A feasibility study to determine if minimally trained medical students can identify markers of chronic parasitic infection using bedside ultrasound in rural Tanzania

doi:10.5847/wjem.j.1920-8642.2015.04.008

Abstract

Abstract:

BACKGROUND: Parasitic infections pose a significant health risk in developing nations and are a major cause of morbidity and mortality worldwide. In the Republic of Tanzania, the CDC estimates that 51.5% of the population is infected with one or more intestinal parasites. If diagnosed early, the consequences of chronic parasitic infection can potentially be avoided.
METHODS: Six first-year medical students were recruited to enroll patients in the study. They underwent ten hours of formal, hands-on, ultrasound which included basic cardiac, hepatobiliary, renal, pulmonary and FAST scan ultrasound. A World Health Organization protocol with published grading scales was adapted and used to assess for pathology in each patient's liver, bladder, kidneys, and spleen.
RESULTS: A total of 59 patients were enrolled in the study. Students reported a sensitivity of 96% and specificity of 100% for the presence of a dome shaped bladder, a sensitivity and specificity of 100% for bladder thickening, a sensitivity and specificity of 100% for portal hypertension and ascites. The sensitivity was 81% with a specificity of 100% for presence of portal vein distention. The sensitivity was 100% with a specificity of 90% for dilated bowel.
CONCLUSIONS: Ultrasound has shown a promise at helping to identify pathology in rural communities with limited resources such as Tanzania. Our data suggest that minimally trained first year medical students are able to perform basic ultrasound scans that can identify ultrasonographic markers of parasitic infections.

Key words: Parasitic infection, Bedside ultrasound, Computed tomography, Tanzania

Maria Barsky, Lauren Kushner, MeganAnsbro, Kate Bowman, Michael Sassounian, Kevin Gustafson, Shadi Lahham, Linda Joseph, John C Fox. A feasibility study to determine if minimally trained medical students can identify markers of chronic parasitic infection using bedside ultrasound in rural Tanzania[J]. World Journal of Emergency Medicine, 2015, 6(4): 293-298.

Figures/Tables 3

Table 1

World Health Organization "Ultrasound in Schistosomiasis" protocol with published grading scales

i) Transverse view of the bladder - The probe was placed in transverse orientation above the pubic symphysis to visualize the bladder. Each bladder was assessed for shape, lesions, masses, pseudopolyps, and calcifications of the bladder wall. Per the WHO grading system, a score of 0 was assigned for bladders that were in a rectangular shape, while 1 was assigned for a rounded, distorted bladder. Bladders without lesions, masses, pseudopolyps, and calcifications were assigned 0 in each category. If present, each category was graded as follows: bladder wall lesions (focal=1, multifocal=2); masses (single=2, multiple=n+2 where n is the number of masses); pseudopolyps (single=2, multiple=n+2 where n is the number of pseudopolyps); calcifications (visible=1). Finally, bladder width and depth were measured with calipers in transverse orientation and recorded for later calculation of post-void residual bladder volumes.

ii) Longitudinal view of the bladder - From the transverse view of the bladder, the probe was rotated 90 degrees to capture the longitudinal view of the bladder. As above, the bladder was assessed for lesions, masses, pseudopolyps and calcifications. Bladder length was measured with calipers and recorded for later calculation of post-void residual bladder volumes.

iii and iv) Right and left coronal for lateral views of the kidneys - The probe was placed in coronal orientation between the mid axillary and posterior axillary lines to visualize the kidney and if visible, the proximal ureter. Dilation of the ureters was graded 0 if absent or not visualized, 3 if visualized at proximal or distal third, and 4 if dilated more than for standard visualization. This was repeated on the left side. While in this orientation, patients were also assessed for presence or absence of fluid in Morrison's Pouch and the splenorenal recess.

