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Acute abdominal pain in patients with lassa fever: Radiological assessment and diagnostic challenges

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  • Nnamdi Azikiwe University, Awka, (Nnewi Cmpus), Anambra State, Nigeria

Abstract and Figures

Background: To highlight the problems of diagnosis and management of acute abdomen in patients with lassa fever. And to also highlight the need for high index of suspicion of lassa fever in patients presenting with acute abdominal pain in order to avoid surgical intervention with unfavourable prognosis and nosocomial transmission of infections, especially in Lassa fever-endemic regions. Materials and methods: A review of experiences of the authors in the management of lassa fever over a 4-year period (2004-2008). Literature on lassa fever, available in the internet and other local sources, was studied in November 2010 and reviewed. Results: Normal plain chest radiographic picture can change rapidly due to pulmonary oedema, pulmonary haemorrhage and acute respiratory distress syndrome. Plain abdominal radiograph may show dilated bowels with signs of paralytic ileus or dynamic intestinal obstruction due to bowel wall haemorrhage or inflamed and enlarged Peyer's patches. Ultrasound may show free intra-peritoneal fluid due to peritonitis and intra-peritoneal haemorrhage. Bleeding into the gall bladder wall may erroneously suggest infective cholecystitis. Pericardial effusion with or without pericarditis causing abdominal pain may be seen using echocardiography. High index of suspicion, antibody testing for lassa fever and viral isolation in a reference laboratory are critical for accurate diagnosis. Conclusion: Patients from lassa fever-endemic regions may present with features that suggest acute abdomen. Radiological studies may show findings that suggest acute abdomen but these should be interpreted in the light of the general clinical condition of the patient. It is necessary to know that acute abdominal pain and vomiting in lassa fever-endemic areas could be caused by lassa fever, which is a medical condition. Surgical option should be undertaken with restraint as it increases the morbidity, may worsen the prognosis and increase the risk of nosocomial transmission.
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Niger Med J. 2014 May-Jun; 55(3): 195–200.
doi: 10.4103/0300-1652.132037
PMCID: PMC4089045
Acute abdominal pain in patients with lassa fever: Radiological
assessment and diagnostic challenges
Kenneth C. Eze, Taofeek A. Salami,1 and James U. Kpolugbo2
Department of Radiology, Irrua Specialist Teaching Hospital, Irrua, Edo, Nigeria
1Department of Medicine, Irrua Specialist Teaching Hospital, Irrua, Edo, Nigeria
2Department of Surgery, Irrua Specialist Teaching Hospital, Irrua, Edo, Nigeria
Address for correspondence: Dr. Kenneth C. Eze, Department of Radiology, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra,
Nigeria. E-mail: ku.oc.oohay@egnellahceze
Copyright : © Nigerian Medical Journal
This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Abstract
Background:
To highlight the problems of diagnosis and management of acute abdomen in patients with lassa fever. And to also highlight the need for high index
of suspicion of lassa fever in patients presenting with acute abdominal pain in order to avoid surgical intervention with unfavourable prognosis and
nosocomial transmission of infections, especially in Lassa fever-endemic regions.
Materials and Methods:
A review of experiences of the authors in the management of lassa fever over a 4-year period (2004-2008). Literature on lassa fever, available in
the internet and other local sources, was studied in November 2010 and reviewed.
Results:
Normal plain chest radiographic picture can change rapidly due to pulmonary oedema, pulmonary haemorrhage and acute respiratory distress
syndrome. Plain abdominal radiograph may show dilated bowels with signs of paralytic ileus or dynamic intestinal obstruction due to bowel wall
haemorrhage or inflamed and enlarged Peyer's patches. Ultrasound may show free intra-peritoneal fluid due to peritonitis and intra-peritoneal
haemorrhage. Bleeding into the gall bladder wall may erroneously suggest infective cholecystitis. Pericardial effusion with or without pericarditis
causing abdominal pain may be seen using echocardiography. High index of suspicion, antibody testing for lassa fever and viral isolation in a
reference laboratory are critical for accurate diagnosis.
Conclusion:
Patients from lassa fever-endemic regions may present with features that suggest acute abdomen. Radiological studies may show findings that
suggest acute abdomen but these should be interpreted in the light of the general clinical condition of the patient. It is necessary to know that acute
abdominal pain and vomiting in lassa fever-endemic areas could be caused by lassa fever, which is a medical condition. Surgical option should be
undertaken with restraint as it increases the morbidity, may worsen the prognosis and increase the risk of nosocomial transmission.
Keywords: Acute abdomen, diagnosis, lassa fever, radiology, ultrasound.
