Chapter 13
Emergency Medicine
Rahim Valani
Contents
Differences in Clinical Presentation
Common Presentations
Infection and Fever
Sickle Cell Disease
Trauma
How to Prepare
Differences in Clinical Practice
Learner Issues
Other Resources
References
Emergency medicine is a relatively new speciality across the globe and its work may differ significantly within and between countries. Undertaking electives in low- to middle-income contries (LMICs) presents unique and variable challenges with respect to resources available and competencies of local medical practitioners in this field. Being cognizant of the determinants of health assists understanding at a meta level of the inequalities that surround access and provision of care. What you might expect to find in a relatively high-resourced city teaching hospital will differ from a rural area staffed only by a nurse or midwife with limited medications.
In addition to the geopolitical and economic landscape, the utilization of care can differ. Lacking the adequate financial resources may preclude these people from seeking medical care until later in the course of the disease process. Thus, rare findings in the developed world with access to care may be more common and knowledge of late symptoms and disease complications will be beneficial.
Finally, the differential diagnosis changes based on the region of practice. While common things are common, one needs to include pathology that is also unique to that area. For example, tuberculosis (TB) osteomyelitis is in the differential in a patient who presents with thoracic back pain in an endemic area. Be aware of the neglected tropical diseases.
Differences in Clinical Presentation
Knowing how death and disease differ in low-income countries and the most common causes of emergency room (ER) visits is helpful to any student considering a health elective in a LMIC. While the leading causes of death are from ischemic heart disease, cerebrovascular disease and chronic obstructive pulmonary disease (COPD) when looking at worldwide statistics, the burden changes by country and region (Institute for Health Metrics and Evaluation, [IHME] 2013), as can be seen in Table 13.1.
Not surprisingly, the largest burden of disease in Africa and South East (SE) Asia is due to infections. However, in Africa the most common infectious culprits are human immunodeficiency virus (HIV)/ acquired immunodeficiency syndrome (AIDS), diarrheal disease and malaria, whereas in SE Asia it is diarrheal disease, TB and childhood cluster diseases (pertussis and measles).
It is important to recognize that Emergency medicine entails a spectrum of clinical presentations. There are common presenting problems that are seen everywhere – headaches, back pain, and so on. Common things are common across the globe. However, the important part is to recognize common presenting problems that have a unique differential diagnosis. Some of these are discussed below.
Common Presentations
Infection and Fever
In North America, a well appearing child who is fully immunized has about a 2% chance of an occult bacteremia, and less than 5% of those proceed on to a serious bacterial infection (Chancey and Jhaveri, 2009; Jhaveri et al., 2011). Fever is common everywhere, but the etiology and differential diagnosis of life-threatening diseases need to be extended. The usual culprits are still common etiological agents for urinary tract infection (UTI), pneumonia and meningitis. However, in places where children are not immunized the causative organism may not be commonly seen in the developed world. For example, vaccines are available for Haemophilus influenzae type B and Neisseria meningitidis serotype A/C/Y/W-135. Infections from these organisms can be seen in areas where routine vaccination is either not available or affordable. Furthermore, malaria, TB and other neglected tropical diseases would enter the picture. A broader and more thorough differential must be considered (malaria and diarrhea are also addressed in more detail in Chapter 14):
Table 13.1 Mortality-Based Stratification by Region and Cause
Source: Adapted from WHO, The Global Burden of Disease – 2004 Update, World Health Organization, Geneva, 2008.
- Malaria: Malaria is common in sub-Saharan Africa where over 600,000 people died from this infection in 2012 (Centers for Disease Control and Prevention [CDC], 2016). Endemic areas are aware of the symptoms and lab technicians are experts at diagnosing it on a smear. Patients can present with any of the following:
- Cerebral malaria: This can have variable presentation, but any neurological symptoms/signs or altered mental status is considered cerebral malaria until proven otherwise. Hypoglycemia is a poor prognostic factor.
- Severe anemia: Check for the size of the spleen, as splenomegaly can result in rupture.
- Sepsis and septic shock: Along with renal failure and acute respiratory distress syndrome (ARDS) – type picture.
Knowing the local resistance patterns to common drugs such as chloroquine and mefloquine helps with effective treatment. Chemoprophylaxis is also important for you as the traveller.
- Diarrhea: Each year, diarrhea is responsible for the death of over 2000 children/day (Liu et al., 2012). Diarrhea causes may be bacterial, viral or parasitic. Lack of appropriate therapy and clean water supplies makes treatment very difficult. While dehydration is the underlying cause of mortality, especially in children, the concomitant malnutrition and lack of proper therapy exacerbates their clinical course. Furthermore, invasive bacterial and parasitic diseases causing bloody diarrhea (dysentery) are more common and carry an even higher morbidity and mortality.