v and vi) Right and left kidneys in cross section - From the coronal orientation, the probe was rotated approximately 90 degrees to obtain a cross-section of the kidney. While in this orientation, the kidneys were assessed for hydronephrosis or dilation of the renal pelvis. Grading was as follows: not dilated=0, moderate dilation with conserved parenchyma (renal pelvis to capsule>1 cm)=6, severe dilation with absence of parenchyma=8. In addition, the renal pelvis was also evaluated for fibrosis based on presence or absence of echodense structures along the borders of the pelvis. If absent, a score of 0 was assigned; if present, a score of 1 was assigned.

vii) Liver view with probe placement at the right anterior axillary line - Probe was placed vertically at the right anterior axillary line for measurement of the right liver lobe using calipers. Presence or absence of ascites was also noted.

viii) Liver view with probe placement between the anterior axillary and midaxillary lines - Liver was scanned between anterior axillary and mid axillary lines to find a portal vein for evaluation of portal flow. Color mode was used in two axes to determine if there was reversal of flow due to portal hypertension. Red was recorded as normal; blue was recorded as reversal of flow. Presence or absence of ascites was also noted.

ix) Substernal transverse view - Probe was placed in transverse orientation just below the xiphoid process for visualization of the left liver lobe.

x and xi) Post-void transverse and longitudinal view of the bladder - Patient's bladder was rescanned in transverse and longitudinal orientation after voiding. Post-void bladder width and depth were measured with calipers and recorded for later calculation of post-void residual bladder volumes.