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INTRODUCTION
Lassa fever is a type of viral haemorrhagic fever caused by lassa virus.1,2 The disease is endemic in some countries of West Africa particularly
Nigeria, Liberia, Guinea and Sierra Leone.1,2,3 About 300,000 to 500,000 infections are estimated to occur annually resulting in about 5,000
deaths in endemic regions.1,2,4 The disease has also been carried sporadically through international travel from the endemic West African countries
to Britain, Netherlands, United States, Japan, Germany, South African. Over 20 cases have been reported in developed countries and it is evident
that only the countries with high reference laboratories have the capacity to conclusively identify the virus.1,2,5,6 Therefore, the other countries
where it is not yet reported may not be necessarily free from the disease by export through international travel. Mastomys natalensis, a multi-
mammate rat that is common and lives in bushes within and around people's houses in endemic regions is the natural host of the virus.1,2,3,4,5 In
homes in endemic regions, Mastomys natalensis constitute 50-60% of captured rats but only 5-20% of rats captured in and around farms; showing
that the rats are more common within and around people's houses.1,2,4,7 Eating of food dried in the open floor, uncovered and contaminated with
the saliva, urine and excreta of the rat is mostly responsible for the infection.1,2 The prevalence of immunoglobin G (IgG) antibody detected in
endemic areas is 12.3% of normal healthy people in Nigeria, 55% in Guinea and 52% in Sierra Leone.1,2 The incubation period is 6-21 days and
the disease affects all age groups and both sexes.1,2,3 Infection at the extremes of life as well as in pregnant women carries worse prognosis.1,2,3,4,5
The clinical features of the disease are similar to those of other infections that are common in endemic areas such as malaria, typhoid fever,
cholecystitis, hepatitis, yellow fever, meningitis, gastroenteritis and other common febrile illnesses.1,3,6 The disease is symptomless in over 80% of
the infected people but 20% may show severe systemic symptoms and signs.1,2,3 It is this 20% that constitute the hospital admitted cases. The
disease is also very difficult to diagnose clinically.1,2,3 The presenting complaints include persistent fever of about 38°C which is unresponsive to
antimalarial treatment and conventional antibiotics, rigors, pharyngitis (sore throat), retro-sternal chest pain, vomiting, abdominal pain, back pain,
muscle pain, weakness, cough, shortness of breath, yellowness of eyes, puffy face/neck/jaw, lymphadenopathy, constipation, gastro-intestinal
bleeding, rib pain and tenderness, restlessness, dizziness, confusion and coma.1,2
Physical examination may show mucosal petechial bleeding from the mucosa of mouth, nose, vagina and anus. Pleural and pericardial effusion,
ascites and scrotal fluid collection often occur and these imply signs of serositis. Other recorded findings are hyphaema, abdominal distension,
lymphadenopathy, signs of intestinal obstruction, shock, multiple organ failure, coma and generalised oedema.1,2,3,5,6,7,8 Case fatality rate occurs in
1-2% in the general population of infected people in endemic regions while hospital mortality rate is 10-87%.2,3 ISTH, Irrua, Edo State, is the
most active lassa fever treatment centre in Nigeria.
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MATERIALS AND METHODS
This is a review article involving the experience of the authors in the management of lassa fever cases over a 4 year period (2004-2008) and
publications on lassa fever. The available literature on the internet and other local sources including libraries, and hospital records were studied for
up to 2010. Relevant articles were reviewed and the necessary information extracted. Practical experience of the authors in clinical management of
lassa fever cases over a-4-year period (2004-2008) at Irrua Specialist Teaching Hospital (ISTH), formed the backbone of the study. ISTH is a
Centre of Excellence for the treatment of lassa fever in Nigeria. Important areas of sources of errors that could lead to false positive or false
negative diagnosis of lassa fever and possible sources of complications were also reviewed.
Many cases had radiological assessment to exclude other diseases. A few cases with radiological investigation that had clinical diagnosis using
criteria provided by the Centre for Disease Control and Prevention/World Health Organisation (CDC/WHO) and the Federal Ministry of Health
(FMoH) of Nigeria, Abuja are presented in this study. Laboratory studies were also used to arrive at the diagnosis and in most cases, both the
clinical diagnostic criteria and the supporting laboratory studies were used for the diagnosis.1,2,8,11,12 The criteria for clinical diagnosis include:8,10
Major criteria are:
(i) Abnormal bleeding from mouth, gum, nose, vagina, urinary tract; (ii) haemoptysis, bleeding from the ear; (iii) Swollen neck and face; (iv) Red
eyes or conjunctivitis (often bilateral); (v) Spontaneous abortion; (vi) Deafness during illness; (vi) Shock or systolic blood pressure <100 mmHg.
Minor criteria are:
(i) Sore throat; (ii) Headache; (iii) Diarrhoea; (iv) Leucopaenia; (v) Nausea and vomiting; (vi) Abdominal pain; (vii) Cough; (viii) Pleural effusion or
ascites; (ix) Swollen lymph nodes, (x) Weakness; (xi) Proteinuria.
A combination of minor and major criteria is used to clinically diagnose lassa fever as follows.
Possible lassa fever
Persistent fever with two or more minor criteria and known contact with lassa fever cases.
Probable lassa fever
Persistence of fever with any of the major criteria.
Suspected case
Patients with persistent fever (100°F or ≥37.8°C) not responding to antimalarial drugs or antibiotics.
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RESULT
In the pathology of lassa fever, thrombocytopaenia occurs early and may lead to spontaneous haemorrhage within the bowel wall with symptoms
of pain, bowel distension and vomiting.1,6 Humoral inflammatory mechanisms causing partial bowel paralysis and subsequent dilatation have been
implicated in some cases of bowel dilatation with diagnosis of intestinal obstruction.1,2,13 Enlarged, inflamed Peyer's patches and lymph nodes also
cause small bowels to dilate due to accumulation of gas and gastrointestinal contents proximal to the inflamed and tender aperistaltic areas.13 The
bowel may be partially adherent to the inflamed glands leading to pain and further distension of the bowels.
Also, bleeding within the bowel wall causes ileus at the point of bleed, and contributes to subsequent dilatation of the bowel proximal to this point.
Both, small and large intestines may be involved.12,14
Contributions of one or all of the above listed mechanism may worsen the bowel dilatation, thus presenting with a clinical and radiological features
(diagnosis) of intestinal obstruction or acute abdomen.1,2
Haemorrhage within the solid organs contained in the abdomen and pelvis, with the accompanying release of some enzymes which may contribute
to tissue necrosis and pain.12,14 Bleeding into the wall of the gall bladder may erroneously lead to diagnosis of cholecystitis when symptoms such as
right hypochondrial pains and tenderness on examination of right hypochondrium are felt by the patients in such cases.
Panorganotropism in lassa fever is observed as the lassa virus affects virtually all the organs of the body where it causes various types of
abnormalities including organomegally, inflammation with reactive fluid formation, and tissue necrosis. These may cause abdominal pain and
distension.2,12,16 Bleeding within the omentum and the peritoneal sac also causes significant abdominal pain with minimal distension.
