Dysentery resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:

Overview

Dysentery is described as blood with stools. It occurs due to inflammatory reaction causing damage to the intestinal tract. The patient also has a fever, abdominal cramping, discomfort, increased bowel movements, fecal urgency, and tenesmus. The underlying cause is mostly an infection due to bacteria. The main aim of the physician is to assess the severity of gastrointestinal symptoms, dehydration, and hypovolemia. In patients with severe symptoms, prompt investigations, and treatment should be carried out to reduce morbidity. This section provides a short and straight to the point overview of the dysentery in adults.

Causes

Life-threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated.

• Does not include any known cause

Common Causes

• Shigellosis
• Shiga toxin-producing E. coli (STEC) (eg, E. coli O157:H7) infection
• Amebic dysentery caused by Entamoeba histolytica
• Salmonella infection
• Campylobacter infection
• Enteric viruses (eg, cytomegalovirus [CMV] or adenovirus)
• Inflammatory bowel disease
• Ischemic colitis

Evaluation

Shown below is an algorithm summarizing the diagnosis of dysentery according to the American College of Gastroenterology guidelines.

Treatment

Shown below is an algorithm summarizing the treatment of dysentery according to the Infectious Diseases Society of America clinical practice guidelines.

Characterize the symptoms: Duration of diarrhea Frequency and consistency of stools Presence of mucus and blood in the stools

To evaluate cause ask the following questions: Food history Occupational exposure (e.g. daycare center, poultry farm) Exposure to animals (pets, poultry, zoo, turtles) Recent travel to endemic areas Medication history (use of proton pump inhibitor increase susceptibility to infection with Shigella)

Does the patient have any of the following clinical signs or history? Old age (more than 70 years) Presence of co-morbidities (advance heart disease, severe immunocompromised state) Fever (>101.3 degrees Fahrenheit) Presence of severe symptoms Need for hospitalization Signs of dehydration (dry mucous membranes, sunken eyes, decreased skin turgor, orthostatic hypotension, oliguria, dark-colored urine, and drowsiness ) abdominal tenderness on palpation, rebound tenderness, abdominal distention, and abdominal rigidity.

Yes

No

Perform the following stool tests: Bacterial culture for Salmonella, Shigella, and Campylobacter. Test for Shigella toxin and E. coli O157: H7 Test for fecal leukocytes and lactoferrin.

Does the patient have any of the following: Clinical signs suggestive of inflammatory bowel disease Symptoms present for more than a week despite conservative management The patient is a health care worker or food handler (which can be a potential health hazard)

Is the fecal leukocytes or lactoferrin test positive?

Yes

No

Yes

No

* Perform routine stool culture. Specific tests should be performed depending upon the patient’s history.

No need to perform Stool culture and additional tests.

Test for Entamoeba histolytica

Amebic dysentery highly unlikely. Look for other causative agents.

Characterize the symptoms of the patient: Presence of severe diarrhea along with systemic symptoms. Two or more clinical signs for dehydration (i.e. Sunken eyes, dry mucous membrane, reduced skin turgor, increased thirst ).

Yes

No

Fluid replacement therapy. Empirical antibiotics therapy. The drug of choice is fluoroquinolones (500mg Levofloxacin (oral) once daily for 3 days). If the symptoms do not improve in a few days, the patient should be switched to either azithromycin (oral) or cephalosporin. Bismuth sulphate and loperamide to relieve abdominal cramps and discomfort.

Oral fluid replacement therapy. Give ORS solution for every bowel movement. Approximately 2 liters of ORS solution is given to the patient. Antimicrobial therapy should be initiated on the basis of stool culture results. Bismuth sulphate and loperamide can be given to relieve abdominal symptoms. Reassess hydration status after every 6 hours.

Assess patient for symptoms of hypovolemia (i.e. altered mental status with lethargy and unconsciousness, weak pulses , and inability to drink)

Yes

No

Patient has severe hypovolemia. Give parenteral fluid replacement with 5 % dextrose or normal saline solution. Give rapid infusion initially and then slow infusion. The aim is to give 200 ml/kg in 24 hours with 100ml/kg in the first 4 hours of infusion. Reassess hemodynamic and hydration status of the patient after 6 hours.

Patient has mild hypovolemia. Give oral fluid replacement therapy. 2.2 to 4 liters of ORS is given in the first 4 hours. Reassess hemodynamic and hydration status of the patient after 6 hours.

Do's

• Important clues regarding the etiology of dysentery can be narrowed down while taking history. If the patient has dysentery more than 16 hours after having an outdoor food consider Enterotoxigenic E.coli. There is an increased risk of acquiring the ''Salmonella'' infection in individuals exposed to turtles and poultry. People working in daycare have an increased risk of infection with enteric viruses and ''Shigella''.
• Physicians can take a rectal swab in patients in whom stool samples cannot be obtained and immediate diagnosis is required. Though the rectal swab has less sensitivity than stool culture in identifying the causative agent.
• If the clinician is suspecting a particular bacteria, it should be mentioned while ordering the test. Certain bacteria require special culture media to grow and methods to be visualized. ''Campylobacter jejuni'' grows on the specific ‘CAMP’ agar plates at a particular temperature and environmental conditions. If infection with ''Yersinia'' is suspected, it should be specified as it is commonly overlooked.
• Physicians need to monitor the patients for the complications of the infection with certain bacteria. Bacteremia and reactive arthritis can occur with infection with non- typhoidal ''Salmonella'' and ''Shigella''. The hemolytic-uremic syndrome can occur due to E 0157:H7 or ''Shigella''. A neurological complication Guillain-Barré syndrome can occur with ''Campylobacter'' infection.

Don'ts

• The empirical antimicrobial treatment for dysentery does not include treatment for E. histolytica. Metronidazole (500mg thrice daily for 7 to days) should be administered to patients only when trophozoites or cysts are visualized under a microscope in the stool sample.
• A complete metabolic profile is not routinely performed in patients with dysentery. Serum electrolytes and glucose levels should only be measured in patients who present with complications (i.e. altered mental status, seizures, anuria, oliguria, and ileus ).