Table 1

Table 2

Table 3

References 29

1	Pullan RL, Smith JL, Jasrasaria R, Brooker SJ. Global numbers of infection and disease burden of soil transmitted helminth infections in 2010. Parasit Vectors 2014; 7:37 doi: 10.1186/1756-3305-7-37 pmid: 24447578
2	Hotez PJ, Bundy DAP, Beegle K, Brooker S, Drake L, de Silva N, et al. Helminth Infections: Soil-transmitted Helminth Infections and Schistosomiasis. In: Jamison DT, Breman JG, Measham AR, Alleyne G, Claeson M, Evans DB, Jha P, Mills A, Musgrove P, editors. SourceDisease Control Priorities in Developing Countries. 2nd edition. Washington (DC): World Bank; 2006. Chapter 24.
3	WHO Fact Sheet N°366: Soil-transmitted helminth infections, April 2014, http://www.who.int/mediacentre/factsheets/fs366/en/
4	Rollinson D, Knopp S, Levitz S, Stothard JR, Tchuem Tchuenté LA, Garba A, et al. Time to set the agenda for schistosomiasis elimination. Acta Trop 2013; 128:423-440. pmid: 22580511
5	UNICEF. Water, Sanitation andHygiene AnnualReport (2010). http://www2.unicef.org:60090/wash/index_3951.html
6	WHO. Schistosomiasis. http://www.who.int/mediacentre/factsheets/fs115/en/
7	USAID's NTD Program: http://www.neglecteddiseases.gov/target_diseases/schistosomiasis/
8	Olveda DU, Olveda RM, McManus DP, Cai P, Chau TN, Lam AK, et al. The chronic enteropathogenic disease schistosomiasis. Int J Infect Dis 2014; 28:193-203. doi: 10.1016/j.ijid.2014.07.009 pmid: 25250908
9	Kardorff R, Gabone RM, Mugashe C, Obiga D, Ramarokoto CE, Mahlert C, et al. Schistosoma mansoni-related morbidity on Ukerewe Island, Tanzania: clinical, ultrasonographical and biochemical parameters. Trop Med Int Health 1997; 2:230-239. pmid: 9491101
10	Malenganisho WL, Magnussen P, Friis H, Siza J, Kaatano G, Temu M, et al. Schistosoma mansoni morbidity among adults in two villages along Lake Victoria shores in Mwanza District, Tanzania. Trans R Soc Trop Med Hyg 2008; 102:532-541.
11	Richter J, Hatz C, Campagne G, Bergquist NR, Jenkins JM. Ultrasound in schistosomiasis: A Practical Guide to the Standardized Use of Ultrasonography for the Assessment of Schistosomiasis-related Morbidity. Second International Workshop, October 22-26, 1996; Niamey, Niger.
12	WHO 2: Ultrasound in Schistosomiasis: A Practical Guide to the Standardized Use of Ultrasonography for the Assessment of Schistosomiasis-related Morbidity. UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR). Second International Workshop, October 22-26, 1996, Niamey Niger.
13	Feldmeier H, Poggensee G. Diagnostic techniques in Schistosomiasis control. A review. Acta Tropica 1993; 52:205-220. doi: 10.1016/0001-706x(93)90009-z pmid: 8094586
14	WHO. Neglected tropical diseases. http://www.who.int/neglected_diseases/diseases/en/ doi: 10.3390/diseases7010031 pmid: 30909425
15	Imperial College of London: Schistosomiasis control initiative. 2015. http://www3.imperial.ac.uk/schisto/wherewework/tanzania.
16	Boros DL. Immunopathology of Schistosoma mansoni infection. Clinical Microbiology Reviews 1989; 2:250-269.
17	Guyatt H, Brooker S, Lwambo NJ, Siza JE, Bundy DA. The performance of school-based questionnaires of reported blood in urine in diagnosing Schistosoma haematobium infection: patterns by age and sex. Trop Med Int Health 1999; 4:751-757.
18	Haidar NA. Schistosoma mansoni as a cause of bloody stool in children. Saudi Med J 2001; 22:856-859. pmid: 11744941
19	Kardorff R, Gabone RM, Mugashe C, Obiga D, Ramarokoto CE, Mahlert C, et al. Schistosoma mansoni-related morbidity on Ukerewe Island, Tanzania: clinical, ultrasonographical and biochemical parameters. Trop Med Int Health 1997; 2:230-239. pmid: 9491101
20	Sippel S, Muruganandan K, Levine A, Shah S. Use of ultrasound in the developing world. International Journal of Emergency Medicine 2011; 4:72.
21	Shah SP, Epino H, Bukhman G, Umulisa I, Dushimiyimana JM, Reichman A, et al. Impact of the introduction of ultrasound services in a limited resource setting: rural Rwanda 2008. BMC Int Health Hum Rights 2009; 9:4. doi: 10.1186/1472-698X-9-4 pmid: 19327157
22	Jamison DT, Breman JG, Measham AR, Alleyne G, Claeson M, Evans DB, et al (Eds.). Disease Control Priorities in Developing Countries (2nd ed.), World Bank. Washington, DC 2006; Chapter 24.
23	Centers for Disease Control. Neglected Tropical Diseases, 2011. http://www.cdc.gov/globalhealth/ntd/diseases/index.html
24	Ferraioli G, Meloni MF. Sonographic training program at district hospital in a developing country: work in progress. AJR Am J Roentgenol 2007; 189:W119-122. pmid: 17715076
25	Arger PH, Schultz SM, Sehgal CM, Cary TW, Aronchick J. Teaching medical students diagnostic sonography. J Ultrasound Med 2005; 24:1365-1369.
26	Collins J, Riebe JD, Albanese MA, Dobos N, Heiserman K, Primack SL, et al. Medical students and radiology residents: can they learn as effectively with the same educational materials? Acad Radiol 1999; 6:691-695. pmid: 10894073
27	Zaidman CM, Wu JS, Wilder S, Darras BT, Rutkove SB. Minimal training is required to reliably perform quantitative ultrasound of muscle. Muscle Nerve 2014; 50:124-128. doi: 10.1002/mus.24117 pmid: 24218288
28	Bahner DP, Adkins EJ, Hughes D, Barrie M, Boulger CT, Royall NA. Integrated medical school ultrasound: development of an ultrasound vertical curriculum. Crit Ultrasound J 2013; 5:6.
29	Adler D, Mgalula K, Price D, Taylor O. Introduction of a portable ultrasound unit into the health services of the Lugufu refugee camp, Kigoma District, Tanzania. International Journal of Emergency Medicine 2008; 1:261-266. pmid: 19384640

