HY lecture notes:
Juvenile dermatomyositis –> shawl rash (over upper back / back of neck); heliotrope rash (violaceous eyelids; don’t confuse with malar rush of SLE); Gottron papules over knuckles, mechanics hands (rough / scaly palms). Proximal muscle weakness; pain and stiffness not mandatory. High ESR, aldolase, and creatine kinase.
Dx next best step with anti-Jo1 and -Mi2 antibodies. Confirmatory is muscle biopsy. Tx with oral steroids.
(In contrast, polymyalgia rheumatica is age >55 and has muscle pain and stiffness without weakness. Associated with temporal arteritis.)
Juvenile rheumatoid arthritis (aka Juvenile idiopathic arthritis) –> recurrent joint pain in a kid –> high ESR, RF, and/or salmon-pink body rash; associated with anemia of chronic disease (showed up on one of the peds forms with a decreased MCV, even though AoCD is typically normocytic 80-100).
They’ll describe multiple joints affected, but must rule out septic arthritis with arthrocentesis as the next best step if they tell you there’s a warm, tender, red knee in a kid with JRA, as arthropathy and abnormal joint architecture is a risk factor septic arthritis.
You’ll see high leukocytes in the joint aspirate. Tx flares with steroids.
Treat sepsis with third-generation cephalosporin. Peds they like cefotaxime over ceftriaxone because it causes less displacement of bilirubin from albumin, but both have shown up as answers. One Q on one of the peds forms has 11-month-old with sickle cell who missed a dose of his penicillin prophylaxis and was septic, and the answer was cefotaxime. Then there’s a Q on NBME 8 where the kid was a little older with sepsis, and the answer was ceftriaxone. Bottom line is: if they list both cefotaxime and cefriaxone as answers for the same Q, go with the former; but both can be answers depending on the Q.
Kawasaki disease –> aka mucocutaneous lymph node syndrome –> super common medium-vessel vasculitis in peds –> fever of 5+ days (this is really important); edema of dorsums of the hands with desquamation of the palms and soles –> cervical lymphadenopathy; injection of the conjunctiva (red eyes) + red lips or tongue; of course kid can get coronary artery aneurysms.
Dx is clinical. Tx with aspirin + IVIG. Only thing we give aspirin to kids for (bc we don’t want Reye syndrome, remember?).
Polyarteritis nodosa (rare in kids but HY quick tangent) is another medium-vessel vasculitis –> fibrinoid necrosis w/ immune complex deposition –> associated with hepatitis B infection –> spares the lungs. Arteriogram may show “beads on a string” (dilatations/constrictions due to inflammation). Tx most simply with corticosteroids.
White-eye reflex (leukocoria) –> congenital retinoblastoma; Rb mutation (tumor suppressor gene but AD condition); kid is at risk of getting osteosarcoma later on. They like that. They’ll show you image of leukocoria then ask what you’ll see later –> osteosarcoma.
Kid with 4+ protein in urine + eyelid swelling +/- edema +/- ascites –> minimal change disease (lipoid nephrosis). Tx with steroids. Very effective.
Minimal change usually due to viral infection, but the 2CK often won’t mention that.
Minimal change can rarely be due to adult with Hodgkin lymphoma (cytokine effect).
Nephrotic syndrome in kid with sickle cell –> focal segmental glomerulosclerosis (FSGS).
Nephritic syndrome in kid with sickle cell –> renal papillary necrosis.
Red urine 1-3 days after viral (or GI) infection in peds –> IgA nephropathy
Red urine 1-2 weeks after strep throat or skin infection –> PSGN. E.g., impetigo for 7 days –> red urine –> PSGN. USMLE won’t ask PSGN Tx because steroids are often given but with controversial effect; Tx generally consists of managing hypertension and edema and giving penicillin to eradicate the nephritogenic strain of Strep.
