Annals of African Medicine

ORIGINAL ARTICLE
Year
: 2013  |  Volume : 12  |  Issue : 3  |  Page : 165--170

Corneal ulcers in a tertiary hospital in Northern Nigeria


Kehinde Oladigbolu, Abdulkadir Rafindadi, Emmanuel Abah, Elsie Samaila 
 Department of Ophthalmology, Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria

Correspondence Address:
Kehinde Oladigbolu
Department of Ophthalmology, Ahmadu Bello University Teaching Hospital, Shika-Zaria
Nigeria

Abstract

Background/Objective: To highlight the pattern of corneal ulcers at the Guinness Ophthalmic Unit, Ahmadu Bello University Teaching Hospital, Kaduna, Nigeria. Materials and Methods: A retrospective review of case notes of patients who presented with corneal ulcer at the Guinness Ophthalmic Unit, Ahmadu Bello University Teaching Hospital between January 1995 and December 2005. Information obtained include demographic data, presenting complaints, predisposing factors, microbiological diagnosis, use of orthodox or traditional medications before presentation, duration before presentation and, presenting and final visual acuity. Results: A total of 228 cases presented within the 10 years study period. There were 129 (56.6%) males and 99 (43.4%) females. The age range was 15 months to 66 years. The commonest presenting complaints was poor vision 109 (47.8%) followed by lacrimation 97 (42.5%) and ocular pains 96 (42.1%). The common predisposing factors were trauma 117 (51.3%), use of traditional eye medications 39 (17.1%), self medication with topical steroids 13 (5.7%) and measles 9 (4.0%). The presenting visual acuity was <6/60 in 49.8% of the patients, <6/18-6/60 in 23.4%, and 6/6-6/18 in 25.5% of the patients. At discharge, 45.6% had a visual acuity of 6/6-6/18, 27.2% had borderline vision (<6/18-6/60), 18.0% had severe visual impairment (<6/60), while 6.6% had no light perception. The commonest organisms isolated were Staphylococcus aureus in 19.7%, fungal hyphae in 15.8% and Streptococcus pneumoniae in 4.8%. Conclusion: In this study most patients with corneal ulcer presented with poor vision and excessive lacrimation. Trauma was the commonest predisposing factor with bacterial organisms as the commonest isolate.



How to cite this article:
Oladigbolu K, Rafindadi A, Abah E, Samaila E. Corneal ulcers in a tertiary hospital in Northern Nigeria.Ann Afr Med 2013;12:165-170


How to cite this URL:
Oladigbolu K, Rafindadi A, Abah E, Samaila E. Corneal ulcers in a tertiary hospital in Northern Nigeria. Ann Afr Med [serial online] 2013 [cited 2021 Jun 22 ];12:165-170
Available from: https://www.annalsafrmed.org/text.asp?2013/12/3/165/117626


Full Text

 Introduction



Corneal ulceration is a significant cause of visual impairment and blindness worldwide. Corneal opacification is the second most common cause of monocular blindness after un-operated cataract in some developing countries. [1],[2] The epidemiologic pattern, aetiology and predisposing factors vary in different parts of the world and even from region to region within the same country. Studies have reported incidence of microbial keratitis as low as 11/100,000 persons/year in the US to as high as 799/100,000 persons/year in some developing countries. Ashaye et al. reported that 26.7% of cases of corneal opacity are due to microbial keratitis in Ibadan, Nigeria. [3],[4]

Despite the fact that many pathogens can cause infectious corneal lesions and that many corneal ulcers are secondary to non-infectious processes, generally the term corneal ulcer is used in the context of bacterial infectious keratitis. Strictly speaking, corneal ulcer is considered as any loss of superficial corneal tissue due to necrosis secondary to an infective process. [5] Almost any organism can invade the corneal stroma if the normal corneal defence mechanism i.e. lids, tear film and corneal epithelium are compromised. However, some organisms penetrate intact epithelium. These are Neisseria gonorrhoeae, Corynebacteriium diphteriae, Pseudomonas aeruginosa, and Haemophilus influenzae.[1],[6]

While viral infections are the leading causes of corneal ulcer in the developed nations (with acanthamoeba infections in contact lens wearers); bacteria, fungi and acanthamoeba are important aetiological agents in the developing world. [1],[6],[7] The common predisposing factors are ocular trauma (which may be trivial in some cases), traditional eye medications, and measles in children. [6],[8],[9],[10]

This report is a 10 year review of the pattern of clinical presentation, predisposing factors and treatment outcome of corneal ulcers in a tertiary hospital in Northern Nigeria.

 Materials and Methods



This is a retrospective study. The case records of all patients who presented with corneal ulcers between January 1995 and December 2005 (10 year period) at the Guinness Ophthalmic Unit, Ahmadu Bello University Teaching Hospital were reviewed after approval by the Ethical Review Board of the institution. Information collected from the patients' records included demographic data, presenting complaints, presence of predisposing factors, microbiological diagnosis, duration before presentation and, presenting and discharge visual acuity.

