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A kid without a rash just isn’t a kid.
- Incubation: 10-21d, infective until crusted over
- Rash: vesicles on macules (dewdrops on rosepetals),
- Very pruritic!
- Other symptoms: 1-3d prodrome of fever and respiratory symptoms
- Treatment: supportive, acyclovir for severe disease, VZIG for post-exposure prophylaxis
- Complications: 1st or 2nd trimester = congenital varicella syndrome
- Incubation: 5-15d
- Rash: pink macules and maculopapules, starts on neck.
- Other symptoms: HIGH FEVER, cough, respiratory symptoms, erythematous pharynx, tonsils & TMs
- Treatment: supportive
- Complications: febrile seizures
- * Generally affects kids <5 years old
- Incubation: 10-14d, dx with measles IgM
- Rash: maculopapular, starts on face.
- Other symptoms: the 3 Cs
- 1) Cough 2) Coryza (runny nose) 3) Conjunctivitis
- Koplik spots in mouth 1-2d before rash
- Treatment: supportive, prophylactic Ig
- Complications: secondary bacterial infection, encephalitis (1:1000), subacute sclerosing panencephalitis (1:100000)
Rubella aka German Measles
- Incubation: 14-21d, infective 5d before rash and 7d after
- Rash: pink maculopapular, starts on face.
- Other symptoms: non-specific
- Treatment: supportive
- Complications: congenital rubella syndrome (very bad*), first four months of pregnancy highest risk (this is why we check rubella immunity status in prenatal screening)
* Congenital Rubella Syndrome
“Blueberry muffin baby” (purpura). Cataracts/congenital glaucoma, congenital heart disease, hepatosplenomegaly, jaundice, microcephaly, developmental delay
Fifth Disease aka Erythema Infectiosum
- Incubation: 4-14d, infective prior to onset of rash
- Rash: slapped cheeks (raised uniform maculopapular lesions on cheeks), may appear on extensor surfaces
- Usually not pruritic
- Other symptoms: flu-like illness ~3d prior to rash
- Treatment: supportive, blood transfusions if aplastic crisis
- Complications: arthritis (10%), vasculitis
- Aplastic crisis: reticulocytopenia, not bad in normal people, very bad anemia if you already have chronic hemolytic anemia
- During pregnancy: fetal hydrops/fetal loss
* This is a good one to actually know the virus name! PARVOVIRUS B19
Other rash descriptors to think about
- Sandpaper rash: scarlet fever (Group A Strep), they also have strawberry tongue, fever and sore throat
- Pink macules with central clearing: erythema marginatum (one of the major Jones criteria for rheumatic fever)
- Palpable purpura: Henoch-Schonlein Purpura
- Non-blanching petechiae: BAD (meningococcal disease), could be other things too, but need to rule out meningitis
When you find someone without a pulse but then hook up the monitor and there is a rhythm, your first thought it probably “CRAP!” But as you start CPR, you need to be thinking about what caused it because not much will help the person except correcting the underlying problem.
So like most of medicine, there is a handy mnemonic for remembering the main causes: The 6 Hs and 5Ts
The 6 Hs
- H+ (acidosis)
- Hyperkalemia/Hypokalemia (potassium disturbances only get counted once)
The 5 Ts
- Tension pneumothorax
(I’ll make a T doodle at a later date)
The other handy mnemonic for the Hs I learned from this video (so I take no credit for it): Diabetic crashing with a wide QRS
- Diabetic = Hypoglycemia or H+ acidosis
- Crashing = bad vitals
- Low BP +/- tachycardia (hypovolemia)
- Low O2 (hypoxia)
- Low temperature (hypothermia)
- Wide QRS = hyperkalemia
A prolapsed (slipped) disc is when the squishy innards of the disc (nucleus pulposus) bulge out past the stiffer wall of the disc (annulus fibrosis). The problem is that sometimes when this happens, the bulge can impinge the spinal cord or the spinal nerve root. This could result in an anterior cord syndrome (remember this doodle) or it could just knock out the nerve root, resulting in a specific radiculopathy (check out this doodle for where to check for numbness and weakness).
The tricky thing to remember is that though, for example, the L3 root exits at L3, if the L3,4 disc herniates, it doesn’t hit the L3 root but the L4.
Slipped L3,4 disc = L4 nerve injury
The disc hits the nerve after it has branched off the spinal cord, but before it has exited the vertebral canal.
For the most part, bleeding in the brain (intracranial hemorrhage) is a pretty bad thing. Though like most things in medicine, there are varying degrees of badness, all with different mechanisms that help us sort of why we really wouldn’t want something to happen.
Intracranial hemorrhages are categorized into 5 subtypes, and are given obvious sounding names depending on where the bleed is in the brain and in relation to the layers of the meninges.
- Epidural (above the dura, right under the skull)
- Subdural (below the dura, above the arachnoid)
- Subarachnoid (below the arachnoid, above the brain)
- Intraventricular (in the ventricles)
- Intraparenchymal (in the meat* of brain)
* The brain is not meaty, “parenchyma” means the functional part of the organ
The poor pia mater did not get any hemorrhage named after it, but if you want you can think of intraparenchymal as “subpial” just so it doesn’t feel left out.
