All UWorld Notes – Comprehensive Medical Study Resource

PARANEOPLASTIC SYNDROMES




SIADH
- Small cell lung cancer, stroke, hemorrhage, pneumonia, or drugs ↑ADH SIADH ↓ plasma
osmolality (hyponatremia) and ↑ urine osmolality >100 mOsm/kg H2O and urine sodium
concentrationinitially vague Sxuntreated significant hyponatremia seizures and comaRx:
fluid restriction is most important in those who can tolerate it if severe symptomatic or non-
responsive give hypertonic saline Demeclocycline is considered if fluid restriction and ↑ salt intake do
not resolve the condition. Demeclocycline can be nephrotoxic as it works at collecting tubule to inhibit
action of ADH.
- No role of thiazide diuretics. Loops + salt tablets can be given




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, DIGITAL CLUBBING




- Digital clubbing—bulbous enlargement and broadening of fingertips due to CT proliferation at nail bed
and distal phalanx
- Dx: when angle between nail fold and nail plate is > 180⁰ (Lovibond angle)




- Can occur itself or in association with hypertrophic osteoarthropathy (i.e. painful joint enlargement,
periostosis of long bones, and synovial effusions)
- May be hereditary, but is most often due to pulmonary or cardiovascular diseases
- Most common causes: lung malignancies, cystic fibrosis, and right to left cardiac shunt
- Pathogenesis: circulatory disruption from tumors, chronic lung inflammationmegakaryocytes skip
normal route of fragmentation by pulmonary circulation megakaryocytes enter systemic circulation
become entrapped in distal fingertips due to large sizesecrete PDGF and VEGF CT hypertrophy,
capillary permeability and vascularityclubbing
- COPD (causing hypoxemia) alone in the absence of occult malignancy DOES NOT cause clubbing. COPD+
clubbing search for occult malignancy.
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HYPERTROPHIC OSTEOARTHROPATHY (HOA)
- Digital clubbing+ sudden-onset arthropathy, commonly affecting wrists and hand joints
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, - Hypertrophic pulmonary osteoarthropathy (HPOA)—subset of HOA due to underlying lung disease.
Usually due to adenocarcinoma
- CXR is appropriate initial study for underlying cause


MEDIASTINAL GERM CELL TUMORS
- Primary mediastinal germ cell tumors—common in young male pts, locally invasive
- Beta-hCG elevated in both seminomatous and non-seminomatous

NON-SEMINOMATOUS GERM CELL TUMORS
- Large mediastinal mass+ ↑ AFP (unlike seminomatous) and ↑beta-hCG (like seminomatous) vitually
diagnostic
- C/f: cough, chest discomfort, dyspnea on exertion
- Confirm with biopsy
- Perform testicular USG to rule out small primary tumor as management and prognosis differ in both
cases
- Almost all germ cell tumors in mediastinum are primary rather than metastatic

SEMINOMATOUS GERM CELL TUMORS
- Mediastinal mass + ↑ beta-hCG

Benign teratomas—from 3 germ layers—may also present as mediastinal mass—but do not produce tumor
markers


PANCOAST TUMOR/SUPERIOR PULMONARY SULCUS TUMOR




- Pt can also develop ↑ sympathetic activity ↑flushing and sweating on contralateral side of face
during exercise (Harlequin sign)
- Most pancoast tumors are non-small cell lung cancers
- Initial evaluation: chest imaging-CXR CT/MRI
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- CT/MRI brain is also part of later evaluation cox of ↑ risk of brain mets
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, ASPERGILLOSIS




- For treatment: itraconazole or bronchial artery embolization can also be used
- Other conditions like TB should be ruled out.
- Can also occur in bronchogenic cysts and bullae
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