Parameters	Schistosomiasis (n=34)	No schistosomiasis (n=25)
Gender
Female	13	18
Male	21	7
Age	Mean=41.3; range=7-77	Mean=30.43; range=9-53
Location
Mwanza	8	3
Ukerewe	26	12
Known liver pathology	7	0
Praziquantel trials	1.1 STD=1.35	0
Concurrent parasites	4 (2 hookworm, 1 amoeba, 1 malaria)	7 (1 helminth, 2 ascaris, 2 hookworm, 1 yeast, 1 amoeba)
Other pathology	3	5

Characteristics	Medical student	Ultrasound director	Concordance (%)
Dome shape bladder	27	28	Sensitivity (96.4)
			Specificity (100)
Bladder thickening/irregularity	12	12	Sensitivity (100)
			Specificity (100)
Presence of bladder mass	0	0	Sensitivity (0)
			Specificity (100)
Visualization of ureters	1	0	Sensitivity (0)
			Specificity (98.2)
Portal hypertension	6	6	Sensitivity (100)
			Specificity (100)
Portal vein distention	9	11	Sensitivity (81.8)
			Specificity (100)
Presence of ascites	4	4	Sensitivity (100)
			Specificity (100)
Dilated bowel	20	16	Sensitivity (100)
			Specificity (90.7)

[1]	Genevieve Mazza, Carina Mireles Romo, Marlene Torres, Ali Duffens, Annasha Vyas, Katherine Moran, Joshua Livingston, Savannah Gonzales, Shadi Lahham, Inna Shniter, Maxwell Thompson, John Christian Fox. Assessment of clinical dehydration using point of care ultrasound for pediatric patients in rural Panama [J]. World Journal of Emergency Medicine, 2019, 10(1): 46-50.
[2]	Sean P. Denny, William B. Minteer, Reece T.H. Fenning, Sahil Aggarwal, Debora H. Lee, Shella K. Raja, Kaavya R. Raman, Allison O. Farfel, Priya A. Patel, MarkLieber, Megan E. Bernstein, Shadi Lahham, John C. Fox. Ultrasound curriculum taught by first-year medical students: A four-year experience in Tanzania [J]. World Journal of Emergency Medicine, 2018, 9(1): 33-40.
[3]	Erden Erol Ünlüer, Rıfat Urnal, Utku Eser, Serkan Bilgin, Mehmet Hacıyanlı, Orhan Oyar, Haldun Akoğlu, Arif Karagöz. Application of scoring systems with point-of-care ultrasonography for bedside diagnosis of appendicitis [J]. World Journal of Emergency Medicine, 2016, 7(2): 124-129.
[4]	Sarah E Frasure, Amy Hildreth, Sukhjit Takhar, Michael B Stone. Emergency department patients with small bowel obstruction: What is the anticipated clinical course? [J]. World Journal of Emergency Medicine, 2016, 7(1): 35-39.
[5]	Kadir Agladioglu, Mustafa Serinken, Onur Dal, Halil Beydilli, Cenker Eken, Ozgur Karcioglu. Chest X-rays in detecting injuries caused by blunt trauma [J]. World Journal of Emergency Medicine, 2016, 7(1): 55-58.
[6]	Yuanting Zha, Michelle Zhou, Anjali Hari, Bradley Jacobsen, Neha Mitragotri, Bianca Rivas, Olga Gabriela Ventura, Janice Boughton, John Christian Fox. Ultrasound diagnosis of malaria: examination of the spleen, liver, and optic nerve sheath diameter [J]. World Journal of Emergency Medicine, 2015, 6(1): 10-15.
[7]	Sohil Pothiawala, Apoorva Gogna. Early diagnosis of bowel obstruction and strangulation by computed tomography in emergency department [J]. World Journal of Emergency Medicine, 2012, 3(3): 227-231.
[8]	Siu Ming Yang, Chor Man Lo. Transition to computed radiography: can emergency medicine doctors accurately predict the need of film printing to facilitate optimal patient care? [J]. World Journal of Emergency Medicine, 2011, 2(1): 33-37.