To view this article in PDF form, click here.

Fever, nausea, and vomiting in a student from Thailand

A detailed history, with an emphasis on any recent travel, is especially important when you are evaluating a patient who presents with a fever without a clear cause.

Adam T. Lloyd, MHS, RPA-C; Dennis P. McKenna, MD, FACEP

Adam Lloyd practices as a physician assistant in the Department of Emergency Medicine, Albany Medical Center, Albany, New York. Dennis McKenna is associate professor of emergency medicine at Albany Medical College. The authors have indicated no relationships to disclose relating to the content of this article.

CASE

The patient is a 20-year-old woman who presented to the emergency department complaining of nausea and vomiting for the past 5 days. The patient reported a decrease in appetite, loose bowel movements, and mild generalized abdominal pain after vomiting. She also described a nonpruritic rash on her bilateral lower extremities and a tactile fever without chills. She denied chest pain, shortness of breath, cough, back pain, hematemesis, melena, myalgia, or arthralgia.

The patient had traveled from Thailand to America 5 days earlier. In Thailand, she lived with two roommates who were healthy and without recent illness. She also had two hamsters and a rabbit, which were not reported to be ill. The patient was in the United States to attend a study abroad program with a classmate. She denied any recent mosquito or insect bites or any exposure to birds or dead animals in Thailand.

The patient had no significant medical or surgical history and said she had not seen a physician in the past 10 years. She was not currently taking any medications and denied any drug allergies. She did not smoke or use recreational drugs but did occasionally drink alcohol.

Physical examination The patient was lying in bed and appeared to be in no acute distress. Her oral temperature was 101.7¼F. BP was 109/71 mm Hg, with a heart rate of 94 beats per minute and a respiration rate of 16 breaths per minute. Oxygen saturation was 98% on room air. The head was atraumatic and normocephalic. Pupils were equal, round, and reactive to light and accommodation, with no conjunctival injection. There was no nasal discharge, tonsillar exudates, or edema. The neck was supple and nontender. The cardiac examination revealed a regular rate and rhythm, with no murmurs. The lungs were clear to auscultation bilaterally, with equal expansion. The abdomen was soft with mid-epigastric and right upper quadrant (RUQ) tenderness and normal bowel sounds; there was no distension, rebound, or guarding and no hepatosplenomegaly or masses. The patient was alert and oriented 3 3, with cranial nerves II through XII intact. No focal or sensory deficits were noted. The skin examination showed petechiae bilaterally on the lower extremities but no edema or cyanosis.

Testing The CBC results were as follows: WBC count, 1,300/μL; hemoglobin, 15.2 g/dL; hematocrit, 43.7%; and platelet count, 45,000/μL. The differential showed 27% bands, 13% lymphocytes, 9% monocytes, and 4% atypical lymphocytes. Serum chemistry results were sodium, 141 mEq/L; potassium, 3.1 mEq/L; chloride, 97 mEq/L; bicarbonate, 27 mEq/L; serum urea nitrogen, 9 mg/dL; creatinine, 0.8 mg/dL; glucose, 102 mg/dL; ALT, 182 U/L; and AST, 206 U/L. The results of panels for hepatitis A, B, and C were negative. The urinalysis showed no abnormalities. Stool cultures and stool tests for ova and parasites were negative. A polymerase chain reaction (PCR) test for malaria was negative. The chest radiograph showed no acute cardiopulmonary disease. Ultrasound of the RUQ revealed no acute gallbladder disease.

A preliminary diagnosis of neutropenic fever was made. The epidemiology and infectious disease services were contacted because the patient had a fever of unknown origin and a significant recent travel history. The patient was admitted to the hospital on the infectious disease service for further evaluation and management.

Hospital course The patient was placed on contact precautions and in respiratory isolation. She was given a 1-L bolus of normal saline and started on maintenance fluids of 100 cc per hour. Initial medications included ibuprofen, 600 mg orally for fever; and promethazine, 12.5 mg IV for nausea. Piperacillin/tazobactam (Zosyn), erythromycin, and oseltamivir (Tamiflu) were given to cover for influenza and typical and atypical infections, including pneumonia caused by Streptoccoccus, Pseudomonas, Mycoplasma, and Chlamydia species and by Moraxella catarrhalis. Doxycycline and quinine (Qualaquin, Quinamm, Quiphile) were added to cover for malaria. The quinine was stopped when the PCR test for malaria was negative, but the doxycycline was continued to cover for Rocky Mountain spotted fever.

Two sets of blood cultures, a throat culture, and a urine culture were obtained, all before antibiotic treatment was initiated. A nasal swab test for influenza was also performed. Laboratory testing for hepatitis, cytomegalovirus, influenza (including avian influenza), malaria, and Legionella infection was done. The results of all these tests were negative.

The patient’s fever subsided after 1 day of hospitalization, and she clinically improved after 3 days. Her WBC count trended upward, and the neutropenia resolved. The platelet counts rose steadily to values greater than 100,000/μL. Her nausea and vomiting resolved, and she resumed having normal bowel movements. After a 5-day hospital stay, all laboratory data had normalized, the patient was asymptomatic, and she was discharged.

