Paraneoplastic Syndromes — MCQs

10 questions

Opsoclonus-myoclonus is a phenomenon seen in:

A 64-year-old woman comes to the physician for her routine health maintenance examination. She feels well. She had cervical cancer and received radiotherapy 8 years ago. Her vital signs are within normal limits. On percussion, the spleen size is 15 cm. Otherwise, the physical examination shows no abnormalities. The laboratory test results are as follows: Hemoglobin 10 g/dL Mean corpuscular volume 88 μm3 Leukocyte count 65,000/mm3 Platelet count 500,000/mm3 Two images of the peripheral blood smear are shown on the image. Which of the following is the most appropriate next step in management?

Malignancy-associated hypercalcemia is due to?

Which is not seen in Tumour lysis Syndrome?

What is the most common cause of hypercalcemic crisis?

Anticancer drug causing syndrome of inappropriate antidiuretic hormone secretion (SIADH) as an adverse effect is:

All of the following are paraneoplastic syndromes for renal cell carcinoma except which of the following?

A 7 – year old boy presented with abdominal pain, vomiting, oliguria, and periorbital puffiness following chemotherapy. Investigations reveal hyperuricemia, raised creatinine levels, and hyperkalemia. What is the next best step in the management of this condition ?

Which of the following is the MOST characteristic feature of Eaton-Lambert syndrome?

Q10

Opsoclonus is associated with:

Paraneoplastic Syndromes Indian Medical PG Practice Questions and MCQs

Question 1: Opsoclonus-myoclonus is a phenomenon seen in:

A. Wilms' tumor
B. Meningioma
C. Cortical tuberculoma
D. Neuroblastoma (Correct Answer)

Explanation: ***Neuroblastoma*** - **Opsoclonus-myoclonus syndrome (OMS)** is a rare paraneoplastic neurological disorder primarily associated with childhood neuroblastoma. - It is characterized by rapid, irregular eye movements (**opsoclonus**), brief, involuntary muscle jerks (**myoclonus**), ataxia, and irritability. *Wilm's tumor* - Wilms' tumor (nephroblastoma) is a kidney tumor of childhood and is not typically associated with opsoclonus-myoclonus syndrome. - While it is also a pediatric cancer, its paraneoplastic manifestations are different and do not include OMS. *Meningioma* - Meningiomas are typically slow-growing tumors arising from the meninges in adults, and are not associated with opsoclonus-myoclonus. - Paraneoplastic syndromes are rare with meningiomas, and OMS is not one of them. *Cortical tuberculoma* - A cortical tuberculoma is a granulomatous lesion in the brain caused by Mycobacterium tuberculosis, often seen in individuals with tuberculosis. - While it can cause neurological symptoms like seizures, headaches, and focal deficits, it does not cause opsoclonus-myoclonus syndrome.

Question 2: A 64-year-old woman comes to the physician for her routine health maintenance examination. She feels well. She had cervical cancer and received radiotherapy 8 years ago. Her vital signs are within normal limits. On percussion, the spleen size is 15 cm. Otherwise, the physical examination shows no abnormalities. The laboratory test results are as follows: Hemoglobin 10 g/dL Mean corpuscular volume 88 μm3 Leukocyte count 65,000/mm3 Platelet count 500,000/mm3 Two images of the peripheral blood smear are shown on the image. Which of the following is the most appropriate next step in management?