Case records without clinical diagnosis of corneal ulcer by the attending doctor and those with chemical burns were excluded.

The results were analyzed using Analyse-It version 2.12 statistical software.

 Results



A total of 228 clinically diagnosed cases of corneal ulcer who presented during the 10 year period were reviewed. Eleven patients had bilateral involvement, thus making a total of 239 eyes. Three cases of chemical burns were excluded. There were 129 (56.6%) males and 99 (43.3%) females. The age range was 15 months to 66 years [Figure 1]. Majority of the patients were students (32.0%) [Table 1].{Figure 1}{Table 1}

Most patients had multiple presenting complaints with poor vision being the commonest in 109 patients (47.8%) [Figure 2].{Figure 2}

Ocular trauma from varying causes was the predisposing factor in 51.3% of the patients. The use of traditional eye medicines (TEM) was a predisposing factor in 17.1% and self medication with topical steroid/steroid-antibiotic preparations in 5.7% of the patients. Measles was the identified predisposing factor in 9 children (4.0%), 6 of whom were not immunised. An undergraduate developed corneal ulcer from the use of contact lens (0.4%). The predisposing factor could not be ascertained in 21.5% of patients [Table 2].{Table 2}

The presenting visual acuity was <6/60 in 44.4% of the patients, 23.4% had <6/18-6/60 and 25.5% of patients had a visual acuity of 6/6-6/18. No light perception (NLP) was recorded in 12 (5.4%) of the patients [Table 3].{Table 3}

Corneal scraping was done in 169 patients (74.1%) with 58.0% culture positive [Figure 3]. Sixteen eyes (6.7%) had dendritic ulcers presumed to be due to herpes simplex virus. Mooren's ulcer was diagnosed in eight eyes (3.3%) with peripheral ulcers based on clinical appearance and history.{Figure 3}

The duration prior to hospital presentation ranged from <12 hours to >2 weeks. Presentation was <1 week in students, civil servants and preschool children, while housewives and farmers presented >1 week after onset of symptoms.

Hospital admission ranged between 4-19 days. At discharge, 45.6% had a visual acuity of 6/6-6/18, 27.2% had borderline vision (<6/18-6/60), 18.0% had severe visual impairment (6/60), while 6.6% had no light perception. A significant proportion of the patients (49.6%) healed with corneal opacity after treatment [Figure 4].{Figure 4}

 Discussion



In this study, more than half of the patients were males (56.6%) and majority below the age of 40 years. This finding is similar to studies in other parts of Nigeria, [4],[8],[9],[10] Africa [11] and East India. [12] This is probably due to the fact that more males are engaged in outdoor works than the females. Also, women in this part of the country often stay indoors and depend on their husband for finance and decision making even during sickness, thus depriving them of medical care, including eye care. Other workers have similar impression. [13],[14],[15] About a third of the patients were farmers and artisans (31.6%) who are more predisposed to ocular injury at work. Children are more likely to be exposed to ocular trauma especially during unsupervised play [16] as well as disease conditions like measles which has corneal complications.

Poor vision was the most frequent presenting complaints; this would be due to the associated haziness and oedema of the cornea that occurs around the ulcer especially if centrally located. In different parts of the world, predisposing factors to corneal ulcers varies from region to region. Most corneal ulcers in the developing world occur after relatively minor corneal trauma. [13] Ocular trauma was the commonest in this study. This is similar to the experience elsewhere. [4],[8],[9],[10],[11],[12],[14] Vegetable matter was responsible for most of the injuries especially in farmers (n=23). Students are likely to sustain injuries while playing or during sports and manual labour.

Severe corneal ulceration following measles was a common condition throughout sub-Saharan Africa in the 60s and 70s. [15] The prevalence then was as high as 44-81%. Sandford-Smith et al. reported prevalence of 42% in Kaduna in the 70s. [17] Onabolu in 1986 reported a prevalence of 16.6% of post measles keratopathy. [18] The trend has changed significantly over the years as shown by the low prevalence of 4.0% in this study. Study by Nwosu et al. in Eastern Nigeria [8] reported no case of measles-related corneal ulcer. The present low prevalence of measles-related corneal ulcer is not unconnected with the wider coverage by the National Immunization Programme. Although in some parts of Northern Nigeria, some people refuse to accept immunization for cultural and religious reasons. Six of the nine children with measles ulcerative keratitis in this study were not immunized.

