Mycobacterium haemophilum scleritis: two case reports and review of literature

Abstract

Background: Mycobacterium haemophilum is a rare and emerging nontuberculous mycobacteria (NTM). It normally causes localized or disseminated systemic diseases, particularly skin infections and arthritis in severely immunocompromised patients. There have been 5 cases of M. haemophilum ocular infections reported in the literature. Only 1 case presented with scleritis with keratitis. Here, we reported 2 cases of M. haemophilum scleritis. One of them was immunocompetent host and had keratitis with radial keratoneuritis as a presenting sign.

Case presentation: Case 1: A 52-year-old Thai female with rheumatoid arthritis presented with scleritis. Conjunctival scraping was carried out and the culture result was positive for M. haemophilum. Despite receiving systemic and topical antibiotics, her clinical symptoms and signs worsened. Surgical debridement was performed. After surgery, the lesion was significantly improved and finally turned to conjunctival scarring. Case 2: A 32-year old healthy Thai male without underlying disease presented with nodular scleritis and keratouveitis with multiple radial keratoneuritis. Surgical debridement of the scleral nodule was performed. Initial microbiological investigations were negative. Herpes ocular infections was suspected. Topical antibiotics, oral acyclovir, low-dose topical steroids and systemic steroids were started. The scleral inflammation subsided but later the keratitis relapsed, requiring corneal biopsy. Histopathology of the specimen revealed acid-fast bacteria and M. haemophilum was identified by polymerase chain reaction (PCR) and sequencing. The diagnosis of Mycobacterial keratitis was made. Although using the combination of systemic and topical antibiotics, his clinical status progressively deteriorated. Multiple therapeutic penetrating keratoplasties were required to eradicate the infection. No recurrence was found during the 1-year follow-up in both cases.

Conclusions: M. haemophilum can cause scleritis and keratitis, even in immunocompenent host. Radial keraoneuritis is first described in M. haemophilum keratitis. NTM keratitis should be considered in the differential diagnosis of patients with radial keratoneuritis. Increased awareness and early diagnosis using appropriate culture conditions and molecular techniques are important for the proper treatment of this infection. Prompt surgical intervention appears to be vital for successful management of M. haemophilum scleritis and keratitis.

Keywords: Case report; Keratitis; Mycobacterium haemophilum; Nontuberculous mycobacteria; Radial keratoneuritis; Scleritis.

Fig. 1

Slit-lamp photography of the right eye at initial presentation shows multiple conjunctival pustules and severe scleral inflammation with overlying conjunctival epithelial defects, extending temporally from the 8 to 10 o’clock position (a). Two days after anti-nontuberculous mycobacterial treatment, central corneal epithelial defect without infiltration and diffuse conjunctival hyperemia developed (b). After the resolution of the infection, conjunctival and thinned corneal scar were left (c)

Fig. 2

Slit-lamp photography of the left eye at initial presentation demonstrates conjunctival congestion with a 2 × 2 mm scleral nodule in the temporal quadrant adjacent to the limbus, with dilatation of the superficial and deep episcleral vessels (a). Few radial keratoneuritis in the upper temporal cornea with intact intervening stroma and overlying epithelium were observed. Some small to medium-sized, non-pigmented keratic precipitates (KPs) were present centrally (b-c)

Fig. 3

Slit-lamp photography of the left eye at 6 months after presentation shows a relapse with rapid clinical deterioration. Central corneal edema overlying an area of medium-sized, non-pigmented KPs, with some degree of superficial, gray-white, dry stromal infiltrates was present (a). One week later, multifocal paracentral stromal infiltrates without epithelial defect developed, along with recurrent radial keratoneuritis and worsening of the anterior chamber inflammation (b). Despite aggressive treatment, the corneal lesions became enlarged and rapidly progressed with dense stromal infiltrates and 2 mm hypopyon (c-d), requiring therapeutic penetrating keratoplasty