FREE Physician Assistant Formulating a Diagnosis Questions and Answers

Question 1

A 4-year-old child is brought to the clinic with a 5-day history of pronounced facial puffiness, especially around the eyes in the morning, and swelling in the legs. The parents also report recent weight gain. Urinalysis reveals 4+ proteinuria, but is negative for blood and white blood cells. Which of the following is the most likely diagnosis?

Accepted Answer

Minimal change disease

Answer

The clinical presentation of a young child with significant edema and massive, selective proteinuria (proteinuria without hematuria) is classic for nephrotic syndrome. Minimal change disease is the most common cause of nephrotic syndrome in children. [1, 4, 8] Post-streptococcal glomerulonephritis typically presents with hematuria, hypertension, and a history of a recent streptococcal infection. IgA nephropathy is the most common cause of glomerulonephritis worldwide but typically presents with gross hematuria following a mucosal infection. A urinary tract infection would present with pyuria and bacteriuria, not massive proteinuria.

Question 2

A 68-year-old female with type 2 diabetes presents to the emergency department with altered mental status. Her family reports a week of increasing polyuria, polydipsia, and lethargy. Laboratory results show a blood glucose of 850 mg/dL, serum bicarbonate of 20 mEq/L, arterial pH of 7.35, and minimal urine ketones. Serum osmolality is calculated to be 345 mOsm/kg. Which of the following is the most likely diagnosis?

Accepted Answer

Hyperosmolar hyperglycemic state (HHS)

Answer

This patient's presentation of profound hyperglycemia (glucose >600 mg/dL), high serum osmolality (>320 mOsm/kg), and altered mental status without significant ketosis or acidosis (pH >7.3, bicarbonate >18 mEq/L) is the hallmark of hyperosmolar hyperglycemic state (HHS). [2, 5, 10] DKA is characterized by lower glucose levels, significant ketosis, and metabolic acidosis. Severe hypoglycemia would present with low blood glucose. Lactic acidosis involves a high anion gap with elevated lactate levels, which is not the primary picture here.

Question 3

A 72-year-old female presents with a six-week history of severe, symmetrical aching and morning stiffness in her shoulders, neck, and hips. The stiffness lasts for over an hour and makes it difficult for her to get out of bed or comb her hair. She reports fatigue but denies new headaches or vision changes. Laboratory studies show an erythrocyte sedimentation rate (ESR) of 85 mm/hr. Which of the following is the most likely diagnosis?

Accepted Answer

Polymyalgia rheumatica

Answer

Polymyalgia rheumatica (PMR) is an inflammatory disorder that characteristically affects adults over 50, causing pain and stiffness in the proximal joints (shoulders, neck, and hips). [9, 26, 28] The presence of prolonged morning stiffness and a markedly elevated ESR are classic findings. [26, 27] Rheumatoid arthritis typically involves smaller, peripheral joints symmetrically. Osteoarthritis does not have a significant inflammatory component (normal ESR) and stiffness is usually brief. Fibromyalgia presents with widespread pain but lacks the objective inflammatory markers seen in this patient.

Question 4

A 38-year-old male presents to his primary care provider after being bitten by a tick while hiking in New England two weeks ago. He now complains of fever, fatigue, and myalgias. On examination, a large, annular, erythematous rash approximately 15 cm in diameter with central clearing is noted on his thigh. Which of the following is the most appropriate term for this rash?

Accepted Answer

Erythema migrans

Answer

Erythema migrans is the pathognomonic skin lesion of early localized Lyme disease, which occurs after a bite from an infected Ixodes tick. It classically appears as an expanding erythematous rash, often with central clearing, resembling a 'bull's-eye'. [7, 13, 14] Urticaria (hives) consists of pruritic wheals. Nummular eczema presents as coin-shaped, scaly plaques. Tinea corporis (ringworm) is a fungal infection with a scaly, advancing border and is typically pruritic.

Question 5

A 45-year-old industrial painter presents with complaints of fatigue, irritability, and diffuse abdominal pain. A complete blood count reveals a microcytic, hypochromic anemia. Which of the following findings on a peripheral blood smear would be most suggestive of lead poisoning as the underlying cause?

Accepted Answer

Basophilic stippling

Answer

Coarse basophilic stippling on a peripheral blood smear is a classic, though not pathognomonic, finding in lead poisoning. [12, 24, 30] It represents aggregates of ribosomes and is a result of lead inhibiting an enzyme involved in red blood cell degradation. Howell-Jolly bodies suggest asplenia. Schistocytes indicate microangiopathic hemolytic anemia. Hypersegmented neutrophils are characteristic of megaloblastic anemia (B12 or folate deficiency).

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FREE Physician Assistant Formulating a Diagnosis Questions and Answers