Differential Diagnoses And Approaches By Chris Krause

Front 1

Give a DDx for chest pain.

Back 1

Cardiovascular causes:
STEMI
ACS/unstable angina
Angina/CHF
Aortic dissection
Pericarditis/myocarditis

Pulmonary causes:
Pneumonia
Pneumothorax
Pulmonary embolism

MSK or soft tissue:
Strain/sprain/fracture/contusion (of any thoracic structure)
Radiculopathy or neuropathic pain (eg shingles)

GI Causes:
GERD/esophagitis
Esophageal rupture
Peptic ulcer disease
Biliary/hepatic disease
Pancreatitis

Anxiety - don't jump to this Dx.

Front 2

Give a DDx for shortness of breath.

Back 2

5 Of The Most Common Causes:
Obstructive lung disease (i.e. asthma or COPD)
Heart failure/cardiogenic pulmonary edema
Pneumonia
Angina or myocardial infarction
Psychogenic

4 Additional Life Threatening Causes:
Upper airway obstruction (angioedema, hemorrhage, foreign body)
Pneumothorax/Tension pneumothorax
Pulmonary embolism

Front 3

Give a DDx for abdominal pain.

Back 3

GI Causes:
Appendicitis
Biliary colic/cholecystitis/cholangitis
Bowel obstruction
Diverticulitis
Mesenteric ischemia
Pancreatitis
Peptic ulcer disease/perforated viscus

Urological causes:
Urinary retention
Cystitis/pyelonephritis
Renal colic

Gynecological causes:
Pelvic inflammatory disease
Ovarian torsion
Ectopic pregnancy
Tubo-ovarian abscess

Cardiovascular and other causes:
Myocardial ischemia/angina/ACS
Ruptured AAA
Pneumonia

Front 4

Give a DDx for headache.

Back 4

Primary headache syndromes e.g. migraine, tension headache, cluster headache
Medication overuse headache

Structural/mechanical causes:
Intracranial bleed, e.g. Subarachnoid hemorrhage, subdural hematoma, epidural hematoma
Cavernous/venous sinus thrombosis
Carotid or vertebral artery dissection
Tumor
Pseudotumor cerebri

Infectious/inflammatory causes:
Meningitis, encephalitis
Abscess
Temporal arteritis

Systemic causes:
Influenza, malaria, other infections
Dehydration
Hypoxia, hypoglycemia, altitude sickness, CO poisoning
Pre-eclampsia
Hypertensive crisis
Pheochromocytoma

Referred pain:
From the ear, e.g. otitis media or mastoiditis
From the eye, e.g. glaucoma, iritis, uveitis
From the jaw or teeth, e.g. dental abscess, TMJ
From the sinuses, e.g. sinusitis

Front 5

Given a patient with suspected sepsis, what is the DDx of possible sources of infection?

Back 5

Head and neck: CNS (e.g. meningitis, abscess, etc), ears (e.g. otitis media), sinuses (e.g. sinusitis), mouth (e.g. dental abscess), deep space neck infection.

Chest: Lungs (e.g. pneumonia), heart (e.g. endocarditis).

GI: biliary tree (e.g. cholecystitis, cholangitis), appendicitis, diverticulitis, perforated viscus.

GU: pyelonephritis, gynecological causes (e.g. septic abortion, tubo-ovarian abscess, endometritis).

MSK/skin/soft tissue: e.g. cellulitis, fasciitis, osteomyelitis. Don't forget back infections such as epidural abscess and discitis!

Front 6

Give an approach to shock (with examples).

Back 6

Four Types of Shock (and one bonus type!):
1) Hypovolemic, e.g. trauma, GI hemorrhage, fluid loss from DKA
2) Obstructive, e.g. PE, cardiac tamponade, tension pneumothorax
3) Distributive, e.g. sepsis, neurogenic shock, anaphylaxis
4) Cardiogenic, e.g. heart failure, MI, cardiomyopathy, maybe valvular disease?
5) Toxic/metabolic, e.g. acute adrenal insufficiency (aka Addisonian crisis), hypothermia, myxedema coma, cyanide poisoning, toxic ingestion (esp CCB, B-blocker, clonidine, TCAs, many others), electrolyte abnormalities such as K+, Ca++, Mg++

Front 7

Give a DDx for vomiting.

Back 7

GI causes:
gastritis, gastroenteritis, gastric outlet obstruction/gastroparesis, biliary colic, hepatitis, pancreatitis, appendicitis, bowel obstruction (especially small bowel).

Non-GI causes originating in the head:
Meningitis, traumatic brain injury, stroke, brain tumor, other intracranial pathology; vestibular diseases such as Meniere's, labyrinthitis, etc.; psychogenic.

Non-GI causes originating in the chest:
Acute coronary syndrome, pneumonia.

Non-GI causes originating in the abdomen:
Renal colic, pregnancy (and pregnancy complications), testicular torsion, AAA.

Systemic causes:
Toxic ingestions, metabolic/electrolyte disturbances (especially DKA), sepsis, medication side effects, drug or medication withdrawal.

