Chemotherapy Side Effects: When “Expected” Symptoms Become an Emergency

Chemotherapy side effects are common. That does not mean every symptom should be watched and waited out.

This scenario follows Marianne, who has become increasingly unwell after her second cycle of chemotherapy. Work through what you notice, what worries you and what you would escalate as a student nurse. The aim is not to diagnose the patient. It is to recognise when the picture has moved beyond routine treatment side effects.

👤 Meet Marianne

Marianne Lowe is 54 and works as a retail manager in a busy shopping centre. She is married with two grown-up children and is normally independent. She is receiving chemotherapy for breast cancer and is currently on cycle 2 of 6.

Her medical history includes hypertension and depression. Her regular medicines include amlodipine and sertraline.

Over the last four days she has developed worsening nausea, diarrhoea, painful oral ulcers and extreme fatigue. She is barely eating and is struggling to keep fluids down. She has now been admitted to the oncology ward for assessment and supportive care.

Her husband is sitting beside her and says, “She looks weaker every day. She can hardly keep water down.”

Before you read on, what are you already thinking about?

What you need to know first

Chemotherapy targets rapidly dividing cancer cells, but it can also affect healthy rapidly dividing cells. This is why treatment can cause problems such as nausea, diarrhoea, mucositis, hair loss, fatigue and bone marrow suppression.

Bone marrow suppression matters because red cells, platelets and infection-fighting white cells can all fall. Neutrophils are particularly important when thinking about infection.

A useful student-nurse habit is to avoid writing off deterioration as “just chemotherapy”. A person receiving systemic anti-cancer therapy who becomes unwell needs careful assessment and timely escalation. Neutropenic sepsis is an acute medical emergency, and serious infection can be present without a high fever.

Marianne now

Observations:
• Heart rate: 104 bpm
• Blood pressure: 98/60 mmHg
• Respiratory rate: 22 breaths/min
• SpO₂: 96% on room air
• Temperature: 37.9°C

You notice dry mucous membranes, cracked lips and several painful oral ulcers. Marianne looks exhausted and says she feels much weaker than usual.

Blood results available so far:
• Haemoglobin: 9.2 g/dL
• White cell count: 1.0 × 10⁹/L
• Platelets: 95 × 10⁹/L
• Sodium: 132 mmol/L
• Potassium: 3.3 mmol/L

Important: a low total white cell count does not by itself confirm neutropenia. You need the neutrophil count. In this scenario, Marianne’s neutrophil count is 0.4 × 10⁹/L.

What should make you uncomfortable here?

It is the whole picture, not one number.

Marianne has recently received chemotherapy, is neutropenic, looks unwell, is tachycardic and tachypnoeic, has a relatively low blood pressure, prolonged capillary refill and significant gastrointestinal fluid loss. Her temperature is 37.9°C, but waiting for it to cross 38°C before escalating would be unsafe.

Other concerns include dehydration, hypokalaemia, poor oral intake, mucositis and thrombocytopenia. Diarrhoea may be treatment-related, but infection and other causes also need consideration.

A–E assessment

A – Airway
Airway patent. Marianne is speaking normally. Oral ulceration is painful but there is no current evidence of airway compromise.

B – Breathing
Respiratory rate 22 breaths/min. SpO₂ 96% on room air. Assess work of breathing, chest symptoms and auscultation findings as appropriate within your role, and report deterioration.

C – Circulation
Heart rate 104 bpm, blood pressure 98/60 mmHg, capillary refill approximately 3 seconds and peripheries cool. Consider the combined effects of dehydration and possible sepsis. Ensure concerns are escalated promptly and support the registered nurse with prescribed fluids, blood sampling, cultures and monitoring as appropriate to your competence.

D – Disability
Alert, GCS 15, but exhausted. Assess for new confusion or reduced responsiveness. Check blood glucose if indicated by the clinical picture/local protocol.

E – Exposure
Temperature 37.9°C. Assess for potential sources of infection and treatment toxicity while maintaining dignity. This includes skin, mouth, vascular-access sites and gastrointestinal symptoms. Do not forget pain, fluid balance and urine output.

What happens next?

This is not a “recheck her in an hour and see” situation.

Escalate immediately to the registered nurse and appropriate medical/acute oncology team and follow the local neutropenic sepsis pathway. NICE recommends treating suspected neutropenic sepsis as an acute medical emergency and starting empiric antibiotic therapy immediately. UKONS guidance also emphasises immediate assessment and antibiotics without waiting for the full blood count result when neutropenic sepsis is suspected.

As a student nurse, you are not expected to diagnose neutropenic sepsis, choose antibiotics or independently manage the emergency. You are expected to recognise deterioration, communicate it clearly, work within your competence and keep reassessing the patient while help arrives and treatment begins.

Depending on local policy and your level of supervision, you may help with repeat observations, blood cultures and other blood tests, lactate, fluid balance, urine output, vascular-access assessment, prescribed IV fluids and preparation for urgent treatment.

Medicines and treatment: what the student needs to notice

Marianne may require IV fluids, electrolyte replacement, antiemetics, analgesia and mouth care alongside urgent treatment for suspected infection. The exact antimicrobial regimen is prescribed according to local policy, allergies, microbiology advice and the individual patient.

Do not allow paracetamol or another antipyretic to create false reassurance or delay escalation. The important question is not simply “Does she have a fever?” It is “Is this patient receiving recent anti-cancer treatment and becoming clinically unwell?”

