Case report 1
A 19-year-old female undergraduate student presented to our hospital on 5 December, 2003, with complaints of high-grade fever of 9 days' duration; vomiting and abdominal pain of 5 days' duration; headache of 4 days' duration; as well as watery, non-mucous, non-bloody diarrhoea and a sore throat, with difficulty in swallowing, of 2 days' duration.
On examination, the patient was acutely ill looking, conscious and alert. Her temperature was 39.4°C; radial pulse was 110 bpm, with regular, normal volume; blood pressure was 100/60 mmHg in the supine position; and the respiratory rate was 22 cycles/minute. A throat examination showed exudative pharyngitis. Petechial haemorrhages, prolonged bleeding from venepuncture sites and nostrils, and bilateral hearing impairment were also noticed. Apart from mild epigastric tenderness, examination of the abdomen, chest- and central nervous systems was unremarkable.
Investigations showed packed cell volume of 33%; erythrocyte sedimentation rate (ESR) of 40 mm/hr (Westergreen); total white blood cell (WBC) count of 2,400 mm; neutrophil count of 30%, lymphocyte count of 70%; proteinuria(++); a throat-swab culture grew alpha haemolytic streptococci; and no malaria parasites were seen on a blood-smear examination.
A clinical diagnosis of probable Lassa fever was made, considering the endemic nature of the disease in our environment. Blood samples were sent for definitive diagnosis. The results were positive for both Lassa virus-specific IgM and Lassa virus-specific reverse transcriptase polymerase chain reaction (RT-PCR), confirming the clinical diagnosis. The patient was admitted and treated with a 10-day course of ribavirin, in addition to other supportive measures. She recovered, but had progressively worsening hearing impairment. She was discharged 11 days after the admission by the physicians and referred to the Ear, Nose and Throat surgeons for management of the worsening hearing disability. A review of our patient showed that the pinnae and external auditory canal appeared normal, while the tympanic membrane was intact and bilaterally shiny. Tuning-fork tests (Rinne and Weber) were equivocal.
A diagnosis of severe sensorineural hearing loss (SNHL) was confirmed with a pure-tone audiogram, revealing a hearing level in the left ear of 70 dB, in the right ear of 75 dB. Four years later, the patient's hearing was still significantly impaired, and currently she uses a hearing-aid.
Case report 2
A 48-year-old female trader presented to our hospital on 20 August, 2007, with a 2-week history of fever and a 6-day history of bilateral hearing loss. There was no history of use of ototoxic drugs.
Physical examination revealed an ill-looking, conscious and alert woman. The temperature at presentation was 36.9°C; pulse was 110 bpm, regular small volume; blood pressure was 90/50 mmHg (supine position); and respiratory rate was 20 cycles/minute. There was bilateral conjuctival haemorrhage. The pinnae appeared normal, whereas the external auditory meatus contained scanty dry wax which was evacuated manually. The tympanic membranes were also intact and shiny. She was audiologically confirmed to have bilateral severe SNHL (68 and 70 dB hearing levels for left and right ear, respectively), culminating in her communicating through sign language. There was no sign of meningeal irritation. The chest and abdominal examinations were normal.
A clinical diagnosis of probable Lassa fever was made. Laboratory investigations showed a packed cell volume of 34%, total WBC count of 7,300/mm3, neutrophil of 82%, lymphocytes of 13% and platelets of 195 000. Urinalysis showed protein (++). Lassa fever virus-specific RT-PCR was positive for Lassa fever, thus confirming the clinical diagnosis (although retrospectively). The patient responded positively to a 10-day course of ribavirin. She was discharged on 4 September, and one year afterwards, severe SNHL still persisted.