Front 8

Give an approach to syncope.

Also, provide high risk features that may suggest a need to admit a syncope patients.

Back 8

Approach to syncope: HEAD, HEART, and VESSELS

Head: Hypoxia, hypoglycemia, SAH, vertebrobasilar insufficiency, seizure (syncope mimic)

Heart: ACS, pulmonary embolism, aortic stenosis, HOCM, bradyarrhythmias such as sick sinus syndrome, and tachyarrhythmias such as those precipitated by long QT syndrome (Torsades de pointes), Brugada syndrome (Vfib), and pre-excitation syndromes such as WPW (atrial tachyarryhthmias).

Vessels: Vasovagal syncope, hypovolemia, situational syncope (e.g. micturition, defecation, Valsalva), subclavian steal, orthostatic hypotension, antihypertensive medication side effect, autonomic dysfunction.

High risk features of syncope - on history:
Age > 65
Hx of cardiovascular disease
Lack of prodrome
Chest pain with episode
Episode related to exertion
Palpitations preceding event
FHx of sudden cardiac death

High risk features of syncope - on physical exam:
Abnormal vital signs
Systolic BP < 90
Abnormal ECG
Clinical evidence of CHF

Front 9

Give an approach to dizziness.

Back 9

The initial goal is to determine whether it was (pre)syncope, vertigo, or disequilibrium.
One stepwise approach is as follows:

QUESTION 1: Was there loss of consciousness?
IF YES --> Stop, work up as syncope.
IF NO --> Go to question 2.

QUESTION 2: Is there true vertigo (i.e. sensation of movement, room spinning, etc)?
IF YES --> Go to question 3.
IF NO --> Work up as non-specific dizziness with history, physical, and labs as indicated. Consider cardiac or structural in elderly or patients with risk factors, consider psychogenic/watch and wait in young and healthy.

QUESTION 3: Was there any evidence of CNS impairment (now or at the time) - e.g. weakness, numbness, dysarthria, etc.?
IF YES, BUT NOW RESOLVED --> Consider TIA, seizure, or migraine.
IF YES, AND IT PERSISTS --> consider stroke, structural lesion, or MS.
IF NO --> Go to question 4.

QUESTION 4: Are the symptoms triggered by sudden head movements, resolving when motionless?
IF YES --> BPPV. Confirm with Dix-Hallpike and cure with Epley's maneuver.
IF NO --> Go to question 5.

QUESTION 5: Is there hearing loss?
IF YES --> Go to question 6.
IF NO --> Vestibular neuritis, a post-viral syndrome which causes severe persistent peripheral vertigo with nausea and vomiting. Symptomatic Tx and time.

QUESTION 6: Is there tinnitus?
IF YES --> Consider labyrinthitis (which is just vestibular neuritis plus hearing problems), or Meniere's disease (a condition which causes recurrent episodes of vertigo, hearing loss, and tinnitus).
IF NO --> Consider acoustic neuroma.

Front 10

DDx of hemoptysis.

Back 10

Infectious:
- Bronchitis
- Pneumonia
- TB

Structural:
- Lung cancer
- Foreign body
- Bronchiectasis
- Congenital AVM
- Aorto-tracheal fistula

Vascular/other:
- PE
- Vasculitis (e.g. Wegener's, Goodpasture's)
- Coagulopathy/anticoagulation therapy

Front 11

Give an approach to the sick neonate.

Back 11

The mnemonic is SCAMS.

1) S - SEPSIS. Initiate treatment for sepsis on all sick neonates.
- Intubate
- 20 cc/kg fluid bolus
- Amp and Cefotax
- Draw cultures/labs/VBG
- DO NOT LP if unstable

2) C- CARDIAC - most of these will be SVT or ductal-dependent lesions.
- First, intubate, give antibiotics, draw labs/cultures/VBG
- ECG
- 4 limb BPs
- If not SVT, and O2 sats persistently low despite intubation and 100% O2, give prostoglandin E1 0.1mcg/kg/min - side effects are apnea and hypotension.

3) A - ABUSE
- Always start with intubate, give fluid, give antibiotics, draw labs/cultures/VBG
- then consider history, look at fundi, skeletal survey
- CT head?

4) M - METABOLIC
- If hypoglycemic give 5cc/kg of D10W, and measure VBG, ammonia and critical labs.
- If not coming around give hydrocortisone 1mg/kg

5) S - SURGICAL
- Diaphragmatic hernia
- Intestinal malrotation
- Volvulus
- Duodenal atresia
- NEC

Front 12

Give a DDx for altered mental status.

Back 12

Intracranial vs Extracranial - IS IT-MEAT

Intracranial causes:
Infectious
Structural
Ischemic
Traumatic

Extracranial Causes:
Metabolic
Endocrine
Anoxia
Toxins/withdrawal

Front 13

Give a DDx for fever in the returning traveler.

Back 13

Malaria
Dengue fever
Typhoid fever
Yellow fever

and a bunch of other stuff I will never remember.