Her potassium is low, so prescribed potassium replacement requires appropriate checks and monitoring. Mucositis also matters because it is painful, can limit oral intake and can provide a route for infection.

SBAR example

S: “I’m calling about Marianne Lowe, 54, who is receiving chemotherapy for breast cancer. I’m concerned about suspected neutropenic sepsis and clinical deterioration.”

B: “She is on cycle 2 of chemotherapy. She has had four days of diarrhoea, nausea, poor oral intake and painful mucositis.”

A: “Her heart rate is 104, blood pressure 98/60, respiratory rate 22, SpO₂ 96% on room air and temperature 37.9. She looks unwell and dehydrated. Her neutrophil count is 0.4 × 10⁹/L, platelets 95 and potassium 3.3.”

R: “Please review her urgently. I think the neutropenic sepsis pathway needs to be started now. I’ll continue observations and support the registered nurse with the immediate assessment and treatment.”

Documentation example

“Marianne Lowe, 54, receiving cycle 2 chemotherapy for breast cancer. Reports four days of worsening nausea, diarrhoea, poor oral intake, fatigue and painful oral mucositis. HR 104 bpm, BP 98/60 mmHg, RR 22, SpO₂ 96% RA, temperature 37.9°C. CRT approximately 3 seconds; peripheries cool. Neutrophils 0.4 × 10⁹/L, platelets 95 × 10⁹/L, K 3.3 mmol/L. Concern regarding suspected neutropenic sepsis and dehydration escalated immediately to RN/medical team. Local pathway commenced. Ongoing observations and fluid balance continued.”

Document what actually happened, who was contacted, when they were contacted, the response and any change in Marianne’s condition. Never document an intervention before it has happened.

Your turn

1. Which findings make Marianne’s presentation more concerning than uncomplicated chemotherapy side effects?

2. Why would it be unsafe to wait for a temperature above 38°C before escalating her deterioration?

3. What information would you include in your SBAR?

4. How would you explain neutropenia to Marianne without using medical jargon?

5. What can a student nurse safely contribute while the registered and medical teams begin urgent management?

Answers & rationale

1. Which findings are concerning?
Marianne is neutropenic following recent chemotherapy and is clinically unwell. Her tachycardia, tachypnoea, relatively low blood pressure, prolonged capillary refill, cool peripheries, diarrhoea, poor intake and dehydration all add to the concern. Her low potassium, thrombocytopenia and mucositis create additional risks.

Rationale: serious deterioration is often recognised from a pattern of findings rather than one abnormal observation. Recent systemic anti-cancer therapy changes the level of concern when a patient becomes unwell.

2. Why not wait for 38°C?
NICE defines neutropenic sepsis using neutrophils of 0.5 × 10⁹/L or lower plus either a temperature above 38°C or other signs or symptoms consistent with clinically significant sepsis. UKONS guidance also recognises that patients may present generally unwell or with other physiological changes.

Rationale: a patient with neutropenia may have a reduced inflammatory response. Marianne already has other signs of deterioration, so waiting for a higher temperature could delay time-critical treatment.

3. What belongs in the SBAR?
Identify Marianne and state your concern immediately. Include her recent chemotherapy, duration of symptoms, current observations, neutrophil count and other relevant blood results, your assessment of dehydration/deterioration and a clear request for urgent review and activation of the local pathway.

Rationale: SBAR works best when the concern and requested action are explicit. The person receiving the call should not have to guess why you are worried.

4. Explaining neutropenia
You might say: “Chemotherapy can temporarily lower a type of white blood cell called a neutrophil. Neutrophils are part of the body’s defence against infection. When the level becomes very low, infections can become serious quickly, and sometimes you do not get the usual signs such as a high temperature. That’s why we want you to tell us straight away when you feel unwell.”

Rationale: the explanation is accurate without overwhelming the patient with terminology, and it tells Marianne why reporting symptoms early matters.

5. What can the student nurse contribute?
Recognise the change, complete and repeat observations within competence, use a structured A–E approach, escalate immediately, communicate clearly, support prescribed care under appropriate supervision, monitor fluid balance and urine output, provide mouth and comfort care, and continue reassessment.

Rationale: student nurses are part of the safety net. You do not need prescribing authority or a diagnosis to notice that a patient is deteriorating and get the right help quickly.

Think beyond the observations

Marianne is not just “the neutropenic patient in bed 4”. She is a working woman who has gone from being independent to needing help with basic things because treatment has knocked her sideways. Ask what is bothering her most rather than assuming it is hair loss, weight or appearance.

Her husband is frightened too. Keep Marianne at the centre of conversations, check what she is happy to share and involve him with her consent. Infection precautions should protect Marianne without making her feel avoided or isolated.

Bleepbook takeaway

The big lesson here is not “chemotherapy causes nausea”. You already know that.

It is this: when someone receiving or recently receiving systemic anti-cancer therapy becomes unwell, do not let the label “side effects” stop you seeing deterioration. Assess the patient in front of you, recognise the pattern, escalate early and keep reassessing.

For a student nurse, that is excellent practice.

References and further reading

National Institute for Health and Care Excellence (NICE) (2012, updated 2024). Neutropenic sepsis: prevention and management in people with cancer (CG151).

UK Oncology Nursing Society (UKONS) (2023). Acute Oncology Initial Management Guidelines, Version 4.

UK Oncology Nursing Society (UKONS) (2025). Oncology/Haemato-oncology 24-Hour Triage Toolkit, Version 3.