Rheumatology and Immunology Practice Questions

Q: Rheumatoid factor in rheumatoid arthritis is important because:

Rheumatoid factor is associated with a poor prognosis.. ### Explanation **1. Why Option A is correct:** In Rheumatoid Arthritis (RA), Rheumatoid Factor (RF) is an autoantibody (usually IgM) directed against the Fc portion of IgG [3]. High titers of RF are a significant prognostic marker. Patients who are **seropositive** (RF+) tend to have a more aggressive disease course characterized by greater joint destruction (erosions), increased risk of extra-articular manifestations (e.g., rheumatoid nodules, vasculitis, Felty’s syndrome), and overall poorer functional outcomes compared to seronegative patients [1]. **2. Why the other options are incorrect:** * **Option B:** RF is not 100% sensitive. Approximately 20–30% of patients with clinical RA are **seronegative**. Therefore, the absence of RF does not rule out the diagnosis. * **Option C:** RF is typically **absent** in most forms of Juvenile Idiopathic Arthritis (JIA), except for the specific subtype known as "Polyarticular RF-positive JIA," which accounts for only a small percentage of childhood cases. * **Option D:** RF titers do **not** reliably fluctuate with disease activity. While they may decrease slightly with treatment, they are not used to monitor flares or remission. Clinical markers (like DAS28) and inflammatory markers (ESR/CRP) are used for that purpose [2]. **3. NEET-PG High-Yield Pearls:** * **Most Specific Marker:** Anti-CCP (Anti-cyclic citrullinated peptide) antibodies are more specific (>95%) for RA than RF and are also associated with poor prognosis/erosive disease. * **RF Specificity:** RF is not specific to RA; it can be found in Sjogren’s syndrome (highest titers), SLE, chronic infections (Hepatitis C, TB, Subacute Bacterial Endocarditis), and even in healthy elderly individuals. * **Diagnostic Criteria:** Both RF and Anti-CCP are included in the **ACR/EULAR 2010 classification criteria** for RA.

Q: A 64-year-old woman with a longstanding diagnosis of mixed connective tissue disorder and pulmonary fibrosis is admitted with symptoms of recent increase in postprandrial retrosternal distress, heartburn, and nocturnal cough. Her ECG shows nonspecific T-wave changes and she finds minimal relief of her symptoms with sublingual NTG. On examination, she is not in any acute distress and is afebrile. Chest exam reveals bilateral crackles. CXR is shown. What is the most likely cause of this patient's acute symptoms?

Large hiatal hernia. ***Large hiatal hernia*** - **MCTD** commonly causes **esophageal dysmotility** and **gastroesophageal reflux**, leading to large hiatal hernias with **retrocardiac air-fluid levels** on CXR. - **Postprandial retrosternal distress**, **heartburn**, and **nocturnal cough** are classic **GERD symptoms**, with minimal relief from **NTG** ruling out cardiac etiology. *Mediastinal abscess* - Would present with **high fever**, **sepsis**, and systemic toxicity, which are absent in this afebrile patient. - CXR would show **mediastinal widening** with **fluid collections**, not the typical **retrocardiac air-fluid level** seen with hiatal hernia. *Pneumopericardium* - Would present with **chest pain** and potentially **pericardial friction rub** on examination. - CXR would show **air around the heart** (**pneumopericardium sign**), not the **gastric air-fluid level** behind the heart. *Ileus* - Would present with **abdominal distension**, **nausea**, **vomiting**, and **absent bowel sounds**. - Symptoms are **abdominal**, not the **retrosternal** and **respiratory symptoms** described in this case.

Q: Temporal arteritis is associated with all of the following except?

Low ESR. Temporal Arteritis, also known as **Giant Cell Arteritis (GCA)**, is a large-vessel vasculitis that primarily affects the branches of the external carotid artery. **Why "Low ESR" is the correct answer:** A hallmark of GCA is a **markedly elevated Erythrocyte Sedimentation Rate (ESR)**, typically exceeding **50 mm/hr** (often >100 mm/hr). A low or normal ESR is extremely rare in active GCA and should prompt a search for an alternative diagnosis [1]. C-reactive protein (CRP) is also usually elevated [1]. **Analysis of other options:** * **Elderly patient:** GCA almost exclusively affects individuals **over the age of 50**, with the peak incidence occurring between 70 and 80 years. It is rarely seen in younger populations. * **Giant cells:** Histopathologically, the disease is characterized by granulomatous inflammation of the arterial wall [1]. The presence of **multinucleated giant cells** and internal elastic lamina fragmentation on temporal artery biopsy is diagnostic [1]. * **Polymyalgia rheumatica (PMR):** There is a strong clinical association; approximately **40–50% of patients with GCA also have PMR**, characterized by proximal muscle pain and stiffness in the shoulder and pelvic girdles [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** New-onset headache, jaw claudication (most specific symptom), and scalp tenderness. * **Dreaded Complication:** Sudden, irreversible blindness due to **Anterior Ischemic Optic Neuropathy (AION)**. * **Management:** If GCA is suspected, start **high-dose corticosteroids immediately** to prevent vision loss [1]; do not wait for biopsy results [1]. * **Gold Standard Diagnosis:** Temporal artery biopsy (look for "skip lesions") [1].

Q: What is a cause of nail bed infarctions?

