Common differentials in internal medicine

Question 1

Differential diagnosis for Chest Pain

Answer 1

Cardiac

• myocardial- MI, angina (atherosclerosis, vasospasm)
• valvular- aortic stenosis
• pericardial -pericarditis
• vascular aortic dissection

Respiratory

• parenchymal-pneumonia, cancer
• pleural- pneumothorax, pneumomediastinum, pleural effusion, pleuritis
• vascular- pulmonary embolism

GI

-esophagitis, esophagael cancer, GERD, peptic ulcer disease, Boerhaave’s, cholecystitis, pancreatitis

Others

costochondritis (musculoskeletal), shingles, anxiety

Question 2

What is the differential diagnosis of troponin elevation?

Answer 2

Cardiac-MI, myocarditis, CHF, pericarditis, vasospasm, tachycardia with hemodynamic compromise, cocaine ingestion

Pulmonary- pulmonary embolism

Hepatic-liver failure

Renal- chronic kidney disease

Neuroogic-stroke, intracranial hemorrhage

Systemic-sepsis, prolonged strenuous exercise

Question 3

What is the differential diagnosis for HF exacerbation/ Dypsnea?

Answer 3

Cardiac

• myocardial-HF exacerbation, myocardial infarction
• valvular- aortic stenosis, acute aortic regurgitation, mitral regurgitation/ stenosis, endocarditis,
• pericardial-tamponade
• dysrhythmia

Respiratory

• airways- COPD exacerbation, asthma exacerbation, acute bronchitis, bronchiectasis, foreign body obstruction
• parenchyma-pneumonia, cryptogenic organzing pneumonia, ARDS, interstitial lung disease exacerbation
• vascular-pulmonary embolism, pulmonary hypertension

pleural-pneumothorax, pleural effusion

Systemic

-sepsis, ARDS, metabolic acidosis, anemia, neuromuscular, psychogenic, anxiety

Question 4

Differential diagnosis of wheezing?

Answer 4

Extrathroacic airway obstruction (inspiratory wheeze–> stridor[most commonly inspiratory monophonic wheezing loudest over anterior neck])

Oropharynx-enlarged tonsils, retropharyngeal abscess, obesity, post nasal drip

larynx-laryngeal edema, laryngostenosis, laryngocele, epiglotitis, anaphylaxsis, severe laryngopharyngeal reflux, laryngospasm

vocal chords- vocal chord dysfunction, parlysis, hematoma, tumor, cricoarytenoid arthritis

Intrathoracic airway obstruction (expiratory wheeze)

tracheal obstruction- tracheal stenosis, tracheomalacia, tracheobronchitis, malignancy, benign tumor, aspiration

Tracheal compression-goiter, right sided aortic arch

lower airway obstruction-asthma, COPD, bronchiolitis, bronchiectasis, carcinoid tumor, aspiration, malignancy

parenchyma-pulmonary edema

vascular-pulmonary embolism

Question 5

Differential diagnosis of Respiratory Acidosis

Answer 5

Increased PCO2 secondary to hypoventilation

Respiratory centre depression

Drugs (anesthesia, sedatives, narcotics)

Trauma

Increased ICP

Encephalitis

Stroke

Supplemental O2 in chronic CO2 retainers

Neuromuscular

Myasthenia gravis

Guillain-Barre syndrome

Poliomyelitis

Muscular dystrophies

ALS

Myopathies

Chest wall disease

Airway obstruction ( asthma, COPD)

Parenchymal disease

COPD

Pneumothorax

Pneumonia

Interstitial lung disease

Acute respiratory distress syndrome ( ARDS)

Inadequate mechanical hypoventiallation

Question 6

Differential diagnosis of respiratory alkalosis

Answer 6

Decreased PaCO2 secondary to hyperventilation

Hypoxemia

Pulmonary disease (pneumonia, edema, PE, interstitial fibrosis)

Severe anemia

Heart failure

High altitude

Respiratory centre stimulation

CNS disorder

Hepatic failure

Gram-negative sepsis

Drugs (ASA, progesterone, theophylline, catecholemines, psychotropics)

Pregnancy

Anxiety

Pain

Mechanical hyperventillation

Question 7

What is the definition of acute diarrhea, and what is the differential diagnosis?

Answer 7

Diarrhea= 3 bowel movements/ day or at least 200g of stool/day.

Acute = < 2 weeks, chronic = > 2 weeks

DDX

1)Inflammatory/ Invasive (fever, bloody, tenesmus)

Invasive infections- YSSEC (Yersinia, Shigella, Salmonella, Enterohemorrhagic E. Coli (EHEC), enteroinvasive E.coli (EIEC) … Vibrio, C.diff

Inflammatory- UC, crohns

Ischemic colitis

Radiation colitis

2)Non-inflammatory

Non-invasive infections

bacteria- vibrio cholera, staph aureus, bacillus cerrus, clostridium perfringens, C. diff, ETEC, EPEC

viral- rotavirus, norovirus, CMV

parasites- giardia, cryptosporidium, amoeba

Medications- antibiotics, laxatives, chemotherapy

Question 8

What is the differential for chronic diarrhea?

Answer 8

MISO

Motility- hyperthyroidism, diabetic neuropathy, bacterial overgrowth, IBS, scleroderma

Inflammatory

infections- YSSEC

inflammatory-UC, crohns, radiation, toxic

Secretory

infections

neuroendocrine tumors

medications- senna, dolcolax

others-bile salt enteropathy, fatty acid induced, collagenous colitis, lymphocytic collitis

Osmotic

Maldigestion- pancreatic insufficiency, celiac disease

medications- antacids, antibiotics, Mg citrate, Mg hydroxide, lactulose, sorbitol, colchicine