Significant amount of fluid may be seen within the uterus and the vagina on sonography studies even before the patients complains of vaginal
bleeding. It should not be used as one of the criteria to diagnose ectopic pregnancy or mistaken for incomplete abortion as vaginal bleeding may
occur in lassa fever. Pregnancy test will prove very useful. Therefore, in an endemic region if lassa fever is suspected, it is prudent to exclude it with
ancillary investigation that could point or exclude the differential diagnosis.
It must be emphasised, however that, the most important factor in the diagnosis of lassa fever using clinical diagnostic criteria is high index of
suspicion of the disease. Any patient with high fever that is unresponsive to antimalarial and conventional antibiotic treatments or fever of unknown
origin, coming from any of the countries of West Africa that the disease is endemic should be suspected of the disease, assessed according to the
earlier specified criteria following which laboratory tests should be conducted.1,2,3,4,5,17 Even the practice of sending samples for laboratory
diagnosis of lassa fever in endemic areas also requires high index of suspicion since the clinical features of lassa fever are similar to other common
febrile illnesses. Radiology studies done in those patients that later proved to be lassa fever are often very informative.
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RADIOLOGICAL ASSESSMENT
Chest radiography may be normal at early stages and this may reassure the clinicians of the absence of chest pathology. This is deceptive as
pulmonary haemorrhage, pulmonary oedema, and acute respiratory distress syndrome [Figure 1], may develop rapidly within hours or days.18,19
Aspiration pneumonia may also occur and may quickly lead to death.9
Plain abdominal radiographs often show dilated gas-filled bowels of mild to moderate severity with no specific feature. This often leads to the
diagnosis of intestinal obstruction or incomplete obstruction. Multiple air-fluid levels more than three in number and greater than 2.5 cm in diameter
may be seen and may lead to diagnosis of dynamic intestinal obstruction. Occasionally large-diameter fluid-level may be observed due to dilated
large bowels. Features of bowel haemorrhage appearing like thumb-printing may be seen especially in the transverse colon but this is more obvious
on barium meal and enema examination which are currently not routinely indicated for patients with acute abdomen. Inflammation and enlargement
of the Peyer's patches may cause dilatation of the small intestines and may give the appearance of low small intestinal obstruction. This eventually
leads to a serious confusion with typhoid enteritis or typhoid perforation.16,17,18
Abdominal ultrasound often shows mild free intraperitoneal fluid collection. This should not be interpreted as ruptured viscus as it may alert the
surgeon for surgical intervention which increases the morbidity, nosocomial transmission and may worsen the prognosis.1,2 It has been observed
that free intraperitoneal fluid is not uncommon in patients with lassa fever.17 Occasionally, mild ascitic fluid may be localised in the pelvis, right iliac
fossa or the sub-hepatic space due to dependency of these areas according to posture in lying down. This should not always be interpreted as
acute appendicitis or ectopic pregnancy. The possibility of mild free intraperitoneal fluid which could be reactive ascites or haemoperitoneum in
lassa fever should be remembered if high index of suspicion is applied. The bowels may show thickened wall with non-propulsive peristaltic activity
on sonography. If bleeding occurs into the bowel wall, the bowel could be dilated and may be filled with fluid, allowing for their identification with
ultrasound [Figure 2]. Lymphadenopathy may be seen in the abdomen and the presentation of major or minor criteria of lassa fever should raise
suspicion of the infection.12,13,16,17,18
The kidneys may be enlarged due to oedema from bleeding and the calyces may show echogenic appearance from numerous small blood clots.
With progression of the disease the kidney may be echogenic with reduction or loss of the cortico-medullary pattern [Figure 3]. Whether this is
bleeding within the renal substance or other inflammatory changes, remains to be accurately ascertained but the renal changes are of different types
and apart from the fact that the renal size is normal could suggest some other acute conditions. However, frequently the initial renal status may not
be known in which the differential diagnosis becomes more difficult or uncertain. Electrolyte imbalance from kidney derangement soon sets in. This
contributes to the bowel dilatation as a result of hypokalaemia which is also worsened by diarrhoea and vomiting that often accompany other
clinical signs of the disease.17,18
Hypoechoic changes in the liver due to non-specific liver inflammation are frequently observed on sonography as well as mildly enlarged liver due
to inflammation. These inflammatory changes are one of the causes of jaundice. Bleeding into the wall of the gall bladder may cause it to be
thickened [Figure 4]. This could be confused with cholecystitis and blood clot within the gall bladder could be confused with
cholelithiasis.12,16,17,19
Whenever any radiologist is carrying out abdominal ultrasound it is a good practice to study the heart. Useful signs that can be obtained from
cardiac ultrasound include pericardial effusion, hypokinesia, dyskinesis (abnormal heart motion), intramural echogenic thrombus, cardiac tumours,
echogenic pericardium due to inflammation and abnormal dilatation of one or more of the cardiac chambers. The most common lesion seen in the
heart in patients with lassa fever is pericardial effusion.16,18 The need to assess the heart with echocardiography is also because some chest
conditions like myocardial infarction can simulate acute abdominal pain.2,3,11,16
Soft tissue ultrasound of the eyes, submandibular glands and the scrotum/testes are invaluable in the study of patients with lassa fever using high
resolution (7.5-15 MHz) ultrasound transducer. The eyes may show hyphaema due to bleeding within the anterior chamber. Bleeding into the
scrotal sac may be seen as hydrocoele. It may be possible to identify bleeding within the scrotal muscle forming localised mild
pseudotumour.2,3,16,17
Computed tomography (CT) of the brain or abdomen is not usually done as workup for acute abdomen in West Africa where lassa fever is
endemic due to cost and the fact that the facility is not readily available in many centres. However, because patients with lassa fever can present
with headache, drowsiness and coma, brain CT scans have been done in a number of cases.17,19,20 The lesions in the brain are in the form of
encephalitis or encephalomyelitis with periventricular and perigyral hyperdense areas. Cerebral oedema may develop with effacement of the lateral
ventricles. Without serological test for lassa fever, it is difficult to ascribe these to lassa fever even in endemic region because cerebral malaria and
other common viral infections can produce similar features. CT scan of the abdomen in patient with lassa fever can show evidence of ascites, or
haemoperitoneum, enlarged para-aortic lymph nodes, thickened bowel walls due to oedema, bowel-wall haemorrhage and inflammation. CT can
exclude intra-abdominal mass lesion and many other causes of acute abdominal pain. Typhoid enteritis and vascular events may be wrongly
diagnosed as the cause of the abdominal lesions.17
Magnetic resonance is not readily available and its high cost greatly limits its use in sub-Saharan West Africa where lassa fever is endemic
particularly in the rural areas. However, where it has been used to study the brain of a patient with lassa fever it shows multiple hyperintense
periventricular lesions on T1-weighted images. The bowel wall distension and bowel wall thickening as demonstrated in CT will also be evident in
abdominal MR imaging. Enlarged lymph nodes within the abdomen has also been observed.17
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DIAGNOSTIC CHALLENGES
The main challenge is that lassa fever is a medical and not a surgical condition, but it often presents with clinical features of acute abdomen which is
in the dormain of surgeons who lack the requisite diagnostic radiologic tools. It is therefore often contentious, whether the patient should go to the
medical or surgical team or ward.
