HIV / AIDS - Epidemiology and Diagnosis MCQs

The alveolar air equation is used to calculate the PAO2. PAO2 = PIO2 - (PaCO2/ R ) Given the barometric pressure of 757 mmHg, FIO2 = 1.0 (100% O2), PaCO2 = 36 mmHg, and R = 0.8, then PAO2 = (1.0)(757 - 47) - (36/0.8) = 710 - 45 = 665 mmHg Pneumocystis is an opportunistic fungal pulmonary pathogen that is an important cause of pneumonia (pneumocystosis) in immunocompromised hosts. HIV patients with a CD4 + cell count below 200/μL have an increased risk of developing Pneumocystis pneumonia. According to new, and still evolving nomenclature, Pneumocystis carinii is the name of the organism derived from rats, and Pneumocystis jiroveci is the name of the organism derived from humans. Reference: Ganong, p 660. Kasper et al., pp 1194-1196, 1583, 1592-1595. Levitzky, p 75. Stead et al., pp 202-204.

In adults, the most common localized form is inguinal/femoral lymphadenopathy In children, it is cervical lymphadenopathy Reference : Harrison's Principles of Internal Medicine, 21 st Ed, Ch: 66 Pg: 458

This question deals with renal autoregulatory mechanism. Under circumstances of reduced perfusion pressure, within the autoregulatory range, the GFR is maintained by the dialation of the afferent arteriole and constriction of the efferent arteriole . The former is mediated by prostaglandins and the latter by Angiotensin II. So drugs that inhibit the production of vasodilatory prostaglandins, eg NSAIDS, will reduce the GFR by inhibiting prostaglandin mediated afferent arteriolar vasodilation. ACEI or ARBs reduce the GFR by inhibiting Angiotensin II mediated efferent arteriolar vasoconstriction. Hence statements 1 and 2 are correct. Reference: Harrison's Principles of Internal Medicine 21st ed, Chap 310 Pg. 2298

Anemia is the most common hematologic abnormality in HIV infected patients and, in the absence of a specific treatable cause, is independently associated with a poor prognosis. Reference: Harrison's Principles of Internal Medicine, 21 st Ed, Ch: 202, Pg:74

There is hyponatremia, hypokalemia and low urea with normal osmolality. This is most likely due to inaccurate sampling from a drip arm. In the other causes of hyponatraemia (true hyponatremia), the plasma osmolality should be low as well. Reference : Harrison's Principles of Internal Medicine 21 st edition Page 2964

This picture could fit Bartter's syndrome , although Bartter's syndrome is rare (1 per million), has an autosomal-recessive pattern of inheritance and commonly presents below the age of 5 years. Features of Bartter's syndrome include volume depletion, tetany and muscle weakness. This woman's occupation is the clue, which unfortunately makes furosemide abuse very much more likely. Conn's syndrome is associated with hypertension and is due to aldosterone excess. Reference : Harrison's Principles of Internal Medicine 21 st edition Page 350

This patient has generalised osteoarthritis (GOA), as there are OA related symptoms in at least three joint areas, namely Bony swellings at distal and proximal IPJs termed Heberden's and Bouchard's nodes respectively Anterior knee pain, worse on climbing stairs, suggesting patella-femoral joint OA, and Low back pain, suggesting spinal degenerative changes. Ankylosing spondylitis typically occurs in young men, and associates with pronounced early morning stiffness and buttock pain. Osteoporosis is not symptomatic, unless accompanied by a spinal fracture. Osteoporotic spinal fractures present with acute pain which improves over a period of few weeks to a couple of months. There are no red-flag symptoms to raise the possibility of discitis or malignancy. Reference: Harrison's Principles of Internal Medicine, 21 st Ed, Ch: 371 Pg: 2858-2859

Answer is B (Secretin injection test) Gastrinomas (Zollinger Ellison Syndrome) are characterized by peptic ulceration due to hypersecretion of gastrin by a non-beta cell tumor. Secretin injection test is the most valuable provocative test in identifying patients with ZES.