These were once common over most of the tropics, but as living standards rise they go. There is some disagreement as to what causes them. They are generally said to start as small infected cuts from the sharp grasses of bush paths, which would explain their characteristic distribution (D, in Fig. 31-1). Others consider that they are primarily infective, which would explain why they sometimes occur in small epidemics in the wet season. Tropical ulcers develop through three stages: Stage One. A pustule, or neglected cut, containing Vincent's and fusiformis organisms (both are penicillin-sensitive). This stage is not seen in hospital. Stage Two. Progression of the cut or pustule to form an acutely painful ulcer with a raised, thickened, and slightly undermined edge. This ulcer grows rapidly for several weeks. A bloody ]]discharge covers the grey slough on its floor, the skin around it is dark and swollen, and muscle, bone, and tendon occasionally lie exposed in its base. After about a month, the pain, swelling, and discharge improve, and it either heals, or it goes on to the next stage. Stage Three. It becomes chronic, and resembles any other long-standing indolent ulcer.
In Stage Two, when an ulcer is still less than 5 or 6 cm, penicillin and dressings will usually cure it. But if it is larger than this, the epithelium from its edges will take a long time to grow across it, so it needs grafting[md]which is something that every health centre should be able to do.
If you first see a patient in Stage Three, his ulcer may have destroyed the whole thickness of his skin; it may have extended through his deep fascia and exposed bone, tendons or a joint. Osteomyelitis is rare, but a reactive periostitis may in time raise an ulcer above the surrounding skin. Sometimes its edge is thickened and everted, and resembles a carcinoma.
Fig. 31-1 TROPICAL ULCERS. A, the earliest stage of a tropical ulcer is a pustule, containing Vincent's organisms and fusiform bacilli. Alternatively, and some would say more commonly, the early stage is a small cut. B, the pustule ruptures to form an acute ulcer. C, a chronic ulcer showing the exposed tendons. D, the characteristic site of tropical ulcers anteriorly on the lower leg, becoming more lateral lower down. E, an acute tropical ulcer, with an everted oedematous edge, and a dirty slough covering much of its base. F, a chronic ulcer, with an edge which is not raised, and a uniform avascular base. G, a squamous cell carcinoma, with an everted edge, and an irregular base. MOST GRAFTING SHOULD BE DONE AT THE ACUTE OR SUBACUTE STAGE
TROPICAL ULCERS DIFFERENTIAL DIAGNOSIS. The site of a tropical ulcer is its most important diagnostic feature. The differential diagnosis includes: (1) a chronic non-specific ulcer, (2) a squamous cell carcinoma, which resembles a chronic tropical ulcer in that it also has an everted edge (32.19). Also, the following:
Suggesting tuberculosis (unusual)[md]a ragged, shallow ulcer, with bluish overhanging edges. Its base is less vascular, and more fibrous. It you manage it as a tropical ulcer, it will not improve. If you are in any doubt, biopsy it, and try chemotherapy[md]a tuberculous ulcer will heal miraculously.
Suggesting a Buruli ulcer (restricted areas only)[md]an otherwise fit child, or young adult, suffering from a huge ulcer with deeply undermined edges, anywhere on his body, and not necessarily on his feet and lower legs (31.2a).
CAUTION ! The macroscopic differentiation of a chronic tropical ulcer from a malignant ulcer (32.19) can be difficult when there is no extension into the surrounding tissues. Be sure to do a biopsy before you do any radical surgery.
TREATMENT [s7]FOR TROPICAL ULCERS ACUTE ULCERS. Treat him as an outpatient. Get his ulcer clean with saline soaks. Soak off the dressing each day and change it. Give him a bottle of half-strength saline (tap water and salt, which need not be sterile) and ask him to pour this on the dressing every 2 or 3 hours to keep it moist. Give him penicillin.
When his ulcer is clean, usually within 7 days, and if it is [mt]5 cm in diameter, admit him for split skin grafting (Chapter 57). Smaller ulcers will heal without grafting. Give him penicillin for 3 days perioperatively. This kills any streptococci which might dislodge the graft with their fibrinolysin (57.4).
If he is an adult, use local anaesthesia for the donor site (57-4), and ketamine or general anaesthesia if he is a child.
If the granulations are abundant, scrape the base of the ulcer with a scalpel. There is no need to anaesthetize it; there are no nerves in granulation tissue, so this does not hurt, provided you avoid the epithelium. Scraping does not improve the ''take', but it does reduce fibrosis under the graft later, and so makes it more stable.
Control bleeding with hot packs. If possible, apply the graft as a single sheet, which has been meshed to allow the escape of exudate and blood, or, less satisfactorily, apply it as patches or pinch grafts (57.9). If the ulcer is over a joint tendon (uncommon), lay strips of graft across it (57.5).
Keep him in bed for a week to avoid movement, and expose the graft on the 7th day (some surgeons expose it on the 3rd day to inspect it). Then soak off the dressing slowly, to avoid removing the graft at the same time. It may need covering for another week. The donor site should have healed in 10 days.
CHRONIC ULCERS. Split skin grafts do not take well on long-standing fibrotic ulcers, or they may take take initially, and break down later. Ideally, these ulcers need a muscle, or a myocutaneous flap (not described here). Chronic ulcers cause long standing morbidity, and may become malignant, so refer him if you can. If you cannot refer him, you will have to do your best with split skin grafting. You will probably succeed temporarily, but his ulcer will probably recur.
If the base of his ulcer is suitable (57.3), and is not too deeply fibrosed or over bone or tendon, some surgeons would excise and graft it as a single procedure.
Alternatively, and preferably, apply a tourniquet (3.9), and excise the ulcer under ketamine (8.1), or a general anaesthetic. Cut away all avascular scar tissue, until you reach a raw, bleeding surface; if necessary, use an osteotome to remove any dead bone. Apply hypochlorite, or a dry dressing, to the ulcer bed, cover it with gauze, cotton wool, and a bandage, and release the tourniquet.
Five to twelve days later, when the base of the ulcer is covered with suitable granulation tissue, graft it, as described above.
DIFFICULTIES [s7]WITH TROPICAL ULCERS If, after many years, the BASE OF AN ULCER BECOMES HEAPED UP and irregular, and its edges protuberant and rolled, a SQUAMOUS CELL CARCINOMA (epithelioma) has developed, so see Section 32.19. This can happen in three years, or it can take thirty.