All patients who presented to the hospital after 2 weeks (n=36; 15.8%) of onset of symptoms had either used traditional eye medicines or topical steroid-antibiotic preparations or both. This could be because traditional healers are well patronized as alternative source of medical care in Nigeria. Also, there is ready availability of patent medicine dealers who assume the role of an "all-round general medical practitioner, dealer chemist and dispenser in one". Another reason that could account for the indiscriminate self-medication could be lack of finance by rural dwellers to travel to the facility where a qualified Ophthalmologist is located and to pay hospital bills. Studies in other parts of Nigeria and rural Malawi reported that 19.5-34.0% of patients with corneal ulcer had used TEM or steroid preparations before presentation. [8],[10],[19]

Unlike other studies in Nigeria [6],[8],[9],[10] that reported no case of contact lens-related corneal ulcer, a female undergraduate student had corneal ulcer from contact lens (CL) use in our study. The cause was probably due to poor maintenance of the CL or cleaning solution. The prevalence in developed countries could be as high as 30%. [20] Studies in Singapore, Malaysia and India have reported gram negative organisms isolated from CL storage case wells and CL solution and Pseudomonas aeruginosa was the commonest organism (71.4-79.7%). The risk is higher in soft CL-wearers as well as overnight use of any CL compared to daily use. [21],[22],[23]

The spectrum of microbial pathogens producing ulceration varies from population to population as shown by large studies in Asia and Africa. Significantly, the most common bacteria pathogen causing corneal ulceration in the majority of these studies was Streptococcus pneumoniae.[1],[2],[7] Bacteria keratitis was the commonest form of corneal ulcer in this study with Staphylococcus aureus, Streptococcus pneumonia and Pseudomonas aeruginosa as common pathogens isolated in descending order of frequency. This is similar to findings by Nwosu et al. in Onisha, [8] Olawoye et al. in Ibadan [6] and Chaha in Kaduna. [24] A similar work by Onabolu [18] at the study centre in 1986 reported Staphylococcus aureus as the most common cultured organism, followed by Pseudomonas aeruginosa and Nisseria gonorrhoea. Studies done in South India and Ghana showed a different pattern with Streptococcus pneumonia being the most common. [7],[25]

We found a relatively high incidence (15.8%) of mycotic corneal ulcer which could be explained by the high number of ocular injuries caused by vegetation related materials in farmers and students. Similar observations were made by Nwosu et al. [8] and Chaha [24] in Nigeria and other workers in developing countries. [11],[19] Gugnani et al. [26] in Nigeria and Garg et al. [27] in India reported Fusarium solani and Aspergillus species as common causes of keratomycosis. In southern Florida, United States, Liesegang et al. [28] recorded a high incidence of Fusarium solani, also Vanzinni et al. reported Fusarium solani as the most frequent agent of fungal keratitis (37.2%) in an eye care hospital in Mexico city. [29]

Corneal ulcers caused by viral agents were diagnosed clinically by assessing the pattern of fluorescein stained corneal lesions seen under the slit lamp bio-microscope. There were no facilities for viral culture and isolation at the study centre. Three patients (1.3%) had facial crops of vesicular rashes typical of herpes zoster ophthalmicus. They all tested positive to HIV I and II and were referred to the retroviral clinic for treatment.

Mooren's ulcer has been reported to be prevalent in Northern and Southern Nigeria. [30],[31] It is a type of peripheral ulcer usually associated with autoimmune disease or immunological reactions to mycobacterial and Staphylococcus aureus toxins. The present study recorded eight eyes with Mooren's ulcer in seven male and one female patients. They were all less than 30 years of age and mostly unilateral. This pattern fits into the type II Wood and Kaufman [18] clinical classification with male preponderance, black race and young adults affected. The patients were treated with peritomy; two patients who had successful cryotherapy eventually became blind.

About half of the patients presented with poor vision in the affected eye (51.2%). At discharge, there was an improvement in visual acuity of 2-3 lines (Snellen's/Illiterate E charts) in 26.4% of the patient while 17.1% had minimal improvement of ≤1 line. Most of those who presented early had better outcome (≥2 lines). There was very little or no improvement in the visual acuity of farmers who had used TEM before presentation and in those with fungal keratitis despite intensive treatment. Studies in Ibadan reported poor visual outcome in farmers as 75% of them still had severe impairment at discharge. [6] Studies have reported failure rate of primary treatment as high as 31% and evisceration rate of 25% in eyes with fungal keratitis. [32] Patients with visual acuity of less than 3/60 were counselled on rehabilitation and referred to one of three rehabilitation centres in the state.

The recommended management guidelines for microbial corneal ulcers stipulates prompt and accurate microbial identification and drug sensitivity test; initial intensive antibiotic therapy based on local epidemiological experience and close monitoring of disease progression with a view of referring cases of failed initial therapy to specialists. [33] Due to inadequate laboratory support and poor patient motivation in developing countries, as in the study centre, patients are usually commenced on broad spectrum topical antibiotics and sub-conjunctival antibiotic injections. Where possible, corneal scrapings were taken before commencing antibiotic treatment and the drugs modified towards the sensitivity result later.

The limitations of this study include the retrospective nature, poor laboratory support to ensure prompt specimen processing and incomplete patient data entry and clinical notes.

 Conclusion



In this study most patients with corneal ulcer presented with poor vision and excessive lacrimation. Trauma was the commonest predisposing factor with bacterial organisms as the commonest isolate.

 Acknowledgement



The authors sincerely acknowledge the contributions of the record staff of the eye clinic that painstakingly retrieved the patients folders. We are also grateful to the resident doctors of the department for collating the data.

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