(a) (i) Enumerate the topical antifungal drugs along with their indication and side effects. 5 marks (ii) Name antihelminitic…

(a)(i) Topical antifungals

The topical antifungals, with indications and side effects, are enumerated below:

Imidazoles — clotrimazole, miconazole, ketoconazole, econazole: indicated in dermatophytosis (tinea corporis, cruris, pedis), cutaneous candidiasis and tinea versicolor; side effects are local burning, itching, erythema and rarely contact dermatitis.

Allylamines — terbinafine, naftifine: indicated in dermatophytosis and tinea versicolor; side effects include local irritation, burning and dryness (taste disturbance occurs with oral, not topical, terbinafine). Butenafine is similar.

Polyenes — nystatin, amphotericin B: nystatin is indicated in oral and cutaneous candidiasis; amphotericin B topically for candidiasis and keratomycosis. Side effects are local irritation; systemic absorption is negligible from intact skin.

Ciclopirox olamine: indicated in tinea versicolor, dermatophytosis and cutaneous candidiasis, and as an 8% nail lacquer in onychomycosis; side effects are local irritation and burning.

Morpholines — amorolfine 5% nail lacquer: onychomycosis; side effects are periungual burning and nail discolouration. Tolnaftate: dermatophytosis (not effective in candidiasis); side effects are rare irritation. Newer azoles such as sertaconazole and luliconazole are widely used in India for dermatophytosis.

Others — Whitfield's ointment (benzoic acid plus salicylic acid) for dermatophytosis, selenium sulfide and sodium thiosulfate for tinea versicolor, and griseofulvin (oral, not topical) is excluded. Rarely, systemic absorption from large eroded areas may cause systemic toxicity.

(a)(ii) Antihelminthics in neurocysticercosis

Albendazole (15 mg/kg/day, maximum 1200 mg/day, in two divided doses for 10–14 days) is the drug of choice; praziquantel (50 mg/kg/day in three divided doses for 10–14 days) is an alternative and is added to albendazole when there are more than two viable parenchymal cysts (IDSA–ASTMH 2017 guideline). Antiparasitic drugs are avoided in cysticercal encephalitis with raised intracranial pressure. Corticosteroids are co-administered to control the inflammatory reaction to dying cysts. Side effects: headache, seizures, raised intracranial pressure, nausea, alopecia, hepatotoxicity (albendazole), and dizziness, drowsiness, abdominal pain and raised transaminases (praziquantel).

(b)(i) Cells of the lymphoreticular system

The cells are: lymphocytes (T cells, B cells, natural killer cells), plasma cells, macrophages, dendritic cells (including Langerhans cells and follicular dendritic cells), reticular cells and sinusoidal lining cells of lymphoid organs.

B-cell maturation (schematic, drawn below):

(b)(ii) Pathogenesis of enteric fever

Schematic flowchart (drawn below):

Two important categories of drug resistance in Salmonella Typhi:

• Multidrug resistance (MDR): plasmid-mediated (IncHI1) resistance to the first-line drugs chloramphenicol, ampicillin and cotrimoxazole.
• Fluoroquinolone resistance / decreased ciprofloxacin susceptibility: chromosomal point mutations in gyrA and parC (quinolone-resistance determining region), sometimes with plasmid qnr genes; now the dominant pattern in South Asia, including India. Building on these, extensively drug-resistant (XDR) typhoid (MDR plus fluoroquinolone plus third-generation cephalosporin resistance via plasmid blaCTX-M-15 ESBL), first reported from Sindh, Pakistan in 2016, leaves azithromycin and carbapenems as the options.

(c) Risk factors for lung carcinoma

Smoking is the dominant risk factor, accounting for about 90% of cases, with risk proportional to pack-years; passive smoking adds risk. Radon exposure, asbestos, arsenic, chromium, nickel, silica and polycyclic aromatic hydrocarbons are occupational carcinogens. Air pollution, including biomass fuel and chulha smoke in Indian households, is an important India-specific factor. Genetic susceptibility, EGFR and ALK alterations in never-smokers, and chronic scarring (tuberculosis, interstitial fibrosis) contribute.

