Mycobacterial Infections MCQs

Nodules on face are not a feature of facies leprosa. Facies leprosa - Seen in lepromatous leprosy Characterized by the resorption of the nasal bone, anterior nasal spine, supra-incisive alveolar region, and anterior alveolar process of the maxilla, with associated sensory or motor damage depending on the type of nerves involved. Reference: Diseases of Ear, Nose and Throat & Head and Neck Surgery by P L Dhingra, 8 th Edition, pg. no 182 International Textbook Of Leprosy, Part I, Section II, Chapter 2.1, Page 16,17

Tuberculoid leprosy(TT) leprosy is the most common form of the disease encountered in India and Africa but is virtually absent in Southeast Asia, where borderline tuberculoid (BT) leprosy is frequent. Reference : Harrison's Principles of Internal Medicine, 21 st Ed, Ch: 179, Pg: 1385

The most commonly affected nerve trunk in leprosy is the ulnar nerve at the elbow, whose involvement results in clawing of the fourth and fifth fingers, loss of dorsal interosseous musculature in the affected hand, and loss of sensation in these distributions Reference : Harrison's Principles of Internal Medicine, 21 st Ed, Ch: 179, Pg: 1387

Dermatophyte species which have the capabilities to infect keratin and keratinized tissue including the hair. the dermatophytes prefer a warm, moist environment for growth, and as a consequence, infections are common in tropical regions. Reference: Rook's Textbook of Dermatology, 9 th Edition, Chapter 32, Page 18

The gold standard for the diagnosis of urogenital chlamydia infections is nucleic acid amplification testing (NAAT). This test is run on either the vaginal swabs for women or first-catch urine for men. Testing can also be performed on endocervical or urethral swabs. Swabs should have a wire or plastic shaft; the tip should be dacron or rayon or a cytobrush. Reference: Rooks textbook of dermatology, chapter 30, page 13 CDC guidelines 2021

Gradually progressive annular plaque with central scarring and active margins – lupus vulgaris. Tinea cruris: itchy erythematous annular plaque with central clearing Granuloma annulare: asymptomatic skin colored leion with annular beaded margins. Annular psoriasis: erythematous annular plaque with silvery white scaling Reference: Rooks textbook of dermatology 9 th edition, chapter 27, page 21

Explanation: Lupus vulgaris is the most common form of cutaneous tuberculosis in India. It is a chronic, progressive, paucibacillary form occurring in patients with a high degree of immunity to the bacillus. Lesions commonly appear on the legs and buttocks. The plaque enlarges peripherally with serpiginous or verrucous borders , often exceeding 10 cm in diameter, with central discoloration and atrophy . On diascopy, the lesion shows characteristic golden-yellow "apple jelly" nodules . Key Takeaways: Lupus vulgaris = chronic progressive plaque with apple-jelly nodules on diascopy; common on buttocks/legs in India.

Diascopy: pressing a glass slide or a stiff clear colorless piece or plastic onto the skin to cause blanching by compressing blood out of small vessels. This allows colors to be seen. Use of diascopy: Apple jelly nodules: yellow brown lesion seen in lupus vulgaris and sarcoidosis Spider naevi: compression of radiating arterioles Differentiation of erythema and purpura Differentiation of nevus anemicus from nevus achromicus Reference: Rooks textbook of Dermatology, 9 th edition, Chapter 4, page 19