Borderline Leprosy

 

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  BB is the immunologic midpoint or mid-zone of the granulomatous spectrum, being its most unstable area, with patients quickly up- or downgrading to a more stable granulomatous posture with or without a clinical reaction. Characteristic skin changes are annular lesions with sharply marginated interior and exterior margins, large plaques with islands of clinically normal skin within the plaque, giving a “Swiss cheese” appearance, or the classic dimorphic lesion. Because of instability, the BB posture is short-lived, and such patients are rarely seen; for example, we have yet to see a nonreactional patient meeting both clinical and histologic criteria.

 

Borderline Lepromatous Leprosy.

 

In BL disease, resistance is too low to significantly restrain bacillary proliferation, but still sufficient to induce tissue-destructive inflammation, especially in nerves. Thus, patients with BL have the worst of both worlds.

The BL category is highly variable in its clinical expression (Fig. 186-3; see eFigs. 186-3.1 through 186-3.3 in on-line edition). Although seen in only one-third of BL patients, the classic dimorphic lesion (one having both morphologies) is the most characteristic, having an annular configuration with a poorly marginated outer border (lepromatous-like) but a sharply marginated inner one (tuberculoid-like; see Fig. 186-3). Poorly or sharply marginated plaques, with “punched out” or “Swiss cheese” sharply marginated areas of normal skin in the interior of the plaque, are also characteristic. Annular lesions with sharply marginated exterior and interior borders are not uncommon. If they occur, lepromatous-like, poorly defined papules and nodules may be numerous, but are usually accompanied by some sharply marginated lesions elsewhere (Fig. 186-4).

Lesions range in number from solitary (something happens first, the tip of an inapparent iceberg) to numerous and widespread. Generally speaking, the annular and plaque lesions, however numerous, are asymmetric, but the lepromatous-like nodules, if numerous, are symmetric. Nerve trunk palsies have their highest prevalence in BL disease but are variable in number, ranging from none to serious deficits, both motor and sensory, in all four extremities. Involvement of both median and ulnar nerves, often symmetrical, is characteristic. If disease is extensive, BL patients may have S-GPSI.

Histologically, one classic response is a dense lymphocytic infiltrate confined to the space occupied by the macrophages (see eFig 186-4.1 in on-line edition). Another classic response is lamination of the perineurium with a lymphocytic infiltrate. The pattern may be that of chronic inflammation. Macrophages may be foamy or undifferentiated. Acid-fast bacilli are easily found.

 

TREATMENT RECOMMENDATIONS

 

Treatment is indicated for all stages of Lyme disease, even though most manifestations resolve over time without therapy. Patients may not be asymptomatic at the time of completion of the antibiotic course but this is not an indication for extending length of therapy; symptoms generally continue to improve steadily over time. Of note, Jarisch-Herxheimer reactions (fevers, chills, and worsening arthralgias and myalgias) are sometimes reported after the initial dose of antibiotics; the reaction is thought to be caused by host reaction to the dying organisms.

The Infectious Disease Society of America has published guidelines for the treatment of all manifestations of Lyme disease,136 although many of the recommendations are

 

 based on expert opinion and not on rigorously controlled clinical trials. Treatment patterns differ in different countries, but no data suggest differences in either the efficacy of specific antibiotics or in the optimal duration of therapy between patients in North America and Europe.

Treatment of all of the cutaneous manifestations of Lyme disease should initially be with oral antibiotics (Table 187-2). Doxycycline is generally considered as first-line therapy, because it has excellent penetration into the central nervous system and is also effective against A. phagocytophilum, the agent of human granulocytic ehrlichiosis. Amoxicillin should be used in children and pregnant women. Cefuroxime is a more expensive first-line agent. These three agents have been found to be equally effective.25,136-138 Macrolides are second-line agents and some evidence suggests that they are less effective than the first-line agents.136 Duration of therapy is generally recommended to be 14 to 21 days; a recent study showed similar outcomes in patients with EM treated with either a 10- or a 20-day course of oral doxycycline.139

Intravenous antibiotics (ceftriaxone, cefotaxime, or penicillin G) may be recommended for patients with cutaneous manifestations that are accompanied by neurologic disease (meningitis, encephalopathy) or high degree heart block. Intravenous antibiotics are also sometimes used for patients with refractory ACA or arthritis.

Treatment of patients with non-specific fibromyalgia-like disease after infection with B. burgdorferi is controversial. There are no controlled trials supporting the use of long-term antibiotic therapy.140

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 PREVENTION

 

Prompt removal of the tick is the most effective measure in preventing disease, as the tick must usually be attached for

24 to 48 hours for transmission to occur. For adult or nymphal I. scapularis ticks that have attached for longer than 36 hours within an endemic area, a single 200-mg dose of doxycycline within 72 hours of tick removal is 87 percent effective in preventing early cutaneous manifestations