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INFECTION, HYPOTHENAR SPACE

Introduction

The hypothenar eminence, located on the ulnar side of the palm, controls abduction and assists with flexion of the little finger. Infection of the hypothenar space is very uncommon. However, when the hypothenar space does become infected, prompt emergent attention involving drainage, irrigation and systemic antibiotics is essential for a positive outcome. Potential concerns include complete removal of necrotic tissue, the increased risk for infections with community-acquired methicillin-resistant Staphylococcus aureus (ca-MRSA) and the heath status of the patient.

Pathophysiology

  • 80% of cases present as mixed infections with S. aureus and Streptococcal species.
  • Closed-space infections result from the accumulation of supportive material within deeper palmar structures, dorsal edema, and increased hypothenar compartmental pressure.
  • As a result of the increased pressure, blood flow is obstructed and affected tissues become ischemic and necrotic and less resistant to infection.
  • In severe cases, necrotic liquefaction is apparent; with venous collapse, the pressure gradient between venous and arterial blood flow is lost.
  • Infection will spread via path of least resistance or by way of lymphatics to the dorsum of the hand.
  • Bacterial Infection can be caused by bacteria, fungal infection or mycobacteria.

Related Anatomy

  • The hypothenar space is located at the base of the little finger. The hypothenar space is a potential space between the combined palmar and superficial hypothenar muscle fascia and the deep hypothenar muscle fascia. The hypothenar fascia contains four muscles: abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi and superficially, the palmaris brevis, which protects the nearby neurovascular structures such as the ulnar nerve and artery in Guyon's canal.  This is key because hypothenar infections are usually caused by puncture wounds.
  • Innervation of the hypothenar muscles is supplied by the ulnar nerve.

Incidence and Related Conditions

  • Very rare 
  • Midpalmar space infections can invade the thenar space if persisting for more than 48 hours, or vice versa

Differential Diagnosis

  • Flexor tendon sheath infection of the little finger
  • Ulnar bursa infection
  • Retained contaminated foreign body
  • Cellulitis of the ulnar side of the hand
  • Gout
ICD-10 Codes

  • INFECTION, HYPOTHENAR SPACE

    Diagnostic Guide Name

    INFECTION, HYPOTHENAR SPACE

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    INFECTION, THENAR, HYPOTHENAR, MIDPALMAR SPACE, CUTANEOUS ABSCESS L02.512L02.511 

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
Hypothenar Space Infection
  • Hypothenar Space
    Hypothenar Space
  • Midpalmar Space
    Midpalmar Space
  • Little finger flexor tendon sheath which usually connects to the more proximal ulnar bursa.
    Little finger flexor tendon sheath which usually connects to the more proximal ulnar bursa.
Symptoms
Pain sometimes throbbing
Redness and swelling on ulnar side of the palm
History of a puncture wound
Typical History

The typical patient is likely to have a history of a penetrating injury, fracture, or spread of infection from the midpalmar space.  In the antibiotic era, patients with hypothenar space infections are likely to either have a neglected puncture wound infection, have diabetes, be immunocompromised and/or be a drug user. Early surgical and antibiotic treatment within the first 12-48 hours will be critical for a positive outcome.

Positive Tests, Exams or Signs
Work-up Options
Treatment Options
Treatment Goals
  • Control the infection.
  • Stop the infection.
  • Maintain hand function by avoiding stiffness and fixed contractures.
Conservative
  • Close observation and IV antibiotics are imperative if the working diagnosis is cellulitis without abscess in the hypothenar space
  • If there aren't signs of marked improvement within 24 hours then imaging studies to verify an abscess in the hypothenar space can be considered or done but rapid surgical intervention must be done.
Operative
  • While mindful of neurovascular structures, a longitudinal incision should be made over the hypothenar area.
  • It may be wise to release Guyon's canal to identify and protect the ulnar artery and nerve.
  • Explore hypothenar space with gentle blunt dissection for cavitations and/or foreign body.
  • Debridement of all necrotic tissue and irrigate the wound with copious amounts of normal saline.
  • Do a fasciotomy of the hypothenar fascia to allow for complete wound drainage
  • Allow wound to heal by secondary intention.
  • Apply wet-to-dry dressings twice daily as needed.
  • Tetanus prophylaxis should be given if indicated.
Complications
  • Delay in presentation may worsen prognosis in terms of joint stiffness, adhesions, contracture, osteomyelitis and potential disability.
Outcomes
  • Favorable outcome can be expected with prompt, emergent care.
Key Educational Points
  • A hypothenar space infection is an abscess requiring surgical incision and drainage and will NOT be controlled by IV antibiotics alone.
  • Patient medical history: patients who are immunocompromised, have a history of chronic infections, diabetes mellitus, drug use or are elderly are more vulnerable.
  • Blood tests: complete blood count (CBC), erythrocyte count (ESR), and C-reactive protein (CRP)
  • Cultures ideally should be obtained before initiating antibiotic therapy - Bacterial (aerobic and anaerobic); Fungal and Mycobacterial
  • Gram staining should also be done.
  • After I&D and obtaining appropriate cultures, give IV antibiotics empirically.
  • As soon as culture results are available, they shhould be used to guide antibiotic therapy.
  • ca-MRSA is becoming more common in the non-immunocompromised patient; however, treatment with IV vancomycin should be first justified to avoid drug resistance.
  • S. aureus carrying PVL gene infers necrosis
References

New Articles

  1. Rigopoulos N, Dailiana Z, Varitimidis S, et al. Closed space hand infections: diagnostic and treatment considerations. Orthop Rev (Pavia) 2012;4(2):83-87. PMID: 22802987
  2. Via AG, Oliva F, Spolit M, et al. Acute Compartment Syndrome. Muscles Ligaments Tendons  J 2015;5(1):18-22. PMID: 25878982

Reviews

  1. Lipschitz H, Litchez S. Measurement of compartment pressures in the hand and forearm. J Hand Surg Am 2010;35:1893-1894. PMID: 20870362
  2. Leversedge F, Moore T, Peterson B, et al. Compartment syndrome of the upper extremity. J Hand Surg Am 2011;36(3):544-559. PMID: 21371631

Classics

  1. Kilgore E. Hand infections. J Hand Surg 1983; 8(5):723-726. PMID: 6630953
  2. Spiegel J, Szabo K. A protocol for the treatment of severe infections of the hand. J Hand Surg Am 1988;13(2):254-259. PMID: 3351254
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