A. Phlebotomy
B. Rituximab
C. Watchful waiting
D. Allogeneic stem cell transplantation
E. Dasatinib (Correct Answer)

Explanation: ***Dasatinib*** - The patient's presentation with **anemia**, **marked leukocytosis (65,000/mm³) with predominantly myeloid cells**, **thrombocytosis (500,000/mm³)**, and **splenomegaly (15 cm)** is highly suggestive of **Chronic Myeloid Leukemia (CML)**. The peripheral smear showing **myelocytes, metamyelocytes, and basophils** (indicated by arrows on the image) further supports this diagnosis. - **Dasatinib** is a second-generation **tyrosine kinase inhibitor (TKI)** that targets the **BCR-ABL fusion protein**, which is the hallmark of CML. TKIs are the first-line treatment for CML. *Phlebotomy* - This is primarily used for **polycythemia vera** to reduce red blood cell mass and hematocrit. - It is not indicated for CML, which is characterized by an overproduction of myeloid cells, not primarily red blood cells. *Rituximab* - **Rituximab** is a monoclonal antibody targeting the **CD20 antigen** on B-lymphocytes. - It is used in the treatment of **B-cell non-Hodgkin lymphoma** and some autoimmune diseases, not CML. *Watchful waiting* - Given the patient's clear signs of **CML (leukocytosis, thrombocytosis, splenomegaly, and characteristic peripheral smear)**, active treatment is indicated, not watchful waiting. - CML, if left untreated, progresses from the chronic phase to accelerated phase and then to **blast crisis**, which is rapidly fatal. *Allogeneic stem cell transplantation* - **Allogeneic stem cell transplantation** is a potentially curative treatment for CML. - However, it is typically reserved for patients who have **failed TKI therapy** or have high-risk features, as **TKIs are the initial first-line treatment** due to their effectiveness and lower toxicity compared to transplantation.

Question 3: Malignancy-associated hypercalcemia is due to?

A. Vitamin D secretion by tumors
B. Cytokine-mediated osteoclast activation
C. Bone metastases causing osteolysis
D. Parathyroid hormone-related peptide (PTHrP) (Correct Answer)

Explanation: Malignancy-associated hypercalcemia is primarily due to **parathyroid hormone-related peptide (PTHrP)**, which mimics the action of parathyroid hormone, causing increased calcium release from bones [1][2]. This condition is often seen in **solid tumors**, particularly squamous cell carcinomas, and can lead to significant **hypercalcemia** [2][3]. *Tumor lysis syndrome* - Tumor lysis syndrome results from rapid cell lysis leading to **release of intracellular contents**, causing hyperuricemia, not directly hypercalcemia. - It is characterized by **electrolyte imbalances** such as hyperkalemia, hyperphosphatemia, but not primarily hypercalcemia. *IGF-b* - Insulin-like Growth Factor (IGF) is primarily involved in **growth processes** and does not lead to hypercalcemia. - While it has an association with cancer, it does not function in the pathway that elevates serum calcium levels. *IL-7* - Interleukin-7 (IL-7) is mainly related to **T-cell development** and does not play a role in hypercalcemia associated with malignancy. - While cytokines can influence various pathways in cancer, IL-7 is not implicated in **calcium metabolism**.

Question 4: Which is not seen in Tumour lysis Syndrome?

A. Hyperkalemia
B. Hypophosphatemia (Correct Answer)
C. Hyperuricemia
D. Hypocalcemia

Explanation: ***Hypophosphatemia*** - **Tumor lysis syndrome (TLS)** is characterized by the rapid breakdown of tumor cells, leading to the release of intracellular components into the bloodstream. - This process typically results in **acute hyperphosphatemia**, not hypophosphatemia, due to the high phosphate content within tumor cells. *Hyperkalemia* - **Hyperkalemia** is a hallmark of TLS because potassium, a major intracellular cation, is released in large quantities as tumor cells lyse. - Excess potassium can lead to potentially life-threatening cardiac arrhythmias. *Hyperuricemia* - **Hyperuricemia** occurs in TLS because nucleic acids (DNA and RNA) released from dying tumor cells are metabolized into purines, which are then converted to uric acid [1]. - High uric acid levels can precipitate in the renal tubules, leading to **acute kidney injury** [1]. *Hypocalcemia* - **Hypocalcemia** develops in TLS secondary to the acute hyperphosphatemia. - The excess phosphate binds with serum calcium to form **calcium-phosphate precipitates**, effectively lowering the concentration of free ionized calcium.

Question 5: What is the most common cause of hypercalcemic crisis?