Wegener's granulomatosis. **Explanation:** **Wegener’s Granulomatosis (Granulomatosis with Polyangiitis - GPA)** is a small-vessel vasculitis characterized by necrotizing granulomatous inflammation [1]. While it classically involves the triad of the upper respiratory tract, lungs, and kidneys, it frequently involves the skin and distal extremities. **Nail bed infarctions** (and splinter hemorrhages) occur due to necrotizing vasculitis of the small dermal vessels, leading to ischemia and tissue necrosis in the nail apparatus [1]. **Analysis of Options:** * **Wegener's Granulomatosis (Correct):** As a small-vessel vasculitis, it directly affects the precapillary arterioles and capillaries of the nail bed, leading to visible infarctions [1]. * **H.D (Hodgkin’s Disease):** While paraneoplastic syndromes can occur, HD is not a primary cause of nail bed infarctions. It is more commonly associated with pruritus or ichthyosis. * **Infective Endocarditis:** While this causes **splinter hemorrhages** (micro-emboli), it typically does not cause frank nail bed *infarction* unless there is a massive embolic event, which is less characteristic than the vasculitic process in GPA. * **Polyarteritis Nodosa (PAN):** PAN is a **medium-vessel** vasculitis. It typically presents with livedo reticularis, skin ulcers, and digital gangrene rather than isolated nail bed infarctions, which are more characteristic of small-vessel involvement. **High-Yield Pearls for NEET-PG:** * **GPA Triad:** Sinusitis (saddle nose deformity), Pulmonary nodules/hemorrhage, and Glomerulonephritis (RPGN). * **Marker:** c-ANCA (anti-PR3) is highly specific [2]. * **Nail Findings in Vasculitis:** Nail fold infarcts are a classic sign of systemic involvement in GPA, Systemic Sclerosis, and Rheumatoid Vasculitis [1]. * **Treatment of choice:** Cyclophosphamide + Corticosteroids (or Rituximab) [2].

Question 1

Which of the following features of rheumatic fever is not due to molecular mimicry?

Accepted Answer

Pericarditis

Answer

Myocarditis

Answer

Polyarthritis

Answer

Valvulitis

Question 2

Rheumatoid factor in rheumatoid arthritis is important because:

Accepted Answer

Rheumatoid factor is associated with a poor prognosis.

Answer

An absent rheumatoid factor rules out the diagnosis of rheumatoid arthritis.

Answer

It is very common in childhood rheumatoid arthritis.

Answer

It correlates with disease activity.

Question 3

A 64-year-old woman with a longstanding diagnosis of mixed connective tissue disorder and pulmonary fibrosis is admitted with symptoms of recent increase in postprandrial retrosternal distress, heartburn, and nocturnal cough. Her ECG shows nonspecific T-wave changes and she finds minimal relief of her symptoms with sublingual NTG. On examination, she is not in any acute distress and is afebrile. Chest exam reveals bilateral crackles. CXR is shown. What is the most likely cause of this patient's acute symptoms?

Accepted Answer

Large hiatal hernia

Answer

Mediastinal abscess

Answer

Pneumopericardium

Answer

Ileus

Question 4

Temporal arteritis is associated with all of the following except?

Accepted Answer

Low ESR

Answer

Elderly patient

Answer

Giant cells

Answer

Polymyalgia rheumatica

Question 5

A 43-year-old woman presents with a year of progressive dysphagia. She notes that her hands turn white and become painful upon exposure to cold. She also observes that her face and hands lack wrinkles, despite her age. Physical examination reveals a blood pressure of 115/75 mm Hg and taut, shiny skin on her face and hands. A punch biopsy of the hand skin shows dermal collagenous fibrosis and focal calcification. She undergoes yearly esophageal dilation for 20 years, with no serious illnesses developing during this period. Which of the following serologic test results is most likely to be positive in this woman?

Accepted Answer

Anticentromere antibody

Answer

Anti-DNA topoisomerase antibody

Answer

Antimicrosomal antibody

Answer

Antimitochondrial antibody

Question 6

What is the mechanism of acute rheumatic fever?

Accepted Answer

Cross-reactivity with endogenous antigen

Answer

Innocent bystander effect

Answer

Due to toxin secretion by streptococci

Answer

Release of pyrogenic cytokines

Question 7

A 36-year-old woman presents with increased trouble swallowing. Physical examination finds hypertension and sclerodactyly. Lab tests find Anti-Scl-70 antibodies. Which of the following biopsies is most characteristic of this disorder?

Accepted Answer

A skin biopsy revealing dermal fibrosis with an absence of adnexal structures

Answer

A conjunctival biopsy revealing noncaseating granulomas

Answer

A peripheral nerve biopsy revealing rare acid-fast bacteria

Answer

A subcutaneous fat biopsy revealing an infiltrate of plasma cells and eosinophils

Question 8

What is the drug of choice for an acute attack of hereditary angioneurotic edema?

Accepted Answer

C1 inhibitor concentrate

Answer

Danazol

Answer

Icatibant

Answer

Methylprednisolone

Question 9

A 45-year-old woman presents with pain in her fingers upon cold exposure, arthralgias, and dysphagia for solids. She has a few telangiectasias over the chest but no facial erythema or erythema of extensor surfaces. Physical examination reveals slight skin thickening of the hands, arms, and torso. What is the most appropriate diagnostic workup?

Accepted Answer

Antinuclear, anti-Scl-70, and anticentromere antibodies

Answer

Rheumatoid factor and anti-CCP antibodies

Answer

Creatine kinase (CK) and antisynthetase antibodies (such as anti-Jo-1)

Answer

Blood urea nitrogen (BUN) and creatinine

Question 10

What is a cause of nail bed infarctions?

Accepted Answer

Wegener's granulomatosis

Answer

H.D

Answer

Infective endocarditis

Answer

Polyarteritis nodosa

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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