Telling them apart
The most confusing thing, and thing that likes to get asked the most on exams, is the difference between epidural and subdural hematomas.
|Above the dura
||Below the dura
||Below the arachnoid
|Respects suture lines
||Doesn’t respect suture lines
||No respect for anything
|High force trauma
||Low force trauma
||Aneurysm rupture or high force trauma
|Arterial blood (commonly the middle meningeal artery)
||Venous (from venous plexus)
||Arterial from the circle of Willis
|Lentiform (lens-shaped) or biconcave on CT
||Cresent (banana-shaped) on CT
||Lining surface, going into fissures and sulci and sella (death-star)
||May be insidious (worsening headache over days)
||Acute presentation (thunderclap headache)
The reason intraventricular and intraparenchymal aren’t included in the table as they each have a bunch of causes, but for both of them trauma is a potential cause as well as hypertension and stroke. It’s good to remember that premature infants are at a much higher risk of intraventricular hemorrhages.
Blood on CTs
- New blood: bright white
- 1-2 weeks: isodense
- Old blood (2-3 weeks): dark grey
The lower leg (and especially the foot) have a pretty fancy pattern of skin innervation by the terminal branches. For example, the skin of the foot is innervated by 7 separate nerves:
- Superficial peroneal nerve
- Deep peroneal nerve
- Sural nerve
- Saphenous nerve
- Calcaneal branch of the tibial nerve
- Medial branch of plantar nerve
- Lateral branch of plantar nerve
Also good to keep in mind that the anterior compartment is innervated by the deep peroneal nerve, the lateral compartment by the superficial peroneal nerve and the posterior compartment by the tibial nerve.
The epidermis is divided into five layers. From outside to inside (dermis). The stem cells are located in the stratum basale and migrate outwards in their differentiation process
- Stratum corneum: The outmost layer, made of dead keratinocytes with a layer of protein around them (they have undergone keratinization)
- Stratum lucidum: Also dead keratinocytes (there is no real distinction here other than that the poor keratinocytes have died but have not finished the keratinization process)
- Stratum granulosum: the keratinocytes are still on the move, by this point they have kertahyalin granules
- Stratum spinosum: the keratinocytes migrating up, they have nice oval nuclei
- Stratum basale: Single layer of proliferating columnar keratinocytes, melanocytes (pigmented cells) and Merkel cells (mechanoreceptors) also live here
Of note, Langerhans cells, which are specialized antigen-presenting cells are present in all layers of the epidermis but are mostly in the stratum spinosum.
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The Glasgow Coma Scale is a scoring system used to evaluate someone’s level of consciousness. It is scored out of 15 with 15 being totally awake and alert and 3 being totally not.
The important thing to remember is that the lowest score possible is 3.
Absolutely anything can score a 3, however if you are a living, breathing human being, hopefully you are scoring well up into the 10s.
Generally the GSC is applied in trauma situations and can be used as part of the decision making process of such thing things like should this patient be intubated?
- ≥13 correlates with mild brain injury (or being ok)
- 9-12 correlates with moderate injury
- ≤8 represents severe brain injury – you should probably consider intubating them as they most likely cannot protect their airway
Thanks to Mike for the guest doodle!
The menstrual cycle. What more of a classic drawing can you get? Though it has been done a million times over, here’s the Sketchy Medicine version of the classic hormonal interplay that allows for the endometrial lining to build up, shed, build up, shed, build up, shed…
The nice thing is the the pituitary hormones are aptly named so that FSH (follicle stimulating hormone) stimulates the follicle to grow and LH (luteinizing hormone) causes ovulation (the infamous LH surge) and subsequent corpus luteum development.
Meanwhile the developing follicle secretes estradiol which stimulates the proliferative phase of the cycle. Then the corpus luteum secretes estradiol and progesterone to kick things into high gear for the secretory phase.
You can now passively study this all the time (and keep your own notes) on a notebook or a mug. Nothing says “mmm, coffee” like the hormonal phases of the female reproductive system.
Meningitis is very literally inflammation of the meninges. Something swollen in a closed space is never good, so it’s important to not miss meningitis when it presents.
Classic triad of meningitis
- Neck stiffness
- Mental status change – in babies this can be an increase in somnolence or irritability (unconsolably crying)
- E. coli*
- GBS (Group B strep)*
- Neisseria meningitidis
- Strep pneumoniae
- Staph aureus
- Gram neg bacilli
- Haemophilus influenza
- Viral (“aseptic”)
* These are the common ones in the neonatal period
- Positive Gram stain
- CSF white blood cell (WBC) count >1000/uL with a predominance of neutrophils
- Low CSF glucose concentration <40 mg/dL (2.2 mmol/L)
- Empiric treatment: high doses of a 3rd generation cephalosporin (cefotaxime, ceftriaxone) and vancomycin (this covers antibiotic-resistant S. pneumoniae, N. meningitidis, and Hib)
Kawasaki Disease is one of the pediatric rashes that you always need to have in the back of your mind. Most of the time the disease is self-limiting, but the consequences of not catching it are pretty bad (turns out coronary artery aneurysms often lead to things like infarction and DEATH).
Warm CREAM is an unrelated (and somewhat unpleasant) mnemonic to help remember the signs and symptoms of Kawasaki. The “warm” is a fever (one lasting more than 5d) and then you need 4/5 of the other criteria (non-purulent conjunctivitis, rash, palmar erythema/swelling, cervical adenopathy, dry and red mucous membranes, the infamous strawberry tongue). The kid doesn’t need all 4 as he or she is sitting in front of you, but the presentation and the history combined should include those criteria.
Treatment is with high doses ASA and IVIG, you do this to prevent the sequelae of coronary artery aneurysms and myocarditis, and it’s best to get an echo to check up on things.