USMLE Case Files

Schistocyte (a.k.a. “helmet cell”) 

This is a pathologic RBC form that results from shear stress. This is an important one not only to recognize, but to know the DD. 

This can be caused by:  DIC, TTP/HUS, HELLP syndrome, or mechanical hemolysis (e.g. mechanical value replacement). 

Hodgkins Lymphoma - Nodular Sclerosing type (most common subtype)

Patient will present with fever, night sweats, painless lymphadenopathy, and generalized puritis. Common in younger patients, and has a good prognosis.

Pneumocystis pneumonia (PCP) 

Chest X-ray will show what is known as a “ground glass” appearance - due to the interstitial pneumonia caused by this bug. Is typically found in immunocompromised patients (i.e. AIDS) with a CD4+ count below 200 cells. This is the same time you want to start prophylactic treatment with TMP-SMX.

Mnemonic: PCP is seen in patients with a CD4 less two-hundred, will see opacities in “both/two lungs, and treat with a two drug combo of TMP-SMX. 

Here is some solid advice that I have compiled from multiple sources of what I think (collectively) is the best approach to this beast of an exam. 

Strategy: 1. Read the last sentence first to know “what is the question really asking” - this will help with active reading while approaching the question stem.

2. Read the question carefully - spend most of you time reading the question, good test takers will spend 2/3 of the time reading the questions and formulating an answer in their head, and the last seconds selecting the best option.

  3. After reading the question, try formulate an answer in your head WITHOUT looking at the answers choices.

4. If you know the answer check to see if it is one of the answer choices. If not pick the next best choice. Even if your answer is there, check to make sure a BETTER answer choice does exist in the options provided.

5. If you cannot come up with an answer choice, try to narrow the choices listed to the two best options. This will increases your chances to 50/50 of getting the question right - rather than flat out guessing which depending on the number of choices in that question can be slim odds.

6. If you still don’t know, then guess and MOVE ON. Good test takers will admit when they dont know the answer and will not get bogged down and waste time on question they know that they do not know - they will guess and move on.

7. Start each question by leaving the previous one in the past, don’t carry the worry and stress of whether you got each question right to your next question. Lets face it, you will not know everything, and you will feel stupid. This is normal. Remember, getting about 65-70% of questions right puts you above average.  

Periventricular calcifications as seen in CMV. 

CMV is the most common congenitally acquired infection in the USA. It presents with multiple hemorrhagic cutaneous lessons on the head, neck and trunk, deafness, and as shown above periventricular calcifications on CT scan.