Review Question - QID 217695

This patient presenting with progressive fever, chills, abdominal pain, pulse-temperature dissociation (inappropriately normal pulse during high fever), and an erythematous macular rash on his trunk most likely has typhoid fever. Typhoid fever is a bacterial infection that is transmitted via the fecal-oral route.

The causative agent of typhoid fever is Salmonella enterica, serotype typhi, which is a gram-negative, facultatively anaerobic bacillus with O, H, and Vi antigens. Ingestion of S. enterica results in systemic dissemination either lymphatically or hematogenously, as the bacterium can survive exposure to gastric acid. S. enterica is then excreted via the stool, and ingestion of fecally-contaminated food or water results in human-to-human transmission. Typhoid fever classically presents with a rising fever and bacteremia during the first week of infection, abdominal pain and salmon-colored macules on the trunk/abdomen during the second week, and intestinal bleeding and hepatosplenomegaly during the third week. As the disease progresses, patients can develop bacterial sepsis. The gold standard diagnostic test is blood and stool culture. However, the diagnosis can be made clinically in resource-constrained settings where it is treated empirically due to the risk for progression and sepsis. Treatment is typically with fluoroquinolones; however, patients with signs of systemic toxicity may require ceftriaxone or a carbapenem.

Buckle et al. reviewed the global burden of typhoid fever. The authors highlighted the significant health burden of typhoid fever in low- and middle-income countries, with over 20 million adjusted typhoid fever episodes occurring globally.

Incorrect Answers:
Answer 1: Animal bites, especially from dogs, can transmit Pasteurella infections. These present as cellulitis or an abscess at the site of a dog bite. If left untreated, the infection can become invasive and the patient can become septic with high fevers, hypotension, and/or tachycardia. An abdominal rash would be atypical; no obvious bite wound was found in this patient.

Answer 3: An insect vector, such as the Anopheles mosquito, can transmit malaria, caused by Plasmodium species. Malaria is endemic in Southeast Asia and presents with cyclic fevers, chills, myalgias, fatigue, diaphoresis, diarrhea, abdominal pain, anemia, and splenomegaly. A rash would be atypical, making typhoid fever more likely in this patient.

Answers 4 & 5: Mucous membrane contact and respiratory droplets are mechanisms of transmission for respiratory viruses such as influenza. Influenza infection presents with fever, cough, sore throat, fatigue, and/or myalgias. Respiratory symptoms would be expected and a rash would be atypical. Roseola can also present with a blanching, macular erythematous rash and high fever, but the rash characteristically starts in the face/neck and progresses down the body. This patient’s travel history to an endemic area and characteristic abdominal rash is more suggestive of typhoid fever.

Bullet Summary:
Typhoid fever is caused by Salmonella enterica, serotype typhi, which is spread via the fecal-oral route.