Surgical Management of Acute Forearm Compartment Syndrome Due to Suspected Edematous Cutaneous Loxoscelism

Introduction

Acute compartment syndrome is defined as a set of clinical signs and symptoms secondary to the increase in interstitial pressure in an anatomical compartment, resulting in a decrease in tissue perfusion and consequently, cell death. This condition can threaten the functionality and integrity of limbs and, in severe cases, be life-threatening [1,2]. If not treated promptly, acute compartment syndrome can lead to a series of complications, including weakness, contractures, deformity, motor paralysis, sensory neuropathy, and necrosis [3].

Forearm compartment syndrome has been associated with various etiologies, including supracondylar humerus fractures in children and distal radius fractures in children and adults. Other less frequent causes include snake bites, complications from certain infections, and, very rarely, spider bites [4].

Initial assessment should include administering oxygen, elevating the arm in a sling, removing all constrictive dressings, and ensuring the patient is normotensive, since hypotension reduces perfusion pressure, causing further tissue injury. However, the mainstay of treatment is urgent surgical decompression in the form of compartment fasciotomies [1,5,6].

Arachnidism is a public health problem in countries such as Chile, Argentina, Brazil, and the United States, with spider bites from the Loxosceles spp., called brown spiders or fiddlers (violinists), being the most common in the first 3 countries [7]. Loxoscelism is the clinical manifestation related to the venom of the spider bite of the Loxosceles spp., which occurs more frequently in warm periods, such as spring and summer. Currently, this genus includes 140 species distributed in the subtropical and tropical areas of Europe, Africa, Asia, Australia, and the Americas. The species of this genus can live in natural habitats (under rocks, logs, inside holes in trees, and in caves) and inside houses [7]. In Mexico, where it is not a notifiable disease, and there are few reports in the form of clinical cases, its true incidence is unknown. Approximately 3000 to 5000 bites per year have been estimated in Mexico. The states with the highest record of fiddler spiders are Guanajuato, Jalisco, and the State of Mexico [8].

Arachnidism has 2 clinical forms of presentation, namely cutaneous loxoscelism (85% of cases) and cutaneous-visceral or systemic loxoscelism (15% of cases). Cutaneous loxoscelism manifests itself locally/regionally with pain, erythema, and edema, with subsequent necrotic plaque formation at the bite site [1,9]. Cutaneous-visceral loxoscelism can manifest signs and symptoms that include arthralgia, chills, fever, and leukocytosis, and, in severe cases, disseminated intravascular coagulation, hemoglobinuria, myoglobinuria, and acute renal failure [9].

A very uncommon variant of cutaneous loxoscelism, known as cutaneous loxoscelism with edematous predominance, has also been described. This variant accounts for only 4% of cases [4]. Its cardinal sign is edema, which may or may not be accompanied by a necrotic lesion. The edema can prevent the necrotic process by diluting the enzymes produced by the venom [10].

Regarding the treatment of loxoscelism, there is currently no consensus on a criterion standard, and its management remains controversial. The general management of cutaneous loxoscelism includes local application of ice, elevation of the limb, simple wound dressings, antihistamines, antimicrobials, dapsone, systemic corticosteroids, and colchicine. In cases of cutaneous-visceral loxoscelism, management should focus on maintaining hydration, monitoring of fluid and electrolyte disturbances, and management of renal failure [11,12].

Acute compartment syndrome is a very rare complication of cutaneous loxoscelism, with edematous predominance. We present a case of a patient with predominantly edematous cutaneous loxoscelism complicated by acute compartment syndrome of the forearm.