A. Carcinoma of the breast
B. Parathyroid adenoma (Correct Answer)
C. Parathyroid hyperplasia
D. Paget's disease

Explanation: ***Parathyroid adenoma*** - **Primary hyperparathyroidism**, most often caused by a solitary parathyroid adenoma, is the leading cause of hypercalcemic crisis, though this is rare [1][2]. - The adenoma autonomously overproduces **parathyroid hormone (PTH)**, leading to increased calcium reabsorption from bone and kidneys, and enhanced intestinal calcium absorption [1]. *Carcinoma of the breast* - While breast carcinoma can lead to **hypercalcemia** through bony metastases or parathyroid hormone-related peptide (PTHrP) production, it's not the most common cause of hypercalcemic crisis. - Metastatic bone disease is a common cause of hypercalcemia in malignancy, but the extent of hypercalcemia varies. *Parathyroid hyperplasia* - **Parathyroid hyperplasia** is a rarer cause of primary hyperparathyroidism compared to adenoma, and thus less frequently causes hypercalcemic crisis [2]. - All four parathyroid glands are typically enlarged and overactive, leading to excessive PTH secretion. *Paget's disease* - **Paget's disease of bone** primarily causes localized areas of increased bone turnover and can lead to elevated **alkaline phosphatase** levels. - It rarely causes significant hypercalcemia, and even more rarely a hypercalcemic crisis, unless there is prolonged immobilization or coexisting hyperparathyroidism.

Question 6: Anticancer drug causing syndrome of inappropriate antidiuretic hormone secretion (SIADH) as an adverse effect is:

A. Paclitaxel
B. Dacarbazine
C. Cyclophosphamide
D. Vincristine (Correct Answer)

Explanation: ***Vincristine*** - Vincristine is a **vinca alkaloid** (microtubule inhibitor) that is **classically associated with SIADH** as a well-documented adverse effect. - The mechanism involves **neurotoxicity** affecting the hypothalamus or posterior pituitary, leading to **excessive ADH secretion**. - This results in **hyponatremia** with concentrated urine and is a high-yield association for medical exams. *Paclitaxel* - Paclitaxel is a **taxane** (microtubule stabilizer) with different adverse effect profile. - Primary adverse effects include **myelosuppression**, peripheral neuropathy, and hypersensitivity reactions. - **SIADH is not a characteristic adverse effect** of paclitaxel. *Dacarbazine* - Dacarbazine is an **alkylating agent** used primarily in melanoma and Hodgkin lymphoma. - Main adverse effects are **myelosuppression**, severe nausea/vomiting, and flu-like symptoms. - **SIADH is not associated** with dacarbazine use. *Cyclophosphamide* - Cyclophosphamide is an **alkylating agent** with well-known adverse effects including hemorrhagic cystitis and myelosuppression. - While cyclophosphamide can rarely cause SIADH, it is **not the classic association** tested in exams. - **Vincristine remains the prototype drug** for anticancer drug-induced SIADH in medical education.

Question 7: All of the following are paraneoplastic syndromes for renal cell carcinoma except which of the following?

A. Fever
B. Amyloidosis
C. Anaemia
D. Acanthosis Nigricans (Correct Answer)

Explanation: Acanthosis Nigricans - Acanthosis nigricans is primarily associated with **insulin resistance** and is not a known paraneoplastic syndrome related to renal cell carcinoma. - Paraneoplastic syndromes typically involve **systemic effects** of tumors rather than dermatological manifestations like acanthosis nigricans. *Fever* - Fever can occur as a result of the body's response to tumors, including renal cell carcinoma, and is classified as a **paraneoplastic syndrome**. - It reflects the **systemic inflammatory response** often seen with malignancies. *Anaemia* - Anaemia is a common paraneoplastic syndrome associated with renal cell carcinoma due to the production of **erythropoietin** or as a result of **chronic disease** [1]. - It can lead to **fatigue** and pallor in affected individuals, making it relevant to renal cancers [1]. *Amyloidosis* - Amyloidosis can occur as a paraneoplastic syndrome in various malignancies, including renal cell carcinoma, due to **protein misfolding** states. - It can lead to complications affecting **kidney function** and other organs, aligning it with renal cell carcinoma, though kidney tumors also frequently present with hypercalcemia [1].

Question 8: A 7 – year old boy presented with abdominal pain, vomiting, oliguria, and periorbital puffiness following chemotherapy. Investigations reveal hyperuricemia, raised creatinine levels, and hyperkalemia. What is the next best step in the management of this condition ?