With high index of suspicion both the medical and surgical teams are expected to be able to clinically diagnose lassa fever in endemic regions.
Samples can be sent to ISTH, Irrua for Polymerase chain reaction (PCR) testing within Nigeria, or to other reference hospitals/diagnostic centre in
other countries. The result should be available within hours, no matter the State the hospital is situated in Nigeria. Proteinurea, bleeding time and
clotting time are important tests that should be done, since derangements are highly suggestive of lassa fever in symptomatic patients. However,
once the clinical diagnosis of lassa fever have been made, it is a prudent practise to refrain from surgical intervention.2 Surgery is additional stress
to a sick body and in the presence of lassa fever may worsen the outcome in patients.
Electrolyte and urea assessment are very vital. However, many of the radiological finding actually raise high suspicion of acute abdomen by other
causes as lassa fever is not readily considered as a cause of acute abdomen in most endemic regions because of the problem of proving the
diagnosis. Unless there is a discrepancy of co-existence of an independent acute abdominal condition and lassa fever, lassa fever should rest the
surgical adventure. If this is not done the patient may succumb to some of the conditions discussed below.
Acute systemic disease with sepsis results in about 20% of infected people with multiple organ failure due to primary systemic viraemia.1,2 Renal,
hepatic, pulmonary and circulatory failure may occur at various degrees.1 This is one of the reasons while surgical option is reserved as the disease
is a medical condition requiring supportive treatment in addition to treatment with ribavirin. The best result being obtained if treatment is started less
than 6 days from the onset of the infection.1,2 At the autopsies of several patients that died from lassa fever, no particular lesion that could explain
the death of the patients were found.13,18 In some other cases of such autopsies, however, various degrees of liver and splenic necrosis were
found.13,17,18 These lesions are probably best treated medically.
In conclusion, high index of suspicion and applying recommended clinical diagnostic criteria are helpful in clinical diagnosis of lassa fever for those
cases of lassa fever presenting with acute abdominal pain in lassa fever-endemic regions. Lassa fever is a medical condition and with high index of
suspicion it is possible to diagnose lassa fever even in the presence of signs and symptoms of lassa fever that might suggest other surgical
conditions. This is necessary in order not to worsen the prognosis and increases the risk of nosocomial transmission to the staff involved in surgical
treatment.
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Footnotes
Source of Support: None declared.
Conflict of Interest: None declared.
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REFERENCES
1. Richmond JK, Baglole DG. Lassa fever: Epidemiology, clinical features and social consequences. BMJ. 2003;327:1271–5. [PMCID:
PMC286250] [PubMed: 14644972]
2. Fisher-Hoch SP, Tomori O, Nasidi A, Perez-Oronoz GI, Fakile Y, Hutwagner L, et al. Review of cases of nosocomial Lassa fever in Nigeria:
The high price of poor medical practice. BMJ. 1995;311:857–9. [PMCID: PMC2550858] [PubMed: 7580496]
3. Ogbu O, Ajuluchukwu E, Uneke CJ. Lassa fever in West African sub-region: An overview. J Vector Borne Dis. 2007;44:1–11. [PubMed:
17378212]
4. Bausch DG, Demby AH, Coulibaly M, Kanu J, Goba A, Bah A, et al. Lassa fever in Guinea: I. Epidemiology of human disease and clinical
observations. Vector Borne Zoonotic Dis. 2001;1:269–81. [PubMed: 12653127]
5. Kitching A, Addiman S, Cathcart S, Bishop L, Krahé D, Nicholas M, et al. A fatal case of Lassa fever in London, January 2009. Euro Surveill.
2009. [Last accessed on 2011 October 12]. p. 14. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19117 .
6. Schmitz H, Köhler B, Laue T, Drosten C, Veldkamp PJ,nther S, et al. Monitoring of clinical and laboratory data in two cases of imported
Lassa fever. Microbes Infect. 2002;4:43–50. [PubMed: 11825774]
7. Demby AH, Inapogui A, Kargbo K, Koninga J, Kourouma K, Kanu J, et al. Lassa fever in Guinea: II. Distribution and prevalence of Lassa
virus infection in small mammals. Vector Borne Zoonotic Dis. 2001;1:283–97. [PubMed: 12653128]
8. Salami TA, Samuel SO, Oziegbe OE. Improving clinical diagnostic accuracy of lassa fever-the use of WBCT-20. Afr J Clin Exp Microbiol.
2006;7:185–9.