Case Report

The patient was a 62-year-old man with a significant medical history of long-term systemic arterial hypertension, which was adequately controlled, and no other relevant medical conditions. He presented to the Emergency Department with swelling, pain, erythema over the right forearm, and inability to move the right upper limb. He reported that his symptoms began 8 h before hospital admission, after sleeping on an old mattress in a warehouse. He first noticed swelling in his right forearm, followed by the onset of other symptoms. Upon his arrival, he was evaluated by the surgical team. Neurological alterations and cardiovascular compromise were not found. No abdominal abnormalities were detected. The examination revealed a well-circumscribed erythematous macula, approximately 10×10 cm, in the right sub-mammary region. Additionally, there was swelling in the right forearm, characterized by shiny and tight skin and an erythematous plaque with blisters on the ventral side of the forearm (Figure 1). The patient exhibited decreased sensitivity in the distal third of all fingers. Radial, ulnar, and humeral pulses were present and of adequate intensity. Capillary refill time was 4 s, and there was pain on passive stretching of the forearm muscles. The remaining limbs showed no evidence of distal neurovascular involvement

Doppler ultrasound revealed intact flow in the humeral, brachial, and radial arteries, with normal flow observed in the palmar arches as well. Examination of the superficial and deep venous systems revealed adequate augmentation, compressibility, and spontaneous flow, although there was slight limitation by extrinsic compression due to edema and the inflammatory process in the muscles and soft tissues. The superficial radial, basilic, and cephalic veins showed no apparent abnormalities or signs of intrinsic obstruction.

Immediately, the Emergency Department team consulted the Vascular Surgery service, with a suspected diagnosis of venous thrombosis. However, based on the clinical presentation and the patient’s recent exposure history, the Vascular Surgery service suspected acute compartment syndrome, likely secondary to a bite from a Loxosceles spp. spider. Consequently, they requested a consultation with the Toxicology Department, which supported this diagnostic suspicion.

To address the acute compartment syndrome, a dermotomy and anterior and posterior fasciotomy of the right forearm were performed. In addition, a 5-mL vial of Loxosceles fabo-therapeutic antidote was administered, which resulted in a slight improvement of signs and symptoms.

However, after 24 h, the patient continued to exhibit signs of compressive syndrome, and paraclinical tests revealed elevated levels of creatine kinase of 24 787 U/L, a slightly elevated MB fraction of 236 U/L, elevated D-dimer of 953 ng/mL, and increased lactate dehydrogenase of 682 U/L. Based on these findings, the Toxicology Department recommended treatment with fluid resuscitation, dexamethasone 8 mg, and diphenhydramine 50 mg. Additionally, a decision was made to proceed with a second intervention in collaboration with the Plastic Surgery Department. This involved enlarging the previously performed fasciotomies and adding 3 more: 2 on the back of the hand and 1 medial to the thenar eminence. The flexor retinaculum was freed, and this incision was connected to the anterior fasciotomy of the forearm. Tension-free sutures were placed, decompressing the anterior, middle, and posterior compartments of the forearm and hand (Figure 2), accompanied by a second dose of a 5-mL bottle of fabotherapeutic antivenom. Liver function test results were mildly elevated, but there were no indications of acute hepatic or renal failure; creatinine levels remained normal, and urinalysis showed no abnormalities, such as myoglobinuria.

Five days after the fasciotomies, the clinical, metabolic, and surgical evolution of the patient was favorable, with normalization of the biochemical parameters of the rhabdomyolysis and resolution of the compartment syndrome. The Plastic Surgery Department decided to perform primary wound closure, and the patient was discharged the following day, without further complications, after a hospital stay of 9 days.

Discussion

Loxoscelism is an intoxication produced by the venom of the Loxosceles spider, which includes the L. gaucho, L. intermedia, L. laeta, L. deserta, and L. reclusa species. The last one is known as being responsible for most cases in Mexico [8]. In the present case, it was not possible to identify the genus and species of the arachnid; therefore, the therapeutic approach was based solely on clinical suspicion, focusing on resolving the surgical urgency.

There is no prevalence by sex, and it is generally not possible to visualize the spider, since many times at the time of the bite there is no pain, which occurs after 2 to 18 h, secondary to ischemia, as occurred in the present case [8].

