goes hematogenous), creates toxins damaging respiratory epithelium.

=== Presentation ===
*Incubation period several days-3 weeks
*3 stages:
**Catarrhal phase: lasts 1-2 wks. Clinically indistinguishable from other URIs; dry cough starts near the end. Greatest infectivity phase.
**Paroxysmal phase: lasts 2-4 weeks => fever improves, cough worsens. Staccato cough + whoop (present in 1/3 kids), post-tussive emesis (often in adolescents, adults). Infants can present as apnea. Pts often appear well between coughing episodes.
***Petechiae, epistaxis, pneumothorax, and/or subconjunctival hemorrhage may occur due to high intrathoracic pressures during coughing.
**Convalescent phase: lasts weeks-months; residual cough

=== Sequelae ===
*PNA superinfections, rib fractures, PTX, aspiration of gastric contents, CNS complications

=== Diagnosis ===
*WBC elevated in infants (20-100), adults may be WNL
*CXR with peribronchial thickening, atelectasis, and/or consolidation
*Nasopharyngeal swab can identify it in 3-7 days; often neg in adults.
*Cough for >2 weeks, post tussive emesis, feeling well otherwise, treat them empirically. Especially if infant or pregnant people at home.

=== Management ===
*Supportive. Suction in infants, hydration. Neonates with apnea should be admitted to the ICU.
*Antibiotics: don’t help much with severity or duration. Decreases infectivity.
*Peds: Azithromycin 10mg/kg (max 500mg/day) Qdaily x3 days
*Adults: Azithromycin 500mg Qdaily for 3 days OR clarithromycin 500mg BID x7 days
*Pregnant: Erythromycin 500mg QID x7 days
*Pts are considered infectious for 3 wks after start of paroxysmal phase, or after 5 days of abx (droplet isolation).

=== Post-Exposure Prophylaxis ===
*Prophylaxis for all household exposures of known Pertussis
*High risk people exposed to pertussis: infants, women in 3rd trimester of pregnancy, immunocompromised, severe asthma, people with close contact to infants <1year, people who work in neonatal ICUs / maternity wards.

=== Vaccination ===
*Tdap for adults, regardless of recent tetanus shot.
*DTaP for infants getting their first immunization.
*Vaccinate women during each pregnancy
*Immunity wanes 8 y after immunization. Often elderly will get the disease and transmit it to young unimmunized infants.

====References====
*Herbert, Mel; Takhar, Sukhjit. “Pertussis Update 2013”. Emergency Medicine Reviews and Perspectives. May 2013
*Marx et al. “Pertussis”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1696-1699.
*“Pertussis Treatment Options”. British Medical Journal Best Practice. http://bestpractice.bmj.com/best-practice/monograph/682/treatment.html. Sept 3, 2014.
*“ Pertussis Postexposure Antimicrobial Prophylaxis”. Centers for Disease Control and Prevention. http://www.cdc.gov/pertussis/outbreaks/pep.html. Aug 28, 2013
*“Pertussis: Clinical Features”. Centers for Disease Control and Prevention. http://www.cdc.gov/pertussis/clinical/features.html. Sept 4, 2014
*http://www.ncbi.nlm.nih.gov/pubmed/25318108
*http://www.ncbi.nlm.nih.gov/pubmed/23287746

Cholera

2014-10-01T01:37:37Z

Kavita: Created page for Cholera

==Background==
* Endemic to Asia, Africa, and Central and South America
* Occasionally seen on the Gulf Coast of US, due to inadequately cooked seafood.
==Pathophysiology==
* Usually Vibrio cholera, which produces an enterotoxin which causes a secretory diarrhea
==Natural History==
* Transmission via ingestion of contaminated food or water, usually undercooked seafood
* Incubation period between hours to 5 days, depending on size of inoculum (usually 1-2 days)
* Most people are asymptomatic, and simply have bacteria in their feces for 7-14 days
* Diarrhea is most severe in days 1-2, usually resolves in 7 days
==Clinical Features==
* Classic “rice water” diarrhea with fishy odor; usually painless
* Fluid losses can be significant, up to 1L/hr, leading to severe fluid and electrolyte depletion. However, most cases are mild.
* Occasionally seen: sudden watery vomiting, borborygmi, abdominal cramping.
Later manifestations:
* Fluid loss may lead to: sunken eyes, dry mouth, cold clammy skin, decreased skin turgor, or wrinkled hands and feet (also known as “washer woman’s hands”)
* Acidosis from loss of bicarbonate; muscle cramps from loss of K, Ca
==Differential Diagnosis of Watery Diarrhea==
* Enterotoxigenic E. coli (most common cause of watery diarrhea)
* Norovirus (often has prominent vomiting)
* Campylobacter
* Non-typhoidal Salmonella
* Enteroaggregative E. coli (EAEC)
* Enterotoxigenic Bacteroides fragilis
==Workup==
* Diagnosis largely clinical presentation + epidemiological risk factors
* Fecal smears will NOT show leukocytes or erythrocytes.
* Diagnosis can be confirmed by stool cultures on TCBS medium (tell the lab cholera is suspected, so appropriate medium is used).
==Management==
* Aggressive volume repletion. Usually can be given orally if mild/moderate volume depletion; give rehydration solution to replete electrolyte loss.
* Oral rehydration solution includes in 1L of water: 2.6g NaCl, 2.9g Trisodium citrate, 1.5 g KCl, and 13.5 g glucose.
:*If severe dehydration, bolus with 100 ml/kg over 3 hrs. LR is solution of choice. May require more than 350 ml/kg in first 24 hours.
* Antibiotic treatment decreases severity and duration of disease. Antibiotic resistance patterns are changing constantly. Most recommended currently is azithromycin 20mg/kg single dose.
:*Alternatives: ciprofloxacin 1g single dose; doxycycline 300mg single dose; TMP-SMX double strength BID for 3 days; erythromycin 500 QID for 3 days.
* Give children Zinc and Vitamin A.

==Sources==
<references/>
* Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.
* Sack DA, et al. Cholera. Lancet 2004; 363:223.
* LaRocque R and Harris J. “Overview of Cholera”, UpToDate.com
* LaRocque R and Pietroni M. “Approach to the Adult with Acute Diarrhea in Developing Countries”. UpToDate.com
* World Health Organization. Cholera Fact Sheet. Feb 2014
* http://www.ncbi.nlm.nih.gov/pubmed/24481887
* http://www.ncbi.nlm.nih.gov/pubmed/20372681

====Authors====
Kavita Joshi, MD and Alex Koyfman MD
<br />
Department of Emergency Medicine, UT Southwestern Medical Center / Parkland Memorial Hospital, Dallas, Texas, USA

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Pertussis

Cholera