Paraneoplastic syndromes
- Created by: MazzaW
- Created on: 05-12-19 14:21
Pleural effusion
Sx: tachypnoea, SOB, cough
Signs: decreased chest expansion, mediastinal shift (often normal but may shift AWAY from effusion, usually apex shift rather than tracheal due to gravity), decreased vocal fremitus/resonance, dull to percussion, reduced air entry, may have bronchial breathing above air-fluid level (aegophony), whispering pectoriloquy, may have pleural rub above air-fluid level if pleura inflamed
Commonly occurs in lung cancer.
SVC obstruction
May be due to extrinsic compression or invasion of SVC. Commonly occurs in small cell lung cancer, also in lymphoma/other lung Ca, can be non-neoplastic.
Sx: facial oedema, head fullness, raised non-pulsatile JVP, distension of chest wall veins (in SVC distribution), arm oedema, facial plethora, chest pain, cough. Sx may be exacerbated on bending forward/lying down. May be quick or gradual onset.
CXR signs: may be normal, superior mediastinal widening, pleural effusion, right-sided hilar mass, anterior mediastinal mass, cardiomegaly, bilateral diffuse infiltrates, calcified paratracheal nodes.
Rx: treat underlying disease (chemo)
Hypercalcaemia
Most common electrolyte disturbance of malignancy. Often due to bony mets. Only a true paraneoplastic syndrome if related to PTHrP.
Sx: nausea, confusion, constipation, polyuria, polydipsia, dehydration, arrhythmias
PTHrP 100x more potent than PTH. Mostly produced by squamous cell lung Ca. Others include squamous cell renal/head+neck/oesophageal. Rarer in breast Ca (usually due to bony mets).
MUST DO serum corrected calcium if suspect this- metabolic emergency.
Ix: serum corrected calcium > 2.7, decreased serum chloride, hypercalciuria, decreased PTH, increased urinary phosphate
Rx: IV saline 1st, then IV bisphosphonates
SIADH
Most common endocrine paraneoplastic syndrome. Usually from small cell lung cancer (also pancreatic Ca, prostate Ca, non-Hodgkin's lymphoma, CNS disease, pulmonary disease, some drugs)
Sx: often asymptomatic but may have CNS toxicity (headaches, fatigue, altered mental state, confusion, seizures).
Ix: exclude non-neoplastic causes, hyponatraemia, normal serum albumin + glucose, serum hypo-osmolality, urin osmolarity > serum osmolarity, high urinary sodium, non-suppressed ADH
Rx: fluid restrict, democlocycline for other Sx
Cushing's syndrome
Ectopic ACTH production, usually from SCLC (50%), also from NSCLC, pancreatic Ca, thymic Ca, carcinoid tumours, phaeochromocytoma, medullary thyroid Ca
Sx: wt gain, central obesity, easy bruising, hirsutism, striae, impaired glucose metabolism, muscle wasting, osteoporosis, amenorrhoea, fatigue, weakness, hypokalaemia, metabolic alkalosis
Presentation: rapid onset, weakness secondary to proximal myopathy, hyperpigmentation, metabolic disturbances
Dx: clinical features, high serum/urinary cortisol, high ACTH, no response to high dose dexamethasone suppression test
Rx: specific anti-tumour Rx, if required decrease cortisol secretion (bilateral adrenalectomy, octreotide, ketoconazole, aminogluthethamide)
Gonadotrophin secretion
Occurs in pituitary tumours, gestational trophoblastic tumours, germ cell tumours, hepatoblastomas, lung Ca
Ix: elevated beta-hCG (urine test as this is faster), gynaecomastia, testicular exam (especially in young patients), CXR/CT chest
Beta-hCG is secreted by lung tumours, GI tract tumours, adrenal tumours, genitourinary tumours and hepatoblastoma. Levels usually correlate with clinical signs
Encephalomyopathies
Commonly in SCLC, also breast and ovarian Ca and non-Hodgkin's lymphoma
Perivascular inflammation and neuronal degeneration, may affect limbic system/brainstem/spinal cord. Loss of neurons in amygdala + hippocampus, insular cortex gliosis, lymphocyte cuffing of blood cells, microglial nodules.
Sx: slow subacute onset, progressive, loss of short term memory, hallucinations, seizures, personality changes
Ix: CSF (increased protein, IgG and lymphocytes- pleocytosis), anti-Hu Ab, MRI changes
Rx: anti-tumour therapy
LEMS
Lambert-Eaton myasthenic syndrome.
Ab-mediated, usually with underlying malignancy (60% cases). Mostly in SCLC, also breast/thymic/GI tract Ca.
Sx: proximal muscle weakness, 30% have dysphagia, Sx improve briefly on starting exercise then get worse again
Dx: EMG
Rx: steroids, treat Ca, plasma exchange (generally effective)
Cholinesterase inhibitors usually ineffective (constrast with myasthenia gravis)
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