Approach to the Patient with Neutropenic Sepsis

This is a classic style of question testing if you do know the criteria rather than making an educated guess. NICE states "Diagnose neutropenic sepsis in patients having anticancer treatment whose neutrophil count is 0.5 x10^9 per litre or lower and and who have either: 1) a temperature higher than 38C or 2) other signs or symptoms consistent with clinically significant sepsis". Therefore, looking at the answer options the only choice that does not meet this criteria is the neutrophil count answer choice as the criteria states it must be 0.5 x10^9 or less.

A clinical application of anatomy here! The cephalic (outdated term Houseman's) vein is often cannulated due to its reliability. The anatomical snuffbox is triangular fossa found at the base of the thumb at the level of the carpal bones, formed by the tendons of extensor pollicis longus, extensor pollicis brevis and adductor pollicis longus. The cephalic vein crosses the anatomical snuffbox from the lateral side of the dorsal venous network. If you are still unsure, TeachMeAnatomy has a good explanation of the anatomical snuffbox.

This question tests your knowledge of anti-neoplastic drugs. Fluorouracil is an antipyrimidine and so inhibits RNA and DNA synthesis and so inhibits the production of cytosine, thymine and uracil. DNA crosslinking is the mechanism of alkylating agents like cyclophosamide. Inhibition of microtubule assembly is the mechanism of taxanes and vinca alkaloids. Antifolates such as methotrexate work by inhibiting dihydrofolate reductase. Targeting HER-2 overexpression is the mechanism of a monoclonal antibody trastuzumab (Herceptin).

Many patients with neutropenic sepsis have pneumonia without a cough or shortness or breath so it is very important to get a chest x-ray to assess for any pneumonia. The other imaging listed may be appropriate to do in specific circumstances but are not first line.

A loading dose is an initial large dose of a drug (or series of doses) given to rapidly achieve a therapeutic concentration in the body. This technique is often used for drugs with a long half life or if a therapeutic steady state is needed immediately. A loading dose can be given by any route.

Chemotherapy produces neutropenia by destroying dividing myeloid progenitor cells, which give rise to neutrophils. Chemotherapy effects are greater in rapidly dividing cells, hence cancerous cells are targeted. In addition to cancerous cells being destroyed, other rapidly dividing cells such as myeloid progenitors and hair cells are destroyed hence neutropenia and hair loss are common side effects with anti-cancer treatments.

Piperacillin and tazobactam often used as first line for neutropenic sepsis (Please remember to check local antibiotic guidelines for your area!) are are both penicillins so come under the Beta Lactam family. A common side effect of penicillins is that they cause a rash. The other answers listed are side effects of other drugs.

The question is getting you to think about the complications of antibiotic therapy rather than looking for another disease process causing a change in bowel habits. Given the recent antibiotic therapy, accompanied by voluminous diarrhoea and crampy abdominal pain, antibiotic induce Closterium difficile colitis is most likely.