infectious diseases
Shigellosis
Symptoms and Signs of Shigellosis
The incubation period forShigellais 1 to 4 days. The most common presentation, watery diarrhea, is indistinguishable from other bacterial, viral, and protozoan infections that induce secretory activity of intestinal epithelial cells. Fever may be present. Inadults,initial symptoms of shigellosis may be Episodes of gripping abdominal pain Urgency to defecate (tenesmus) Passage of formed feces that temporarily relieves the pain These episodes recur with increasing severity and frequency. Diarrhea becomes marked, with soft or liquid stools containing mucus, pus, and often blood. Rectal prolapse and consequent fecal incontinence may result from severe tenesmus. However, adults may present without fever, with nonbloody and nonmucoid diarrhea, and with little or no tenesmus. The disease usually resolves spontaneously in adults—mild cases in 4 to 8 days, severe cases in 3 to 6 weeks. Significant dehydration and electrolyte loss with circulatory collapse and death occur mainly in debilitated adults and children<2 years. Rarely, shigellosis starts suddenly with rice-water or serous (occasionally bloody) stools. The patient may vomit and rapidly become dehydrated. Infection may manifest as delirium, seizures, and coma but with little or no diarrhea. Death may occur in 12 to 24 hours. Inyoung children,onset is sudden, with fever, irritability or drowsiness, anorexia, nausea or vomiting, diarrhea, abdominal pain and distention, and tenesmus. Within 3 days, blood, pus, and mucus appear in the stools. The number of stools may increase to≥20/day, and weight loss and dehydration become severe. If untreated, children may die in the first 12 days. If children survive, acute symptoms subside by the 2nd week. Thrombotic Thrombocytopenic Purpura (TTP) (HUS) may complicate shigellosis due to Bacteremia may occur, especially in children under 5 years of age and in adults over 65 with underlying disease. Severe mucosal ulcerations may cause significant acute blood loss. Patients (particularly those with the human leukocyte antigen [HLA]-B27 genotype) may develop Reactive Arthritis (arthritis, conjunctivitis, urethritis) after shigellosis (and other enteritides). Other complications are uncommon but include seizures in children, myocarditis, and, rarely, intestinal perforation. Infection does not become chronic and is not an etiologic factor in ulcerative colitis. 