Case Quiz: An Unusual Diagnosis in a Young Woman With Abdominal Pain
Author
David Vearrier, MD
Core Faculty, Division of Medical Toxicology, Department of Emergency Medicine Albert Einstein Healthcare Network
Philadelphia, Pennsylvania
Disclosure: David Vearrier, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Diagnostic Radiology
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewers
Richard S. Krause, MD
Senior Faculty
Department of Emergency Medicine
State University of New York at Buffalo School of Medicine
Buffalo, New York
Disclosure: Richard S. Krause, MD, has disclosed no relevant financial relationships.
Burke A. Cunha, MD
Professor of Medicine
State University of New York School of Medicine at Stony Brook
Chief, Infectious Disease Division
Winthrop-University Hospital Mineola, New York
Disclosure: Burke A. Cunha, MD, has disclosed no relevant financial relationships.
The 2001 anthrax attacks brought the specter of bioterrorism to the American public. Pictured is a letter addressed to Senate Majority Leader Tom Daschle containing anthrax spores that caused infection killing 2 post office employees. The 2001 anthrax attacks resulted in 22 cases of anthrax (18 confirmed and 4 suspected) causing 5 deaths and over $1 billion in economic costs. The attacks also resulted in increased funding for biological warfare research and public health preparedness. Image courtesy of Wikimedia Commons.
In order to prioritize public health preparedness efforts, the Centers for Disease Control and Prevention (CDC) categorizes potential biological agents into 1 of 3 categories. These categories represent highest priority agents (Category A), second highest priority agents (Category B), and emerging threats (Category C).
Anthrax is caused by Bacillus anthracis, a spore-forming gram-positive rod, and was traditionally an occupational disease associated with exposure to wool, animal products, and livestock. Endemic cases in the United States are rare. Anthrax causes 3 forms of disease -- cutaneous, inhalational, and gastrointestinal -- with the type of disease depending on the route of exposure. Cutaneous anthrax with a characteristic black eschar is shown. Cutaneous anthrax is acquired by inoculation with the bacteria or spore through damaged skin. This is the most benign form of anthrax. The mortality rate is 1% with antibiotic treatment.
The form of anthrax usually associated with bioterrorism is inhalational anthrax. Of the 22 cases of anthrax occurring with the postal attacks in 2001, a total of 11 were inhalational. The chest x-ray frequently features a widened mediastinum (shown). Inhalational anthrax has a high mortality rate with 95% of untreated patients and 45% of treated patients dying of the infection in the 2001 attacks. Early treatment is associated with a better outcome. Due to this high mortality rate, anthrax is considered a Class A agent by the CDC. Treatment: 2 drug regimens with ciprofloxacin (preferred) or doxycycline plus an agent with central nervous system penetration such as rifampin or ampicillin for 60 days are currently recommended.
Plague is caused by Yersinia pestis, a facultative anaerobic gram-negative rod. Plague is considered a Category A agent by the CDC. Reservoirs include numerous rodents with fleas acting as vectors. Three forms of plague exist: bubonic, pneumonic, and septicemic. Bubonic plague is the most common form, accounting for 80%-95% of cases worldwide. Following cutaneous inoculation, the bacteria travel to local lymph nodes and cause a "bubo," an infected, necrotic, inflamed lymph node (shown).
Pneumonic plague is the more likely form associated with bioterrorism. Inhalation of aerosolized Y pestis released from a biological weapon causes a rapidly progressive multilobar pneumonia. Bilateral infiltrates are common in pneumonic plague (shown). Treatment: streptomycin (gentamicin), doxycycline, or a quinolone is preferred for pneumonic and bubonic plague. Patients with plague meningitis should also receive chloramphenicol due to its excellent CNS penetration. Strict respiratory isolation is required in cases of confirmed or suspected pneumonic plague. Mortality is high and very early treatment is associated with a better outcome.
Septicemic plague may occur late in the course of either pneumonic or bubonic plague. Y pestis septicemia causes a disseminated intravascular coagulation with acral necrosis of the digits, nose, and penis (shown). In the 14th century a European epidemic of plague that killed between 30% and 60% of the population was termed the "Black Death," probably in reference to the acral necrosis and gangrene associated with the disease.
Smallpox is one of the few diseases to be completely eradicated, with the last natural case occurring in 1977. However, stocks of the virus are still kept within 2 government laboratories, the CDC in the United States and the Institute of Viral Preparations in Russia, leading to the possibility of future use of the virus in a bioterrorist attack. Smallpox is considered a Category A agent by the CDC due to high lethality (30% mortality rate) and ease of transmission. Following a febrile prodromal stage, the characteristic rash of smallpox includes centrifugally distributed lesions all in the same stage of development (as compared with chicken pox in which lesions are in different stages of development). The child pictured is on day 7 of the rash with lesions in the pustular stage. There is no specific treatment for smallpox but early vaccination may hinder spread of the disease and ameliorate the course of the illness if given during the incubation period.
Botulinum toxin has the distinction of being the most deadly known toxin with fatal inhalational doses on the order of 3 ng/kg. Due to its lethality, botulinum toxin has been weaponized by several countries. The mechanism of action is to prevent the release of acetylcholine at neuromuscular junction resulting in a descending symmetric flaccid paralysis (shown). Treatment: antitoxin, preferably within 24 hours as antitoxin cannot reverse already established paralysis. Botulinum toxin has been labeled a Category A agent by the CDC. Image courtesy of the CDC.