9. Omilabu SA, Badaru SO, Okokhere P, Asogun D, Drosten C, Emmerich P, et al. Lassa fever, Nigeria, 2003 and 2004. Emerg Infect Dis.
2005;11:1642–4. [PMCID: PMC3366737] [PubMed: 16355508]
10. FMOH/WHO. Viral haemorrhagic fever (Lassa) Recommended chart for use in health facilities following surveillance to ease definition for
reporting suspected cases of priority diseases and conditions at L.G.A level. 2001
11. McCormick JB, King IJ, Webb PA, Johnson KM, O’Sullivan R, Smith ES, et al. A case-control study of the clinical diagnosis and course of
Lassa fever. J Infect Dis. 1987;155:445–55. [PubMed: 3805772]
12. Schmitz H, Köhler B, Laue T, Drosten C, Veldkamp PJ, Günther S, et al. Monitoring of clinical and laboratory data in two cases of imported
Lassa fever. Microbes Infect. 2002;4:43–50. [PubMed: 11825774]
13. Walker DH, McCormick JB, Johnson KM, Webb PA, Komba-Kono G, Elliott LH, et al. Pathologic and virologic study of fatal Lassa fever
in man. Am J Pathol. 1982;107:349–56. [PMCID: PMC1916239] [PubMed: 7081389]
14. Fleischer K, Köhler B, Kirchner A, Schmid J. Lassa fever. Med Klin (Munich) 2000;95:340–5. [PubMed: 10935419]
15. Monson MH, Cole AK, Frame JD, Serwint JR, Alexander S, Jahrling PB. Pediatric Lassa fever: A review of 33 Liberian cases. Am J Trop
Med Hyg. 1987;36:408–15. [PubMed: 3826501]
16. Hirabayashi Y, Oka S, Goto H, Shimada K, Kurata T, Fisher-Hoch SP, et al. An imported case of Lassa fever with late appearance of
polyserositis. J Infect Dis. 1988;158:872–5. [PubMed: 3171229]
17. Macher AM, Wolfe MS. Historical lassa fever report and 30-year clinical update. Emerg Infect Dis. 2006;12:835–7. [PMCID:
PMC3374442] [PubMed: 16704848]
18. McCormick JB, Walker DH, King IJ, Webb PA, Elliott LH, Whitfield SG, et al. Lassa virus hepatitis: A study of fatal Lassa fever in humans.
Am J Trop Med Hyg. 1986;35:401–7. [PubMed: 3953952]
19. Solbrig MV, McCormick JB. Lassa fever: Central nervous system manifestations. J Trop Geogr Neurol. 1991;1:23–30.
20. Cummins D, Bennett D, Fisher-Hoch SP, Farrar B, Machin SJ, McCormick JB. Lassa fever encephalopathy: Clinical and laboratory findings.
J Trop Med Hyg. 1992;95:197–201. [PubMed: 1597876]
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Figures and Tables
Figure 1
Plain chest radiograph of a patient with lassa fever showing massive bilateral consolidations due to acute respiratory distress syndrome
Figure 2
Dilated fluid-filled bowel loops in a patient who was clinically diagnosed and treated for lassa fever
Figure 3
Bilateral echogenic kidneys due to bleeding within the renal substance in a patient with acute renal failure caused by lassa fever
Figure 4
Gallbladder sonogram showing distended gall bladder with thickened wall and sludge within the gallbladder in a patient with lassa fever
Articles from Nigerian Medical Journal : Journal of the Nigeria Medical Association are provided here courtesy of Medknow Publications
... However, there is a paucity of literature on renal sonographic findings in Lassa fever, especially in our environment. Eze, et al. [10] in a retrospective study on the radiological assessment of acute abdomen in Lassa fever reported increased renal size as well as increased parenchymal echogenicity and loss of corticomedullary A total of 80 subjects were recruited into this study; 40 of these were confirmed Lassa fever subjects admitted to the Lassa fever isolation ward and 40 equal number age and sex-matched apparently healthy volunteers of which majority were members of staff as well as other individuals who had come for routine medical screening at the ISTH. The procedure was adequately explained to all subjects and written informed consent was obtained from all subjects or their relatives. ...
... These are in agreement with reports from studies by Hamper, et al. which showed the degree of increasing echogenicity to be directly proportional to the severity of the disease [19]. The finding of increased echogenicity in this study is also consistent with reports from a retrospective study by Eze, et al. [10] who earlier reported findings of increased renal cortical echogenicity and loss of cortical medullary differentiation in Lassa fever patients. ...
... Although similar to findings seen in Lassa fever, however, values stated are higher than what was obtained in this study, these differences between both study populations may possibly be due to the different imaging modalities used as well as a larger sample size used in their study. Eze, et al. [10] in a retrospective study on Lassa fever patients reported an increase in renal size, this is contrary to findings from the current study. ...
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Background: Lassa fever is an acute viral haemorrhagic fever that affects all major organs of the body including the kidneys. Renal complications of this disease are an important cause of morbidity and mortality in affected patients. Early detection of renal involvement will facilitate the initiation of measures to improve the clinical outcome of such patients as treatment is more effective if initiated early. Ultrasonography is a valuable imaging modality in the evaluation of the kidneys and is useful in assessing early changes in the Kidneys. This study aimed at sonographically evaluating the kidneys in affected patients and correlating findings with serum creatinine. Material and methods: Eighty subjects comprising forty confirmed Lassa Fever patients and forty healthy adults were evaluated. Grayscale ultrasound measurements of the renal parameters; length, width, depth, volume, cortical thickness, and parenchymal echogenicity were done with a 3.5 MHz probe. Findings were correlated with serum creatinine. Data was analyzed using Statistical Package for the Social Sciences version 20.0 (SPSS INC II USA). A statistical test was considered significant at p values less than or equal to 0.05 at a 95% confidence interval. Results: The renal parameters measured were lower in the Lassa fever patients compared to the controls and were statistically significant for length, depth, and cortical thickness. Thirty-seven (92.5%) of Lassa fever patients had increased echogenicity. There was a significant strong positive correlation between serum creatinine and echogenicity (r = 0.731; p = 0.000) in the Lassa fever patients. Conclusion: Although there was a significant reduction in the renal dimensions, serum creatinine levels correlated more strongly with renal parenchymal echogenicity, thus making it a better predictor of parenchymal damage than the renal dimensions.
