In this review, chronic lower limb ulcers were in the third decade of life and tended to affect more males than females, with a male to female ratio of 2:1 which is comparable with other studies in developing countries[16, 17]. Our demographic profile is in sharp contrast to what is reported in developed countries where the majority of the patients are in the sixth decade and above[17–19]. Male predominance in this age group may be due to their increased susceptibility to trauma which was found to be the major etiological agent of chronic lower limb ulcers in this study.
The presence of pre-morbid illness, such as diabetes mellitus, chronic obstructive pulmonary disease, arteriosclerosis, peripheral vascular disease, heart disease, and any conditions leading to hypotension, hypovolaemia, edema, and anemia has been reported elsewhere to have an effect on the outcome of patients with chronic lower limb ulcers[20, 21]. Pre-morbid illnesses influence the healing process as a result of their influence on a number of bodily functions[20–23]. In the presence study, diabetes mellitus was the most common premorbid illness accounting for 59.3% of cases which is agreement with other studies in developing countries[21, 22, 24]. Diabetes mellitus is associated with delayed cellular response to injury, compromised cellular function at the site of injury, defects in collagen synthesis, and reduced wound tensile strength after healing. Diabetes-related peripheral neuropathy, reducing the ability to feel pressure or pain, contributes to a tendency to ignore pressure points and avoid pressure relief strategies.
In the present study, cigarette smoking was reported in 22.7% of cases which is in keeping with other studies[26, 27]. Cigarette smoking has been reported to have an impact on wound healing through impairment of tissue oxygenation and local hypoxia via vasoconstriction. Tobacco smoke has high concentration of carbon monoxide, which binds hemoglobin, forming carboxyhemoglobin. Carboxyhemoglobin binds to oxygen with high affinity and thereby interferes with normal oxygen delivery to hypoxic tissues.
The etiological pattern of chronic lower limb ulcers have been reported in literature to vary from one part of the world to another depending on the prevailing socio-demographic and environmental factors[2, 9]. In Western societies, most chronic lower limb ulcers are due to vascular diseases, whereas in developing countries, trauma, infections, malignancies and poorly controlled diabetes remain the most common causes of chronic lower limb ulceration[2, 9, 10]. In the present study, traumatic ulcers secondary to road traffic accidents were the most common type of chronic lower limb ulcers accounting for more than sixty percent of cases, which is in keeping with other studies done in developing countries[9, 10, 20, 21]. High incidence of traumatic ulcers secondary to road traffic accidents may be attributed to recklessness and negligence of the driver, poor maintenance of vehicles, driving under the influence of alcohol or drugs and complete disregard of traffic laws.
In agreement with other studies in developing countries[3, 24], the majority of patients in the present study presented late to hospital with advanced and complicated chronic lower limb ulcers which may end up being treated by limb amputation with increased risk of recurrence and malignant change. Late presentation in this study may be attributed to poor economic capabilities in cost shared healthcare systems, inadequate knowledge of self-care and socio-cultural reasons. Other contributing factors for late presentation include attempts at home surgery, trust in faith healers, poor management of acute lower limb ulcers and delayed referral in most health centers and peripheral hospitals.
As reported in other studies[30, 31], the leg was the most frequent anatomical site affected in our series and the right side was frequently involved. We could not find the reasons for this anatomical site distribution.
The microbiological profile of chronic ulcers of the lower limbs has application to general principles of treatment as well as institution-specific guidelines for management. In the present study, Pseudomonas aeruginosa was the most frequent gram negative bacteria isolated, whereas gram positive bacteria commonly isolated was Staphylococcus aureus. Similar bacterial profile was reported by Lim et al.. The study also found that most of the pathogens were multiply resistant to the commonly prescribed antibiotics such as Ampicillin, Augmentin, Cotrimoxazole, Tetracycline, gentamicin, erythromycin, and Ceftriaxone. Similar antimicrobial susceptibility pattern has been reported previously. These findings reflect the widespread and indiscriminate use of antibiotics, coupled with poor patient compliance and self treatment without prescription among African patients[32, 33]. The majority of gram negative isolates were sensitive to Meropenem while gram positive being sensitive to Vancomycin; this could be explained by the fact that these antibiotics are relatively rare in the hospital and are more expensive so they are rarely misused.
The prevalence of HIV infection in the present study was 6.7% that is relatively similar to that in the general population in Tanzania (6.5%). High HIV seroprevalence among patients with CLLUs was reported in a Zimbabwean study. HIV seropositive patients have been reported to have a higher risk of developing postoperative complications and have a greater risk of prolonged hospital stay and mortality[16, 18]. HIV infection has been reported to increase the risk of wound sepsis and poor healing. However, in the present study, there were no significant differences in the outcome between patients who are HIV infected and those who are non-HIV infected.
