Regarding the clinical manifestation of malignant spinal cord compression (MSCC), which ONE of the following is TRUE?
Answer: A: Pain is by far the most common presenting symptom of MSCC, occurring in approximately 90% of patients. It is typically worse at night when the patient is recumbent due to lengthening of the spine, or with Valsalva manoeuvre. Initially, the pain is localised and confined to the area of spinal metastases. As the tumour compresses or invades the nerve roots, radicular pain will be experienced. Most patients (80%) with MSCC have a prior diagnosis of cancer and it is therefore important to maintain a high clinical index of suspicion and low threshold for imaging in cancer patients presenting with back pain.
Motor deficit is the second most common symptom of MSCC (60–85%), followed by sensory deficits (40–80%). Weakness is most apparent in the proximal muscles. Frequently, it is rather described as clumsiness or heaviness, and can progress to complete paralysis. Sensory deficits rarely occur before motor deficits or pain, and they usually begin distally and ascend as the disease advances. Autonomic/sphincter dysfunction is typically a later finding (40–60%).
References:
Regarding hypercalcaemia associated with malignancy, which ONE of the following is TRUE?
Answer: B: There are three main mechanisms by which malignancy can cause hypercalcaemia of which the production of parathyroid hormone-related protein is responsible for 80% of cases (paraneoplastic syndrome). Other mechanisms include local bone destruction (metastases) and production of vitamin D analogues. In general, calcium levels do not correlate with symptoms, since the acuity of the rise is more important. Hypercalcaemia associated with cancer normally occurs rapidly and, therefore, the symptoms of hypercalcaemia are more dramatic. A slow increase in serum calcium may be relatively asymptomatic until reaching high levels.
Hypercalcaemia produces an osmotic diuresis and patients are often profoundly dehydrated; therefore, initial treatment should begin with volume expansion with intravenous saline. Volume expansion increases calcium excretion by decreasing passive reabsorption in the proximal tubule and the loop of Henle. Furosemide has little additive effect to the use of intravenous saline alone in the treatment of patients with normal cardiac and renal function and should be restricted to patients with heart failure and renal insufficiency to prevent fluid overload, as it may cause even greater intravascular volume depletion. The standard treatment for symptomatic hypercalcaemia is rehydration and the use of a bisphosphonate. However, failure to rehydrate before the use of bisphosphonates can lead to renal failure due to deposition of calcium complexes in the kidney. Pamidronate is a commonly used intravenous bisphosphonate. Adverse effects include transient flu-like illness attributed to an acute reaction to initial infusions, a transient exacerbation of bone pain, a fall in serum calcium concentration that is usually asymptomatic, and a transient lymphopenia. Severe local reactions and thrombophlebitis have followed administration of pamidronate as a bolus injection, so it should be given by slow intravenous infusion (<60 mg/hour).
Additionally, it should be used with caution in patients with renal impairment. If creatinine clearance is <30 mL/min, pamidronate should be avoided unless there is life-threatening hypercalcaemia. With less severe renal impairment, the rate of infusion should be reduced to approximately 20 mg/hour. Other therapies include calcitonin and glucocorticosteroids.
Regarding the assessment of haematological malignancies in children, which ONE of the following is TRUE?
Answer: D: Acute leukaemia is the most common cancer in children and ALL accounts for approximately 75% of these cases. AML and ALL present in a similar manner, with symptoms and signs that are due to ANSWERS 215 replacement of bone marrow by malignant cells and secondary bone marrow failure. Deep bone pain due to marrow involvement is not associated with tenderness. However, bone and periosteal leukaemic infiltration may have exquisite tenderness over the bone. Bone marrow infiltration with leukaemia ‘blasts’ results in anaemia, thrombocytopaenia and neutropenia, which often manifest as fever and infection, pallor, easy bleeding and petechiae. The peripheral white blood cell count may be high, low, or even normal at presentation. In addition to bone marrow failure, patients with AML present with signs and symptoms that are uncommon in ALL; extramedullary involvement as well as signs and laboratory findings of disseminated intravascular coagulation. Manifestations of extramedullary nvolvement include gingival hyperplasia, subcutaneous nodules or ‘blueberry muffins lesions’, and discrete masses composed of AML blasts called chloromas. Gingival hyperplasia in a child is unusual and should raise alarm to the presence of a myelogenous leukaemia, even if no other signs or symptoms are present. Chloromas can occur anywhere but are common in the orbit or peri-orbital region.