... In a review article that reported acute abdominal pain in patients with LF, the inclusion criteria were abnormal bleeding from the orifices, conjunctivitis, deafness, spontaneous abortion (for pregnant females), and shock [17]. The resulting complication of LF on the pulmonary system included pulmonary edema, pulmonary hemorrhage, acute respiratory distress, pleural effusion, and aspiration pneumonia [17]. ...
... In a review article that reported acute abdominal pain in patients with LF, the inclusion criteria were abnormal bleeding from the orifices, conjunctivitis, deafness, spontaneous abortion (for pregnant females), and shock [17]. The resulting complication of LF on the pulmonary system included pulmonary edema, pulmonary hemorrhage, acute respiratory distress, pleural effusion, and aspiration pneumonia [17]. ...
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INTRODUCTION: Lassa fever (LF) affects all body systems, however, inadequate knowledge exists on the involvement of the pulmonary system in LF infections. This scoping review, therefore, aimed to describe the pulmonary involvement of LF. MATERIAL AND METHODS: We conducted an extensive search of the literature on two databases, namely PubMed and Google Scholar. Overall, 5,217 articles were retrieved from a database search, out of which 107 duplicates were removed. Overall, 12 articles were included: four review articles, three case reports, three experimental inoculation studies, one retrospective study, and a prospective case-control study. RESULTS: Symptoms experienced included fever, pharyngitis, retrosternal pain, respiratory distress, and proteinuria. Complications included unique pulmonary arteritis, pulmonary embolization, mucosal bleeding, pleural or pericardial effusion, pulmonary edema, and interstitial pneumonitis. Consequences of the effect of Lassa virus infection were impairment of the immune system alongside continual replication of Lassa virus infection in affected tissues and death of affected individuals. LF has varied but serious effects on the pulmonary system. CONCLUSIONS: These symptoms, particularly in areas where LF is known to be endemic, should prompt clinicians to request LF polymerase chain reaction for confirmatory diagnosis. These features should promote the provision of respiratory support for patients in need of such.
... Shock, seizures, tremor, disorientation, and coma have also been reported during this stage of the disease. 7,23,24 Approximately 15-20% of hospitalized LF patients (roughly estimated at 1-3% of all cases) die from the illness, 7 generally within 2 weeks after the onset of symptoms due to multi-organ complication and/ or failure involving the liver, spleen or kidneys. Signs of acute kidney failure have been associated with fatal outcomes and hepatitis is frequent and moderately severe in patients diagnosed with LF. 25 Pregnant women are more likely to have severe illness due to infection with LASV than women who are not pregnant, 4 with maternal case fatality rates as high as 80% and nearly 100% mortality in fetuses. ...
... Infection in infants can result in "swollen baby syndrome" with edema, abdominal distension, bleeding and often death whereas symptoms in children (2 years of age and older) are similar to those seen in adults. 23,25 Neurological problems have also been described in LF patients including hearing loss and encephalopathy. Various degrees of deafness, which may develop during both mild or severe cases, 24 have been shown to occur in patients who survive the disease. ...
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Lassa fever (LF) is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by the Lassa virus (LASV), a member of the family Arenaviridae. It is generally assumed that a single infection with LASV will produce life-long protective immunity. This suggests that protective immunity induced by vaccination is an achievable goal and that cell-mediated immunity may play a more important role in protection, at least following natural infection. Seropositive individuals in endemic regions have been shown to have LASV-specific T cells recognizing epitopes for nucleocapsid protein (NP) and glycoprotein precursor (GPC), suggesting that these will be important vaccine immunogens. The role of neutralizing antibodies in protective immunity is still equivocal as recent studies suggest a role for neutralizing antibodies. There is extensive genetic heterogeneity among LASV strains that is of concern in the development of assays to detect and identify all four LASV lineages. Furthermore, the gene disparity may complicate the synthesis of effective vaccines that will provide protection across multiple lineages. Non-human primate models of LASV infection are considered the gold standard for recapitulation of human LF. The most promising vaccine candidates to date are the ML29 (a live attenuated reassortant of Mopeia and LASV), vesicular stomatitis virus (VSV) and vaccinia-vectored platforms based on their ability to induce protection following single doses, high rates of survival following challenge, and the use of live virus platforms. To date no LASV vaccine candidates have undergone clinical evaluation.
... (Macher and Wolfe, 2006;Shehu et al., 2018) Patients may develop a maculopapular rash, nonpruritic and nonexudative conjunctivitis, pharyngitis, cough, and gastrointestinal symptoms including nausea, vomiting, diarrhea, epigastric discomfort, and intense abdominal pain. (Eze et al., 2014;Brosh-Nissimov, 2016;Kofman et al., 2019;Karnam et al., 2023) Edema may follow decreased blood pressure and increased vascular permeability followed by proteinuria, shock, hemorrhagic diathesis, a comatose state, and death. Survivors may develop neurologic symptoms such as confusion, tremors, ataxia, and seizures weeks to months later. ...