Morphological features of three major histological types:

Squamous cell carcinoma: typically central, arising from main or lobar bronchi; shows keratin pearls, intercellular bridges, squamous differentiation, cavitation and local invasion; strong association with smoking.

Adenocarcinoma: typically peripheral; shows glandular or lepidic patterns, mucin production, and is the commonest type in non-smokers and women; EGFR mutations are frequent in Asian populations.

Small cell carcinoma: central, arising from neuroendocrine cells; shows small cells with scant cytoplasm, hyperchromatic nuclei, nuclear moulding, crush artefact and high mitotic rate; strongly associated with smoking and paraneoplastic syndromes.

(d) Classification of CIN/SIL

Cervical intraepithelial neoplasia is classified as CIN 1 (dysplasia confined to the lower one-third of epithelium; Bethesda: low-grade squamous intraepithelial lesion, LSIL), CIN 2 (lower two-thirds; HSIL) and CIN 3 (full thickness, including carcinoma in situ; HSIL). The Bethesda system groups CIN 1 as LSIL and CIN 2 with CIN 3 as HSIL, reflecting the biological behaviour and management.

Role of HPV in pathogenesis: high-risk HPV types 16 and 18 cause about 70% of cervical cancers. Viral E6 oncoprotein binds and degrades p53, and E7 inactivates pRb, releasing E2F and driving uncontrolled proliferation. Integration of viral DNA into the host genome, with loss of E2 repression, leads to persistent E6/E7 expression, genomic instability, accumulation of mutations and progression from LSIL to HSIL to invasive carcinoma. Co-factors include early age at first intercourse, multiple partners, multiparity, smoking, immunosuppression and long-term oral contraceptive use.

(e) Classification of poisons by chief symptoms

Corrosives — strong acids and alkalis: cause burning pain in mouth, throat and stomach, with haematemesis and stricture formation.

Irritants — metallic salts, phosphorus, arsenic: cause vomiting, diarrhoea, abdominal pain and dehydration.

Neurotics — cerebral poisons: somniferous (opium, barbiturates) causing coma with pin-point pupils, inebriants (alcohol, anaesthetics) causing excitement then coma, and deliriants (datura, cannabis) causing delirium with dilated pupils; spinal poisons (strychnine) causing tetanic convulsions with a clear mind; peripheral nerve poisons (curare, hemlock) causing paralysis. Organophosphates, commonly grouped with agricultural poisons, cause a cholinergic crisis with miosis, secretions and fasciculations.

Asphyxiants — carbon monoxide, cyanide, hydrogen sulphide: cause cyanosis, hypoxia and respiratory failure.

Cardiac poisons — aconite, digitalis, oleander: cause arrhythmias, bradycardia and cardiac arrest.

Miscellaneous — drugs, food poisons, snake and scorpion venom, and pesticides.

Legal duties of a medical practitioner in suspected poisoning, under Indian law: treat first, since emergency care cannot be withheld for police formalities (Parmanand Katara v Union of India, 1989); register it as a medico-legal case and inform the police immediately (Section 39 CrPC, now Section 33 BNSS). A government doctor is bound to inform, and omission can attract Section 176/202 IPC (now Sections 211/239 BNS); a private practitioner is expected to inform in the interest of the patient and justice. The doctor must also preserve the stomach wash, vomitus, urine and blood for chemical analysis, maintain detailed and legible records of history, treatment and findings, arrange a dying declaration by a magistrate if the patient's condition is critical (recording it himself, before witnesses, only if there is no time), and attend court as a witness when summoned. The doctor must not refuse treatment, must report suspected homicide or suicide, and must be aware of Section 304B IPC/Section 80 BNS (dowry death) Section 302 IPC/Section 103 BNS where poisoning is suspected to be homicidal, and Section 328 IPC/Section 123 BNS (causing hurt by means of poison). In a death, the body is not to be released without a police inquest (Section 194 BNSS) and post-mortem, and the viscera are preserved for the forensic science laboratory.