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Kidney’s & Ureters

Zinner's Syndrome

  • Triad:
    • Ipsilateral renal agenesis
    • Seminal vesicle cysts (SV cysts)
    • Ejaculatory duct obstruction (Infertility due to Azoospermia)
  • Relevance:
    • INI 2021 (Dec) exam.

Fusion Anomalies in Kidney

  • Most Common Fusion Anomaly:
    • Horseshoe Kidney
      • Fusion at L3 vertebra due to Inferior Mesenteric Artery (IMA).
      • Isthmus of fusion located at L4 or L5.
      • More common in males.
  • Most Common Fusion Anomaly in Ectopic Kidney:
    • Crossed Fused Ectopic Kidney

Weigert-Meyer Rule

  • Governs duplex kidney anatomy.
  • Describes the relationship between the upper and lower moieties of a duplex ureter.
    • Upper moiety:
      • Drains inferiorly [Caudal & Medial] and is more prone to obstruction.
      • Often associated with a ureterocele or hydronephrosis.
    • Lower moiety:
      • Drains superiorly [Cranial & Lateral] and is more prone to vesicoureteral reflux (VUR).

Management:

  • Upper pole obstruction: Surgical intervention like heminephrectomy or ureterocele excision.
  • Lower pole reflux: Managed with antibiotic prophylaxis or ureteral reimplantation if severe.

Paraneoplastic Syndromes in RCC

  • Most Common Paraneoplastic Syndrome in RCC:
    1. Elevated ESR
    2. Hypercalcemia: Due to ectopic production of parathyroid hormone-related peptide (PTHrP).
  • Other Common Paraneoplastic Syndromes:
    • Hypertension: From increased renin production.
    • Polycythemia: Due to excess erythropoietin production.
    • Anemia also can be seen
    • Hepatic dysfunction (Stauffer's syndrome).

Stauffer's Syndrome

  • Definition: A rare paraneoplastic syndrome associated with RCC, characterized by non-metastatic liver dysfunction.

  • Key Features:

    • Elevated liver enzymes (alkaline phosphatase, bilirubin, transaminases, IL -6).
    • Hepatomegaly (without liver metastasis).
    • Reverses after nephrectomy.

Lambert-Eaton Myasthenic Syndrome (LEMS)

  • Definition: A paraneoplastic syndrome commonly associated with small cell lung carcinoma (SCLC) but can occur in RCC.
  • Cause: Autoimmune attack on presynaptic calcium channels, leading to reduced acetylcholine release at the neuromuscular junction.
  • Key Features:
    • Muscle weakness, especially in the proximal muscles (legs more than arms).
    • Improvement of strength with repeated muscle use (opposite of Myasthenia Gravis).
    • Autonomic symptoms: Dry mouth, constipation, and orthostatic hypotension.
  • Diagnosis:
    • Electromyography (EMG): Shows incremental response with repeated stimulation.
    • Voltage-gated calcium channel antibodies in serum.
  • Management:
    • Treat the underlying malignancy.
    • Immunotherapy: Corticosteroids, IVIG, or plasmapheresis for symptom management.

Meteorism in Renal Injury

  • Definition: Meteorism refers to excessive accumulation of gas within the intestines, leading to abdominal distension.
  • Association with Renal Injury:
    • While meteorism is not a direct consequence of renal injury, it can occur in the context of abdominal trauma that affects the kidneys.
    • Renal injury can lead to retroperitoneal hematoma, inflammation, or associated trauma to the surrounding tissues, which can indirectly cause ileus (intestinal paralysis), leading to meteorism.
    • Renal trauma or post-operative states (e.g., following nephrectomy) may contribute to abdominal distension due to altered bowel motility.
  • Clinical Considerations:
    • Abdominal distension following renal injury or surgery requires evaluation to rule out other intra-abdominal injuries or complications like peritonitis.
    • Monitoring for signs of bowel obstruction or ileus is critical in the management of such patients.

Bosniak Classification Features:

  1. Bosniak I:
    • Features: Simple cysts with thin walls, no septations, calcifications, or solid components.
    • Workup: No follow-up required.
    • Risk of Malignancy: ~0%.
    • Treatment: No treatment needed.
  2. Bosniak II:
    • Features: Minimally complex, thin septa, possible fine calcifications in the wall or septa, no contrast enhancement.
    • Workup: No follow-up required.
    • Risk of Malignancy: ~0%.
    • Treatment: No treatment required.
  3. Bosniak IIF (Follow-up):
    • Features: More septa than Bosniak II, minimal enhancement, possible thickened or nodular calcifications, but no measurable enhancement of any solid components.
    • Workup: Follow-up imaging recommended (typically at 6 months, then yearly).
    • Risk of Malignancy: ~5%.
    • Treatment: Follow with serial imaging; intervene if changes occur.
  4. Bosniak III:
    • Features: Indeterminate cystic masses with thick, irregular septa or wall enhancement.
    • Workup: Requires further evaluation with enhanced imaging or biopsy.
    • Risk of Malignancy: ~50-60%.
    • Treatment: Surgical excision (partial or radical nephrectomy) or close follow-up based on individual risk.
  5. Bosniak IV:
    • Features: Clearly malignant characteristics, such as enhancing soft tissue components, thick walls, irregular septa with measurable enhancement.
    • Workup: Immediate further evaluation and workup.
    • Risk of Malignancy: ~85-100%.
    • Treatment: Surgery is typically required (partial or radical nephrectomy).

Wunderlich Syndrome

  • Definition: A rare condition characterized by spontaneous non-traumatic renal hemorrhage confined to the subcapsular and perinephric space.
  • Causes:
    • Renal Angiomyolipoma (AML) (most common cause).
    • Renal cell carcinoma.
    • Other vascular abnormalities (e.g., aneurysms).

Lenk’s Triad (Classic Triad of Wunderlich Syndrome):

  1. Flank pain.
  2. Tenderness.
  3. Signs of internal bleeding (hypovolemic shock: low blood pressure, rapid heart rate, pallor).
  4. This triad indicates a potential retroperitoneal hemorrhage.

Angiomyolipoma (AML)

  • Definition: A benign renal tumor composed of blood vessels, smooth muscle, and fat.
  • Associations:
    • Frequently associated with tuberous sclerosis.
    • Larger tumors (>4 cm) carry a higher risk of spontaneous rupture, leading to Wunderlich Syndrome.
  • Imaging:
    • CT or MRI often shows a characteristic fat-containing mass.
  • Management:
    • Small asymptomatic AML (<4 cm): Observation with periodic imaging.
    • Large AML (>4 cm) or symptomatic: Embolization or partial nephrectomy to prevent hemorrhage.

Treatment for Wunderlich Syndrome:

  • Initial Management:
    • Stabilize the patient (IV fluids, blood transfusion if necessary).
    • Monitor for signs of hemodynamic instability.
  • Definitive Treatment:
    • Angioembolization: First-line treatment to control active bleeding.
    • Surgery (partial or radical nephrectomy) may be required in cases of ongoing bleeding or if malignancy is suspected.