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Lassa virus (LASV) causes an acute multisystemic hemorrhagic fever in humans known as Lassa fever, which is endemic in several African countries. This manuscript focuses on the progression of disease in cynomolgus macaques challenged with aerosolized LASV and serially sampled for the development and progression of gross and histopathologic lesions. Gross lesions were first noted in tissues on day 6 and persisted throughout day 12. Viremia and histologic lesions were first noted on day 6 commencing with the pulmonary system and hemolymphatic system and progressing at later time points to include all systems. Immunoreactivity to LASV antigen was first observed in the lungs of one macaque on day 3 and appeared localized to macrophages with an increase at later time points to include immunoreactivity in all organ systems. Additionally, this manuscript will serve as a detailed atlas of histopathologic lesions and disease progression for comparison to other animal models of aerosolized Arenaviral disease.
... There have been instances of persistent false-negative tests of Lassa fever in patients presenting with classic symptoms of the disease and many of these patients have been managed as Lassa fever and they recovered. 11 It is also known that with highly diverse pathogens such as Lassa virus, genetic diversity can be problematic for nucleic acid-based assays, as even a single nucleotide variant in one of the primers can have a significant negative impact on assay sensitivity depending on the location of the nucleotide variant. 9 This may affect the demonstration of positivity of a particular symptomatic case. ...
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Lassa fever (LF) is an acute viral hemorrhagic fever caused by the Lassa virus, a zoonotic infection transmitted by the infected multimammate mouse which is endemic in West African countries. It affects all ages contributing to high maternal and neonatal mortality rates. Neonates are at risk of vertical and horizontal transmission of Lassa virus. We report a series of six newborns, three of whom were delivered to Lassa fever positive mothers and were managed as exposed babies while the remaining three were diagnosed with neonatal Lassa fever. None of the babies exposed to the virus became infected and two of these exposed babies had a positive outcome. All the babies with neonatal Lassa fever died days after birth even before confirming the diagnosis and initiating ribavirin treatment. This highlights the need for prompt diagnosis in utero with treatment of mother before delivery to improve the neonatal outcome. Also, the need to commence intravenous ribavirin treatment in highly suspicious cases of neonatal Lassa fever while awaiting confirmation of the diagnosis is emphasized.
... Although AAC and acute myocarditis may potentially occur as part of the multiorgan involvement of some systemic infectious diseases (such as Lassa fever, 10 Dengue fever, 11 Chagas disease 12 or viral infections such as Epstein-Barr virus 13 ), less is known about the simultaneous occurrence of this 'odd couple' in otherwise healthy individuals. In 2018, Zenda et al. 14 reported the case of a young Japanese man with co-existing perimyocarditis and gallbladder edema mimicking AAC who thereafter presented with a profound surge of eosinophils. ...
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Acute myocarditis is an inflammatory cardiac disease with different underlying causes and a wide spectrum of clinical presentations from asymptomatic cases to sudden or rapidly evolving acute heart failure. Furthermore, the initial diagnosis can be challenging as it can mimic other respiratory or gastrointestinal disorders. We report the case of an otherwise healthy 24-year-old Caucasian man with a fulminant myocarditis successfully treated with mechanical circulatory support, which was initially misdiagnosed as an isolated uncomplicated acute acalculous cholecystitis.
... Other clinical features are generalized oedema, deafness, respiratory distress and hypotension. Symptoms referable to the neuronal system include: tremors, deafness, and encephalitis [3,25]. In fatal cases, cardiovascular shock and multi-organ failure may precede death. ...
... The lack of inadequacy of knowledge of the disease by healthcare workers plays a definite role in the delayed diagnosis [4]. The lack of specificity of clinical and paraclinical manifestations, especially at the beginning of the disease, makes it impossible to think about it very early [1,[5][6][7][8]. Clinical manifestations sometimes simulate a surgical emergency and diagnosis is only obtained post-operatively [9]. ...
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Background Lassa fever is one of the most lethal neglected tropical diseases in West Africa. It is a serious public health problem in this region of Africa where it is endemic in several countries. However, it remains a very little known disease by healthcare workers. The lack of specificity of its clinical manifestations makes its diagnosis difficult even in an epidemic context. Case presentation We report here a confirmed case of Lassa fever whose diagnosis could not be suspected until 11 days after the symptomatology began. This case was recognized as a suspected case of Lassa fever in the Internal Medicine Department of the Regional and Teaching Hospital of Borgou due to the persistence of the fever and the worsening of the patient’s clinical condition despite triple antibiotic therapy in general and especially due to the appearance of hemorrhages. Confirmation of the presence of Lassa fever virus by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) assay on blood sample was obtained after his death despite late initiation of Ribavirin treatment. Conclusion This case challenges Benin’s health authorities on the need to facilitate access to diagnosis of viral hemorrhagic fevers and to train caregivers at all levels of the health system for better management of these diseases.
Article
Background: Managing Lassa fever (LF) patients is challenging because of the complexity of this life-threatening infectious disease, the necessary isolation measures, and the limited resources in countries where it is endemic. Point-of-care ultrasonography (POCUS) is a promising low-cost imaging technique that may help in guiding the management of patients. Methods: We conducted this observational study at the Irrua Specialist Teaching Hospital in Nigeria. We developed a POCUS protocol, trained local physicians who applied the protocol to LF patients and recorded and interpreted the clips. These were then independently re-evaluated by an external expert, and associations with clinical, laboratory and virological data were analysed. Findings: We developed the POCUS protocol based on existing literature and expert opinion and trained two clinicians, who then used POCUS to examine 46 patients. We observed at least one pathological finding in 29 (63%) patients. Ascites was found in 14 (30%), pericardial effusion in 10 (22%), pleural effusion in 5 (11%), and polyserositis in 7 (15%) patients, respectively. Eight patients (17%) showed hyperechoic kidneys. Seven patients succumbed to the disease while 39 patients survived, resulting in a fatality rate of 15%. Pleural effusions and hyper-echoic kidneys were associated with increased mortality. Interpretation: In acute LF, a newly established POCUS protocol readily identified a high prevalence of clinically relevant pathological findings. The assessment by POCUS required minimal resources and training; the detected pathologies such as pleural effusions and kidney injury may help to guide the clinical management of the most at-risk LF patients.
