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Relative risk (RR) compares the probability of disease in exposed vs unexposed groups. An RR of 8.0 means that smokers are 8 times more likely to develop lung cancer than nonsmokers. It does not indicate absolute risk or incidence. For example, if nonsmokers have a 1% risk, smokers would have an 8% risk (not 80%). RR >1 indicates increased risk; RR <1 indicates protective effect. RR is used in cohort studies, while odds ratios are typically used in case-control studies. Accurate interpretation of RR is critical for epidemiology, risk communication, and public health interventions. Smoking cessation reduces RR over time, highlighting its clinical significance.

Foreign body aspiration is common in young children, often involving peanuts or small toys. Clinical features include sudden onset coughing, wheezing, stridor, or unilateral decreased breath sounds. Chest X-ray may show hyperinflation of the affected lung due to air trapping. Asthma exacerbation causes bilateral wheezing and is usually triggered by infection or allergens. Bronchiolitis, caused by RSV, presents with cough, wheezing, and respiratory distress but is diffuse, not unilateral. Pneumonia causes fever, productive cough, and focal crackles with infiltrates on chest X-ray. Diagnosis of aspiration is confirmed with bronchoscopy, which is also therapeutic. Prevention includes avoiding small objects and nuts in young children.

Hyperprolactinemia in women presents with amenorrhea, galactorrhea, and infertility due to inhibition of GnRH and subsequent hypogonadism. The most common cause is a pituitary prolactinoma. Initial workup includes ruling out pregnancy, thyroid disease, and medication-induced hyperprolactinemia. Once elevated prolactin is confirmed, MRI of the brain focusing on the pituitary is the imaging modality of choice. Pelvic ultrasound evaluates ovarian/uterine causes of amenorrhea but not pituitary pathology. CT abdomen and hysterosalpingogram are not indicated. Treatment of prolactinomas includes dopamine agonists (cabergoline, bromocriptine). Surgery is reserved for resistant or compressive tumors. Early detection prevents infertility and compressive complications.

Prostate adenocarcinoma is the most common cancer in men and often metastasizes to bone, producing osteoblastic lesions (contrasting with lytic lesions seen in most other cancers). Clinical features include urinary obstruction, bone pain, and elevated prostate-specific antigen (PSA). Testicular seminomas present with testicular mass, not bone metastases. Bladder carcinoma presents with painless hematuria. Renal cell carcinoma metastasizes to lung and bone but usually causes lytic lesions. Diagnosis is confirmed with prostate biopsy. Management includes surgery, radiation, androgen deprivation therapy, and chemotherapy depending on stage. PSA is useful for monitoring treatment response but not definitive for diagnosis alone.

Fidelity refers to maintaining trust, honesty, and loyalty in the physician–patient relationship. Accepting gifts that influence prescribing undermines fidelity, as decisions should be based solely on patient welfare. Beneficence means acting in the patient’s best interest; nonmaleficence is avoiding harm; justice involves fairness and equity. While all are important, the primary violation here is fidelity, since physician integrity and independence are compromised. Ethical guidelines prohibit accepting gifts that may affect clinical judgment. Physicians should disclose conflicts of interest and ensure prescribing is evidence-based, safeguarding patient trust and professional responsibility.