Tularemia is a zoonotic disease caused by Francisella tularensis. Tularemia is considered Category A by the CDC due to its high infectivity: inhalation of only 10-50 organisms is sufficient to cause pneumonic tularemia. The 6 types of tularemia include ulceroglandular, glandular, oculoglandular, oropharyngeal, typhoidal, and pneumonia, any of which may be complicated by pneumonia. A case of ulceroglandular tularemia with a black eschar on the thumb at the site of inoculation (in this case, a rabbit bite) is shown.
Conversely, inhalation of the microorganism F tularensis is associated with typhoidal forms of tularemia, which can be further subdivided into typhoidal and pneumonic tularemia. These typhoidal forms of tularemia are most likely to occur following dispersal of aerosolized F tularensis in a bioterrorist attack. Typhoidal tularemia manifests as a febrile, prostrating illness with accompanying gastrointestinal distress. Pneumonic tularemia prominently features pulmonary symptoms including cough, pleuritic chest pain, and shortness of breath. Chest x-ray findings may include infiltrates, pleural effusions, hilar lymphadenopathy, or granulomatous lesions. Note the left lung infiltrate (blue circle), enlarged left hilum (red circle), and tenting of the left diaphragm in the x-ray (arrow). Treatment: streptomycin (or gentamicin) or a quinolone. Oral antibiotics are recommended in certain mild cases.
Q fever is considered a potential bioterrorism agent due to the high infectivity of the responsible microorganism, Coxiella burnetii. Inoculation with only 1 organism of C burnetii is sufficient to cause clinical disease, making it the most infectious known organism. Q fever typically causes a flu-like illness lasting 1-2 weeks, which may lead to pneumonia or disseminated disease of the liver, heart, or pericardium. A case of Q fever is shown in which the patient developed a granulomatous pericarditis 2 months after presenting with pneumonia (arrows). Q fever is considered Category B by the CDC. Treatment: Doxycycline or a quinolone. Image courtesy of the CDC.
Viral hemorrhagic fevers (VHF) are a group of distinct illnesses with similar vascular manifestations caused by viruses from 4 different viral families. All of these illnesses induce a bleeding diathesis that leads to mucosal hemorrhage (gastrointestinal, subconjunctival), cutaneous bleeding (ecchymosis, petechiae), and multisystem organ failure. Morbidity and mortality vary. VHF is considered a Category A agent by the CDC due to high infectivity of the causative organisms with human-to-human transmission and high morbidity and mortality associated with infection. A patient with Crimean-Congo hemorrhagic fever with profound ecchymosis of the left upper extremity is shown. Treatment is primarily supportive with a role for ribavirin in cases due to some, but not all, VHF viruses.
Brucellosis is a zoonotic disease caused by several species of genus Brucella. As with some other potential biological warfare agents, Brucella spp. is remarkable for its infectivity with only 10-100 bacteria necessary to establish an infection, making it a useful bioweapon. Symptoms of brucellosis include a febrile prostrating illness with myalgias, arthralgias, and gastrointestinal distress. More severe infections can cause a meningoencephalitis or granuloma formation in the liver (shown), spleen, and other organs. Treatment: doxycycline plus rifampin.
Ricin has long been a biological warfare agent. Derived from the castor bean plant (Ricinus communis, shown), ricin is a toxalbumin that impairs the function of ribosomes, resulting in multiorgan toxicity. Due to its easy production and dissemination, ricin is labeled a Category B agent by the CDC. Symptoms of ricin toxicity depend on the route of exposure: ingestion, injection, or inhalation. Bioterrorist attacks would likely involve aerosolized ricin, which causes fever, cough, acute respiratory distress syndrome, and respiratory failure starting 8 hours after exposure and culminating in death 36-48 hours after exposure. Treatment is supportive. Image courtesy of Wikimedia Commons.
Melioidosis (related to glanders) is caused by bacteria of genus Burkholderia. These diseases are both considered Category B by the CDC due to their high infectivity by the inhalational route and resistance to routine antibiotics. Melioidosis typically forms abscesses in the lungs and skin/subcutaneous tissues. Approximately 45% of patients will present with a disseminated septicemia that carries an 87% mortality rate. These patients present with a febrile illness and septic shock. One characteristic skin finding in septicemic melioidosis is multiple abscesses on an erythematous base, resulting from seeding of small dermis vessels with Burkholderia organisms. Pictured is a culture of Burkholderia pseduomallei grown on sheep blood agar, a causative agent of melioidosis. Treatment: ceftazidime plus imipenem. Image courtesy of the CDC.
Author
David Vearrier, MD
Core Faculty, Division of Medical Toxicology, Department of Emergency Medicine Albert Einstein Healthcare Network
Philadelphia, Pennsylvania
Disclosure: David Vearrier, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Diagnostic Radiology
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewers
Richard S. Krause, MD
Senior Faculty
Department of Emergency Medicine
State University of New York at Buffalo School of Medicine
Buffalo, New York
Disclosure: Richard S. Krause, MD, has disclosed no relevant financial relationships.
Burke A. Cunha, MD
Professor of Medicine
State University of New York School of Medicine at Stony Brook
Chief, Infectious Disease Division
Winthrop-University Hospital Mineola, New York
Disclosure: Burke A. Cunha, MD, has disclosed no relevant financial relationships.
Case Quiz: The Febrile Traveler
Common but Dangerous Plant Poisonings
Viral Hemorrhagic Fever (VHF)
Vital Clues Not to Miss in Food Poisoning