Fungal infections have been reported to be common in chronic lower limb ulcers with the prevalence ranging from 4.5%–50% and[36, 37], are also responsible for some chronic lower limb ulcers e.g. Madura foot[38, 39]. In the present study, fungal infection was not investigated due to logistic problems. This calls for other authors to investigate on this.
Histopathological examination remains the most important definitive diagnostic procedure, and it should be performed on any suspicious lesion or any chronic non-healing ulcers, especially those with any recent change in appearance or considerable drainage. In the present study, malignant ulcers were histopathologically proven in 8.4% of cases, a figure closely to 10.4% reported by Senet et al.. In our study, malignant melanoma was the most frequent histopathological type as previously reported by Chalya et al. at the same centre, but at variant with Senet et al. who reported squamous cell carcinoma as most common histopathological type. This difference in histopathological type reflects geographic differences in exposure to risk factors for developing malignant ulcers. While solar radiation has been suggested as a major cause of malignant melanoma among Caucasians, many of malignant melanoma among black Africans has been reported to be unrelated to solar exposure since they occur on the unexposed plantar of the foot[43–51]. Higher incidence of malignant melanoma in our study may be attributed to repeated trauma and constant pressure on the weight bearing areas of the foot as shoe-wearing is less frequent among people especially those from rural areas[42, 52]. In the present study, Kaposi’s sarcoma ranked third after squamous cell carcinoma. Since the emergence of HIV infection, there has been a steady increase in the prevalence of KS worldwide[53, 54]. The rate of HIV infection among patients with Kaposi’s sarcoma in our study was 60%, a figure slightly lower than that reported by Chalya et al.. Thus it is obvious that successful HIV control will go a long way to reduce the incidence of this vascular malignancy.
The treatment of chronic lower limb ulcers requires multidisciplinary approach[54, 55]. The treatment modalities of chronic lower limb ulcers include surgical treatment (such as wound debridement, wide local excision, split thickness skin graft (STSG) or flap cover, block dissection of the regional nodes and limb amputation in advanced lesions) and non-surgical treatment such daily dressing, compressive bandages and antimicrobial agents bases on drug sensitivity pattern[54, 56–58]. In the present study, wound debridement with or without STSG or flap cover was the most common surgical procedure performed which is in keeping with studies done elsewhere.
The presence of complications has an impact on the final outcome of patients presenting with chronic lower limb ulcers. Most complications are related to late presentation to hospital following ignorance, treatment at home, cost, poverty, advanced malignancy, premorbid conditions like diabetes mellitus, hypertension, and the treatment choices made and the procedures performed. In the present study a total of 178 complications were recorded in 175 (58.3%) patients, mostly being post operative complications. Of these, surgical site infections (77.5%) was the most common post operative complication followed by recurrent ulceration (11.2%) and skin grafting failure (6.2%). Callam et al. reported a similar observation.
The length of hospital stay is an important measure of morbidity in which estimates of length of hospital stay are important for financial matters and accurate early estimates so as to facilitate better financial planning by the payers since it takes long for the chronic lower limb ulcers to heal so increasing the costs as well as seen in other studies as well[16, 18]. In this study, the overall mean length of hospital stay was 28.9 days, a figure which is higher than that reported in other studies[59, 60]. A mean length of hospital stay of 38.2 days was also reported in Nigerian study. A mean of 36.2 days and 64.2 days were reported in Tanzanian and Nigerian studies respectively[16, 24]. Prolonged LOS in our study was observed in patients with diabetic foot ulcers and in patients who required surgical treatment.
In this study, the mortality rate was 4.3% which is relatively lower than that reported in other studies. Mortality rate in the present study was attributed to complications of diabetes mellitus, hypertension, HIV infection and advanced malignancy. The causes of death in our study is at variant with a Nigerian study which reported anemic heart failure, septicemia and multiple organ failure as causes of death. Addressing these factors responsible for mortality in our patients is mandatory to be able to reduce mortality associated with chronic lower limb ulcers.
In this study, complete healing at discharge from the hospital was achieved in more than 90% of the patients, which is comparable with other studies[16, 61]. This is satisfactorily acceptable to both the patient and the surgical team.
Self discharge by patient against medical advice is a recognized problem in our setting and this is rampant, especially amongst patients with chronic lower limb ulcers. In the present study discharge against medical advice was noted in 0.7% of cases. Discharge against medical advice in our study is attributed to patients feeling well enough to leave and dissatisfaction with treatment received.
Poor follow up visits after discharge from hospitals remain a cause for concern in most developing countries. These issues are often the results of poverty, long distance from the hospitals and ignorance. In the present study, only 33.1% of patients were available for follow up at three months, the reasons for low follow up rate at our study may be attributed to long distance from the hospital, lack of funds for transport and feeling of being cured.
Delay in getting histopathological results was the major limitation in this study and this might have affected the treatment outcome of patients who needed this confirmatory diagnostic investigation for definitive treatment.