By the time of her discharge, we suspected that our patient—based on symptoms, travel history, physical and laboratory findings, and improvement with symptomatic treatment—had had dengue fever. This diagnosis was confirmed after discharge when we received the results of an enzyme-linked immunosorbent assay (ELISA) that was positive for IgM antibodies to dengue virus. The patient followed up with the infectious disease clinic 2 weeks after discharge; she had remained asymptomatic, and her hematology and chemistry panels had normalized.

DISCUSSION

Dengue fever is a viral infection most commonly found in warm weather climates. There are four dengue viruses, which are flaviviruses; because each can cause dengue fever in the same person, a person can become ill four times—but the person is immune to each serotype after infection.^1,2 The illness is widespread in Thailand, and there are 50 to 100 million reported cases worldwide every year.¹ However, only 100 to 200 cases are reported annually in the United States, most along the Mexican border or introduced by travelers.^1,2 The disease is carried by Aedes mosquitoes, especially Aedes aegypti as the principal vector (see Figure 1). This species of mosquito is seasonally abundant in some southern parts of the United States, including Texas, Arizona, New Mexico, Mississippi, Alabama, Georgia, and mid to south Florida.² The species has also been sporadically reported in parts of North Carolina, South Carolina, Tennessee, Arkansas, Maryland, and New Jersey.²

The dengue viruses have a short incubation period, and symptoms typically develop 3 to 14 days after exposure through the bite of an infected mosquito.² Patients usually experience an abrupt onset of high fever, frontal headache, retro-orbital pain, nausea, vomiting, myalgia, and rash.² The myalgia can be so severe that dengue fever has earned the nickname break bone fever. These acute symptoms generally last for about a week, after which weakness, malaise, and anorexia can persist for several weeks.²

When dengue fever is suspected, the clinician should be on the lookout for signs of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS).² These conditions will develop in some patients with dengue fever, and they can be severe and sometimes fatal. DHF manifests as fever begins to subside. The patient may exhibit restlessness or lethargy, show signs of circulatory failure, or demonstrate hemorrhagic signs such as petechiae or microscopic hematuria. Epistaxis, bleeding gums, hematemesis, and melena may also occur. Thrombocytopenia and hemoconcentration due to plasma leaking from the intravascular compartment may develop. The loss of intravascular volume—not hemorrhage—is what causes shock, and if DSS is not recognized and treated appropriately, death can result.² Several hundred thousand cases of DHF occur each year worldwide, and 5% to 10% of patients die.^1,2 Signs that DSS is approaching include severe abdominal pain, protracted vomiting, marked change in body temperature (from fever to hypothermia), and mental status changes.²

Confirmation of dengue fever is made either by isolating the virus or detecting specific antibodies on ELISA.² An acute-phase serum specimen collected within 5 days after the onset of fever is required for virus isolation. Alternatively, a convalescent-phase specimen obtained at least 6 days after symptoms began may be used for antibody testing. The CDC says that samples should be sent to the state health department or the CDC for testing.² The agency notes that because most antibody tests for anti-dengue antibodies are nonspecific among the flaviviruses and because commercial kits vary in sensitivity and specificity, results may require confirmation by a reference laboratory.²

Treatment of dengue fever includes fever control, IV fluids, and symptomatic relief.³ The CDC recommends the use of acetaminophen for fever and the avoidance of aspirin and NSAIDs, as these may aggravate any tendency for bleeding.² Patients must be closely monitored until clinical improvement occurs and the hematology panel returns to baseline.⁴

CONCLUSION

Patients who present with fever, myalgias, nausea, and vomiting may have any one of a number of diseases. The clinician may not be able to make a definitive diagnosis right away, and a number of tests may be necessary to narrow the differential. As this case illustrates, a detailed history, with an emphasis on recent travel, is very important in any patient who presents with a fever without a clear cause. Given the ease of international travel, PAs should be aware of diseases that originate in all regions of the world. Dengue fever is rare in the United States, but clinicians should know the epidemiology and typical manifestations if they hope to make the right diagnosis when a patient such as our young student from Thailand presents to their emergency department. JAAPA

REFERENCES

	1.	Fact sheet: Dengue and dengue hemorrhagic fever. Centers for Disease Control and Prevention Web site. http://www.cdc.gov/NCIDOD/DVBID/DENGUE/facts.htm. Reviewed November 10, 2003. Accessed March 21, 2008.
	2.	Dengue and dengue hemorrhagic fever: information for health care practitioners. Centers for Disease Control and Prevention Web site. http://www.cdc.gov/NCIDOD/DVBID/DENGUE/dengue-hcp.htm. Updated October 22, 2007. Accessed March 21, 2008.
	3.	VanRooyen MJ, Dey CC, Venugopal R. World travelers. In: Tintinalli JE, Kelen GD, Stapczynski JS, eds. Emergency Medicine: A Comprehensive Study Guide. 6th ed. New York, NY: McGraw-Hill; 2004:1253.
	4.	Shandera WX, Shelburne S. Infectious diseases: viral & rickettsial. In: Tierney LM Jr, McPhee SJ, Papadakis MA, eds. Current Medical Diagnosis & Treatment 2003. 42nd ed. New York, NY: Lange Medical Books/McGraw-Hill; 2003:1328-1329.