The most common complications of the acute leukaemias encountered in the ED include:
1- Bleeding due to either:
2- Tumour lysis
3- Hyperleucocytosis
4- Sepsis
These patients typically have functional neutropenia, even if their neutrophil count is normal, and they are at high risk for gram-positive and gram-negative bacteraemia or sepsis.
Regarding hyperleucocytosis in children with acute leukaemia, which ONE of the following is TRUE?
Answer: B: Hyperleukocytosis is an extreme elevation of the blast count or white blood cell count greater than 100 × 109 /L. The clinical presentation depends largely on the lineage and the number of circulating leukaemic blasts. Risk factors for hyperleukocytosis include age <1 year, male gender, certain subtypes of leukaemia (French-American-British (FAB) Classification M4, M5), and select cytogenetic abnormalities (11q23 rearrangements and the Philadelphia chromosome).
Complications associated with hyperleukocytosis include:
1. Leukostasis: Hyperleukocytosis and leukostasis should be considered a medical emergency because the mortality rate approaches 40%. It is caused by the increased viscosity and sluggish flow of circulating leukaemic blasts in tissue microvasculature resulting in microvascular obstruction with injuries to the lung (dyspnoea, hypoxaemia and respiratory failure) and central nervous system (headache, mental state changes, seizure and stroke) most commonly observed. The frequency of complications is higher in AML than in ALL because the myeloblasts are larger and more adhesive than lymphoblasts.
2. Increased risk for TLS
3. Increased risk for DIC. Disseminated intravascular coagulation occurs in 30–40% of patients with AML and in 15–25% of patients with ALL
4. Increased risk for intracranial hemorrhage if platelets <20 × 109 /L
Patients with hyperleukocytosis should urgently be referred to the haematologist as rapid reduction in the number of circulating blast cells (leukocytoreduction) is essential. Prompt introduction of chemotherapy remains the mainstay of treatment with leukapheresis an important adjunct. ED management includes aggressive intravenous hydration, prevention of TLS and avoidance of treatments that can increase blood viscosity such as pRBC and diuretics. Platelets do not increase the blood viscosity and should be administered for levels <20 × 109 /L to decrease the risk of cerebral haemorrhage. If coma is present and the diagnosis established, a temporising measure can be a 2 U phlebotomy with concomitant volume replacement with 2–3 L of normal saline.
Regarding solid tumours in children, which ONE of the following is TRUE?
Answer: C: Brain tumours are the most common solid tumour in children, and are the second most common childhood cancer. Medulloblastoma, a neuronal tumour of the posterior fossa, is the most common malignant brain tumour in children. A large study of 3300 newly diagnosed pediatric brain tumour patients performed by the Childhood Brain Tumor Consortium reported that nearly two-thirds of patients had chronic or frequent headaches before their first hospitalisation. However, headache is a common complaint in the pediatric population with the prevalence in elementary school children approximately 40–50% and up to 60–80% in the high school years. Additionally, The Childhood Brain Tumor Consortium Study also showed that more than 98% of patients with newly diagnosed brain tumours presenting with headache also had objective neurologic findings. Recommendations for further imaging in children with headache includes occipital location, association with seizures, association with recumbent position, association with vomiting, exacerbation with straining, presence of ominous signs (Cushing’s triad, altered mental status), presence of objective neurologic findings (abnormal eye movements, optic disc distortion or papilledema), asymmetric examination (motor, sensory, deep tendon reflexes), coordination problems (ataxia, dysmetria) and macrocephaly in infants and toddlers.
The most common malignant abdominal tumours in children typically occur before the age of 5 years. Renal tumours and neuroblastoma are the most frequently diagnosed cancers arising in the abdomen. Wilms’ tumour is the most common tumour of the kidney with a peak age of diagnosis at 2–3 years. The most common presentation of Wilms’ tumour is the incidental discovery of a non-tender abdominal mass by parents, caregivers or primary care providers on routine examination. Most children appear well at diagnosis. Neuroblastoma is the most common extracranial solid tumour diagnosed in children. It is a cancer of neural crest origin and can arise in the adrenal gland or as a paraspinous mass anywhere along the sympathetic chain. As with Wilms’ tumour, neuroblastoma is typically a disease of young children with 90% of cases diagnosed in children <5 years of age. Two-thirds of primary neuroblastoma tumours occur in the abdomen. Although neuroblastoma may also present as a painless abdominal mass, constitutional symptoms often occur due to a high prevalence of metastatic disease at diagnosis. Children with neuroblastoma may appear ill and are often irritable. Periorbital ecchymoses and proptosis are classic signs due to metastatic involvement of periorbital bones.
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