A. Hydration (Correct Answer)
B. Probenecid
C. Allopurinol
D. Rasburicase

Explanation: ***Hydration*** - This patient presents with **tumor lysis syndrome (TLS)**, characterized by rapid tumor cell breakdown releasing intracellular contents (uric acid, potassium, phosphate) following chemotherapy. - **Aggressive intravenous hydration** is the **first-line and most critical initial step** in TLS management, aiming to maintain urine output at 2-3 mL/kg/hour to prevent uric acid crystal precipitation in renal tubules. - Even with oliguria present, optimizing intravascular volume and renal perfusion is essential before other interventions can be effective - without adequate hydration, rasburicase-generated allantoin cannot be excreted. - **Hydration forms the foundation** upon which all other TLS therapies depend, making it the priority "next best step." *Probenecid* - **Probenecid** is a uricosuric agent that increases renal uric acid excretion by blocking tubular reabsorption. - It is **contraindicated in tumor lysis syndrome** as it increases uric acid concentration in renal tubules, potentially worsening uric acid nephropathy and crystal formation. *Allopurinol* - **Allopurinol** is a xanthine oxidase inhibitor that prevents new uric acid formation by blocking purine metabolism. - While valuable for **prophylaxis** in high-risk patients before chemotherapy, it **does not reduce existing hyperuricemia** in established TLS. - Less effective than rasburicase for treating active, symptomatic hyperuricemia. *Rasburicase* - **Rasburicase** is a recombinant urate oxidase that rapidly converts uric acid to allantoin (5-10 times more soluble). - Highly effective for **treating established hyperuricemia** in TLS and often used in severe cases. - However, as the "next best step," **hydration must be established first** to ensure adequate renal perfusion and allow excretion of metabolites - rasburicase is typically administered **after or concurrent with** hydration initiation. - In clinical practice, both are often started together, but hydration is the foundational intervention.

Question 9: Which of the following is the MOST characteristic feature of Eaton-Lambert syndrome?

A. Repeated electrical stimulation enhances muscle power in it. (Correct Answer)
B. Neostigmine is not effective for this syndrome.
C. It is commonly associated with small cell lung cancer.
D. It can affect the ocular muscles.

Explanation: ***Repeated electrical stimulation enhances muscle power in it.*** - A hallmark feature of **Lambert-Eaton Myasthenic Syndrome (LEMS)** is the **potentiation of muscle strength** with repeated or high-frequency nerve stimulation [2]. - This is due to the disease pathophysiology where repeated stimulation allows the accumulation of **intracellular calcium**, leading to increased acetylcholine release at the neuromuscular junction. *Neostigmine is not effective for this syndrome.* - While it's largely true that **acetylcholinesterase inhibitors** like neostigmine are less effective in LEMS compared to myasthenia gravis, they can still provide some minor symptomatic relief [1]. - Therefore, stating it's *not effective* might be an oversimplification, and it's not the *most characteristic* feature. *It is commonly associated with small cell lung cancer.* - Although LEMS is frequently a **paraneoplastic syndrome** linked to **small cell lung cancer (SCLC)**, this association is a cause/etiology, not a direct characteristic feature of the neuromuscular dysfunction itself [1], [2]. - Approximately 50-60% of LEMS cases are paraneoplastic, with SCLC being the most common underlying malignancy [2]. *It can affect the ocular muscles.* - **Ocular muscle involvement** (e.g., ptosis, diplopia) is a prominent and often initial symptom in **myasthenia gravis** [2]. - In LEMS, ocular muscle weakness is **much less common** and typically mild, if present, distinguishing it from myasthenia gravis.

Question 10: Opsoclonus is associated with:

A. Renal cell carcinoma
B. Neuroblastoma (Correct Answer)
C. Wilms tumor
D. Retinal tumor

Explanation: ***Neuroblastoma*** - **Opsoclonus-myoclonus syndrome (OMS)**, characterized by rapid, chaotic eye movements (opsoclonus) and myoclonus, is a well-recognized paraneoplastic syndrome associated with **neuroblastoma** in children. - This syndrome is thought to be caused by an **autoimmune response** against neural antigens shared by the tumor and the central nervous system [1]. *Renal cell carcinoma* - While renal cell carcinoma can present with various paraneoplastic syndromes, **opsoclonus** is not typically associated with it. - Common paraneoplastic syndromes for renal cell carcinoma include **polycythemia**, hypercalcemia, and hypertension [2]. *Wilms tumor* - **Wilms tumor**, a common pediatric kidney cancer, is generally not associated with neurological paraneoplastic syndromes like opsoclonus. - It is known for its association with certain **congenital anomalies** (e.g., aniridia, hemihypertrophy) but not opsoclonus. *Retinal tumor* - Retinal tumors primarily affect vision and are associated with **ocular symptoms**, such as vision loss or visual field defects. - They do not typically cause systemic neurological paraneoplastic syndromes like **opsoclonus-myoclonus**.

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