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In January 2009, the eleventh [corrected] case of Lassa fever imported to the United Kingdom was diagnosed in London. Risk assessment of 328 healthcare contacts with potential direct exposure to Lassa virus - through contact with the case or exposure to bodily fluids - was undertaken. No contacts were assessed to be at high risk of infection and no secondary clinical cases identified.
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To investigate two hospital outbreaks of Lassa fever in southern central Nigeria. Hospitals and clinics in urban and rural areas of Imo State, Nigeria. Medical records were reviewed in hospitals and clinics in both areas. Patients with presumed and laboratory confirmed Lassa fever were identified and contracts traced. Hospital staff, patients, and local residents were questioned, records were carefully reviewed, and serum samples were taken. Serum samples were assayed for antibody specific to Lassa virus, and isolates of Lassa virus were obtained. Among 34 patients with Lassa fever, including 20 patients, six nurses, two surgeons, one physician, and the son of a patient, there were 22 deaths (65% fatality rate). Eleven cases were laboratory confirmed, five by isolation of virus. Most patients had been exposed in hospitals (attack rate in patients in one hospital 55%). Both outbreak hospitals were inadequately equipped and staffed, with poor medical practice. Compelling, indirect evidence revealed that parenteral drug rounds with sharing of syringes, conducted by minimally educated and supervised staff, fuelled the epidemic among patients. Staff were subsequently infected during emergency surgery and while caring for nosocomially infected patients. This outbreak illustrates the high price exacted by the practice of modern medicine, particularly use of parenteral injections and surgery, without due attention to good medical practice. High priority must be given to education of medical staff in developing countries and to guidelines for safe operation of clinics and hospitals. Failure to do so will have far reaching, costly, and ultimately devastating consequences.
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Clinical and laboratory findings are reported in nine patients who developed acute encephalopathy during the course of Lassa fever. The encephalopathy manifested 3-17 days after disease onset with confusion, followed rapidly by tremor (seven patients), grand mal convulsions (seven), abnormal posturing (three) and coma (eight); focal neurological signs and evidence of raised intracranial pressure were not seen. Eight patients died, most commonly from respiratory arrest following a protracted fit. Development of encephalopathy did not correlate with the presence of virus in cerebrospinal fluid (CSF), nor with virus antibodies in CSF and/or serum; thus, neither direct cytopathic nor immune-mediated mechanisms seem to be involved in its pathogenesis.
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A prospective case-control study of Lassa fever was established in Sierra Leone to measure the frequency and case-fatality ratio of Lassa fever among febrile hospital admissions and to better delineate the clinical diagnosis and course of this disease. Lassa fever was responsible for 10%–16% of all adult medical admissions and for rv30% of adult deaths in the two hospitals studied. The case-fatality ratio for 441 hospitalized patients was 16.5%. We found the best predictor of Lassa fever to be the combination of fever, pharyngitis, retrosternal pain, and proteinuria (predictive value together, .81); of outcome, the best predictor was the combination of fever, sore throat, and vomiting (relative risk of death, 5.5). Complications included mucosal bleeding (17%), bilateral or unilateral eighth-nerve deafness (4%), and pleural (3%) or pericardial (2%) effusion. Lassa fever is endemic in this area and is a more-common cause of hospital admission and death than has previously been described; this disease must be considered when diagnosing febrile illness in West Africa.
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Thirty-three cases of pediatric Lassa fever were identified at Curran Lutheran Hospital and Phebe Hospital in Liberia between January 1980 and March 1984. All 18 fetal cases died and the case-fatality rate for 15 childhood cases was 27%. We identified four clinical presentations according to age, including a case of congenital Lassa fever, a condition not reported previously. Two cases of Lassa fever were found serologically during a one-month survey of all pediatric admissions at Curran Lutheran Hospital, 2.4% of those children who had serum pairs collected. We also identified a "swollen baby syndrome" consisting of widespread edema, abdominal distention, and bleeding. This distinctive clinical presentation of Lassa fever ended in death in three of four cases and was present in three of the four childhood deaths in this series. Its absence seems to be a good prognostic indicator in children.
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In order to explore the significance of a previous observation that the most important pathologic changes in fatal Lassa fever are hepatic, we have studied postmortem liver biopsies from 19 patients with fatal Lassa fever. We observed a vigorous macrophage response to cellular damage, but we found no evidence of lymphocyte infiltration in infected hepatic tissues. Using semi-quantitative estimates of liver cell damage, we found a wide range in the severity and progression of Lassa virus hepatitis in our fatal cases. We have classified for descriptive purposes three general nosopoeitic phases: active hepatocellular injury (less than 20% necrosis), continued damage and early recovery, and mitotic activity representing hepatic recovery. We conclude that the liver goes through cellular injury, necrosis and regeneration and any or all may be present at death. In no instance was the degree of hepatic damage sufficient to implicate hepatic failure, and all three phases were represented among our cases. We conclude that the hepatitis of Lassa fever in humans is not the primary cause of death.
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Postmortem examination of 21 virologically documented cases of Lassa fever, including 6 complete autopsies, was performed as part of a field study of community-acquired Lassa fever in Sierra Leone. The most consistently observed lesions were hepatocellular, adrenal, and splenic necrosis and adrenal cytoplasmic inclusions. Neither these lesions, nor other milder and less constantly observed lesions such as myocarditis, renal tubular injury, and interstitial pneumonia, appeared severe enough to explain the cause of death in Lassa fever. The central nervous system (CNS) contained no specific lesions. Viral titrations demonstrated high viral content in liver, lung, spleen, kidney, heart, placenta, and mammary gland. Clinical laboratory data included elevation of hepatic enzymes, creatine phosphokinase (CPK), and blood urea nitrogen (BUN). Because of the paucity of pathologic lesions in spite of widely disseminated viral infection, further investigation of humoral inflammatory mechanisms is indicated.