In regard of loxoscelism treatment, in 2018, del Puerto et al analyzed a retrospective cohort of patients. The authors reported that most of their patients with cutaneous loxoscelism showed an excellent response after a combined therapy with systemic corticosteroids, antibiotics, antihistamines, and dapsone. They found that up to 59% healed their cutaneous lesions after 1 month of treatment, without associated mortality [11].

The administration of anti-Loxosceles serum has been shown to inhibit the formation of necrotic skin lesions only when administered up to 1 h after the bite [11]. In addition, it does not inhibit venom-induced hemolysis; therefore, its benefits and the period in which its administration would be useful, remain controversial [11,12].

Compartment syndrome has been documented in the medical literature for more than a century. In 1881, Richard Von Volkmann related contracture to muscle ischemia caused by trauma, fractures, bandages, and subsequent inflammation. This pathology is an entity of abrupt onset in which the increase of tissue pressure in an osteofascial space produces a compromise of the microcirculation and subsequently of the function of the structures contained in it, becoming irreversible after 4 to 6 h if fasciotomy is not performed [5]. In our patient, despite a slight increase in the time of evolution, irreversible tissue damage was avoided.

Compartment syndrome of the forearm occurs more frequently in the dorsal and volar compartments, coinciding with the presentation of this case. The main symptom is pain. Intense pain should cause clinicians to suspect this pathology. Likewise, pain on passive stretching of the fingers is a sensitive clinical finding in the onset of compartment syndrome of the forearm; this sign was presented by our patient, and that set the tone for the diagnosis [5,13].

The signs associated with this syndrome have traditionally been described in the English literature as the “5 Ps”: pain, paleness, absence of pulses, paresthesia, and paralysis. The absence of a pulse is considered a late finding and is not always present in compartment syndrome [4,13].

In a 2005 article, Cohen et al described the first reported case of compartment syndrome associated with a black widow bite in a 55-year-old patient who, similar to the patient reported here, presented with swelling and pain in the left arm. Their patient presented immediate symptoms but subsequently developed intense pain that made movement of the fingers and wrist impossible, as well as paresthesia and a single occurrence of vomiting. In the same way as our patient developed compartment syndrome, in their patient, fasciotomy was not indicated, with his symptoms improving after administration of the antidote [2].

In a study in pediatric patients conducted by Hubbard et al, most patients diagnosed with Loxosceles bites presented one or more signs of local inflammation, with cellulitis being the most frequent admission diagnosis. Necrosis was present in 65% of the patients, and in 10% of them, jaundice and rash appeared. Another important finding was the presence of hemolysis in 61.5% of the patients [9].

In 2020, Jara et al reported a case similar to ours, in which a 22-year-old woman developed compartment syndrome after a Loxosceles spider bite. She was initially treated with prednisone and oral antihistamines, and, when acute compartment syndrome was diagnosed, immediate surgical management was decided, and decompressive fasciotomies were performed, with subsequent rehabilitation of the limb. She was discharged 7 days after the intervention [1]. Similar to what they reported, the extensive edematous progression of the cutaneous loxoscelism could have been one of the triggering causes for the development of compartment syndrome in our patient’s forearm.

Edematous-predominant cutaneous loxoscelism as a cause of forearm acute compartmental syndrome is extremely uncommon but should be considered a diagnostic possibility in endemic areas for Loxosceles spp. The mainstay of management is surgical decompression of the affected compartments to restore perfusion to the limb and prevent irreversible sequelae [1,5,12].

Conclusions

Despite the relatively rare occurrence of arachnid bites in urban hospitals, it is crucial for general, vascular, and plastic surgeons to maintain a high clinical suspicion for this condition. It is important to make an accurate differential diagnosis from other pathologies that can present with similar clinical features. Equally important is the interdisciplinary approach to managing this condition, ensuring prompt medical treatment and, if necessary, early surgical intervention. This approach is essential for resolving any complications requiring urgent surgical management, such as compartment syndrome. This case not only serves to document a rare disease, which is already underreported, but also sheds light on an even rarer complication: Compartment syndrome resulting from cutaneous loxoscelism with predominant edema.