Splenic Functions: The Short Version

So I percussed an enormous spleen this week during my clinical rotation. It was the first time that I had felt a spleen that clearly crossed the midline... what a perfect occasion to discuss some pathophysiology of the SPLEEN!

Location: LUQ

Histology: It is divided into red pulp and white pulp.
          Red pulp = transient circulating RBC and mononuclear phagocytic cells - primary function = removal of foreign stuff from the blood (including old and damaged RBC)
          White pulp = lymphoid tissue (similar to the stuff in lymph nodes) - primary function = initiating  and propagating the immune response to foreign antigens

Pathology: Primary pathology = rare (most are secondary to systemic problems)

Big Spleens (Splenomegaly)
Possible causes: infections (mono), congestion (cirrhosis), blood malignancies, systemic inflammation dz (RA), metabolic storage dz

Source: HARDCORE: Pathology, Carter Wahl


Hematology Pimping...

So this week I was asked some hematology questions (not my strength by far) and my answers were, let's just say, less than seamless. I was able to articulate the general idea, but nothing in detail. Needless to say I spent part of my weekend brushing up on heme!

Here are some of general questions that I was asked... I put the answers further down so you can test yourself to see if you can answer them.

1) What are 3 phases of response to vascular damage that lead to cessation of bleeding?
2) What is "platelet bleeding" vs "coagulation bleeding"?
3) What is PT and what factors does it assess?
4) What is aPTT and what factors does it assess?
5) What are the Vit K dependent anticoags?
6) What (enzyme) is responsible for the conversion of fibrinogen to fibrin?

1) vasoconstriction, primary hemostasis (platelet adhesion and aggregation), secondary hemostasis (fibrin clot formation)

2) Platelet = bleeding at mucosal sites, multiple little bruises, immediate bleeding after surgery/trauma

Coagulation = soft-tissue bleeding, occasional large bruises, delayed bleeding after surgery/trauma

3) Prothrombin time: fibrinogen, factors II, V, VII, X [extrinsic and common pathways]
{How I remember: if you're a PRO, then you're EXTRa good}

4) Activated partial thromboplastin time: fibrinogen, factors II, V, VIII, IX, X, XI, XII, prekallikrein, HMW kiniogen [intrinsic and common pathways]

5) Protein C and S

6) Thrombin

Source: Medicine Recall (Bergin)


Acute Otitis Media

What is it?
Acute Otitis Media is an infection of the middle ear... usually bacterial, but could also be viral.

Why should you care?
75% of kids get it by the time they are 1 year old - often due to eustachian tube dysfunction (kids have a shorter/more horizontal tubes than adults). You will see lots of this on your pediatric rotation. I'm still in my first week and have seen 7 cases.

3 Main Bugs:
1. Strep pneumo
2. H.Flu
3. Moraxella

Things that can obstruct the eustachian tubes:
1. Enlarged adenoids
2. Allergies
3. Viral infections

Once obstructed:
1. Mucocilliary drainage is impaired
2. Resorption of gases w/in the middle ear that create a vacuum... this pulls bacteria from the nasopharynx into the middle ear which causes a secondary infection

Major risk factors for getting it:
1. Young age
2. Family hx
3. Day care
4. Smoking environment
5. Not breast-feeding (if mom is bottle feeding - be sure to tell her not to prop a bottle up in the crib while the baby is going to sleep and to also use a fully ventilated bottle)

3 Signs Necessary to Diagnose OM:
1. Signs of middle ear effusion
     Usually seen via an immobile tympanic membrane (TM) - use a pneumatic insufflator to check
     *Note - the movement of the TM is very subtle, I couldn't really tell on my first patient.

2. Signs of middle ear inflammation
     Seen as a bulging TM and it is usually discolored
     *Note - it is not always RED, it can be gray or yellow too! I have found that most kids have very waxy ears and it is difficult to see the TM every time -  in addition- Often when kids are screaming, their ear canals will turn bright red anyway-  so don't be fooled!

3. Acute onset of sx related to the ears
     Ear pain (pulling at ears, irritability)

1. Most cases resolve on their own! Only about 10% of cases need antimicrobial.
2. Talk to parents about pain control (tylenol/advil)
3. Options:
     a. Watchful waiting: observe child for 24-48 hrs w/o Rx or provide a safety net Rx for the antimicrobial only to be filled if patient is not better in 24-48hrs
     b. High dose amoxicillin is for when watchful waiting is not appropriate or sx have not improved

*Watchful waiting is appropriate if the kid is > 6m old, they are not having severe illness, fever < 39C, reliable parents (will they follow up if things get worse?)

Hope this helps! I will try to write about things that I see frequently throughout my rotation. I have plenty of stories to share from my first week. Let's just say it has been eventful! Kids are so much fun!

Source: PEDSCASES: Stollery Children's Hospital Podcast