Therapy should be with the World Health Organization (WHO) recommended oral rehydration salts made from clean water. In cases of severe dehydration, intravenous fluids may be required. For severe dehydration, getting intravenous (IV) access may be difficult and intraosseous access or hypodermoclysis should be considered. Patients also need nutrition to help develop enough metabolic reserves to fight off the offending agents. As a traveller, ensure clean water sources and take appropriate therapy if you develop diarrhea.
- Tuberculosis: Over 95% of deaths caused by TB occur in developing countries, with SE Asia and Western Pacific regions accounting for most of the new cases (WHO, 2016b). TB should not be thought of as only a respiratory disease – extrapulmonary TB can affect all of the other organ systems. Miliary TB constitutes 10% of extrapulmonary TB, often seen as generalized nodules that are <2 mm in size. Lymphadenitis is the most common form of extrapulmonary TB and any person with lymphadenopathy should be suspected of having TB until proven otherwise. The most important risk factor for having TB is HIV, and concomitant infection is the norm rather than the exception. The use of protease inhibitors also worsens the clinical symptoms of TB.
The Bacillus Calmette–Guérin (BCG) vaccine is used in countries with a high prevalence of TB meningitis in the pediatric population and miliary TB. The issue with treatment of TB is ensuring adequate duration of therapy, recognizing multi-drug-resistant TB and being cognizant of the high risk of prevalence among patients with HIV.
- HIV: HIV is transmitted through unprotected intercourse, blood/blood products transfused from an HIV-positive donor, parenteral inoculation (sharing needles) and perinatally. The WHO estimates 36.7 million people with HIV globally, with 2.1 million new cases/ year and 1.1 million HIV-related deaths annually (Joint United Nations Programme on HIV/AIDS [UNAIDS], 2016). The acute infection occurs within days to weeks after exposure and presents as nonspecific viral-type illness. Progressive decrease in CD4 counts is the hallmark of this infection, and a count of <200 cells/mL requires Pneumocystis jiroveci pneumonia (PCP) prophylaxis, and patients should not be given any live virus vaccines. For those with a CD4 count less than 50 cells/mL, Mycobacterium avium complex (MAC) prophylaxis should be initiated.
A new diagnosis of HIV is often devastating to the patient and their families. The stigma associated with it along with lack of information about the disease and its transmission leads to alienation. Also, with poor resources, there may not be access to antiviral medications. There are major ethical and cultural issues to tackle based on the local beliefs behind HIV, and appropriate counselling for patients and their families is crucial.
Secondary infections are common in patients who are HIV positive, and some are pathognomonic for defining those with AIDS. The most common ones are
- PCP: This is usually seen when CD4 counts are <200 cells/mL. Staining of induced sputum is reasonable in making the diagnosis. Treatment is with trimethoprim-sulfamethoxazole for 21 days. Adjuvant steroid therapy may be beneficial.
- Tuberculosis: See the section ‘Tuberculosis’.
- MAC: Seen when the CD4 counts are <50 cells/mL. Typical anti-TB drugs do not work well for these organisms and multidrug therapy is the key.
- Cryptococcal disease: The spores of this yeast are usually inhaled, resulting in pneumonia. It can also disseminate, usually to the central nervous system (CNS) causing cryptococcal meningitis (usually when the CD4 counts are <50 cells/mL).
- Cytomegalovirus (CMV) infection: Again seen in those whose CD4 counts are <50 cells/ mL and presents as chorioretinitis.
In addition to opportunistic and coinfections, patients with HIV are also prone to several malignancies. Kaposi’s sarcoma is the most common malignancy seen in this patient population which is due to infection with human herpesvirus 8. Lymphoma is the other common malignancy.
Management of HIV is through antiviral medications. There are six classes of drugs, and treatment is usually with the use of drugs from more than one class:
- Nucleoside/nucleotide reverse transcriptase inhibitors
- Non-nucleoside/nucleotide reverse transcriptase inhibitors
- Protease inhibitors
- Fusion inhibitors
- Integrase inhibitors
- Chemokine co-receptor antagonists
There are combination drugs available that improve compliance for patients taking multiple medications. The WHO is working with other groups to improve access to medications globally, and an estimated 17 million people are on retroviral therapy (HIV/AIDS, 2016).
- Protozoan infections: Protozoan infections are from ingestion of contaminated food/water. The cysts are ingested, and excystation occurs in the bowel lumen. The resulting trophozoites then form more cysts, which then cause the symptoms and are also excreted, thus repeating the cycle. A summary of the common protozoan infections is provided in the following table, including common presentations, complications to be aware of and treatment (the medications listed may not be available where you are working, ...
