EXAM: Spot/Practical Examination — Notes OmpathStudy

--- Mount Kenya University — School of Medicine, Department of Pathology Bachelor of Medicine and Bachelor of Surgery (MBChB) — Year 3 Unit: MBPA 3500 — Pathology Practical Exam Type: Spot/Practical Examination Papers Referenced: Special/Supplementary 2025/2026 & Regular 2023/2024 Compiled: June 2026 Purpose: Revision Q&A for Pathology Practical Spot Examination — Part 1 of 2 --- This article is Part 1 of a 2-part revision series compiled from past MKU Pathology Practical Spot papers. Questions are in point-form Q&A format for easy revision. Where a topic appears in more than one paper it is marked (×2). Image-dependent questions have been excluded. --- 1. Fine Needle Aspiration Cytology (FNAC) (×2) Q: What is FNAC? A minimally invasive procedure used to aspirate cells from a solid mass or cystic lesion Purpose: determine if lesion is benign, malignant, or inflammatory through cytological examination Q: What instrument holds the syringe? Cameco handle (syringe pistol) Allows one-handed aspiration while the other hand immobilizes the mass Q: What needle size is used? 22–27 gauge Q: Common sites for FNAC? Breast masses Thyroid nodules Lymph nodes (cervical, axillary, inguinal) Salivary glands Subcutaneous soft tissue masses Q: Why is negative pressure applied? To shear cells off the stroma and draw them into the needle hub Q: Critical step before withdrawing the needle? Release negative pressure first If withdrawn under suction, cells get sucked into the barrel — poor quality smear Q: What happens to the sample after extraction? Expelled onto a glass slide Smeared into a thin layer Either air-dried (for Romanowsky stain) or alcohol-fixed (for Papanicolaou or H&E stain) Q: Advantages of FNAC? Minimally invasive, often no local anaesthesia needed Rapid turnaround time Cost-effective Outpatient/bedside procedure Reduces unnecessary surgical biopsies Q: Limitations of FNAC? Only provides cytological detail — no tissue architecture Cannot reliably distinguish in situ from invasive carcinoma Q: Complications? Local pain Bruising/haematoma Infection Rare: pneumothorax (if near chest wall without ultrasound guidance) --- 2. Otitis Externa (Swimmer's Ear) Q: What is otitis externa? Inflammation/infection of the external auditory canal Also called "swimmer's ear" Q: Common causes? Bacterial: Pseudomonas aeruginosa, Staphylococcus aureus (most common) Fungal: Aspergillus, Candida Irritants: water exposure, trauma (cotton swabs), eczema Q: Clinical features? Ear pain (otalgia) Itching of the ear canal Redness and swelling of canal Discharge from ear Possible hearing loss due to canal swelling Q: Gross pathological findings? Erythema and swelling of external auditory canal Possible scaling and white discharge Thickening of ear canal skin Q: Complications if untreated? Spread to surrounding tissues (perichondritis, cellulitis) Malignant otitis externa — especially in diabetics and immunosuppressed Chronic otitis externa Q: Management? Topical antibiotics (e.g. ciprofloxacin ear drops) Topical steroids to reduce inflammation Aural toilet (cleaning the canal) Analgesics for pain Avoid water exposure until healed Q: At-risk populations? Swimmers Diabetics Chronic skin conditions (eczema, psoriasis) Hearing aid users Frequent ear cleaning habit Q: Prevention? Keep ears dry Avoid insertion of objects into ears Use earplugs while swimming if prone Maintain proper ear hygiene without trauma --- 3. Sickle Cell Disease (×2) Q: What is shown on the blood smear? Sickle Cell Disease (sickle cell anaemia) Q: Describe the abnormal findings? Numerous RBCs with crescent/sickle shape Contrast to normal biconcave disc-shaped RBCs Q: What genetic abnormality causes it? Point mutation in HBB gene (chromosome 11) Valine substituted for glutamic acid at position 6 of the beta-globin chain Forms haemoglobin S (HbS) Q: Why do RBCs take on a sickle shape? HbS polymerizes under low oxygen conditions Distorts RBCs into rigid sickle shape Q: Clinical manifestations? Chronic anaemia Vaso-occlusive crises (painful episodes) Increased risk of infections Dactylitis (swelling of hands/feet in children) Aplastic crises Acute chest syndrome Splenic sequestration Q: Complications of sickle-shaped RBCs? Obstruction of microvasculature → ischaemic organ damage (spleen, bone, brain) Haemolysis (shortened RBC lifespan) Increased risk of stroke and organ dysfunction Q: How is it inherited? Autosomal recessive Q: Laboratory tests to confirm diagnosis? Haemoglobin electrophoresis (detects HbS) Sickle cell screening test (sodium metabisulfite test) Peripheral blood smear Q: Treatment? Hydroxyurea (increases fetal haemoglobin) Regular blood transfusions Pain management Infection prophylaxis/antibiotics Curative: haematopoietic stem cell transplant (select cases) Q: Normal RBC vs sickle cell appearance? Normal RBC: round, biconcave disc Sickle RBC: elongated, crescent-shaped --- 4. Xanthomas / Familial Hypercholesterolaemia Q: What findings are seen? Multiple subcutan